THE HIGH COST OF MUSCULOSKELETAL TRAUMA
Trauma is the "neglected disease." It is the leading cause of death for people age 1 to 34 years of all races and socioeconomic levels and the third leading cause of death for all age groups. Injuries create a substantial burden on society in terms of medical resources used for treating and rehabilitating injured persons, productivity losses caused by morbidity and premature mortality, and pain and suffering of injured persons and their caregivers. Each year in the United States, one in six residents requires medical treatment for an injury, and one in 10 residents visits a hospital emergency department (ED) for treatment of a nonfatal injury. Data on injury prevalence and costs from the 2000 Medical Expenditure Panel Survey (MEPS) and the National Health Accounts (NHA) reported that injury-attributable medical expenditures cost as much as $117 billion in 2000, approximately 10% of total U.S. medical expenditures. In 2001, there were 157,078 trauma-related deaths, 64% of which were due to unintentional trauma, half of which were caused by motor vehicle crashes. An estimated 29.7 million persons sustained nonfatal injuries during the same period. In 2001, the death rates for motor vehicle-related injuries were 15.3 per 100,000 people, totalling 43,987. Crash injuries result in about 500,000 hospitalizations and four million emergency department visits annually. The economic burden of motor vehicle-related deaths and injuries is also enormous, costing the United States more than $150 billion each year. In 2001, approximately 140,000 Americans sustained gunshot injuries. Twenty-nine thousand of these (21%) died as a result. In the pediatric population, 10,000 deaths associated with trauma are recorded annually in the United States. Trauma accounts for 30% of pediatric emergency room visits and is the most common cause of mortality in the noninfant child.
Musculoskeletal disorders generated 3.5 million admissions to acute-care hospitals in the United States in 1988, more than 40% of which were trauma-related. Musculoskeletal injuries have a tremendous effect on the patient, the family, and the society in general because of the
Musculoskeletal injuries occur frequently, result in significant disability, and consume a major portion of health care resources. For example, the cost of hip fracture is estimated at $8.7 billion, or 43% of the total cost of all fractures. Direct costs are about 80% of the total, of which inpatient hospital care amounts to $3.1 billion and nursing home care $1.6 billion. More recent estimates show an increasing effect on the U.S. economy, including over $150 billion per year in direct and indirect cost from lost labor productivity due to trauma.
Mass casualty situations as a result of terrorism are the challenge of the new millennium, requiring a highly organized and effective trauma system. The capability to respond in an organized manner has gained importance after terrorist attacks within United States. In a mass casualty situation, limited resources must be allocated for a great number of victims. The terrorist attacks in Oklahoma City (1995) and at the World Trade Center (1993, 2001) showed the inefficiencies of the civilian disaster response system. The Orthopaedic Trauma Association has developed strategies to educate and optimize the response to mass casualties.
THE HEALING PROCESS
Bone is a unique tissue because it heals by the formation of normal bone, as opposed to scar tissue. In fact, it is considered a nonunion when a bone heals by a fibroblastic response instead of by bone formation. Whatever part of the skeleton it comes from, bone has a fine fibroid structure. This is true for cortical and cancellous bone from the diaphysis, epiphysis, or metaphysis. Bone will, therefore, heal by the same mechanism wherever it breaks.
Fracture healing can be divided into primary and secondary healing. In primary healing, the cortex attempts to reestablish itself without the formation of callus (osteonal or haversian healing). This occurs when the fracture is anatomically reduced, the blood supply is preserved, and the fracture is rigidly stabilized by internal fixation. Secondary fracture healing results in the formation of callus and involves the participation of the periosteum and external soft tissues. This fracture healing response is enhanced by motion and is inhibited by rigid fixation.
Fracture healing can be conveniently divided, based on the biologic events taking place, into the following four stages
HEMATOMA FORMATION AND ANGIOGENESIS
Initially, there is an inflammatory phase characterized by an accumulation of mesenchymal cells around the fracture site. The formed hematoma is a source of growth factors. Transforming growth factor beta (TGF-) and platelet derived-growth factor (PDGF) are released from platelets at the fracture site. TGF- induces mesenchymal cells and osteoblasts to produce type II collagen and proteoglycans. PDGF recruits inflammatory cells at the fracture site. Bone morphogenetic proteins (BMPs) are osteoinductive mediators inducing metaplasia of mesenchymal cells into osteoblasts. IL-1 (interleukin-1) and IL-6 recruit inflammatory cells to the fracture site. In fractures where the periosteum is intact, these cells probably come from the cambium. In higher energy fractures where the periosteum has been compromised, the appearance of spindle-shaped cells that are able to differentiate into osteogenic cells has been found to coincide with the appearance of capillary buds. These cells are possibly derived from the pericytes found around capillaries, arterioles, and venules.
Whatever their origin, these cells ensheathe the fracture and differentiate into chondrocytes or osteoblasts. Low-oxygen tension, low pH, and movement favor the differentiation into chondrocytes; high-oxygen tension, high pH, and stability predispose to osteoblasts. Bone morphogenetic proteins (BMPs) and cytokines (IL-1, IL-6) are present during cartilage formation. This initial callus acts as an internal splint against bending and rotational deformation and, less effectively, against shearing and axial deformation. Because the stiffness of this callus in bending and torsion varies with the fourth power of the radius, its distribution around the fracture is important; peripheral distribution adds to rigidity. Clinically, the fracture becomes "sticky," and although some motion is detectable, the fracture is stable.
CARTILAGE FORMATION WITH SUBSEQUENT CALCIFICATION
Radiologic evidence of mineral formation signals the onset of this phase. Cartilage in callus is replaced by woven bone by a process analogous to the endochondral ossification seen in the fetus. The mechanism of mineralization is poorly understood but is thought to involve active transport of minerals and their precipitation from a supersaturated solution. Mineralization causes the chondrocytes themselves to degenerate and die. Capillary buds then invade the mineralized cartilage, bringing osteoblasts, which resorb part of the calcified cartilage and deposit coarse fibroid bone on its residuum. The proliferating cambium layer of the periosteum also lays down new bone on the exposed surface of the bone, if conditions are favorable.
The phase of mineralized callus leads to a state in which the fracture site is enveloped in a polymorphous mass of mineralized tissues consisting of calcified cartilage, woven bone made from cartilage, and woven bone formed directly.
CARTILAGE REMOVAL AND BONE FORMATION
The woven-bone mineralized callus has to be replaced by lamellar bone arranged in osteonal systems to allow the bone to resume its normal function. Before this stage of remodeling can start, it is necessary to consolidate the fracture site. The concept of consolidation is poorly defined but includes filling the gaps left by the previous phase between the ends of the bone; it is also calledgap-healing bone. This bone has three major characteristics:
Gap-healing bone is essentially coarse fibroid bone and, therefore, is not normal lamellar bone.
This final phase involves the replacement of woven bone by lamellar bone in various shapes and arrangements and is necessary to restore the bone to optimal function. This process involves the simultaneous meticulously coordinated removal of bone from one site and deposition in another.
Two lines of cells, osteoclasts and osteoblasts, are responsible for this process. Osteoclasts are derived from monocytes and are large multinucleated cells that remove bone. They are located on the resorption surfaces of the bone. Osteoblasts are mononuclear and are responsible for the accretion of bone.
Articular cartilage consists of extracellular matrix (ECM) and chondrocytes. The ECM is formed by water (65% to 80%), collagen (95% type II) and proteoglycans (chondroitin sulfate and keratan sulfate). Collagen in the ECM provides form and tensile strength. Proteoglycans and water give the cartilage stiffness, resilience and endurance.
Chondrocytes are sparse in the adult cartilage, which is not a vascularized tissue. Their nutrition comes from the synovial fluid and depends on the health of the synovial membrane and adequate circulation of the fluid through the spongelike cartilage matrix. Motion of the joint is responsible for most of this circulation. A good part of the rationale behind rigid internal fixation of fractures is to allow early motion of the joints. The same argument can be made for early weight bearing of immobilized joints, which allows cyclical compression of the cartilage and circulation of the synovial fluid.
Rapidly applied forces to the articular cartilage prevent adequate fluid movement and load distribution leading to rupture of the ECM macromolecular framework and cell damage. Articular cartilage lesions are classified according to the type of damage and reparative response:
Articular cartilage has limited reparative capacities because chondrocytes have a low baseline metabolic rate, a small cell-to-matrix ratio, and a restricted mode of nutrition. If the defect in the cartilage does not go through the calcified plate, the body attempts repair with hyaline cartilage. It will be, however, incomplete, except for the smallest defects. If the calcified plate is violated, the subchondral capillaries bring an inflammatory reaction, which fills the defect with granulation tissue and, eventually, fibrocartilage. The quality of this fibrocartilage can be improved by passive or active motion of the joint. Basic and clinical research has shown the potential of artificial matrices, growth factors, perichondrium, periosteum and transplanted chondrocytes and mesenchymal stem cells to stimulate the formation of cartilage in articular defects.
Tendons are specialized structures that allow muscles to concentrate or extend their action. The Achilles tendon, for example, concentrates the action of the bulky muscles of the calf over a small area where a large force needs to be applied for pushoff. Tendons consist of long bundles of collagen scattered with relatively inactive fibrocytes. These cells are nourished by the synovial fluid secreted by the one-cell-thick synovial membrane that covers the tendon (endotenon) and the parietal surface of the sheath (epitenon). The flexor tendons are covered by a richly vascularized adventitia (paratenon).
Human skeletal muscle is divided into fiber types depending on their metabolic activity and mechanical function. Type 1 fiber, known as slow twitch, slow oxidative, or red, muscle, has a slow speed of contraction and the greatest strength of contraction. It functions aerobically and, therefore, is fatigue-resistant. Type 2 fiber, known as fast twitch or white muscle, is subdivided into two types, according to metabolic activity level: fiber that functions by oxidative and glycolytic metabolism (type 2A) and fiber that is largely glycolytic (type 2B). Both subtypes of white fast-twitch muscles are fatigable but have high strength of contraction and high speed of contraction. Fiber type interconversion can occur, but this is generally believed to happen only under extreme conditions. It is generally conceded that the relative proportions of type 1 and type 2 fibers are defined genetically, with little capacity for change. Thus, sprinters are unlikely to become cross-country runners, and vice versa. Interconversion between type 2A and 2B fibers is much more likely, depending on the type of athletic training.
Traumatic injury to muscle can occur from a variety of mechanisms, including blunt trauma, laceration, or ischemia. Recovery occurs through a process of degeneration and regeneration, with new muscle cells arising from undifferentiated cells. Traumatic injuries include muscle laceration, muscle contusion (blunt injury), and strains resulting from excessive stretching. In addition to muscle regeneration, laceration repair requires reinnervation of denervated muscle areas. Muscle contusion frequently results in hematoma. The normal repair process includes an inflammatory reaction, formation of connective tissue, and muscle regeneration. Blunt trauma may result in myositis ossificans and may cause decreased function. Muscle strains go by a variety of names, including muscle pulland muscle tear. The failure frequently occurs at the myotendinous junction in experimental animals but may also be within the muscle itself rather than at the bone-tendon junction.
Of particular concern to the traumatologist is the effect of immobilization on muscle tissue. As with all tissues, immobilization and lack of activity result in atrophy. Loss of muscle weight initially occurs rapidly and then tends to stabilize, and loss of strength occurs simultaneously. Resistance to fatigue diminishes rapidly. These changes are minimized if immobilization occurs with some stretching of the muscle. Prevention of "fracture disease" after trauma requires an understanding of muscle physiologic principles.
Peripheral nerves have a distinct anatomic structure, with multiple nerve fibers combined to form a fascicle surrounded by perineurium. Multiple fascicles are surrounded by epineurium. Nerves fall into patterns of monofascicular, oligofascicular, and polyfascicular structures. The size and distribution of fascicles change as a function of length, reflecting greater or lesser nerve fibers in each fascicle. Around joints, fascicles typically tend to be multiple and small, perhaps to reduce injury from mechanical trauma. In addition, these nerves tend to have thicker epineurium near joints, with many small fascicles, and this may tend to protect the nerve from flexion and extension cycles. Nerve damage may occur through direct compression or stretching injuries. Ischemic damage from stretching may occur at elongation of 15%. Nerve injuries are now rated from 1 to 5 degrees. First-degree injury is the least severe and is equivalent to neurapraxia. The nerve (axon) is in continuity, and loss of function is reversible. Second-degree injury is equivalent to axonotmesis, with degeneration of the axon. The endoneurial sheath remains in continuity, however, and regeneration occurs by growth of the axon down its original endoneurial tube. Third-degree injury is the same as second-degree injury with the addition of loss of continuity of the endoneurial tube. The perineurium is preserved, however. Because of damage to the fascicle, some misdirection of regenerating axons may occur, and the extent of functional return depends on the extent of misdirection. Fourth-degree injuries preserve only the continuity of the nerve trunk but involve much more extensive degeneration of the fascicles. Despite the continuity of the nerve trunk, this injury may require excision of the damaged segment, with reapproximation of the nerve ends to achieve a functional outcome. Fifth-degree injury involves complete loss of continuity of the nerve trunk. Surgical repair, obviously, is required to achieve restoration of function.
Functional recovery after nerve injury depends on a number of variables. The outcome is much more optimistic for children than adults, and the prognosis diminishes with age. Increasing distance from the nerve injury to the distal point of innervation reduces the likelihood of recovery. Other factors include the length of the damage to the nerve, the technical ability of the surgeon, and the length of time prior to repair.
ORTHOPEDIC ASSESSMENT & MANAGEMENT OF POLYTRAUMA PATIENTS
A thorough understanding of the pathophysiology of trauma is essential for prompt diagnosis and timely treatment of musculoskeletal injuries. Sound therapeutic principles improve the overall outcome for the patient and optimize the utilization of limited health care resources.
Life-Threatening Conditions: The ABCs of Trauma Care
A systematic approach is required in all cases. The patient is assessed and treatment priorities are established according to the type of injury, stability of vital signs, and mechanism of injury. In a severely injured patient, treatment priorities are dictated by the patient's overall condition, with the first goal being to save life and preserve the major functions of the body. Assessment consists of four overlapping phases:
This process, identifies and treats life-threatening conditions, and can be remembered as follows:
Airway maintenance (with cervical spine protection);
Breathing and ventilation;
Circulation (with hemorrhage control);
Disability (neurologic status);
Exposure and environmental control (undress the patient but prevent hypothermia).
A brief overview of the treatment of polytrauma patients, with special emphasis on the orthopedic aspects, follows:
Great care should be taken while assessing the airway. The cervical spine should be carefully protected at all times and not be hyperextended, hyperflexed, or rotated to obtain a patent airway. The airway should be rapidly assessed for signs of obstruction, foreign bodies and facial, mandibular, or tracheal/laryngeal fractures. A chin lift or jaw thrust maneuver should be used to establish an airway. A Glasgow Coma Scale of 8 or less is an indication for the placement of a definitive airway. The history of the trauma incident is essential because it provides immediate clues to associated injuries. A normal neurologic examination or cross-table lateral radiograph of the cervical spine, including the C7-T1 disk space, does not rule out cervical spine injuries; it only makes them less likely. Any patient with a blunt injury above the clavicle should be considered at risk for cervical spine injury).
The trauma surgeon should evaluate the patient's chest. Adequate ventilation requires not only airway patency but also adequate oxygenation and carbon dioxide elimination. Remember that the following four conditions, if present, must be addressed emergently:
Hemorrhage is the principal cause of postinjury deaths that are preventable. Postinjury hypotension is considered hypovolemic in origin until proved otherwise. Level of consciousness, skin color and pulses are simple to assess and reliably mirror the hemodynamic status of the patient, especially if recorded serially. Fractures of the femur or the pelvis can cause major blood loss, which can severely compromise the ultimate survival of the patient. (See sections on pelvic and femoral fracture.)The orthopaedic surgeon as a member of the trauma team should be alert to the possibility of extremity blood loss and communicate its estimate to the trauma team leader.
DISABILITY (NEUROLOGIC STATUS)
The Glasgow Coma Scale (see Chapter 13) should be used to assess neurologic status; it is quick, simple, and predictive of patient outcome. An even simpler way to monitor central neurologic status is to remember the mnemonic AVPU and check if the patient is
Alert and oriented,
or responds to Vocal stimuli,
or responds only to Painful stimuli,
or is Unresponsive.
EXPOSURE AND ENVIRONMENTAL CONTROL
Recognition of lacerations, contusions, abrasions, swelling and deformity can only be accomplished in the completely disrobed patient. The safest way to achieve this is to cut off all clothing. This permits complete examination of the patient, prevents further displacement of fractures and minimizes the risk of overlooking significant problems. Hypothermia must be avoided, as cardiac function may be affected, especially when there is decreased blood volume. Sterile dressings should be applied to any wounds and wound exploration in the emergency department should be avoided to prevent further contamination.
CARE OF PATIENT BEFORE HOSPITALIZATION
The diagnosis and treatment of musculoskeletal injuries in polytrauma patients should be initiated in the field by the paramedics. Recognition and appropriate splinting of major fractures, adequate immobilization of the cervical spine, and proper handling of the injured patient are essential to prevent further damage to the neurovascular elements and limit hemorrhage. In many cases, proper care at this stage will prevent or limit shock as well as avoid catastrophic damage to the spinal cord.
The old saying "splint them where they lie" remains especially true when the exact nature and extent of the fractures remain obscure. As a general rule, the following measures should be taken:
Injury mechanism: an adequate assessment of the conditions in which the injury was sustained is crucial. Information from paramedics, patient relatives and bystanders should be recorded. Obtain the following information according to injury mechanism:
Environmental exposure, comorbidity, pre-hospital care and observations at the accident scene should be determined. Estimated bleeding, open wounds, deformity, motor and sensory function and delays in extrication or transport are recorded.
The clinical orthopedic examination requires assessment of the axial skeleton, pelvis, and extremities. The extent of this examination depends on the patient's overall central neurologic status. Swelling, hematomas, and open wounds are assessed visually in the undressed patient. It is obligatory to palpate the entire spine, pelvis, and each joint. Examination soon after trauma may precede telltale swelling in joint or long bone injuries. In the unresponsive patient, only crepitation and false motion may be discerned. Patients with a better mental status, however, can provide feedback regarding pain resulting from palpation. The pelvis is examined by gentle compression of the iliac wings in a mediolateral, anterior-posterior direction and palpation of the pubis. However, if the patient is hemodynamically unstable, manipulation of the pelvis should be avoided in order to prevent increased bleeding. The AP pelvis x-ray must then be used to assess the pelvis as a potential source of shock.
The neurologic examination of the extremities should be documented to the fullest extent possible, in light of the patient's mental status, as it is central to subsequent decision making. This examination includes delineation of sensory function in the major nerves and dermatomes in the upper and lower extremities. Perianal sensation is also important. Thus, in the upper extremity, dermatomes from C5–T1 and radial, ulnar, and median nerve function must be assessed.
Motor examination can be difficult because of pain or impaired mental status, but even in such cases, useful and relatively complete information can be obtained. In the upper extremity, the function of the deltoid, biceps, brachioradialis, extensor pollicis longus, flexor carpi radialis, and intrinsic muscles (first dorsal interosseus and opponens pollicis muscles) must be examined. A more complete examination is indicated if there is obvious trauma to this area. In the lower extremity, the motor supply to the extensor hallucis longus, tibialis anterior, peroneal muscles, gastrocnemius, and quadriceps muscles must be tested and graded. Muscle strength grading is desirable, but demonstration of a minimum of volitional control (even if withdrawal to painful stimuli) is important in verifying the presence of intact central sensory-motor integration.
Particularly important in the face of spinal cord injury or suspected injury are the reflexes of the anal "wink" and bulbocavernosus muscle. Other spinal reflexes (ie, of the biceps and triceps muscles, of the knee and ankle, and the Babinski reflex) are important in "fine-tuning" the neurologic examination. (These are discussed more fully in Chapter 5, "Disorders, Disease, & Injuries of the Spine.")
Radiologic assessment follows the same general hierarchy as the clinical assessment. The severely injured polytrauma patient requires plain films of the chest, abdomen, and pelvis to indicate sources of respiratory and circulatory compromise. The second level of examination requires the cervical spine cross-table lateral view. The information obtained from this film dictates treatment and the need for any further evaluation of the cervical spine. In the hemodynamically unstable patient, the AP pelvis film is sufficient to make immediate treatment decisions. Complementary pelvis films can be obtained later on.
Subsequent evaluation is dependent on clinical findings. Any long bone or joint with a laceration, hematoma, angulation, or swelling must undergo roentgenographic evaluation. Any long bone fracture requires complete evaluation of the joints proximal and distal to the fracture. At the minimum, two views of the extremities are needed, usually the anteroposterior and lateral views. Coordination of more sophisticated studies with other trauma specialties (eg, neurosurgery or urology) is necessary to allow cardiorespiratory monitoring of the patient while efficiently performing these studies. For example, magnetic resonance imaging (MRI) and computed tomographic (CT) scanning should be performed with the fewest changes of position possible that will also provide the necessary information for all surgical subspecialists.
"Clearing" the Cervical Spine
In the evaluation of the trauma patient, an important consideration is the status of the cervical spine. The cervical spine is easily injured because of the large mass of the head relative to the neck, especially in motor vehicle accidents involving rapid acceleration or deceleration. Consequently, the cervical spine can receive significant force and suffer injury. In the conscious and responsive patient, swelling or tenderness on physical examination of the cervical spine is readily apparent. In the unconscious patient, cervical spine injuries can go undetected, and a careful physical examination must be performed with heavy reliance upon radiographic evaluation.
The essential radiographs for evaluation of the cervical spine include anterior-posterior views, lateral views, and an open-mouth odontoid view. It is essential to be able to see to the top of T1. If this level is not visualized through these conventional views, then a "swimmer's view," which is a lateral cervical spine radiograph with the arm abducted and elevated, should be obtained.
After the cervical spine x-ray films have been reviewed, the ligamentous stability of the cervical spine can be further evaluated. Lateral cervical spine flexion and extension views can be analyzed to see if the lateral alignment of the anterior cervical spinal segments is correct. These can only be obtained in the alert and cooperative patient who can safely sit upright. These films are often delayed for a several-week period.
In the obtunded patient, CT and/or MRI scan is necessary to delineate further soft tissue injury. On the open-mouth view, the lateral masses of C1 should line up with the body of C2. The amount of total overhang of C1 over C2 should be less than 7 mm. On the lateral view, the anterior border of the bodies of the cervical segments should describe an arc. The distance from the basion to the posterior arch of C1 divided by the distance from the opisthion to the anterior arch of C1 should be less than 1 (Powers ratio) (Figure 3–1). A basion to odontoid tip distance above 10mm in children and 5 mm in adults indicates craniocervical dislocation, a potentially fatal injury. The posterior border of the anterior arc of C1 should be within 2–3 mm of the anterior border of C2. There should be no diastasis of the spinous processes, and the joints and facet joints should all be visible. If there is a change in orientation from one cervical spine level to another, then cervical fracture, jumped facets, or dislocation should be suspected. Suspected cervical spine fracture should be investigated with appropriate imaging, such as CT scan, to further delineate the injury pattern. Suspected cervical spine injuries should be treated with provisional stabilization using a cervical collar. Rotational subluxation should be managed with evaluation of soft tissues and reduction maneuvers. In the case of neurologic deficit, careful evaluation of the neurologic status is important, and immediate decompression-stabilization must be considered.
IMMEDIATE MANAGEMENT OF MUSCULOSKELETAL TRAUMA
The orthopedic injuries in the polytrauma patient are seldom truly emergency situations, except for those involving neural or vascular compromise.
For example, fracture-dislocation of the ankle or knee resulting in distal ischemia justifies immediate attempts at reduction to minimize the sequelae of ischemia. A more subtle situation requiring emergent treatment would be dislocation of the hip in which vascular compromise of the femoral head may result. Arterial bleeding from an open fracture should be treated immediately with pressure to minimize blood loss. Other bone and joint injuries, although urgent, may be approached in a more deliberate manner.
Orthopedic management of traumatic injuries requires consideration of the entire individual as well as the entire extremity. It is short-sighted to treat only the area of injury revealed on radiograph, as the soft-tissue envelope around the bone is essential to fracture healing and the ultimate function of the patient. Repair of soft-tissue damage is clearly important in achieving satisfactory function after healing has occurred. A break in the skin is important, but the damage done to the entire extremity is more important than the extent of laceration.
From the orthopedist's viewpoint, the major complications associated with trauma are acute respiratory distress syndrome (ARDS), systemic inflammatory response syndrome (SIRS), fat embolism syndrome (FES), multisystem organ failure (MOF), thromboembolic disease, atelectasis, compartment syndrome, sepsis, and ectopic bone formation. The first five disorders involve pulmonary complications and must constantly be kept in mind in managing the polytrauma patient. The institution of early fixation of fractures with concomitant mobilization of the patient has helped to reduce the incidence of these four conditions significantly. They continue to be problems, however, and constant vigilance is necessary to prevent serious consequences. New research has begun to identify subsets of highly injured patients in whom some forms of early definitive fixation may accelerate the development of ARDS, SIRS, and MOF.
ACUTE RESPIRATORY DISTRESS SYNDROME
Acute respiratory distress syndrome (ARDS) can be a sequela of trauma with subsequent shock. Massive tissue injury activates the immunological system and releases inflammatory mediators, with subsequent disruption of the microvasculature of the pulmonary system. Some acute orthopaedic procedures have been shown to similarly activate the immune system. Pulmonary endothelial damage results, with decreased partial pressures of oxygen and arterial oxygen saturation and increased carbon dioxide levels. The onset is frequently within 24 hours after trauma and is revealed by hypoxemia, inflammatory reaction, and progressive decrease in arterial oxygen saturation if appropriate treatment is not instituted.
Fat embolism syndrome is a unique orthopedic manifestation of ARDS caused by the release of marrow fat into the circulation following fractures, particularly of the long bones. Pathologic examination of the lungs shows fat droplets, usually diffusely distributed throughout the pulmonary vasculature. This syndrome may also occur in nonfracture situations, as when the medullary canal of a long bone is pressurized during total knee replacement. Fat embolism syndrome occurs frequently as a subclinical occurrence that is insufficient to compromise the patient's pulmonary reserve, but in some cases it can result in severe pulmonary compromise and death.
The clinical diagnosis of ARDS is confirmed by a decrease in arterial PO2, an increase in systemic PCO2, infiltrates on chest radiograph, presence of petechiae, and mental confusion in a patient at risk. Relatively minor injuries can result in this syndrome in patients with limited pulmonary reserve. Treatment is directed toward minimizing hypoxemia with ventilatory support as needed. Prevention is enhanced by early mobilization of the patient, which often implies early fracture fixation.
Atelectasis, or localized collapse of alveoli, is a frequent postoperative complication in elective patients and can be prominent in trauma patients because of the required immobilization. Significant hypoxemia can result, and the onset may be relatively rapid. This may be the source of postoperative fevers in the early recovery phase. Occasionally, radiograph examination, showing platelike collapse of areas of the lung, will confirm the diagnosis. By encouraging coughing and deep breathing, using incentive spirometry, and, in resistant cases, using respiratory therapy, rapid resolution can be expected.
PULMONARY EMBOLISM AND DEEP VENOUS THROMBOSIS
Although ARDS and atelectasis are seen in the early postoperative period, pulmonary embolism (PE) is uncommon sooner than 5 days after the onset of immobilization or bed rest. The trauma patient is at risk for PE, and the patient with spinal cord injury even more so. Population based studies have demonstrated recent trauma to be associated with a 13-fold increased risk of venous thromboembolism. Young multiple-trauma patients without prophylaxis have been shown to have a 1–2% incidence of fatal PE, which appears to decrease with a variety of prophylactic measures. Other groups of patients at risk include the elderly (>70 years), the obese, those with a history of prior venous thromboembolism, major surgery of the abdomen, pelvis or extremities, and fractures of the pelvis, hip or leg, and those with malignancy. Although it is uncommon, even a young (<30 years) healthy person can develop deep venous thrombosis (DVT) and be at risk for PE after a long car or airplane trip in which the legs are dependent. Oral contraceptive and smoking use may also increase the risk for a young healthy patient.
Geerts and colleagues examined the incidence of DVT and PE in trauma patients in a prospective series with venography. They found patients to be at significantly increased risk if they had suffered a pelvis or long bone fracture with greater than 5 days immobilization in bed, were obese, had a preexisting coagulopathy or an Injury Severity Score (ISS) greater than 8. Overall, they reported an incidence of 58% with 18% proximal DVT in patients without prophylaxis. The authors noted that fatal PE was the most common yet preventable form of death in the hospitalized trauma patient.
Patients at high risk for PE are those with DVT in the lower extremities, and pelvic veins. Clinically significant PE usually arise from the large veins proximal to the knee. Prevention of DVT in the venous system in this area reduces the risk of PE. Various strategies used to accomplish this include drug therapy with low-dose heparin, low-molecular-weight heparin, pentasaccharide, or sodium warfarin; and mechanical prophylaxis with intermittent pneumatic compression devices or inferior vena cava filters in the high risk patients with contraindications for pharmacologic prophylaxis.
Clinical diagnosis of DVT is unreliable. Definitive diagnosis is made with venography, duplex ultrasound scanning, impedance plethysmography, or CT or MRI venography. Prevention appears to be the best strategy as even routine surveillance screening in a trauma populations is cost-ineffective and does not appear to lower the overall rate of PE.
Pulmonary embolism is suspected in the orthopedic patient suffering an onset of tachypnea and dyspnea usually more than 5 days after an inciting event. The patient frequently reports chest pain and can often point to the painful area. Hemoptysis may also be present. On physical examination, tachycardia, cyanosis, and pleural friction rub can be noted.
Arterial blood gas studies demonstrate hypoxemia, although this is a nonspecific finding. Use of the d-dimer is unreliable in the early trauma patient but may be useful later in the recovery period. Definitive diagnosis is best made with pulmonary angiogram. Perfusion ventilation scanning is less invasive and may help determine whether there is a high or low probability of pulmonary embolus. Spiral CT is becoming useful in diagnosis of PE.
Treatment involves pulmonary support and heparin therapy. The natural history of treated PE is gradual lysis of the emboli, with the return of flow through the pulmonary arterial tree. The natural history of proximal DVT involves recanalization and arborization to bypass the clot. Patients may suffer from postphlebitic syndrome characterized by chronically painful swelling in the extremity.
The term compartment syndrome refers to pathologic developments in a closed space in the body caused by buildup of pressure. Most commonly, such compartments are circumscribed by fascia and incorporate one or more bones. Pressure rises from edema or bleeding within the compartment, compromising circulation to the contents of the compartment over a period, and can result in necrosis of muscle and damage to nerves.
Compartment syndrome may result from a fracture; a soft-tissue injury; a vascular injury causing ischemia, necrosis, and edema; or from a burn. In an alcohol or drug user, it may be caused by external compression from immobilization that prevents normal postural changes. Failure to redistribute pressure through postural changes results in ischemia of the area under pressure because of collapse of capillaries.
The diagnosis of compartment syndrome must be considered in the postoperative or posttrauma patient who has pain out of proportion to that expected from the inciting injury. As the pain worsens, it can become totally unresponsive to narcotic medication. Epidural narcotics may mask the onset of compartment syndrome in the lower extremity.
The five P's (pulselessness, paresthesia, paresis, pain, and pressure) characteristic of compartment syndrome are helpful, but not diagnostic, for the experienced clinician. Pulses are poor indicators of compartment syndrome as they generally remain intact until late. Paresthesias occur only when the syndrome is significantly advanced. This points to the importance of careful documentation of sensory examination prior to the potential onset of compartment syndrome. Paresis, if present, is an unreliable finding. Subsequent to fracture or injury, pain is likely to induce guarding and thereby is also an unreliable finding. If normal muscle function is present, however, compartment syndrome is unlikely unless it is early. Pain with passive stretching of involved muscles is also a subjective finding and must be differentiated from pain arising from the original injury. To the experienced clinician, pain with passive stretching is a reliable clinical sign. Pressure is a key component of compartment syndrome, but palpation of a soft compartment does not rule out the diagnosis of compartment syndrome. Patients with equivocal clinical findings or those at high risk but without a reliable clinical examination (eg, those who are comatose, have psychiatric problems, or are under the influence of narcotics) should have compartmental pressure measurements. Intracompartmental pressure readings within 30 mm Hg or less of the diastolic blood pressure are indications for fasciotomy. Prior to fasciotomy, circular dressings including casts should be removed, and the patient should be observed for a short period for signs of improvement. Positive clinical findings may justify fasciotomy even despite normal pressures. Late fasciotomy may result in muscle damage or possible necrosis, with resulting risk of infection.
Although compartment syndrome can occur in almost any portion of the body, the two most common locations are the forearm and calf. In the forearm, an extensile volar incision to permit complete release, including the carpal tunnel distally and the lacertus fibrosus proximally, is necessary. Dorsally, a longitudinal incision is used. In the calf, two incisions are used to release the four compartments of the leg. The anterior and lateral compartments are decompressed using a longitudinal incision approximately over the anterior intermuscular septum. Posteromedially, a second incision is used to approach the superficial and deep posterior compartments. While single and limited incision approaches have been described, these may be unreliable and have a higher incidence of iatrogenic nerve injury in the trauma patients.
HETEROTOPIC BONE FORMATION
Clinically significant heterotopic ossification occurs as a consequence of trauma in perhaps 10% of cases and may cause pain or joint motion restriction even to the point of ankylosis. Trauma patients without head injuries frequently manifest heterotopic ossification on radiograph 1–2 months following trauma; if the ossification is clinically significant, resection may be indicated when the bone has matured as indicated by radiographs and bone scan. This can take up to 18 months to achieve.
Resection is accomplished by removing the entire piece of heterotopic bone. Selected patients may benefit from low-dose radiation (7 Gy) and oral indomethacin for 3–6 weeks. Further discussion of this topic can be found in Chapter 13, "Rehabilitation." Heterotopic bone is a much more common occurrence in patients with head injuries. This is believed to result from release of humeral modulators that have not yet been characterized.
Classification of Open Fractures
GUSTILO AND ANDERSON CLASSIFICATION
Gustilo and Anderson made a significant contribution to trauma care of long bones by introducing their classification of open fractures, which includes the degree of open or closed soft-tissue injury. Their system was initially designed for open tibial fractures; however, it has gone on to include all types of long bone fractures. This system uses three grades and divides the third most severe grade into three subtypes.
Grade I fracture is a low-energy injury with a wound less than 1 cm in length, often from an inside-out injury rather than an outside-in injury. These are generally simple transverse or short oblique fractures.
Grade II fracture involves a wound more than 1 cm long and significantly more injury, caused by more energy absorption during the production of the fracture. Grade II fractures usually display some comminution and have a minimal to moderate crushing component.
Grade III open fracture has extensive wounds more than 10 cm in length, significant fracture fragment comminution, and a great deal of soft-tissue damage. It is usually a high-energy injury. This type of injury results typically from high-velocity gunshots, close range shotgun blasts, motorcycle accidents, or injuries with contamination from outdoor sites such as with tornado disasters or farming accidents. Indeed, any open fracture resulting from a natural disaster, highly contaminated or comminuted, independent of wound size, is automatically classified as a grade III open fracture.
Grade III injuries are divided into subtypes A, B, and C. Grade IIIA fractures have extensive soft-tissue laceration with minimal periosteal stripping and have adequate bone coverage. These injuries include some gunshot injuries and segmental fractures and do not require major reconstructive surgery to provide skin coverage. Grade IIIB fractures, in contrast, have extensive soft-tissue injury with periosteal stripping and require a flap for coverage. Grade IIIC injuries involve vascular compromise requiring surgical repair or reconstruction to allow for reperfusion of the limb. The presence of an intact skin envelope may imply somewhat reduced severity of trauma. The soft-tissue and bony damage may be as severe for closed fractures, however, except for the lower risk of infection.
Severe soft-tissue and bony injuries, especially when open, raise the question of immediate amputation. This problem most frequently arises in the lower extremity between the knee and the ankle. The advent of microvascular surgery has reduced the absolute indication for amputation resulting from ischemia. Two years of reconstruction may be necessary to achieve a united tibia fracture without infection, and even then, function may be compromised by muscle or nerve damage. The patient may have also endured multiple operations, loss of work time, and the emotional trauma accompanying an injury of this magnitude. Prosthetic replacements, particularly in the trauma patient at the below-knee level, may well be a viable alternative to a poorly functioning, insensate lower extremity.
Early Total Care
The desirability of early total and appropriate orthopedic care in multiply injured patients has become well established. Benefits of timely and aggressive treatment include decreased rates of mortality, primarily due to reductions in ARDS and multisystem organ failure (MOF). In a classic study by Bone et al., 178 patients with femoral fractures were entered into an early fixation group (treatment within 24 hours) or a delayed fixation group (treatment after 48 hours). The incidence of pulmonary complications, such as ARDS, fat embolism, or pneumonia, was higher, the hospital stay was longer, and the intensive care unit requirements increased when the femoral fixation was delayed. Bone and collaborators did a follow-up retrospective, multicenter study of 676 patients who had an ISS (Injury Severity Score) greater than 18 and who had major pelvic or long-bone injuries treated under an early fixation protocol within 48 hours at one of six major US trauma centers. These results were compared with historical records of 906 patients from the American College of Surgeons Multiple Trauma Outcomes Study Database. The study, despite shortcomings in methodology, revealed a lower mortality rate for patients whose fractures were stabilized early.
In a study by Reynolds, Richards, and Spain, records of 424 consecutive trauma patients were reviewed. Of these, 105 had an ISS of 18 or greater. These patients did not receive definitive early long bone fixation. In general, femur fractures were stabilized on the day of admission if the patients were hemodynamically stable. These authors noticed that progressive surgical delays caused by decline in the patient's condition resulted in a significant increase in pulmonary complications for patients having an ISS less than 18. However, there was no relation between pulmonary complications and timing of femoral fixation when patients had an ISS of 18 or more. The authors concluded that the severity of injuries, not the timing of fracture fixation, tended to determine patient pulmonary outcome.
Damage Control Orthopaedics
Controversy exists, however, regarding the appropriate timing of orthopedic intervention for specific subsets of severely injured patients, particularly those with head injury or systemic hypotension. Long bone fracture fixation with reamed intramedullary rods, in particular, may cause intraoperative hypotension or an increased release of inflammatory mediators with deleterious results in specific patients.
The multiply injured patient's immunological system is stimulated or primed after trauma (first event). Subsequent resuscitation, hemorrhage, blood products, hypotension and surgery (second event), may produce an exaggerated systemic inflammatory response syndrome (SIRS), potentially leading to ARDS or MOF. Activated neutrophils are the principal effector of the inflammatory response, releasing active oxygen species, which damage the vascular endothelium. Bone marrow contents pushed to the systemic circulation during reaming and nailing can activate neutrophils leading to SIRS in polytrauma patients, particularly during the first 96 hours after trauma. Damage control Orthopaedics aims to decrease the additional surgical trauma through external fixation, and secondary definitive surgery. One study demonstrated that conversion of an external fixator to a reamed intramedullary nail is safe and effective if performed within 2 weeks.
Alternatives to modify the inflammatory response are currently under investigation. The potential advantage is to allow early total fracture care avoiding secondary surgeries.
Soft-Tissue Injuries & Traumatic Arthrotomies
Lacerations of the extremities can result in neural or vascular compromise to an extremity and may also cause traumatic arthrotomies. Compromise of the sterility of any joint requires surgical debridement of that joint. For many joints, arthroscopic irrigation and debridement will minimize trauma and improve the return to function. Other soft-tissue lacerations may require neural or vascular repair. Laceration of a tendon or muscle belly is often involved. Tendon repairs are frequently performed in the foot and the hand. All tendon lacerations of the hand, except for those of the palmaris longus, should be repaired. In the foot, extrinsic tendons are repaired to prevent late imbalance or loss of function. Muscle belly injuries generally require surgical debridement because their subfascial location makes simple irrigation difficult. Laceration involving only the muscle belly requires no surgical repair. Frequently, however, muscle belly laceration involves the continuation of the origin or the insertion tendon of the muscle. In this case, optimal function is obtained by reattaching the lacerated ends. Generally, they can be located by poking into the muscle with a forceps at the site of the blood clot on the surface of the cut end. The tendon portion has retracted and the muscle has expanded because of swelling, leaving a track with a blood clot inside.
In most cases, immediate treatment of open fractures and lacerations consists of surgical debridement. Prior to formal debridement, it is appropriate to splint fractures and cover open wounds with sterile dressings soaked in povidone-iodine. Antibiotic therapy is begun immediately, usually with a cephalosporin bactericidal antibiotic. Tetanus prophylaxis is administered if needed. Antibiotic therapy is continued based on the clinical course.
Irrigation and debridement are intended to convert a clean contaminated wound into a sterile wound. Copious irrigation, using an irrigating solution containing antibiotics, is effective in cleaning the wound. Debridement removes nonviable tissue. Generally, care should be taken to remove only tissue that is necrotic. Skin edges should be debrided, as should dead muscle, and the surface of any contaminated fat or fascia.
After debridement, bone surfaces and exposed tendons should be covered as well as possible with tissue to maintain moistness. Maintain soft tissue attachments to bone whenever possible. Fragments of bone, particularly cortical bone, without attachments, should be removed from the wound. Although the axiom "open fractures should be left open, closed fractures should be left closed" was suitable many years ago, experience has demonstrated that in certain cases minimal risk is assumed in closing the wound. It is acceptable practice, however, to leave any wound open. Grade I wounds may in some cases be closed completely, or the part that was opened to permit debridement may be closed, leaving the original débrided laceration open. This may close spontaneously. Grade II wounds may be treated in a similar fashion, with somewhat more risk. The possibility of gas gangrene must be entertained whenever such a wound is closed. Primary closure of Grade III wounds is rarely if ever done. Adequate closure to cover bone and other structures that may be damaged by desiccation, without completely closing the wound, may be attempted. Patients with massive wounds should be returned to the operating room in approximately 48 hours and then every 48 hours until the wound is completely clean and granulating. Smaller wounds that are left open may be closed safely at 3–5 days.
Flaps and Soft-Tissue Coverage for Open Trauma
Soft-tissue wounds in association with skeletal trauma (Gustilo grades I, II, and some IIIA wounds) can be treated by appropriate skeletal fixation, wound debridement, and limited skin grafts or rotation flaps to close the skin successfully. Larger wounds, however, require more aggressive surgical management. These wounds may be treated best by large regional soft-tissue flap reconstruction. Before the advent of microsurgery, the standard of care was pedicle flaps, such as chest wall flaps, applied to the arm for burn contractures around the elbow, cross-leg grafts for lower-extremity trauma, or groin flaps for soft-tissue trauma of the hand. With the advent of microsurgical techniques for skin, muscle, and fascia transplantation, the treatment of large soft-tissue trauma has changed. The classic study by Godina in Plastic and Reconstructive Surgery describes the results of immediate free flap reconstruction. Immediate free flap reconstruction is done within the first 48 h after trauma. The requirement for this procedure is radical debridement of the zone of injury, similar to the way one would resect a tumor. Using these techniques, there is little fibrosis of the bed and a fairly large soft-tissue defect for the viability of tissues with which to work and with which to place a free flap.
If radical debridement is not performed, then flap reconstruction should be delayed until soft tissues have healed at the margins, and there is no sign of infection. However, with large wounds, this often becomes a dilemma. Therefore, the use of free flaps gives an overall improved outcome by bringing a new source of vascularity to a compromised extremity, preventing infection and simultaneously providing soft-tissue coverage.
There are many sites that can be harvested for flaps. The most common and the hardiest flaps to use on a large scale include fasciocutaneous flaps from the latissimus dorsi, gracilis, serratus anterior, and rectus abdominis muscles. These are suitable for medium- to large-size wounds in a variety of locations. Additionally, there are a host of smaller tissue transfers designed for more specific uses that have some advantages in the matching of defect to donor and minimizing problems at the donor site. However, the flaps that have been listed are the mainstays of the reconstructive microsurgeon for the extremities.
A recent innovation in wound management is the Vacuum Assisted Closure Therapy (VAC). The VAC system exposes the wound bed to negative pressure in a closed system. The stretching stimulus is transformed into microchemical forces that promote wound healing through increased cell division and proliferation, angiogenesis stimulation, and local increase of growth factors. Also, edema fluid is removed from the extravascular space, eliminating the extrinsic cause of microcirculatory alteration and improving local blood supply. Although this device does not replace the need for surgical debridement, it may avoid the need for a free tissue transfer in patients with large traumatic wounds. Additional orthopaedic indications include the treatment of infected wounds after debridement, and fasciotomy wounds closure.
Optimum treatment of fractures caused by gun-shots relies upon an appreciation of the kinetic energy of injury, direction, caliber and, distance. This is particularly true with regard to soft-tissue injuries. Visual inspection alone at the time of initial evaluation is not always sufficient because it can underestimate the extent of damage. Gun-shot wounds to the musculoskeletal system result in complex soft-tissue lesions, fractures that are often comminuted, and related nerve, artery, and tendon involvement. Differences between high-velocity (>2000 feet/second) and low-velocity (<2000 feet/second) weapons and civilian and military settings for these wounds are also important. Additional characteristics are the efficiency of energy transfer, including deformation and fragmentation, kinetic energy, stability, profile of entrance, path through the body, and the biologic characteristics of the tissues. In general, kinetic energy (KE) associated with an injury is calculated by the formula
where M equals mass and V equals velocity. Thus velocity and missile mass are the determinants of resultant tissue damage. Velocity is more important than mass, doubling the velocity quadruples the kinetic energy. Shotgun injuries are different from single gun-shot wounds, because the weight of the shot causes an increase in the kinetic energy, resulting in a more severe injury. Additionally, shotgun shells have wadding that is made of plastic, felt, paper, or cord, between the powder and the shot charge, and this wadding can become embedded in the wound and be another important factor in wound management.
In gun-shot wounds and high-velocity missiles, shock waves, laceration and crushing, and cavitation result in tissue damage. Shock waves can produce injury in areas that are relatively distant from the direct path of the missile. Cavitation is an important mechanism of tissue damage in high-velocity injuries. The subatmospheric pressure in the cavity sucks contaminants in from both ends. Secondary missiles are the result of bone or bullet fragmentation, and can increase the extent of damage. Missile wound tracks close to a major vessel may be associated with occult vascular injury despite normal pulses. Doppler ultrasound is indicated when a vascular injury is suspected.
Low-velocity civilian gun-shot wounds and fractures are relatively simple to treat, because tissue damage is confined to the missile path, and local wound care, with or without antibiotic therapy, can effectively treat the injuries and decrease the incidence of wound sepsis and osteomyelitis. The use of immediate fixation by either internal or external fixator means is somewhat controversial. On the one hand, the danger of treatment of these open fractures with foreign material is a deterrent for immediate stabilization. However, in grossly unstable injuries, treatment that would be used for other open fractures appears to be reasonable in selected cases. The impact of gun-shot wounds in ballistic injuries can be significant. In a study by Brown in the Journal of Orthopaedic Trauma, a university-affiliated level-1 trauma center conducted a retrospective study through calendar year 1994 in which all patients admitted through the emergency department with a gun-shot wound for which the orthopedic surgery service was consulted were evaluated. These 284 patients were responsible for 24% of all orthopedic admissions, 33% of the average daily orthopedic census, and 14% of all the orthopedic surgery cases. Forty-five percent tested positive for alcohol and 65% for drugs. Eighty-seven percent of patients were male; only 4% of patients were privately insured. The authors concluded that during this 1-year study, gun-shot wound injuries required more orthopedic trauma resources than any other surgical areas. The majority of low-velocity gunshot wounds can be managed with local wound care and outpatient treatment. The wound should be left open for drainage. If the fracture requires surgical treatment, antibiotic prophylaxis is recommended. High velocity and shotgun fractures require surgical irrigation, appropriate debridement and at least 24 to 48 hours of IV antibiotics treatment.
Multiple Trauma Treatments—Strategies and Traumatic Scoring Systems
The surgeon who has to provide fracture care to patients who have multiple injuries will find that they fall into several categories. In the first are patients with multiple, isolated extremity injuries. In the second are patients with multiple orthopedic injuries who are otherwise medically stable. In a third category are patients with multiple orthopedic injuries and multisystem organ injuries.
Within these categories, orthopedic injuries are either life- or limb-threatening, emergent, urgent, or elective injuries in the timing of treatment. Timing of treatment is also related to the presence and severity of other injuries.
Several classification systems have been used to try to stratify these injuries and to determine severity. The classification systems serve as a guide for both patient treatment and eventual outcomes. The Revised Trauma Score (RTS) was developed to help with patient triage. The scores for systolic blood pressure and respiratory rate are separated into five domains with each assigned a point value from 0 to 4. These scores are added to the Glasgow Coma Score to yield a Revised Trauma Score. In the United States, the American College of Surgeons' guidelines directs patients with an RTS of 11 or less to a designated trauma center.
The Abbreviated Injury Scale (AIS) divides injuries into nine body regions and stratifies the injuries from minor to fatal on a 6-point scale. These scores take into account life-threatening aspects of injuries, anticipated permanent impairment, treatment, and injury pattern.
The Injury Severity Score (ISS) is the sum of the squares of the highest AIS scores in the three most severely injured body regions, which are chosen from head and neck, chest, abdomen, extremities and pelvic girdle, and external. Multiple-trauma patients are defined as patients with ISS greater than or equal to 14. A good prognosis is associated with an ISS of less than 30, whereas an ISS greater than 60 is usually fatal.
Factors at the time of injury, which have a bearing on the decision to amputate, include status of the opposite leg, the time of limb ischemia, and the age of the patient. Many of these factors have been taken into account by Johansen and associates, who have defined a Mangled Extremity Severity Score (MESS). The MESS was previously used as a predictor of eventual amputation; however, recent studies have shown the MESS and other scoring systems to be inaccurate in predicting the functional outcome for mangled limb patients (Table 3–1).
FAILURE OF FRACTURE HEALING
Fracture union is a gradual, continuous process where the mechanical integrity of a fractured bone is restored. The treating clinician needs measures of healing and definitions of failure that allows rational treatment decisions. Bone regeneration can occur by various histologic processes such as intramembranous, endochondral and/or osteonal remodeling. The speed of healing by periosteal callus depends on the extent of soft tissue disruption.
Generally, a fracture has united when there is radiographic evidence of bony bridging of the fracture on at least three cortices on orthogonal projections. Clinical criteria, such as absence of motion and resolution of pain at the fracture site, while helpful, are much less sensitive in confirming that a fracture has healed.
Many variables have an effect on the fracture healing process, including the fracture site, the blood supply, initial displacement of fracture fragments, whether the fracture is open or closed, the patient's age and nutritional status, and, possibly, medication use (eg, steroids, anticoagulants). In general, fractures will heal when the bone ends are in close apposition and the affected area has been adequately immobilized, has a good blood supply, is surrounded by a muscle envelope, and is not infected.
Nonunion of Fracture
Despite the best efforts and treatment, a certain percentage of fractures will fail to unite. The treatment of nonunited fractures has developed into a subspecialty area of orthopedic surgery. According to the Food and Drug Administration, delayed union of a long bone is defined as a fracture that has not gone on to full bony union after 6 months. Delayed union is represented by evident cessation of periosteal new bone formation before union has been achieved.
Nonunion is less well defined. Clearly, a fracture that fails to show progressive evidence of healing over a 4 to 6-month period can be considered a nonunion. One can immediately declare a fracture with a 2 inch bony defect, for example, a nonunion, as one knows that bony reconstitution will not occur spontaneously if this fracture is simply left immobilized.
Nonunion corresponds to scar formation in which the rate of endosteal and periosteal osteogenesis is zero or low and outweighed by bone resorption, with sclerosis of the medullary canal at the fracture surfaces. If the periosteum is active and there is no bridging despite new bone formation, the result is hypertropic nonunion. If no new bone formation is taking place, the morphology will be atrophic.
REASONS FOR NONUNION
There are many reasons why a fracture might not heal. The two most common reasons are lack of adequate blood supply at the fracture site and inadequate stabilization of the fracture. Other less common reasons include soft-tissue interposition at the fracture site, fractures stabilized in an unacceptable amount of distraction, metabolic abnormalities, and infection. Infection at the fracture site does not in and of itself preclude a fracture from healing, but it can be a contributing cause to the development of nonunion. Rosen has outlined the known causes of nonunion (Table 3–2).
The location of the fracture is also an important factor in healing. Certain areas of the skeleton are more prone to developing nonunion, even when appropriate treatment is rendered. The distal tibial diaphysis, scaphoid, and proximal diaphysis of the fifth metatarsal classically have a higher incidence of nonunion than other locations in the body. Fracture pattern also plays a role in the development of nonunion. Segmental fractures of long bones are much more prone to nonunion, as are fractures with large "butterfly" fragments, because of devascularization of the intermediary segment.
CLASSIFICATION OF NONUNIONS
Nonunions have been classified according to their radiologic characteristics. The most widely used classification is that developed by Weber and Cech, who classified nonunion of long bones as being either hypertrophic or atrophic. They utilized standard radiographs and strontium isotope studies to differentiate these two categories. Hypertrophic nonunions have viable bone ends, whereasatrophic nonunions have nonviable bone ends. This differentiation has importance both in prognosis and in determining appropriate treatment. They further subdivided hypertrophic nonunions into "elephant's foot type," "horse's foot type," and oligotrophic nonunions (Figure 3–2). It is somewhat confusing as to what actually causes a viable hypertrophic nonunion to behave by laying down exuberant callus (elephant's foot type) versus no callus (oligotrophic type.) As a generalization, those nonunions with better blood supply and some degree of micromotion at the fracture site develop more callus, while those with either no motion, excess motion, or distraction and a less rich blood supply produce less callus.
COMPLICATIONS OF NONUNION
Grossly mobile hypertrophic or atrophic nonunions that are left untreated for an extended period often develop into a pseudarthrosis (false joint) (Figure 3–3). There is an actual synovial-lined capsule enveloping the bone ends. Synovial fluid is present in the cleft. As a joint now exists between the ununited bone ends, surgical intervention is the only treatment option available.
Once nonunion has been established, the physician must establish treatment goals. The joints above and below the nonunion must be evaluated to determine their function and motion. The degree of shortening or deformity of the affected limb must also be determined. One must also determine the general health of the patient as well as the degree of functional impairment the patient is actually experiencing. This is especially important as some patients are actually asymptomatic and therefore do not warrant treatment. In the sick or elderly (>70 years), treatment must also be tailored, as these patients may not be able to safely tolerate surgical intervention.
Stimulation of Osteogenesis by External Forces
It is now known that several pathways exist to stimulate healing of nonunion. The pathways can be divided into the type of force required to stimulate osteogenesis. These inductive forces can be categorized as mechanical, electrical, and chemical and can be applied with varying success both operatively and nonoperatively.
Application of mechanical forces to achieve bony union has remained the most time-honored, well-tested method to date. Sarmiento has shown that the use of functional bracing incorporated with weight bearing can lead to union of documented tibial nonunions. His results for treating femoral nonunions were less successful using this method. Cyclic mechanical force of ambulation while the fracture reduction is maintained with an external support is the presumed mechanism with which fracture healing is achieved without surgical intervention.
Mechanical forces can also be generated by surgical means. Mechanical stabilization of a long bone nonunion can be achieved either by placement of an intramedullary rod or compression plating. The rod works by providing mechanical stabilization of the fracture, hence allowing for cyclic axial loading of the limb without shearing forces caused by weight bearing. The compression plate provides stability as well as immediate rigid compression across the fracture fragments. These forms of treatment are often all that is necessary in elephant's foot type nonunions.
Electrical fields have also been shown to stimulate the dormant chondrocytes and mesenchymal cells in the nonunion cleft to "turn on" and produce bone that results in healing. The mechanism of why this occurs has been postulated but to date is not well understood. Currently, most electrical bone growth stimulators used are external devices that are incorporated in a cast or functional brace around the site of nonunion. Surgically implanted devices with internal coils wrapped into the nonunion site have also been used with somewhat equivocal success. Sharrard showed in a controlled double-blind study that application of an external pulsed electromagnetic field led to a statistically significant increase in healing of documented delayed tibial unions as compared with a control group. New interest in this field is now focusing on the use of nonpulsed electromagnetic fields and ultrasound. Nonunions being treated with adjuvant electrical fields are in fact being treated with mechanical forces as well, as these fractures are usually immobilized and weight bearing is often allowed on the affected limb.
Chemical modulators also play an important role in promoting nonunion healing. Application of autogenous cancellous bone graft (most frequently obtained from the iliac crest) is a potent stimulator of fracture healing. As a rigid nonunion will heal with autogenous bone grafting alone and no internal fixation, it is apparent that chemical modulators from the grafted cancellous bone are responsible for stimulating the healing response. There has been recent intense interest in determining the growth factors present in this cancellous bone responsible for "turning on" the healing process. Some surgeons have even reported success by obtaining bone marrow via a large-bore needle from the iliac crest and injecting this into the nonunion site. In the future, it is likely that the humoral modulator responsible will be isolated, synthesized in sufficient quantities by genetic engineering techniques, and simply injected into nonunion clefts to attain union.
PATHWAYS OF SIMULATION
It is interesting to note that although three separate forces exist that can stimulate healing, it is unknown whether they act via a common pathway. As often happens in the body, these forces could actually work by different pathways so as to allow for some duplicity to help ensure that most fractures will heal.
Atrophic nonunions are not as easily treated as hypertrophic nonunions, and fewer treatment options are available. Electrical stimulation and nonoperative treatment methods have not been effective. The treatment most commonly utilized, and most successfully, is "freshening up" of the avascular bone ends, combined with rigid internal fixation and autogenous bone grafting. This same procedure is used in treating pseudarthroses.
The Ilizarov method has also shown great success in the treatment of complex hypertrophic and atrophic nonunions, sometimes in combination with autogenous bone grafting. This method allows not only for achievement of bony union but also for treatment of any accompanying deformity, segmental bone loss, or shortening that may be present.
Malunion of Fracture
A fracture that has healed with an unacceptable amount of angulation, rotation, or overriding that has resulted in shortening of the limb is defined as malunion. Shortening is better tolerated in the upper than the lower extremity, and angulatory deformities are better tolerated in bones such as the humerus than in the femur or tibia. Hence, no absolute guidelines can be given as to an acceptable versus an unacceptable malunion. Generally, shortening greater than 1 inch is poorly tolerated in the lower extremity. Smaller discrepancies, however, are well treated with just a shoe lift in most situations. When the degree of deformity is sufficient to cause pain (eg. caused by walking on the side of the foot secondary to varus malunion of the distal tibia) or impair normal function, then surgical correction of the malunion is indicated.
When correction of malunion is undertaken, proper preoperative planning is imperative. One must determine the true mechanical axis of the limb to determine the actual site of deformity. If an osteotomy is performed, the surgeon must decide whether to use a closing wedge (where a wedge of bone is removed) or an opening wedge (where a wedge of autogenous or allograft bone is added). This is important, as it will alter the limb length. If the limb is already short, the surgery should also include a limb-lengthening procedure. Proper fixation and often autogenous cancellous bone grafting should be incorporated to ensure that the osteotomy heals, for converting a malunion to a nonunion is only worsening an already bad situation. Special care must be paid to treatment of the soft tissues to prevent wound breakdown and infection.
Determination of the true plane of deformity is essential in planning for the surgical correction. Green and associates have shown in tibial malunions and nonunions that it is rare for the plane of deformity to be in the true sagittal or coronal plane. The true degree of deformity is therefore not fully appreciated on anterior to posterior and lateral radiographs, as the axis is usually in a plane somewhere between these. Thus, treatment of malunions can be appreciated as a difficult task that requires careful planning and execution to achieve anatomic results.
The Ilizarov apparatus and the concepts of distraction osteogenesis have dramatically revolutionized the application of the principles of external fixation in the management of bony defects, nonunions, malunions, pseudarthroses, and osteomyelitis. Since its introduction in Kurgan, Siberia, in 1951 by Gavril A. Ilizarov, surgeons throughout the world have employed this method to pioneer modern limb salvaging and lengthening procedures. This method has numerous advantages, including immediate loading of the limb postoperatively and the use of healthy viable bone to replace devascularized bone in situ by corticotomy, localized transport, and osteogenesis. Accordingly, leg length discrepancy, deformity, nonunions, and infections may all be treated effectively.
The basic premise of the Ilizarov technique is that osteogenesis can occur at a specially controlled osteotomy site (referred to as acorticotomy), given the appropriate degree of retained vascularity, fixation, and quantified distraction. Ilizarov realized that healing and neogenesis both required a dynamic state, which could occur in either controlled distraction or compression. This dogma is a function of many principles that Ilizarov classified into three categories: biologic, clinical, and technical. Important biologic concepts include preservation of endosteal and periosteal blood supply via corticotomy and stable fixation. Ilizarov fixation prevents shearing forces but permits axial micromotion with postoperative weight bearing, which enhances bone formation. Distraction osteogenesis occurs at a rate of approximately 1 mm/day. Division of distraction into four equal increments appears to be more physiologically sound than one distraction per day, as used previously in lengthening procedures. At the termination of distraction, neutral fixation is required to allow maturation, calcification, and strengthening of the new bone. In essence, the technique fools the body into believing it is a child again, with the corticotomy site acting as a physis.
Clinical principles such as the geometry of the apparatus once it is constructed, adjustment of the rate of transport, and wound care directly affect the outcome of the procedure. The initial operation for the application of the apparatus is only one small part in the whole treatment scheme. The construct should be as safe and comfortable as possible because for an extended period of time. Pin tract infections are common and must be addressed aggressively with oral antibiotics and local pin care.
From a technical viewpoint, Ilizarov methodology relies on the use of an extremely rigid (in all planes except the axial loading plane), extremely versatile external fixator, employing K-wire fixation under tension. It is this "tension stress" phenomenon of gradually controlled distraction of bone ends at the corticotomy site that makes possible the limb lengthening or osteogenesis required in bone transport. Neogenesis of the accompanying soft tissues, including vessels, nerves, muscle, and skin, also occurs. Likewise, because of the dynamic nature of the apparatus, constant high loads of compression can be maintained across fracture sites to help stimulate fracture healing.
During distraction osteogenesis, the new tissues are aligned parallel to the distraction force vector. Accordingly, the surgeon has fine control over the direction of the regenerating bone. Ilizarov noted that tension stress neogenesis was similar to the natural conditions present in musculoskeletal growth. Mesenchymal cells fill the early distraction gap and soon differentiate into osteoblasts. A hyperemic state exists during distraction osteogenesis, with abundant neovascularization in the distraction gap. The overall blood flow to the affected limb is also increased up to 40%.
As noted earlier, the circular external fixator is attached to the limb using wires under tension. Two diameters of wires are used: 1.5 mm in small children and in upper extremities in adults, and 1.8 mm (twice as stiff in bending) in lower extremities in adults and adolescents. Beaded wires (olive wires) are utilized for bony transport, as well as to provide for rigidity of fixation, to prevent unwanted translation of the bone on the frame. An appropriately applied frame on the lower extremity should allow full weight bearing on the limb, irrespective of the extent of the bony defect present. In fact, Ilizarov felt that ambulation and the restoration of function to the limb were essential to achieve good bone regeneration and union. This cyclic axial loading of the affected limb is a crucial element of the Ilizarov method.
With the incorporation of hinges, plates, rods, and other elements, correction of a deformity can be accomplished in any plane. Hence, the apparatus has become an increasingly useful tool in the treatment of congenital, acquired, and posttraumatic limb deformities, as well as nonunion and malunion. What makes this treatment method unique is that all problems affecting a limb can be managed with the application of one apparatus. For instance, nonunion of the tibia with angulatory deformity and 5 cm of shortening can often be successfully treated with one operation. The surgery would entail application of the Ilizarov apparatus with either acute correction of the angulatory deformity or gradual correction via application of hinges. A corticotomy of the tibia is also performed at the time of surgery to proceed with distraction osteogenesis to restore the 5 cm of limb length. The nonunion is then compressed (once properly aligned) to achieve bony union. The lengthening of the limb is occurring at the same time that the nonunion is being compressed. Ilizarov also found that certain more rigid nonunions could actually heal in distraction. Therefore another treatment approach in the previous example would be primary gradual controlled distraction across the nonunion site for the purpose both of achieving bony union and restoring some of the limb length at the nonunion site. In essence, Ilizarov found that with few exceptions, healing could occur as long as a dynamic force, be it compression or distraction, was properly applied across a nonunion site. This dynamic force, when properly applied, causes the dormant mesenchymal cells in the nonunion gap to differentiate into functioning osteoblasts and allow for bone synthesis and resultant healing.
The Ilizarov method has revolutionized thinking about fracture healing and osteogenesis. It has greatly broadened the scope and indications for limb lengthening and has incorporated limb lengthening as a tool in both fracture and nonunion management. Ilizarov's introduction of the concept of distraction osteogenesis and the tension stress effect have changed Western thinking regarding limb lengthening and fracture healing. Close adherence to Ilizarov's principles makes it now possible to successfully treat a host of orthopedic conditions that previously were fraught with high morbidity rates and poor results. As experience broadens, application of the Ilizarov method will continue to grow.
PRINCIPLES OF OPERATIVE FRACTURE FIXATION
Fractures occur when one or more types of stress, in excess of failure strength, are applied to bones. Fractures may occur from axial loading (tension, compression), bending, torsion (a twisting force), or shearing. All of these are observed at one time or another. It is frequently (but not always) helpful to recognize the type of failure in order to treat the fracture. Examples of these mechanisms are shown in Figure 3–4.
Biomaterials Used in Fracture Fixation
Operative fracture fixation requires strength and flexibility of the fixation materials. Two materials found to be useful in these regards are titanium alloy and stainless steel, both of which may be contoured to fit irregularities in bone surfaces at the time of surgery. They provide adequate strength and fatigue resistance to allow fracture healing to occur. The elastic modulus of titanium is half that of stainless steel, resulting in half the flexural rigidity in plates of equal size. Although it is recognized that more flexible devices decrease the disuse osteopenia underneath the plates, the clinical advantage of this difference has not been demonstrated. Other potential materials, including composites, cannot be contoured in the operative suite for particular applications.
Biomechanical Principles of Fracture Fixation
The principles of operative fracture fixation are demonstrated by several examples described here. These examples illustrate the importance of the location of a bone plate on a bone in relation to the loading applied to the bone and plate composite. They will demonstrate the bending stiffness of bone plates as a function of thickness and the load sharing that goes on between bone plates in bone. In addition, the effect of bending on the composite of an intramedullary rod and bone will be examined.
BONE PLATE THICKNESS
One approach to solving the problem of bone plate fractures is to increase the thickness of the plate. If a bone plate is subjected to bending stress, the stress in the plate, assuming no loading is carried by the bone, can be calculated from the flexure formula: smax = Mc/I, where M is the bending moment applied to the plate, c is one-half the thickness of the plate, and the area moment of inertia, I,is expressed by
where h is the thickness of plate and b is the width of the plate. The maximum stress would then be equal to
because c is equal to one-half of h. Doubling the thickness decreases the stress to
Thus, increasing the thickness of the plate by a factor of 2 reduces the stress by a factor of 4, meaning that the load would have to be four times higher before the failure stress would be reached. If one considers the area moment of inertia, I, to be proportional to the bending stiffness, then doubling the size of the plate would double h, which would mean that the plate is eight times stiffer (but only four times stronger). Because the endurance limit of steel is approximately one-half the ultimate strength, four times higher cyclic loads can be tolerated without fear of failure caused by fatigue.
TITANIUM AND STAINLESS STEEL RODS
The second consideration is the difference in the stress carried by an intramedullary rod made of titanium alloy as compared with one constructed of stainless steel. Assume a tibia is a round bone with a hollow, round intramedullary canal 10 mm in diameter. The flexural rigidity is defined as the area moment of inertia times the elastic modulus. A higher flexural rigidity indicates a greater resistance to bending. The area moment of inertia of a thin tube is
where r is the average radius and t is thickness. Assuming this equation holds for bone also, the ratio of the flexural rigidity of the intramedullary rod to the bone is expressed by the equation
The rave for the metal is 5 mm and for the bone 7.5 mm; tm is 1 mm and tb is 5 mm. The ratio Em/Eb is approximately 10 for stainless steel and 5 for titanium alloy. Thus, the flexural rigidity ratio is
This indicates that the geometric contribution to stiffness of the construct is greater for bone than for metal. Thus, for a stainless steel rod, the bone and metal rod share the bending stress after healing in a 60:40 ratio, respectively, (75:25 for titanium alloy). It can be seen that the bone is much stiffer than titanium alloy or stainless steel alloy rods. The difference between the two metals is probably not significant for bone remodeling, but maximum strength of the bone would be attained by removal in either case.
The placement of a plate on a bone has a significant bearing on its function. For example, on a curved bone such as the femur, which bows anteriorly, placement of the plate anteriorly tends to place the plate in tension and the posterior cortex of the femur in compression, owing to muscle action of the hamstrings and quadriceps. Conversely, placement of a plate posteriorly tends to cause the fracture to gap open anteriorly because of muscle action. This means that the bone in posterior placement is bearing none of the bending stress resulting from muscle forces and the bone plate has to resist all of this loading. When the bone plate is placed laterally, the axis of bending bisects the broad aspect of the plate, and thus the bone plate is much more able to tolerate the stress caused by muscle load. The plate, however, is susceptible to high stresses if abduction forces are applied to the femur or lower extremity. Thus, optimal placement of a bone plate is on the tension side of the bone, so that the bone will be placed in compressive loading as a result of muscle action. This stimulates healing and minimizes the stresses on the bone plate.
The conventional plate and screw system requires substantial bone exposure for access for open reduction and internal fixation. The surgeon-contoured plate is compressed onto the bone with screws resulting in anatomical reduction and absolute stability. The compressive forces acting on the bone-plate interface can compromise the blood supply and hence the healing process. The Low Contact Dynamic Compression (LCDC) plate was developed to reduce the bone-plate contact surface area.
The recently developed locking plates or internal fixators use a system where the screw head threads into the plate hole, thereby locking the plate just above the bone to minimize contact surface area and the resulting compressive forces. The locked screws in the plate also act as a second bone cortex and therefore self-tapping unicortical screws can be used. This achieves relative stability and therefore promotes callus formation at the fracture site. During fixation, the working length of the plate and screws should be kept in mind with the aim of increasing the working length of the plate and reducing the number of screws used.
External fixation is an important treatment modality for musculoskeletal injuries. The basic principles are that pins are placed within the musculoskeletal system proximal and distal to the zone of injury. These pins are then placed on an external frame, a frame outside the confines of the bone and soft-tissue envelope to stabilize fractures. These devices can be useful as temporary treatment for musculoskeletal injuries, or as definitive treatment, depending on their location and the type of bone and soft-tissue trauma. In the upper extremity, they play a significant role in treating comminuted distal radius fractures by providing both provisional and definitive stabilization for healing as well as provisional treatment for grade III open fractures with segmental bone loss and large soft-tissue injuries in the forearm, elbow, and humerus.
For the pelvis, rapidly applied external fixation with compression for pelvic injuries can stabilize the pelvis, reduce blood loss, be of assistance in initial resuscitation, and provide definitive treatment of such injuries. In the lower extremity, external fixators are important in the treatment of tibia fractures, particularly open or comminuted fractures, and in the treatment of open forefoot injuries and femur injuries with segmental defects. For femur and tibia fractures, external fixation may provide excellent initial or provisional stabilization, which can then be followed by intramedullary fixation for definitive care.
These specific uses of external fixation will be discussed in the individual sections on specific fractures.
Bone Substitutes Used in Fracture Fixation
AUTOGENOUS BONE GRAFTING
The gold standard for bone grafting material to stimulate bone growth is cancellous bone from the iliac crest. Obtaining bone graft is a process with potential morbidity, blood loss, infection, and, acute and/or chronic pain. Because of these possible problems, alternatives to autogenous bone grafting have been investigated.
OSTEOCONDUCTIVE GRAFT SUBSTITUTES
Hydroxyapatite and tricalcium phosphate, are inorganic structural bone graft substitutes that are primarily osteoconductive and do not stimulate bone formation. These materials can be injected into fracture sites to provide stabilization from compressive loads. A plethora of materials have come to market with variable degrees of clinical testing. The common denominator is that these are osteoconductive: They provide a scaffold for new bony ingrowth. They have been shown to be effective in well-vascularized areas such as the tibial plateau, distal radius and calcaneus.
DONOR BONE ALLOGRAFTS
The third alternative bone substitute is allograft derived from living or cadaveric donors. Femoral heads obtained at the time of hip replacement provide a source of living donor bone. Bone collected in the same fashion as transplant organs can also be made available for transplantation. It should be noted that all allograft bone is not the same. Immunogenicity, sterility, mechanical properties, and bone stimulation potential are all dependent on the treatment the bone receives from the time of collection until the time of implantation. The highest risk bone, because of occult viral and bacterial contamination, is that collected in a sterile manner from cadaveric donors and delivered in a sterile manner without further sterilization or processing. This bone also has the highest potential for containing bone growth factors and, therefore, the ability to stimulate new bone formation. Sterilization treatments, such as irradiation and ethylene oxide, are known to compromise these qualities to some extent, with ethylene oxide perhaps being worse than irradiation. Freeze-dried bone is convenient for storage at room temperature but must be sterilized secondarily with ethylene oxide. Because ethylene oxide is unable to penetrate to the depths of large pieces, secondary sterilization of large structural allografts is safer with radiation. The accepted dosage of gamma radiation is 2.5 mrad, but even this dose may not be sufficient to eradicate the human immunodeficiency virus.
Initially, bone substitutes consisted either of autogenous bone grafts, bone allografts, or material substitutes for bone growth such as hydroxyapatite. However, bone-derived protein extracts or bone morphogenic proteins (BMPs) have been identified as other important components of musculoskeletal repair for bone and cartilage growth. The identification of such specially purified BMPs, which had been shown to induce bone formation in a variety of ectopic and endogenous locations, has been coupled with recent advances in molecular biology and recombinant DNA techniques. Recombinant human bone morphogenic protein has been developed and has been undergoing human trials. These proteins can potentially be coupled with a collagen matrix and the addition of blood products from the patient to stimulate bone healing.
Demineralized bone matrix (DBM) is another osteo-inductive agent containing decalcified bone treated to reduce the potential for an immunogenic host reaction and transmissible infection. The resulting product is a biological scaffold with some remaining growth factors (BMPs). This has the potential to impart a greater osteoconductive effect than standard allograft, as the growth factors have not been exposed by demineralization in the latter.
Fractures & Dislocations of the Distal and Mid-Forearm
Anatomy & Biomechanical Principles
The articular surfaces of the radius, ulna, scaphoid, lunate and triquetral (in adduction) form the condyloid synovial joint of the wrist. The distal radius has three articular components (Figure 3–5): distally the scaphoid and lunate fossae, which allow articulation with the scaphoid and the lunate bones respectively; and the sigmoid notch, which allows articulation with the ulna medially. Between the scaphoid and the lunate fossa is a ridge that corresponds with the scapholunate interval. This entire surface is covered with articular cartilage. The radial styloid allows attachment of the brachioradialis tendon. Also, it is the origin of several important wrist ligaments, including the radial scapholunate and radial lunocapitate ligaments.
The third articular component of the distal radius is the sigmoid notch. This convex structure allows the radius to rotate around the distal ulna. The distal ulna itself has an ulnar styloid, which contains attachments to the triangular fibrocartilage complex, including the meniscus homolog, the volar and dorsal ulnar carpal ligaments, and the ulnar collateral ligament at the wrist. The concave elliptical distal radius is oriented in the sagittal plane with an average of 11 degrees of volar tilt. In the frontal plane, the average radial inclination is 23 degrees. Radial length is measured from the tip of the radial styloid to the ulnar articular surface and averages 13 mm.
In addition to the bony surfaces, the articular cartilage, joint capsule, and wrist ligaments, there are other soft tissues within the distal forearm and wrist. On the dorsal surface, six dorsal compartments contain wrist and digital extensor tendons (Figure 3–6). On the volar surface reside the contents of the carpal tunnel, with nine flexor tendons and the median nerve. On the ulnar surface, the flexor carpi ulnaris tendon can be palpated near its insertion on the pisiform. The boundaries of the ulnar tunnel, or Guyon's canal, are the volar carpal ligament and transverse carpal ligament, the hook of the hamate radially and the pisiform ulnarly. Guyon's canal contains the ulnar artery and nerve. In the most superficial soft tissue layer of the wrist reside the flexor carpi radialis layers, flexor carpi ulnaris, and palmaris longus.
The radius and the ulna structurally support the forearm. The distal radius and ulna have specialized articulations with the carpus and with each other. The shafts of the radius and ulna are approximately parallel. The ulnar shaft, however, remains fixed in its rotation at the ulnohumeral joint, and the radius rotates around the ulna in pronation and supination. The radius has a lateral bow that is crucial to the maintenance of full pronation and supination.
The interosseus membrane in the interosseous space connects the shafts of the radius and ulna. The central portion is thickened and has been shown to be important in force transmission between the radius and ulna. Origins of flexor and extensor muscles are located along the anterior and posterior surfaces of the radius, ulna, and interosseus membrane.
DISTAL RADIUS & ULNA INJURIES
Distal Radius & Ulna Fracture
Fractures of the distal radius account for approximately 14% of all fractures. In 1814, Abraham Colles described distal radius fracture prior to the advent of radiographs. In his purely descriptive definition, the fracture most commonly involves the distal metaphysis of the radius. He described the resulting volar angulation, dorsal displacement, loss of radial inclination and resultant radial shortening as a "silver fork deformity." In contrast, the Smith's fracture, or reverse Colles' fracture, is a dorsally angulated fracture of the distal radius, with the hand and wrist displaced volarly with respect to the forearm. The fracture may be extraarticular, intraarticular, or a part of a fracture-dislocation involving the wrist. Barton's fracture is a fracture-dislocation with an intraarticular fracture in which the carpus and a rim of the distal radius are displaced together (Figure 3–7). The Chauffeur's fracture is a radial styloid fracture, described initially in car drivers operating automobiles, which required hand cranking to start. When the engine engaged, the crank would "kick back," and the Chauffeur's fracture would result.
In modern day fracture care, the emphasis has shifted from "named" fractures to anatomic descriptions of the injury.
No one fracture classification system is comprehensive in describing all important variables of distal radius fractures.
The Frykman classification categorizes fractures by the presence or absence of an ulnar styloid fracture and by whether fracture lines are extraarticular, intraarticular involving the radial carpal joint, intraarticular involving the distal radioulnar joint, or intraarticular involving both radiocarpal and distal radioulnar joints (Figure 3–8).
The AO classification and its derivative, the OTA fracture classification system are the most comprehensive systems currently used to classify distal radius fractures. Broadly, distal radius fractures are separated into three groups: extraarticular (type A), partial articular (type B), and complete articular (type C). Within these are sub-classifications that relate to the particular amount of displacement and comminution (Figure 3–9). These sub- classifications are primarily used for research.
Another useful classification that addresses intraarticular fractures is that popularized by Melone (Figure 3–10). The Melone classification describes four major fracture components including the shaft, radial styloid, and dorsal and volar medial fragments. Often, the lunate fossa is fractured into dorsal and volar components, with the scaphoid fossa a separate component. Four-part articular fractures can have varying degrees of displacement and comminution.
Treatment of distal radius fractures should be influenced by fracture pattern and bone quality with a goal of restoring normal alignment and articular congruity. The normal alignment as measured in the AP and Lateral radiographs of the wrist are: radial inclination 22 degrees, volar tilt 11 degrees to 12 degrees and radial length 11 to 12 mm. Additional factors to consider are fracture displacement, intraarticular components, angulation, and degree of comminution; age of the patient; and functional level. Additional imaging techniques can be used to assess complex fracture patterns including CT scan for preoperative planning of intraarticular fractures; MRI to rule out injuries to the carpal ligaments or to the triangular fibrocartilage complex. Soft tissue injuries are commonly associated and should be carefully examined, including the triangular fibrocartilage complex (TFCC), lunotriquetral and scapholunate ligament.
Closed Reduction with Splinting and Casting
Extraarticular distal radius fractures in certain individuals (classic Colles' fracture) can be treated successfully with closed reduction and splinting with conversion to a cast once swelling subsides. Radial length is generally not fully restored, nor is radial angulation with closed reduction techniques. Small amounts of radial shortening can lead to increased load in the lunate fossa, distal ulna, and triangular fibrocartilage. In most low-demand patients, however, this treatment can be successful, and functional wrist motion can be obtained. If shortening is significant, midcarpal instability may occur. Another potential problem is distal radioulnar joint arthrosis and ulnar carpal abutment, which may necessitate later reconstruction. In minimally displaced fractures, a rapid cast conversion to a supportive splint (2 or 3 weeks) and early mobilization can be safely done and may yield improved outcomes.
Percutaneous Pin Fixation
Percutaneous pins can be an effective adjunct to cast treatment or external fixation. The pins can hold large metaphyseal fragments in good position and prevent collapse or malalignment. In the intrafocal pin technique, the pin is placed in the fracture site itself. This can be an effective means of achieving anatomic alignment and preventing loss of reduction. The pins can be removed after 4 weeks but additional immobilization (cast or external fixation) should be used for 6 to 8 weeks. This technique requires good bone stock and additional stabilization using cast or external fixation. Loss of reduction is a potential complication in older patients. Also, granuloma formation around the pin can be seen.
External fixation is an effective way to handle distal radius fractures. In particular, it provides more direct control of the overall length of the distal radius, and to some extent the inclination, compared with cast treatment. Use of indirect traction on fracture fragments, taking advantage of "ligamentotaxis" via the fixator pins, can be effective. There is the additional advantage of not devascularizing bony fragments and not creating a surgical wound. In cases of open fractures an external fixator can facilitate wound care. External fixation is effective in preventing loss of reduction and length in situations where there is comminution of bone. In intraarticular fractures, external fixation can be used but reductions are difficult to maintain without percutaneous pins or internal fixation. Complications are common however with external fixation including, pin tract infection, superficial radial nerve neuropathy, pin loosening, and stiffness.
OPEN REDUCTION AND INTERNAL FIXATION
Plate and Screws
Plate and screws can be extremely effective in achieving and maintaining reduction. If bone fragments are large, it is also an effective way to maintain reduction. This technique has a tendency to fail, however, if there are multiple fragments and if there is sufficient comminution so that rigid internal fixation is difficult, or impossible, to achieve. Other drawbacks to this technique include creation of an incision, with potential subsequent scarring, and also the possibility of future hardware removal. Additionally, the operative technique involves soft-tissue stripping and potential devascularization of small fragments during the process of open reduction and internal fixation.
Recently, distal radius plates with fixed-angle screws have been devised specifically for comminuted distal radius fractures. These feature multiple small locking holes in a T configuration, allowing multiple screws for small fragment fixation. This highly stable construct allows early functional treatment. Recent studies indicate that locked plates and early postoperative range of motion may provide improved long-term results.
Arthroscopically Assisted Reduction
Arthroscopically assisted reduction can address the associated ligament injuries improving the final result, with limited scarring. A recent study reported that patients undergoing arthroscopically assisted procedures had a greater degree of supination, flexion, and extension than patients undergoing fluoroscopy-assisted fixation of intraarticular distal radius fractures.
Besides fracture type and comminution, additional factors that modify treatment decisions include patient comorbidities, available resources for treatment and surgeon expertise. For a non-comminuted, non-displaced, methaphyseal distal radius fracture, nonoperative treatment with initial splint until the edema subsides and subsequent cast application is the appropriate treatment. In contrast, intraarticular comminuted fractures are difficult if not impossible to reduce and maintain without the addition of hardware. In presence of osteoporosis and intraarticular displacement, ORIF using a fixed angle device is probably the best option. When facing severe comminution, pinning and external fixator can be the most suitable treatment.
Extraarticular Nondisplaced Fractures
Extraarticular nondisplaced fractures can be treated with cast immobilization for 4-6 weeks, until fracture healing occurs, following by mobilization with an off the shelf brace.
Extraarticular Displaced Fractures
Closed reduction should be attempted on extraarticular displaced fractures. If radial length and volar tilt are restored, then a sugar tong splint or long arm cast can be effective in holding the reduction. If the reduction is not adequate by closed means then an external fixator (for ligamentotaxis) and percutaneous pins (to manipulate the fracture) may be necessary. Current trends toward plating via a volar approach with specialized locking plates may improve wrist motion and long-term outcomes even in extraarticular fractures.
The treatment of intraarticular fractures aims to restore the congruity of the articular surface and the anatomic axis of the distal radius in order to improve the outcome. Open reduction and internal fixation is the treatment of choice. For volar Barton's fractures, the treatment of choice is the volar buttress plate. The only contraindications to this treatment are cases with excessive comminution such that open reduction and internal fixation will fail to achieve a stable bony construct. In these situations, use of an external fixator as a distractor and neutralization device is generally indicated. Using a fluoroscopy unit to visualize the fracture will help ascertain that both articular alignment and overall radial length have been adequately restored with external fixation. Minor adjustments as necessary can be effectively done with adjunct percutaneous pins. These maneuvers may fail to achieve the appropriate articular alignment, particularly if some healing has already occurred or if the displacement is severe. In this case, open reduction and internal fixation should be performed. Justification for aggressive treatment of distal radius fractures in young patients (<60 years) comes from several studies. The goal should be articular step-off <2 mm, radial shortening <4 mm, dorsal tilt <15 degrees, volar tilt <20 degrees and loss of radial inclination <10 degrees. Arthroscopically assisted repair of distal radius fractures has been advocated. Intraarticular step-off and associated injuries such as triangular fibrocartilage, scapholunate, and lunotriquetral tears as well as osteochondral lesions can be accurately assessed. Some authors advocate bone grafting in the acute treatment of comminuted fractures.
Distal Radioulnar Joint Dislocation
The distal ulna transmits significant loads to the forearm through the distal ulna via the triangular fibrocartilage complex. Even minor disruptions of the precise anatomic relationships between the distal radius and ulna and ulnar carpus results in pain syndromes. The distal radioulnar joint (DRUJ) can be dislocated by a variety of mechanisms, including low- and high-energy trauma. These are associated with disruption of the ulnar soft-tissue triangular fibrocartilage complex, including the articular disk and associated ligaments. There should be a high index of suspicion in order to diagnose this lesion because radiographs that are not taken in the perfect lateral orientation will tend to look relatively normal. A displaced fracture at the ulnar styloid base indicates a high risk of distal radioulnar instability. In the presence of forearm and elbow fracture-dislocations, further evaluation of the radioulnar joint is mandatory.
The clinical examination is key, with identification of the distal radioulnar joint surface anatomy and clinical evaluation of the joint. The amount of stability should be carefully assessed and compared with that of the opposite wrist. The patient should position the wrist to reproduce the pain. With the hand pronated, the examiner tries to displace the ulnar head applying a dorsal to volar load 4 cm proximal to the DRUJ (piano key test). Little resistance to ballottement and volar movement of the ulna head corresponds to a positive "piano key test." Subluxation is much more common than anterior or posterior dislocation. Limitation of pronation and supination, or pain associated with such motion, would be expected in such a situation. Palpation of the sixth extensor compartment during resisted pronation is useful to identify any subluxation. The other common cause of distal radioulnar joint problems is rheumatoid arthritis.
Dorsal dislocation, or subluxation, should be treated by reduction of the ulnar head into the sigmoid fossa and placement of the forearm in full supination. The arm should be immobilized in supination, which requires a long-arm cast or splint. Volar dislocation is relatively rare and is usually stable after reduction. If dorsal or volar dislocation or subluxation of the distal ulna cannot be reduced with manipulation in the outpatient setting, closed treatment can be attempted under anesthesia. If this fails, open reduction and soft-tissue reconstruction may be necessary. If this is performed, a retinacular flap may be used to transpose the extensor carpi ulnaris to a more dorsal position to stabilize the distal ulna, as has been described for Darrach reconstruction of the joint.
Malunion of Distal Radius
Malunion of the distal radius can have a variety of negative consequences. Alteration of the biomechanical function of the wrist may lead to weakness, limitation of motion, and midcarpal instability. Associated distal radioulnar joint arthrosis may be present, as well as ulnocarpal abutment. Also, rotational deformity is common with angulated malunions. CT of both wrists can be used to identify and measure malrotation preoperatively.
The treatment of choice in such a situation, if conservative treatment fails, is reconstructive surgery. Fernandez has elegantly described the strategy. An osteotomy of the radius with iliac crest bone grafting and plate fixation is performed (Figure 3–11). The distal radioulnar joint must be addressed and, depending upon the degree of subluxation or arthrosis, may require closed reduction, open reduction, or reconstruction using the Darrach or Sauve-Kapandji procedures (Figure 3–12). In this procedure, instead of distal ulnar resection as in the Darrach procedure, transverse segmental resection of the ulnar metaphysis is followed by creation of an arthrodesis of the distal ulna to the radius, using the resected bone as grafting material. Forearm rotation occurs through the ulnar metaphyseal pseudoarthrosis. Additionally, restoration of the radial length may be difficult with manipulation alone. Useful adjuncts to achieve restoration of appropriate length and orientation in severe malunion include use of laminar spreaders to distract the proximal and distal fragments of the radius after osteotomy. Alternatively, an external fixator may prove useful in helping to achieve appropriate length after osteotomy.
If the distal radius has settled into a position of shortening and significant angulatory deformity but the fracture is not yet fully healed, osteotomy for early or "nascent" malunion is justified. The advantage of taking down a nascent malunion is that the operation is technically simpler to perform, shortens the time of disability, and leads to better long-term results. Additionally, the distal radioulnar joint can be restored more reliably in these early reconstructions than when osteotomy is required for established malunion. The latter often requires adjunctive distal radioulnar joint reconstruction with Darrach resection, Sauve-Kapandji, hemiresection, or matched resection arthroplasty.
DISLOCATION OF THE RADIOCARPAL JOINT
Dislocation of the radiocarpal joint is usually accompanied by significant carpal-ligamentous injury or fracture. Treatment of these injuries involves restoration of the bony architecture through immediate closed reduction, if possible, elective closed reduction, open reduction and internal fixation, or a combination of these procedures. Associated fractures, such as transscaphoid perilunate or distal radius fracture associated with carpal dislocation, should be treated with open reduction and internal fixation. Ligamentous repair should be performed at this time (see Chapter 10, Hand Surgery). Median nerve evaluation is mandatory, and surgical exploration indicated, if a dense neuropathy is present.
FOREARM SHAFT FRACTURES
In general, any fracture requires evaluation both clinically and radiographically of a joint above and joint below the fracture. It is not uncommon for fractures of the midshaft of the forearm to have significant consequences to either the wrist or elbow.
Isolated Fracture of the Ulna (Nightstick Fracture)
Nondisplaced or minimally displaced fractures of the ulnar shaft are fairly common and usually result from a direct blow.
A variety of treatment options are possible for managing minimally displaced ulnar diaphyseal injuries. The time to union is about 3 months, with union achieved with cast immobilization and early mobilization of the wrist and elbow. Less stringent immobilization protocols have also resulted in satisfactory results. Sarmiento and Latta achieved excellent results using a functional brace for isolated ulnar fractures. After initial long arm cast fixation for immobilization until acute symptoms and swelling have subsided, cast removal is followed by Orthoplast sleeve or cast bracing with Velcro straps, with no limitation of pronation and supination. Some investigators report excellent results with minimal or no immobilization. In general, some sort of immobilization until pain subsides is preferable. With displaced fractures with angulation greater than 10 degrees or displacement greater than 50%, one must be extremely suspicious of an associated injury at the elbow or wrist. In isolated fractures of the ulna in the adult with displacement >50% or angulation >10 degrees (or both), open reduction and internal fixation is the treatment of choice. Current recommendations include fixation with a 3.5 mm dynamic or limited contact compression plate with six to eight cortices of fixation proximal and distal to the fracture. Intramedullary pinning seems to provide comparable results to plate fixation, but further studies are needed at this point.
Isolated Radial Shaft Fractures
A fracture anywhere along the length of the radius with or without associated ulnar fracture with injury to the distal radioulnar joint (DRUJ) is defined as a Galeazzi fracture. Injuries associated with the DRUJ include ulnar styloid fractures, radial shortening >5 mm, and DRUJ dislocation.
Open reduction and internal fixation with plate fixation is recommended in adult patients to ensure a reasonable chance of restoration of the distal radioulnar joint. Hughston's series in 1957 had a 92% incidence of poor results with closed treatment. After open reduction and internal fixation of the radial shaft through a volar Henry approach using compression plating, the distal radioulnar joint should be carefully inspected. If it is unstable, pinning in a position of stability (usually full supination) is required. If it is frankly dislocated and cannot be reduced closed, and maintained by closed or percutaneous means, then open stabilization with repair of associated ligaments or removal of interposed soft tissue is mandatory.
Classification of Fractures
In 1814, Monteggia of Milan described an injury involving fracture of the proximal third of the ulna, with anterior dislocation of the radial head. This definition was extended by Bado to include the entire spectrum of these fractures with associated radial head dislocations, regardless of the direction of dislocation. They are classified in the following ways:
Type 1: Fracture of the ulnar diaphysis with anterior angulation and anterior dislocation of the radial head (60% of cases)
Type 2: Fracture of the ulnar diaphysis with posterior angulation or posterior or posterolateral dislocation of the radial head (15% of cases)
Type 3: Fracture of the ulnar metaphysis, with lateral or anterolateral dislocation of the radial head (20% of cases)
Type 4: Fracture of the ulna and radius at the proximal third, with anterior dislocation of the radial head (5% of cases).
Other authors have noted that type 3 fractures may be more common than type 2 fractures, but all agree that type 1 lesions are the most common.
Associated lesions include injury to the radial nerve; palsies of both the deep branch of the radial nerve and the posterior interosseous nerve have been described with Monteggia fractures. It is important to perform an adequate neurovascular examination at the time of evaluation. The index of suspicion must be high because radial head dislocation may be missed if appropriate radiographs are not obtained and scrutinized.
Closed treatment is usually satisfactory for children, but open reduction and internal fixation is the treatment of choice for Monteggia lesions in an adult. Optimal results require early diagnosis, rigid internal fixation of the fractured ulna, complete reduction of the dislocated radial head, and immobilization for approximately 6 weeks to allow healing with sufficient stability. Internal fixation is best performed with a compression plate technique. The radial head can often be completely reduced by closed means once the ulnar fracture is reduced and rigidly fixed. If this is not possible, open reduction is required; attention should be paid to the relationship between the annular ligament, the lateral epicondyle, and the radial head. Entrapment of the soft tissues is the most common reason for inability to obtain concomitant closed radial head reduction at the time of open reduction and internal fixation of the ulna.
Fractures of Both the Radius & Ulna
Fractures of both the radius and ulna (both-bones fractures) usually result from high-energy injuries. These fractures are usually displaced because of the force required to produce such an injury. Careful neurovascular examination and adequate radiographs to show both the wrist and the elbow are mandatory.
Treatment of choice for both-bones fractures is open reduction and internal fixation. The volar Henry approach should be used for radius repair, between the flexor carpi radialis and brachioradialis, with the ulna approached subcutaneously. Open reduction and internal fixation offers the best chance of restoring the normal positions of the radius and ulna, which is critical to forearm function and in particular pronation and supination. For fractures of the proximal half of the radius, the dorsal Thompson approach can be used; however, the risk of iatrogenic injury to the posterior interosseous nerve is increased. Technical points to be considered include minimal subperiosteal stripping only of the fracture site. The plates can be placed on top of the periosteum to preserve the blood supply as much as possible. A 3.5-mm dynamic compression plate or limited contact compression plate can be used for AO/ASIF compression plating. Bone grafting can be used for severely comminuted fractures with significant bone loss. Only the skin is closed so as not to cause compartment syndrome or Volkmann's contracture. Splinting of the affected extremity, as in all upper extremity surgery, is recommended, with early digital active and passive motion exercises.
Many authors recommend plate fixation for Gustilo type I, II, and IIIA open both-bones fractures. Use of an external fixator is a viable alternative, however, particularly if severe open wounds are present with skin and soft-tissue loss as in Gustilo type IIIB and IIIC injuries. Criteria for bone grafting include comminution involving more than one third the cortical circumference and comminution that compromises interfragmentary compression; however, the success of acute bone grafting has not been proved in long-term studies.
Injuries Around the Elbow
Anatomy & Biomechanical Principles
The elbow is one of the most confined articulations in humans. The trochlear notch covers almost 180° of the trochlea. The articular surface of the distal humerus is angulated 30° anteriorly, which is matched by a similar posterior angulation of the trochlear notch. Accessible surface structures at the elbow that can be inspected and palpated include the medial and lateral condyles and the olecranon. With the elbow in 90 degrees of flexion, these three palpable points form a triangle. Distally, the radial head can be palpated at the lateral aspect of the elbow joint, and the contour can be appreciated with pronation and supination. These bony landmarks are important when clinically assessing the elbow for fractures, dislocations, or effusions. Effusions can be discerned by swelling between the lateral epicondyle and the olecranon. On cross-section, the humerus is circular at the midshaft but flared and flattened at the distal end. Medial and lateral supracondylar columns diverge to increase the diameter of the distal humerus in the mediolateral plane. Each condyle contains an articulating portion for the radial head, or ulna, and nonarticulating epicondyles, which are terminal portions of the supracondylar ridges on which pronator-flexor muscles and supinator-extensor muscles originate. The three articulations at the elbow are the ulnotrochlear joint, the radiocapitellar joint, and the proximal radioulnar joint. The radial head articulates with the capitellar portion of the lateral condyle. The articular surface of the medial condyle has prominent medial and lateral ridges that aid in stabilizing the articulation with the ulna. Anterior to these two condyles are the coronoid and radial fossa, which receive the coronoid process of the ulna and the radial head when the elbow goes into full flexion. The proximal ulna contains the olecranon process posteriorly, the coronoid process anteriorly, and the sigmoid, or semilunar notch, which articulates with the trochlea. The triceps has a broad tendinous insertion into the olecranon posteriorly; anteriorly, the brachialis inserts on the coronoid process and the tuberosity of the ulna. The radial head lines up in its lesser sigmoid, or radial notch, with the annular ligament surrounding it. Collateral ligaments make up the remainder of the soft-tissue structures of the elbow, with the most important portion being the anterior band of the medial or ulnar collateral ligament arising from the medial epicondyle and attaching to a small process on the medial surface of the coronoid. The lesser posterior portion of the medial collateral ligament attaches to the medial surface of the olecranon process. There is a similarly triangular fan-shaped lateral collateral ligament, whose origin is the lateral epicondyle inserting on the annular ligament of the radius. The ulnar nerve passes through the cubital tunnel at the medial column of the elbow and must be appropriately assessed following injury.
DISTAL HUMERUS FRACTURES
Intercondylar-T or -Y Fractures
Intercondylar humerus fractures are among the most challenging fractures treated by the orthopedic surgeon. The usual mechanism of injury is axial loading of the ulna in the trochlear groove. Studies have demonstrated increasing numbers of these injuries in the older (>60 years) population. It is critical to assess the integrity of the medial and lateral column for reconstructible bone fragments and the degree of comminution.
Jupiter and Mehne classified distal humerus fractures into intraarticular and extraarticular patterns. Intraarticular fractures are divided into the following types:
Extraarticular fractures are classified into intracapsular and extracapsular (Table 3–3).
Traditional treatment favored closed techniques because of the difficulty of fracture fixation for intercondylar fractures. Cast immobilization probably represents the worst of all possible worlds: inadequate reduction plus prolonged immobilization, leading to stiffness and ankylosis. Recent studies recommend open reduction, internal fixation (ORIF) in even the elderly (>70 years) population. Total elbow arthroplasty has similarly given good results in elderly patients with severely comminuted fractures involving osteoporotic bone. The goals of treating intraarticular distal humerus fractures include stable fixation with early motion.
Early operative methods consisted of pins and plaster or limited open reduction and internal fixation. With modern techniques, full ORIF is preferred for most fractures. Surgical exposure is through a transolecranon approach (ie, either transverse osteotomy or chevron osteotomy). A triceps-sparing, and a triceps-splitting posterior approach have also been described.
Intercondylar T fractures have two distinct components: the intraarticular intercondylar component and the supracondylar one. The intracondylar portion of the fracture can usually be secured surgically with provisional K-wire fixation, followed by definitive screw fixation. After intercondylar fracture, stabilization with restoration of either the medial or lateral column is required to complete the operative fixation. When possible, dual plate fixation can be used. The AO group recommends a posterolateral and a medially applied dynamic compression plate. The 90° plate configuration has been demonstrated to be the most stable construct. Locking compression plates are helpful for achieving stable fracture fixation in patients with osteoporosis and comminuted fractures.
In summary, intraarticular distal humerus fractures should in general be treated with (1) anatomic restoration of the articular surface with lag screw fixation of periarticular fragments (2) stable attachment of the metaphysis to the diaphysis with reconstruction or locking plates and (3) early range of motion.
Fracture of the Humeral Condyles
Both medial and lateral condyles can be disrupted. These fractures can correspond with the ossification centers of the distal humerus.
Lateral Condylar Fracture
Lateral column fractures are single-column injuries and are divided into "low" and "high." Low fractures have the lateral wall of the trochlea attached to the main mass of the humerus and are generally stable, whereas high fractures involve a majority of the trochlea and are unstable. "Low" and "high" correspond to Milch type I and II injuries, respectively. Stable internal fixation with early range of motion is generally recommended for displaced fractures.
Medial Condylar Fracture
Medial condyle fractures are similarly single-column injuries with low fractures (Milch type I) involving a portion of the trochlea, with preservation of the trochlear ridge and are generally stable. In high medial condyle fractures (Milch type II), the lateral trochlear ridge is included with the fracture portion.
Both fractures, if displaced, should be treated with ORIF and early range of motion.
Fracture of the Epicondyles
Although lateral epicondylar fractures are rare, medial epicondylar fractures are fairly common, especially among children or adolescents. They commonly present as avulsion fractures. Treatment depends on the amount of displacement. If displacement is minimal, then closed reduction is appropriate. A displaced fracture may require percutaneous pinning or open reduction. Elbow instability is not generally a problem; however, irritation of the ulnar nerve can result. Early motion seems to be important for restoration and ultimate function. If a displaced fracture results in ulnar symptoms or is itself symptomatic, the fragment can be excised at a later date.
The olecranon is the most proximal posterior eminence of the ulna. It is on the dorsal subcutaneous border and contains broad attachments for the triceps posteriorly. Anteriorly, the olecranon forms the greater sigmoid (semilunar) notch of the ulna, which articulates with the trochlea. The ulnar nerve passes behind the medial epicondyle at the posterior medial aspect of the elbow and then pierces the volar forearm between the two flexor carpi ulnaris muscle heads.
Fracture of the olecranon commonly occur with a direct blow or as an avulsion injury with triceps contracture. The fractures generally are transverse or oblique in orientation and enter the semilunar notch.
Radiographic evaluation consists of a true lateral radiograph of the elbow, and classifications or descriptions generally analyze the fracture based on the percentage of articular surface involved in the fractured proximal fragment. This factor, the amount of comminution, the fracture angle, intraarticular step-off, and the degree of displacement, are all critical in evaluating the injury and selecting the appropriate treatment.
Methods of treatment vary from closed treatment to ORIF. Nondisplaced fractures, or fractures with <2 mm displacement and an intact extensor mechanism, should be immobilized in a long arm cast with the elbow in 90 degrees of flexion.
Displaced transverse or short oblique fractures generally are best treated with ORIF. The optimal method for treating this fracture is tension banding with two longitudinal K-wires placed across the fracture site and stabilized with a figure-of-8 wire loop (Figure 3–13). More oblique fractures can be treated with interfragmentary screws with a neutralization plate. Wire protrusion and pain frequently result and may necessitate removal of the hardware.
If the articular surface is significantly comminuted, a low-profile, limited contact compression plate can be applied to the dorsal surface of the ulna. Selected comminuted fractures may be treated by selective bony excision or complete excision of the fragment followed by reattachment of the triceps. All these treatments generally can be accompanied with early protected range-of-motion exercises.
FRACTURE OF THE RADIAL HEAD
The incidence of fractures of the radial head is between 15% and 25% of elbow fractures. The radial head is seated in the lesser sigmoid notch and has contact axially with the capitellum of the distal humerus. The lateral portion contacts the ulna throughout forearm pronation and supination. Gripping or loading forces are transmitted through the interosseous membrane from the radius proximally to the ulnar distally. Load bearing occurs through the radial head.
Radial head fractures are generally caused by longitudinal loading from a fall on an outstretched hand; dislocation of the elbow is another cause.
One generally describes these fractures based on their location, percentage of articular involvement, and amount of displacement. Radiographs in the anteroposterior and lateral projections show the injury. The fat pad sign is usually present on the lateral projection (Figure 3–14).
Mason proposed a classification scheme for radial head fractures: Type I is a nondisplaced fracture; type II is a fracture that is displaced usually involving a single large fragment; type III is a comminuted fracture and type IV is a fracture associated with an elbow dislocation (Figure 3–15).
For type I fractures, nonoperative treatment with early motion can generally produce a good outcome.
The treatment of type II fractures is controversial. For fractures with near normal motion, <2 mm step-off and without associated injury, nonsurgical treatment is indicated.
Type II fractures with associated injuries that may compromise elbow stability or fractures with a mechanical block to full motion after injection of anesthetic into the elbow joint are indications for ORIF. Open reduction and internal fixation can be performed with pins, articular screws, or Herbert screws. Implants should be placed into the nonarticular safe zone to avoid impingement on the sigmoid fossa of the ulna. The safe zone corresponds to the lateral 100° arc with the forearm in neutral rotation.
The result of ORIF is less predictable when there is more than one fragment in Type II fractures, and limitation of forearm rotation not attributable to implant prominence can be expected.
Early excision with immediate motion is recommended for type III fractures with no associated elbow instability, coronoid fracture, wrist pain, or distal radio-ulnar joint injury. If any of these conditions exist, then current literature recommends placement of a metallic radial head prosthesis. The silastic implant has been associated with material failure and particulate synovitis that preclude permanent use of the implant. Replacement of the radial head becomes most important when there is evidence of soft-tissue disruption involving the interosseous membrane and the distal radioulnar ligaments. This can be determined through the clinical examination. Sometimes radiographic evidence will show proximal migration of the radius and carpus relative to the ulna if the radial head has not been replaced; this is called the Essex-Lopresti injury. Some authors suggest that replacement of the radial head should be considered in healthy, active patients even if the elbow and forearm are stable. Broberg and Morrey noticed a 92% incidence of arthrosis ten years after fracture-dislocation treatment without repair or replacement of the radial head.
Capitellar fractures frequently accompany and result from the same mechanism that causes radial head fractures. The medial collateral ligament, the interosseous ligament, and the distal radioulnar joint may also be injured. Various levels of injury, from cartilage damage to large osteochondral portions of the capitellum, can occur from impaction of the radius against the capitellum. Shearing forces can result in two different, more significant injuries: an osteochondral injury or complete fracture (type 1 or Hahn-Steinthal), an articular-cartilage-only injury (type 2 or Kocher-Lorenz), a comminuted fracture (type 3), or a fracture line extending into the trochlea (Hahn-Steinthal II). CT reconstructions are useful to further delineate the fracture and for surgical planning. Osteochondral pieces can be overlooked or confused with bone chips from radial head fractures.
Today, anatomic reduction and early motion is the standard treatment for these injuries, whether obtained by open or closed means. Open reduction is performed through a lateral approach between the anconeus and extensor carpi ulnaris.
Dislocations of the elbow occur when loads are placed on the structures about the elbow that exceed the intrinsic stability provided by the anatomic shape of the joint surfaces and soft-tissue constraints. These are potentially limb-threatening, as vascular compromise is a possible sequela. Expeditious reduction of the elbow joint is the goal of treatment.
Although diagnosis of elbow dislocation can be made easily prior to the onset of swelling, the type of dislocation may not be obvious. Elbow dislocations are characterized, like all dislocations, according to direction of the distal bone. Thus, pure elbow dislocations are categorized as anterior, posterior, medial, or lateral, depending on the direction of displacement of the radius and ulna. Because two bones are present in the forearm, one more dislocation is possible, the divergent dislocation, but this is rare. This occurs when the radius and ulna are forced apart by the distal humerus. "Partial dislocations" also occur, in which the radial head or the ulna alone dislocate. The ulna has been observed to dislocate anteriorly or posteriorly. The radial head has more latitude and can dislocate laterally as well as in the anterior or posterior direction. Isolated radial head dislocation is rare; it is usually accompanied by an ulnar fracture (Monteggia fracture). When combinations of dislocations with concomitant fractures occur, treatment of the combined injury is usually dictated by the treated fracture. Adequate fracture care will usually cause secondary reduction of the dislocation.
Posterior Elbow Dislocations
Posterior dislocations are the most common type (80%) of elbow dislocations, resulting from an axial force applied to the extended elbow. Both collateral ligaments are disrupted, whether the dislocation is posteromedial or posterolateral.
Diagnosis is made by clinical examination and verified by radiograph to rule out associated fractures. The extremity is typically shortened and the elbow held slightly flexed.
Treatment is initiated after documenting the neurovascular examination. Anesthesia, either injected locally into the joint or administered intravenously is necessary. Traction on the extremity with correction of the medial or lateral displacement usually produces reduction with a "clunk." The elbow is put through a range of motion to ensure that reduction has been obtained and that there is no soft-tissue or bony mechanical blockage to motion. The elbow is generally splinted in flexion and pronation to maintain stability. Postreduction radiographs are necessary to rule out occult fracture.
Anterior Elbow Dislocations
Anterior dislocations are relatively rare. Soft-tissue damage is typically severe. Treatment is similar to that for posterior dislocations, except that the method of reduction is reversed.
Medial & Lateral Elbow Dislocations
The radius and ulna may be displaced medially or laterally. Some semblance of joint motion may be present with lateral dislocations, as the ulna may be displaced into the groove between the trochlea and the capitellum. The anteroposterior radiograph is diagnostic. Medial or lateral force is used, after attempting to distract the joint surfaces, to reduce these dislocations.
Isolated Ulnar Dislocations
Isolated ulnar dislocations occur when the humerus pivots around the radial head, causing the coronoid process to be displaced posterior to the humerus or the olecranon anterior to the humerus. The more common injury is posterior dislocation, which causes cubitus varus deformity of the forearm. Traction in extension and supination reduces the ulna.
General Treatment Procedures
The elbow is tested for stability to varus and valgus stress and to pronation and supination. Stable dislocations are splinted for comfort at 90 degrees of flexion, and motion is instituted as soon as possible, generally within a few days. Maintenance of reduction is necessary, and radiographs should be taken periodically if any doubt exists. Immobilization does not guarantee maintenance of reduction. Unstable reductions are rare. Immobilization for longer periods may be necessary in these cases, as a stiff but stable elbow is preferable to an unstable elbow.
Uncomplicated elbow dislocations have a favorable long-term prognosis. A loss of extension of 5–10 degrees compared with the contralateral elbow can be expected following this injury. Posterolateral dislocation has been associated with persistent valgus instability in some patients, which is associated with a worse overall clinical result.
It would seem impossible for a patient not to seek immediate care for elbow dislocation. Treatment may be delayed, however, because of failure to seek medical attention, altered mental status, or missed diagnosis by the initial physician. Late reduction of elbow dislocations can be accomplished with closed techniques for up to several weeks from the time of injury. Dislocations left untreated for longer periods generally require open reduction techniques. Better function with less flexion contracture after open reduction of posterior dislocations is obtained by lengthening the triceps tendon.
ELBOW DISLOCATION AND CORONOID FRACTURE
An elbow dislocation and associated fracture of the coronoid process increases the risk of recurrent and chronic instability. The size of the coronoid fragment varies from a small marginal fragment (Reagan-Morrey Type I) to a larger fragment (Reagan-Morrey Type II), or includes the insertion of the anterior bundle of the medial collateral ligament (Reagan-Morrey Type III). The decision to fix a coronoid fracture should be made based on elbow stability. Even small rim fractures may require surgical fixation if instability is present after repair of associated fractures. Interfragmentary screws can be used to fix a large fragment. Otherwise a pullout technique can be used.
ELBOW DISLOCATION WITH RADIAL HEAD AND CORONOID FRACTURES
Denominated the terrible triad of the elbow, these injuries are difficult to treat and the reported results have been poor. The most common problems after these lesions are recurrent and chronic instability, stiffness, posttraumatic arthrosis, and pain. Appropriate treatment should include open reduction and internal fixation of the coronoid fracture and/or repair of the anterior capsule, ORIF or replacement of the radial head, and repair of the lateral ligament complex. Residual instability after treatment represents an indication for medial collateral ligament repair and/or application of a hinged external fixator.
SHOULDER & ARM INJURIES
Anatomy & Biomechanical Principles
The humeral shaft extends from the level of the insertion of the pectoralis major muscle proximally to the supracondylar ridge distally. The upper portion of the shaft is cylindrical and then becomes more flattened in an anteroposterior direction as it proceeds distally. Medial and lateral intermuscular septae divide the arm into anterior and posterior compartments. In the anterior compartment reside the biceps brachii, coracobrachialis, and brachialis muscles, along with the neurovascular bundle coursing along the medial border of the biceps with the brachial artery and vein and the median, musculocutaneous, and ulnar nerves. In the posterior compartment reside the triceps brachii muscle and the radial nerve. Understanding the insertions of the muscle forces around the humerus helps explain the tendency for fractures to displace in predictable patterns, based on the influence of these muscles (Figure 3–16).
The shoulder girdle is a complex arrangement of bony and soft-tissue structures. The shoulder has the largest range of motion of any major joint in the body. The glenoid cavity is a shallow socket, approximately one third the size of the humeral head. Stability of the joint depends on capsule, ligament, and muscle. A redundant capsule allows for motion; the rotator cuff controls the joint itself.
The proximal humerus contains the humeral head, lesser and greater tuberosities, bicipital groove, and proximal humeral shaft. The anatomic neck lies at the junction of the head and the tuberosities. The surgical neck lies below the greater and lesser tuberosities. The major blood supply to the humeral head is through the ascending branch of the anterior humeral circumflex artery, which penetrates the head at the bicipital groove and becomes the arcuate artery. Important structures that lie in the vicinity of the shoulder joint include the brachial plexus and axillary artery, which are anterior to the coracoid process of the scapula and humeral head. Nerves innervate muscles around the shoulder include the axillary, suprascapular, subscapular and musculocutaneous nerves. Fractures of the anatomic neck have a poor prognosis because of complete disruption of the blood supply to the head. Surgical neck fractures are common, and with these the blood supply to the head remains preserved. Within the bicipital groove lies the biceps tendon, which is covered by the transverse humeral ligament. The greater tuberosity provides attachment for the supraspinatus, infraspinatus, and teres minor muscles. The lesser tuberosity contains the attachment of the subscapularis muscle. The neck-shaft inclination angle measures an average of 145 degrees, and the humeral head is retroverted an average of 30 degrees. It is thought that the fusion of the three distinct ossification centers for the humeral head, greater and lesser tuberosities remains an area of weakness, and fractures occur in the areas corresponding to the epiphyseal scars. The acromion protects the superior aspect of the glenohumeral joint, provides origin for the deltoid muscles, and forms the lateral aspect of the acromioclavicular joint. The rotator cuff consists of four muscles: the subscapularis, supraspinatus, infraspinatus, and teres minor muscles. The teres major is not a rotator cuff muscle. The cuff muscles serve as depressors of the humeral head to allow the deltoid to efficiently abduct the humerus. The infraspinatus and teres minor are external rotators, while the subscapularis is an internal rotator of the humerus. Two other important muscles in this region are the deltoid and the pectoralis major muscles. These muscles, along with the rotator cuff, cause predictable displacement of fractures around the proximal humerus. Additionally, injury to the rotator cuff, independent of injuries to the insertion of the tuberosities, may be encountered and need to be considered when evaluating the shoulder.
Injuries to the nerves around the shoulders occur with fractures and dislocations. The brachial plexus and axillary artery can also be injured with anterior shoulder dislocations.
The most important evaluation consists of a neurovascular examination after injury around the arm and shoulder girdle. The radial nerve is commonly injured in humeral shaft fractures, particularly at the junction of the middle and distal third (Holstein-Lewis fracture). Careful evaluation of radial nerve sensory and motor function is critical. Evaluation should include sensation of the dorsal web space between the thumb and index finger, independent digital extension, and wrist extension.
Around the shoulder girdle, fractures of the proximal humerus and fracture-dislocations can on occasion result in axillary nerve and artery injuries. An axillary nerve injury from proximal humeral fracture or fracture-dislocation would result in paralysis of the deltoid muscle and anesthesia over the 'badge' region at the lateral proximal arm. Axillary artery injuries, although uncommon, generally result from fractures or fracture-dislocations in which a medial bone spike injures or penetrates the axillary artery. The index of suspicion is high if the arm, upon evaluation, shows significant color differences compared with the uninjured arm or has a bluish or cadaveric appearance. Pulses should be palpated and evaluated by Doppler studies; even if the pulse is present, if it is significantly different from the uninjured side, arterial injury should be suspected. Appropriate arterial studies should be obtained on an emergent basis or in the operating room. In late diagnosis, the outcome is determined by the neurological morbidity, even though the results of vascular reconstruction are good.
More subtle associated injuries involve the rotator cuff. This can generally be expected with fractures of the tuberosities, but it can also result from strictly soft-tissue injuries such as shoulder dislocations. Generally, rotator cuff avulsion is suspected when radiographs reveal no evidence of fracture but the patient is unable to actively externally rotate the shoulder against resistance. Evaluation of the integrity of the rotator cuff may be difficult in the acute setting, and special studies such as ultrasound, MRI, arthrogram or arthroscopy may be valuable in making this diagnosis.
HUMERAL SHAFT FRACTURE
Fractures of the shaft of the humerus usually result from a direct blow, a fall, an automobile injury, or a crushing injury. Missiles from firearms or shell fragments may pierce the arm and cause an open fracture. Other indirect means of injury, such as a fall on an outstretched upper extremity or violent muscle contracture, can cause midshaft fractures.
Fractures are classified according to whether they are open or closed and according to the level of the fracture in relation to the insertions of the pectoralis major and deltoid muscles. Characteristics of fracture and associated injury are also factors.
Clinical signs and symptoms include a shortened extremity with crepitus and pain at the diaphysis of the humerus. Confirmation should be obtained by radiographs in two planes. Both the shoulder and elbow joints should be thoroughly evaluated, clinically and radiographically, as should the neurovascular status.
The recommended treatment in isolated diaphyseal humeral fractures involves closed methods. Nonoperative methods lead to good results with high union rates. Nonoperative methods include traction by hanging casts, coaptation splints, shoulder spica casts, Velcro bracing, cast humeral bracing, and skeletal traction. Cast bracing appears to be the most effective closed treatment.
Treatment with a hanging cast involves placement of the arm in a Velcro cast with the elbow flexed to 90 degrees, with a sling fashioned over a loop placed on the radial aspect of the wrist. To correct angulation, loops may be placed on the dorsum or volar aspect of the wrist, and anterior or posterior angulation can be adjusted by the length of the sling or suspension apparatus. This treatment requires weekly radiographic evaluations; exercises both for shoulder and digital motion are helpful.
Patients with a large body habitus may develop more significant angulation at the time of healing with this technique, compared with slimmer patients. The vertical position must be maintained even at night. Spiral, comminuted, and oblique fractures have additional advantages of large fracture surfaces for ready healing. Transverse fractures may have more difficulty in healing. The musculature of the upper arm will accommodate 20 degrees of anterior angulation, 30 degrees of varus angulation and 3 cm of shortening without apparent deformity. One risk of this treatment is distraction of the fracture site and eventual nonunion.
A TU-shaped coaptation splint with cuff and collar is another method for treating humerus fractures. The more modern version of this is functional bracing, as popularized by Sarmiento. The sleeve is ready-made or custom-made from thermoplastic splinting materials and fixed with Velcro straps that can be adjusted to achieve the appropriate level of compression. Stand-alone slings or cuffs are used. Alternatively, a cast brace may be used with a hinge brace at the elbow with upper arm and forearm components. This can control flexion and protect against varus and valgus stresses as well as translational forces; it may be most useful for healing the more distal diaphyseal fractures.
Abduction Humeral Splinting and Shoulder Casting
Spica casting may be useful in certain unstable fractures, though it is a complex method of immobilization and requires close follow-up.
In special circumstances, skeletal traction has been used for humeral fractures. When treating other injuries, massive swelling, or open fractures requiring patient recumbency, skeletal traction may be indicated. Increasingly, however, multiple trauma patients are treated with aggressive internal fixation to allow early mobilization. The traction pin is inserted through the olecranon, going from a medial to lateral directions to avoid injury to the ulnar nerve. Differential traction on one side of a Steinmann pin bow or Kirschner wire bow can be used to achieve varus and valgus alignment; traction of the humerus longitudinally and flexion of the forearm and hand suspended overhead help to correct angulation. Positioning is checked with portable radiographs.
Sling and Swathe
Elderly patients may be best treated by reducing fracture motion in a sling and stockinette body swathe for comfort. Aggressive maintenance of anatomic reduction is not a critical goal in this patient population; shoulder exercises should be initiated as early as possible to avoid shoulder contractures and adhesive capsulitis.
External fixation is applicable to the humerus in the case of burns, gunshot wounds or severe comminuted open injuries with defects of skin, bone, or soft tissue. Other indications may include osteitis and infected non-union. Because of the soft-tissue envelope around the humerus, one uses external fixation only when other means of management are not applicable or appropriate. Half pins are generally inserted above and below the fracture with access to the soft-tissue defect between the pins.
Special circumstances may merit open reduction and internal fixation. Selected segmental fractures, inadequate closed reduction, "floating" elbow, bilateral humeral fractures, open fractures, multiple trauma, pathologic fractures, and trauma with associated vascular injuries requiring exploration may benefit from internal fixation. There are two general forms of internal fixation: (1) Compression plate and screw fixation using the AO techniques, with posterior, modified lateral and anterolateral surgical approaches. (2) Intramedullary nailing is especially useful in osteopenic bone, segmental and pathological fractures. In multiply injured patients, humeral stabilization, permitting mobilization, pulmonary toilet, and pain control, may be beneficial. The incidence of radial nerve palsy with acute fracture is about 16%; however, current literature does not recommend operative fixation and nerve exploration in these injuries.
FRACTURES & DISLOCATIONS AROUND THE SHOULDER
The classification of shoulder fractures and dislocations developed by Neer in 1970 is based on the work of Codman in 1934 and before that of Kocher in 1896. This comprehensive system considers the anatomy and biomechanical forces resulting in displacement of fracture fragments as they relate to diagnosis and treatment. Although useful, this system has been demonstrated to have significant interobserver variability. Fractures are classified by the number of parts that are displaced more than 1 cm or angulated more than 45 degrees. Displaced parts can include the anatomical neck, surgical neck, or tuberosities; other categories include fracture-dislocations and head-splitting injuries. The relationship of the humeral head to the displaced parts in the glenoid, as well as the blood supply, is also taken into consideration. The incidence of proximal humerus fractures has been estimated at 4–5% of all fractures. The likelihood of proximal humerus fractures increases in the older age groups (>65 years), especially with concomitant osteoporosis. The incidence of proximal humerus fractures was reported to be 105 per 100,000 people per year in 2002, while the mean patient age has increased from 73 in 1973 to 78 in 2002.
Clinical presentation is usually with pain, swelling, and ecchymosis.
Radiographic evaluation is a cornerstone for diagnosis and planning of treatment. The recommended series of radiographs is the so-called Neer trauma series, which consists of an (1) anterior-posterior view, (2) lateral view in the scapular plane, and (3) Velpeau modified axillary view. The lateral radiograph in the scapular plane is the tangential Y-view of the scapula. The combination of three of these views allows evaluation of the shoulder joint in three separate perpendicular planes. The axillary view is important for evaluating the glenoid articular surface and the relationship of the humeral head anteriorly and posteriorly. It can be obtained even in the traumatized patient, with gentle abduction of the arm, with the x-ray beam aimed toward the axilla and the plate placed above the patient's shoulder. On occasion, other studies, including CT scanning for detailing bony anatomy and MRI for detailing soft tissues such as the rotator cuff, may prove helpful.
Approximately 85% of proximal humerus fractures are minimally displaced or nondisplaced and can be treated non-operatively with a sling for comfort and early motion exercises. The remaining 15% require supplemental techniques. The mainstay of closed treatment is initial immobilization and then early motion. Physical therapy or physician-directed exercises are essential and should be started at 7–10 days if possible. Monitoring of the exercises is important to prevent a program that is either too conservative (thus causing unnecessary contractures) or too aggressive (leading to displacement, with excessive pain and swelling).
Techniques useful for the smaller percentage of fractures include closed reduction and percutaneous pinning, skeletal traction, and ORIF using a variety of techniques and implants. Good bone quality and simple fracture patterns are essential to make use of the minimal soft tissue dissection in the closed reduction and percutaneous pinning method. For severe fractures, especially four-part fractures or fracture-dislocations in elderly patients, primary prosthetic replacement of the injured humeral head is generally the treatment of choice due to the high risk of avascular necrosis of the humeral head. In younger patients ORIF may be possible even in comminuted fractures.
TWO-PART ANATOMIC NECK FRACTURES
Two-part anatomic neck fractures are rare. No single optimal method of management has been established. Closed reduction is difficult because controlling the articular fragment, which is usually rotated and angulated within the joint capsule, is difficult. The fragment can be preserved in a young (<40 years) patient with ORIF with pins or interfragmentary screws. It may be difficult to obtain adequate screw purchase without violating the articular surface. Additionally, the prognosis for head survival is poor because the blood supply is usually completely disrupted. In general, prosthetic hemiarthroplasty provides the most predictable result in the elderly (>75 years).
TWO-PART GREATER TUBEROSITY FRACTURES
Greater tuberosity fractures generally displace posteriorly and superiorly because of traction by the supraspinatus muscle. This is often associated with anterior glenohumeral dislocation. It is appropriate to attempt closed reduction, which may result in an acceptable position for the greater tuberosity. Neer has reported that displacement of the fragment by more than 1 cm is pathognomonic of a rotator cuff defect. The result of fracture healing in this position is subacromial impingement, with limitation of forward elevation and external rotation. In one series, patients with fractures that healed with more than 1 cm of displacement suffered permanent disability, whereas those with less than 0.5 cm of displacement did well. The group of patients in the midrange, 0.5–1 cm of displacement, had a 20% incidence of revision surgery for persistent pain. Open reduction and internal fixation is recommended if displacement is >5 mm with some references recommending ORIF with >3 mm displacement in the high-performance athlete as impingement symptoms may develop in these individuals. A variety of methods, including screws, pins, wires, and suture, can be used to repair the greater tuberosity. Nonabsorbable sutures can be used successfully; the rotator cuff defect can be repaired in a similar fashion. Treatment of this condition should be directed at rotator cuff repair as well as bony reconstruction. Percutaneous pinning tends to be inadequate for preventing re-displacement of greater tuberosity fractures. Despite these injuries being well recognized, there is a need for more studies to specifically evaluate the long-term outcome.
TWO-PART LESSER TUBEROSITY FRACTURES
If the displaced fragment (usually medially by subscapularis) is small, closed reduction of this rare injury is satisfactory. This fracture may be associated with posterior dislocation and may be treated by closed reduction in the acute setting. The position of immobilization in this case would be either neutral or slight external rotation. Larger fragments may require internal fixation.
TWO-PART SURGICAL NECK FRACTURES
In these conditions, both tuberosities remain attached to the head, and the rotator cuff in general remains intact. The diaphysis is often displaced anteromedially by the pull of the pectoralis major muscle. Reduction may be blocked by interposition of the periosteum, biceps tendon, or deltoid muscle, or by buttonholing of the shaft in the deltoid, pectoralis major, or fascial elements. One attempt at closed reduction is advisable; if this fails, operative intervention is recommended. If, on the other hand, the reduction is successful, percutaneous pinning under fluoroscopic control may be an excellent choice for the reducible but unstable fracture (Figure 3–17). If open reduction is required to remove displaced soft tissues, internal fixation can be accomplished by means of percutaneous pinning or intramedullary fixation in conjunction with a tension band wiring technique. In the past, an AO buttress plate has been used; however, complications including screw loosening (particularly in osteoporotic patients), retention of the plate, persistent varus, and interference with the blood supply have been reported. In the osteoporotic patient, wire or suture material for tension banding can be passed through the soft tissues and the rotator cuff, which may be superior to bone for fixation.
Another technique for internal fixation utilizes intramedullary devices such as Enders nails or Rush rods, which can be inserted through a limited deltoid-splitting incision. This may serve well to prevent displacement of the head in relation to the shaft; however, the control of rotational alignment is poor. For elderly (>75 years) or debilitated patients, this may be the best solution to achieve overall alignment with minimal surgical morbidity. Hardware removal is often necessary to treat resultant subacromial impingement. For complicated fractures, patients with osteoporotic bone, or other special circumstances, olecranon traction may be incorporated.
Avascular necrosis in three-part fractures has been reported to be as high as 27%. Open reduction and internal fixation is the treatment of choice with the aim of achieving anatomic reduction and enough stability to allow early rehabilitation. The AO buttress plate has had significant complications, including a high rate of avascular necrosis related in part to extension of soft-tissue displacement and dissection, superior placement of the plate with secondary impingement, loss of plate and screw fixation, malunion, and infections. Recent studies indicate that blade-plate devices tend to have stronger fixation than standard buttress plates. Other studies indicate that Ender nails combined with tension banding are good alternatives in osteoporotic bone. However, the properties of the locking compression plate (low stiffness and elasticity) have been shown to minimize peak stresses at the bone-implant interface. Screws, which lock into the plate, may decrease pullout in osteoporotic fractures. Finally, hemiarthroplasty should be considered in the elderly.
Open reduction and internal fixation of four-part fractures (as with three-part fractures) has generally produced unsatisfactorily high rates of complications such as avascular necrosis and malunion. Some authors recommend gentle open reduction and limited internal fixation in the active patient. In the less active or elderly (>75 years) patient, the accepted method of treatment is hemiarthroplasty, particularly because the avascular necrosis rate may be as high as 90% and the bone is usually osteoporotic. Appropriate prosthesis level and humeral retroversion, as well as the attachment of greater and lesser tuberosities, are critical in achieving a good result. Repair of any rotator cuff defects is necessary to prevent proximal migration of the humeral component as well as loss of rotator cuff power. With rehabilitation post-operatively, generally good pain relief can be expected, however function is usually limited.
Fracture-dislocations require reduction of the humeral head, and their management is generally based on the fracture pattern. These injuries usually produce impression defects or head-splitting fractures, with concomitant posterior dislocation. Management is determined by the size of the impression defect and the time of persistent locked dislocation. Fractures of less than 20% will generally be stable with closed reduction and can be treated with immobilization in external rotation for 6 weeks to restore long-term stability. If the defect is 20–50%, however, transfer of the lesser tuberosity with the subscapularis tendon into the defect by open means is indicated. With impression fractures of greater than 50% or chronic dislocations, hemiarthroplasty may be the best treatment. If concomitant glenoid destruction is present, total shoulder arthroplasty may be required.
Complex Regional Pain Syndrome (CRPS)
This is defined as an abnormal reaction to injury characterized by pain, stiffness, vasomotor changes, swelling and osteoporosis of the affected limb. It is classified into 2 types: Type 1 (formerly reflex sympathetic dystrophy), and Type 2 (formerly causalgia). Type 1 is associated with pain out of proportion to the initial injury, hyperesthesia, restricted mobility and movement disorder, skin changes (color, texture and temperature), edema, patchy osteoporosis and spreading symptoms to become more diffuse. Type 2 includes the features of Type 1 with an identified nerve lesion. CRPS can be precipitated by trauma, infection, myocardial infarction, stroke, surgery, spinal cord disorders, and sometimes, without obvious cause. The pathophysiology is not fully understood but damage to the nervous control of the affected part has been speculated. There is an increased incidence in people aged 40–60. Early diagnosis is key to try to prevent chronic changes (muscle wasting and contractures) and can be made based on history and examination. Investigations include x-rays, bone scans, nerve conduction studies, and thermography. Primarily the cause, if identified, should be treated. Physical and occupational therapy, medications (tricyclic antidepressants, vasodilators and steroids) and sympathetic blockade (chemical or surgical) can be useful.
Clinically, reflex sympathetic dystrophy has three stages, which are not completely distinct from one another. During the first, or early, stage, a burning or aching pain may be present and may be increased by external stimuli; the pain is out of proportion to the severity of the injury and physical findings. The second stage generally develops at approximately 3 months and is characterized by significant edema, cold glossy skin, and joint limitations. Radiographs may reveal diffuse osteopenia. The third, or atrophic, stage is marked by progressive atrophy of skin and muscle and significant joint contractures.
Sudeck's atrophy is a radiographic term that is extended to a clinical condition. Spotty rarefication is distinguished from generalized diffuse atrophy of bone and may occur 6–8 weeks after the onset of symptoms. Shoulder-hand syndrome is a variation of this phenomenon that often occurs with upper extremity disorders. Stiffness is characteristic, both at the shoulder and at the wrist and hand level.
Because the cause is unclear, the recommended treatment is an aggressive program of physical therapy modalities to help with soft-tissue sensitivity as well as prevention or treatment of joint contractures. Sympathetic blocks may be important. More recently, multidisciplinary pain management services that incorporate counseling, evaluation of orthopedic musculoskeletal neurologic problems, and sympathetic blocks administered typically by anesthesiologists, have proved successful in helping to limit the time and extent of disability associated with these conditions. Progressive loading of the extremity and progressive resistance-type exercises can also be of benefit in the appropriate setting.
Foot & Ankle Injuries
The appropriate investigation of any foot injury requires obtaining, initially, a precise history of the mechanism of injury. A thorough physical examination will compare the injured extremity to the uninjured contralateral side (looking for ecchymosis, swelling, or deformity), palpating carefully all points of tenderness, stressing the different joints when indicated, and assessing the neurovascular status. Associated injuries and certain systemic disorders (particularly diabetes and peripheral vascular disease) should be identified. An appropriate radiographic evaluation is mandatory. Anteroposterior and lateral views are standard. Oblique and special views are requested according to clinical suspicion. Although some fracture patterns are still best delineated by conventional tomography, CT scanning with 3D rendering has recently proved to be valuable, especially for ankle and calcaneal fractures. Volume rendering helps demonstrate structures surrounding the fracture and shaded surface display is useful for obtaining disarticulated views in intraarticular fractures. Radionuclide imaging is helpful to identify occult injuries. MRI is gaining popularity and is particularly helpful in diagnosing soft-tissue damage to the tibialis posterior tendon or gastrocnemius muscle, osteochondral fractures, and avascular necrosis.
Anatomy & Biomechanical Principles
The foot is a complex, highly specialized structure that permits weight bearing in a smooth, energy-conserving pattern. The delicate balance between bones and soft tissues is necessary for optimal function. When planning treatment of an injured foot, both need to be addressed with equal rigor. High-energy injuries, such as crush injuries, generally have a poorer prognosis, even if the bones are anatomically reduced. Scarring of soft tissues, particularly specialized tissues like the heel fat pad or the plantar fascia, prevents normal function and is often painful.
Embryologically, the foot develops from proximal to distal into three functional segments: the tarsus, metatarsus, and phalanges. Anatomically, it is divided into the hindfoot (talus and calcaneus), the midfoot (navicular, cuboid, and three cuneiforms), and the forefoot (five metatarsals and 14 phalanges). Besides skin, vessels, and nerves, the soft tissues include extrinsic tendons, intrinsic musculotendinous units, a complex network of capsuloligamentous structures, and some uniquely specialized tissues such as fat pads.
The bones, ligaments and muscles of the foot actively maintain the integrity of the 3 arches of the foot. The 2 longitudinal arches aid in weight bearing and absorbing the forces during motion. The transverse arch helps with the movements of the foot.
Classically, the plantar aspect of the foot is divided into four layers, from superficial to deep. The first layer consists of the abductor hallucis, flexor digitorum brevis, and abductor digiti minimi. The second layer is made up of the tendons of the flexor hallucis longus and flexor digitorum longus, flexor digitorum accessorius, the quadratus plantae and lumbricales muscles. In the third layer are the flexor hallucis brevis, adductor hallucis, and flexor digiti minimi muscles. The peroneus longus and tibialis posterior tendons, as well as the unipennate plantar and bipennate dorsal interossei muscles, comprise the fourth and deepest layer.
These 28 bones, 57 articulations, and extrinsic and intrinsic soft tissues work harmoniously as a unit resembling functionally a ball and socket to allow walking, running, jumping, and accommodation of irregular surfaces with a minimal expense of energy.
Energy-effective gait requires optimal integration of all segments involved in locomotion, and proper coordination involves extremely complex pathways. Fluid motion minimizes energy expenditure, and a lot of the fine-tuning to attain this goal occurs in the foot. For example, the subtalar joint everts at heel strike, unlocking the midtarsal joint. Increasing the flexibility of the foot allows for better energy absorption and foot-to-ground accommodation. Conversely, the subtalar joint inverts at push-off, locking the midtarsal joint. This creates a rigid lever more mechanically advantageous for forward propulsion.
This superficial overview of the anatomy and biomechanical principles of the foot serves only to stress the complex relationship between bone and soft-tissue structures. Restoration of this relationship is often challenging, but is the goal of treatment of foot injuries.
FRACTURES COMMON TO ALL PARTS OF THE FOOT
Also known as stress, march, or insufficiency fractures, fatigue fractures occur when damage from cyclical loading of a bone overwhelms its physiologic repair capacity. Repetitive stress stimulates an attempt to strengthen areas of bone that are experiencing excessive stress. This process begins with resorption of bone to make room for the deposition of new stronger bone. Continued loading can lead to gross failure of the bone weakened by resorption.
This disorder is commonly seen in young active adults involved in vigorous and excessive exercise. A history of a single significant injury is usually lacking. Sites of fracture are most frequently the metatarsals and the calcaneus, but fatigue fractures can be found anywhere.
Incipient pain of varying intensity at rest is then accentuated by walking. Swelling and point tenderness are likely to be present. Depending on the stage of progress, radiographs may be normal or may show an incomplete or complete fracture line or only extracortical callus formation that can be mistaken for osteogenic sarcoma. Radionuclide imaging, CT and MRI can be helpful for occult fractures. Persistent unprotected weight bearing may cause arrest of bone healing and even displacement of the fracture fragment.
Treatment is by protection in either a short leg cast, walking boot or a heavy stiff-soled shoe. Weight bearing is restricted until pain has subsided and restoration of bone continuity is confirmed radiographically, usually within 3–4 weeks.
Multiple High-Energy Injuries
Violent forces applied to the foot may cause more extensive damage than initially appreciated. Certain mechanisms of injury tend to produce specific patterns of lesions, and a high index of suspicion is necessary so as not to overlook some of the associated bony or ligamentous injuries.
High-energy fractures are often open, and the basic principles of open fracture management should be applied. The objectives are to preserve circulation and sensation (particularly of the plantar region), maintain a plantigrade position of the foot, prevent or control infection, preserve plantar skin and fat pads, preserve gross motion of the different joints (both actively and passively), achieve bone union, and, ultimately, preserve fine motion. Fasciotomies of the severely injured foot may be necessary to avoid compartment syndromes and their serious sequelae.
Early stabilization of multiple fractures and dislocations will simplify wound management. This can be accomplished through external fixation or internal fixation with K-wires, plates, or screws. Early soft tissue coverage with local or free flaps is also beneficial.
Neuropathic Joint Injuries & Fractures
Fractures and other foot disorders often present in the patient with Charcot arthropathy. Neuropathic fractures are frequently seen with diabetes, tabes dorsalis, syringomyelia, peripheral nerve injury or degeneration, leprosy, and other rare neurologic syndromes.
The potential for bone healing is normal if no other comorbidities exist. It has been found, however, that healing of fractures is often delayed in this patient group. Protection, rest, and elevation can result in union without deformity. Open reduction and internal fixation is sometimes necessary. Rarely, arthrodesis is indicated; however, the rate of nonunion is higher than for normal joints.
FOREFOOT FRACTURES & DISLOCATIONS
Metatarsal Fractures & Dislocations
Fracture of the metatarsals and dislocation of the tarsometatarsals are frequently caused by a direct crushing or indirect twisting injury to the forefoot. Besides osseous and articular injury, complicating soft tissue lesions are often present. With severe trauma, circulation may be compromised from injury to the dorsalis pedis artery, which passes between the first and second metatarsals.
Metatarsal Shaft Fractures
Undisplaced fractures of the metatarsal shafts cause only temporary disability, unless failure of bone healing occurs. Displacement is rarely significant when the first and fifth metatarsals are not involved because they act as internal splints.
These fractures can be treated with a hard-soled shoe with partial weight bearing, or, if pain is marked, a short leg walking cast.
For displaced fractures of the shaft, it is of paramount importance to correct angulation in the longitudinal axis of the shaft. Residual dorsal angulation causes prominence of the metatarsal head on the plantar surface. The concentrated local pressure may produce a painful skin callus. Residual plantar angulation of the first metatarsal will transfer weight to the heads of the second and third metatarsals. After reduction of angular deformity, a cast should be well molded to the plantar surface to minimize recurrence of deformity and support the transverse and longitudinal arches. If significant angulation or intraarticular displacement persists, open or closed reduction and internal fixation should be considered.
Metatarsal Neck & Head Fractures
Fractures of the metatarsal "neck" are close to the head but remain extraarticular. Dorsal angulation is common and should be reduced to avoid reactive skin callus formation from pressure on the plantar skin. Intraarticular fractures of the metatarsal heads are rare. Even when they heal in a displaced position, some remodeling occurs and the functional outcome is surprisingly good. The indications for open reduction with or without internal fixation remain controversial.
Closed reduction of metatarsal fractures is best achieved by applying traction (Chinese finger traps) to the involved toes. Reduction is evaluated with intraoperative radiographs, and if judged unacceptable, ORIF with K-wires or plates and screws is indicated. Unstable reductions should also undergo percutaneous pinning under fluoroscopic imaging.
Tarsometatarsal (Lisfranc) Dislocations
The stability of the tarsometatarsal joint complex relies in part on strong ligamentous structures and in part on the bony architecture itself. The base of the second metatarsal is recessed proximally to the base of the other metatarsals in a cleft between the first and third cuneiforms, thus "locking" the joint. Injuries to this structure should alert the clinician to the possibility of other injuries along the entire tarsometatarsal complex.
The original injury, described by Napoleon's field surgeon Lisfranc, was attributed to a soldier falling from his horse with his foot trapped in the stirrup. The mechanism of the injury was an axial load acting on a hyper-plantarflexed foot. Three commonly occurring patterns of this injury are identified: total incongruity, partial incongruity, and divergent (Figure 3–18). The medial border of the second and fourth metatarsals should align with the medial borders of the middle cuneiform and the cuboid, respectively. Associated soft-tissue damage is almost always significant, with open wounds, vascular impairment, swelling, and blistering.
An attempt at closed reduction should be made as soon as possible; however, open reduction is often required. Gentle manipulation can be successful; however, residual instability is common. Postreduction radiographs are obtained, and if anatomic reduction is not obtained, then ORIF with K-wires on the lateral side of the foot to preserve mobility and screws on the medial side of the foot is indicated. The foot is then immobilized and elevated. Timing of hardware removal is controversial with some authors recommending 3 months and others recommending 6 months. Prognosis depends on maintenance of anatomical reduction. However, one study has reported that even in cases where anatomic reduction, normal walking patterns and excellent radiographic results were accomplished post tarsometatarsal fracture dislocation, subjective patient outcomes were less than satisfactory.
Some tarsometatarsal injuries present late (>3–4 weeks), when the healing process will prevent successful closed treatment. If displacement and deformity are significant, open reduction is indicated, but the patient should be advised to expect some residual joint stiffness. If displacement is minimal, it may be better to defer surgery and direct treatment toward functional recovery. Reconstructive operations can be planned more suitably once residual disability is established.
Complications of this injury include chronic foot swelling, residual deformity making shoe fitting difficult, painful degenerative joint disease, and reflex sympathetic dystrophy. Arthrodesis should be considered for symptomatic post-traumatic arthritis.
Fracture of the Base of the Fifth Metatarsal
Three distinct patterns occur: (1) avulsion fracture of a variably sized portion of the tuberosity (styloid process) that may, on rare occasions, involve the joint between the cuboid and the fifth metatarsal; (2) acute Jones fracture involving the intermetatarsal joint(located at the metaphysial-diaphysial junction), and (3) transverse fracture of the proximal metatarsal diaphysis.
Avulsion fractures usually occur after adduction injury to the forefoot. The peroneus brevis muscle may pull and displace the fractured fragment proximally.
Symptomatic treatment is most often successful in a hard-soled shoe, and bony healing rarely fails to occur. Nonunions are rarely symptomatic but can be treated by internal fixation or fragment excision. In the rare event of a significant displaced intraarticular component, ORIF may be indicated.
Acute Jones fractures are best treated in a non-weight bearing cast for 6-8 weeks. Some authors recommend acute ORIF of Jones fractures in the high-performance athlete. Proximal diaphyseal fractures or "chronic Jones fractures" are most probably secondary to fatigue failure. Again, conservative treatment in a non-weight–bearing short leg cast for 6 weeks will usually bring healing of the fracture. Nonunions do occur (due to the poor inherent blood supply) and are often symptomatic. If there is no evidence of bone healing at 12 weeks, internal fixation and bone grafting are recommended.
Fractures & Dislocations of the Phalanges of the Toes
Fractures of the phalanges of the toes are most commonly caused by a direct force such as a crush injury. Spiral or oblique fractures of the shaft of the proximal phalanges of the lesser toes may occur as a result of an indirect twisting injury. The injury should be assessed in terms of deformity, soft tissue injury, neurovascular status and radiographically.
Comminuted fracture of the proximal phalanx of the great toe, alone or in combination with fracture of the distal phalanx, is a disabling injury. Because wide displacement of fragments is not likely, correction of angulation and support by a splint usually suffices. A weight-bearing removable cast boot may be useful for relief of symptoms arising from associated soft-tissue injury. Spiral or oblique fracture of the proximal or middle phalanges of the lesser toes can be treated adequately by binding the involved toe to the adjacent uninjured toe (buddy taping). Comminuted fractures of the distal phalanx are treated as soft-tissue injuries.
Dislocation of the metatarsophalangeal joints and dislocation of the proximal interphalangeal joints usually can be reduced by closed manipulation. These dislocations are rarely isolated and usually occur in combination with other injuries to the forefoot.
Fracture of the Sesamoids of the Great Toe
Fractures of the sesamoid bones of the great toe are rare but may occur as a result of a crushing injury. These injuries must be differentiated from a bipartite sesamoid by comparing radiographs of the contralateral uninvolved foot.
Undisplaced fractures require no treatment other than a hard-soled shoe or metatarsal bar. Displaced fractures may require immobilization in a walking boot or cast, with the toe strapped in flexion. Persistent delay of bone healing may cause disabling pain arising from arthritis of the articulation between the sesamoid and the head of the first metatarsal. If conservative modalities have been exhausted excision of the sesamoid may be necessary; however, this should be a last resort treatment.
MIDFOOT FRACTURES & DISLOCATIONS
Avulsion fractures of the tarsal navicular may occur as a result of severe midtarsal sprain and require neither reduction nor elaborate treatment. Avulsion fracture of the tuberosity near the insertion of the posterior tibialis tendon is uncommon and must be differentiated from a persistent ununited apophysis (accessory navicular) from the supernumerary sesamoid bone, or os tibiale externum. Dorsal lip avulsions also occur.
Body fractures occur either centrally in a horizontal plane or, more rarely, in a vertical plane. They are occasionally characterized by impaction. Non-comminuted fractures with displacement of the dorsal fragment can be reduced. Closed manipulation by strong traction on the forefoot and simultaneous digital pressure over the displaced fragment can restore normal position. If a tendency to re-displace is apparent, this can be counteracted by temporary fixation with a percutaneously inserted Kirschner wire. Non-weight–bearing immobilization in a cast or splint is required for a minimum of 6 weeks. Comminuted and impacted fractures cannot be anatomically reduced in a closed manner. Where fragments involve >25% of the bone, ORIF may be required to prevent dorsal subluxation of the navicular fragment. Bone graft may be used for depressed areas. Some authorities offer a pessimistic prognosis for comminuted or impacted fractures. It is their contention that even though partial reduction has been achieved, posttraumatic arthritis supervenes, and that arthrodesis of the talonavicular and naviculocuneiform joints will be ultimately necessary to relieve painful symptoms.
The navicular is also a frequent site of fatigue fracture in runners. CT or radionuclide imaging is often necessary to make the diagnosis. Six weeks in a non-weight–bearing short leg cast is usually required for fracture healing.
Cuneiform & Cuboid Bone Fractures
Because of their relatively protected position in the midtarsus, isolated fractures of the cuboid and cuneiform bones are rarely encountered. Avulsion fractures occur as a component of severe midtarsal sprains. Extensive fractures usually occur in association with other injuries of the foot and often are caused by severe crushing. A "nutcracker" fracture is a compression fracture of the cuboid and, when associated with lateral column shortening, can be treated by lateral column lengthening, ORIF, and bone grafting.
Midtarsal dislocation through the naviculocuneiform and calcaneocuboid joints, or more proximally through the talonavicular and calcaneocuboid joints (Chopart's joint), may occur as a result of a twisting injury to the forefoot. Fractures of varying extent of adjacent bones are frequently associated.
When acute treatment is administered, closed reduction by traction on the forefoot and manipulation is generally effective. If reduction is unstable and displacement tends to recur upon release of traction, stabilization for 4 weeks by percutaneously inserted Kirschner wires is recommended.
HINDFOOT FRACTURES & DISLOCATIONS
Three fifths of the talus is covered with articular cartilage. The blood supply enters the neck area and is tenuous. Fractures and dislocations may disrupt this vascularization, causing delayed healing or avascular necrosis.
Major fractures of the talus commonly occur either through the body or the neck. Head fractures involve essentially a portion of the neck with extension into the head. Indirect injury is usually the cause of most fractures of the talus. Compression fracture or impaction of the tibial articular surface may be caused by the initial injury or may occur later in association with complicating avascular necrosis.
Fractures of the Neck of the Talus
The most common mechanism of talar neck fracture is hyperdorsiflexion with an axial load causing impingement between the talar neck and tibia. The most widely used classification is that of Hawkins:
Type 1: Nondisplaced vertical fracture
Type 2: Displaced fracture of the talar neck with subluxation or dislocation of the subtalar joint
Type 3: Displaced fracture of the talar neck with dislocation of the body of the talus from both the tibiotalar and subtalar joints
Type 4: Later, a type 4 fracture was described by Canale and Kelly to include rare variants which are essentially type 3 injuries with talonavicular subluxation or dislocation (Figure 3–19).
This classification is of prognostic value for avascular necrosis of the body: 0–13% for type 1 fractures, 25–50% for type 2 fractures, 80–100% for type 3 fractures, and 100% for type 4.
Less frequent complications of talar neck fractures include infection, delayed union or nonunion, malunion, and osteoarthritis of the tibiotalar and subtalar joints.
Treatment is aimed at minimizing the occurrence of these complications. Type 1 fractures are best treated with a non-weight–bearing below-knee cast for 2–3 months until clinical and radiologic signs of healing are present. Closed reduction is first attempted for type 2 fractures and, if this is successful in attaining anatomic alignment, treatment is as for a type 1 fracture. In about 50% of cases, closed reduction is unsuccessful and open reduction and internal fixation with K-wires, pins, or screws is indicated. Closed reduction of types 3 and 4 fractures is almost never successful; ORIF is the rule. The postoperative regimen is the same as above. Progressive weight bearing will be allowed after fracture union if there is no avascular necrosis of the body. This can be determined on the anteroposterior radiograph of the ankle, taken out of the cast by the eighth week, if there is a subchondral lucency in the dome of the talus. This "Hawkins' sign" is possible only if the talar body is vascularized. The most sensitive method, however, appears to be MRI, which can, as early as 3 weeks, clearly define the extent of osteonecrosis in the body of the talus. When avascular necrosis is evident, revascularization can take up to 3 years. To avoid collapse of the talar dome during this process, partial weight bearing is recommended. One should also remember that there is not a direct correlation between avascular necrosis and permanently disabling symptoms.
Fractures of the Body of the Talus
Talus body fractures occur mainly due to shear and axial compression forces. The Hawkins classification describes 5 types of fracture:
Type 1: Osteochondral fracture
Type 2: Coronal, sagittal or horizontal fracture
Type 3: Posterior process fracture
Type 4: Lateral process fracture
Type 5: Crush fracture of the body
Minimally displaced fractures of the talar body are not likely to cause disability if immobilization is continued until union is restored. If significant displacement occurs, the proximal fragment is apt to be dislocated from the subtalar and ankle joints. Associated fractures of the malleoli, talar neck and calcaneus occur frequently. Anterior-posterior, mortise, lateral and Broden (45 degrees internal oblique) views aid radiographic assessment of the injury and enable the quantification of articular surface involvement and displacement. CT is also used to assess comminution and associated fractures.
Reduction by closed manipulation is often difficult but is best achieved by traction and forced plantar flexion of the foot. Immobilization in a short leg cast, with the foot in plantar flexion for about 8 weeks, should be followed by further casting with the foot out of equinus until the fracture line has been obliterated and new bone is present on serial radiographs. Even though prompt adequate reduction is obtained by either closed manipulation or open reduction, extensive displacement of the proximal body fragments may be followed by avascular necrosis. If reduction is not anatomic, delayed healing of the fracture may follow, and posttraumatic arthritis is a likely sequela. If this occurs, arthrodesis of the ankle or subtalar joints may be necessary to relieve painful symptoms.
Osteochondral Fractures of the Talar Dome
These can occur with any type of injury to the ankle area, including sprains. A history of trauma is usual, but not always, present. Classically, lesions of the medial aspect of the talar dome are thicker, more extensive, and less likely to displace, whereas the lateral lesions are shallower, more wafer-like, and more prone to be displaced and symptomatic.
Initial radiograph evaluation often does not demonstrate these lesions. Presently, MRI is the best imaging modality for osteochondral talar lesions.
The Berndt and Harty classification is generally used:
Stage 1: Localized compression
Stage 2: Incomplete separation of the fragment
Stage 3: Completely detached but nondisplaced fragment
Stage 4: Completely detached, displaced fracture
A modified version of this classification to include MRI findings can help radiologists better classify these fractures.
Symptomatic stage 1, 2, and 3 lesions are usually initially treated conservatively with immobilization and restricted weight bearing. Healing is monitored radiographically with anterior-posterior and mortise views. Lesions that fail conservative treatment and all stage 4 lesions require surgical treatment. Reduction and pinning or fixation with screws and excision with or without drilling have been recommended. Arthroscopic management seems to give as good a result as arthrotomy, with fewer complications. Degenerative disease of the tibiotalar joint is a frequent long-term complication.
Compression fractures of the talar dome are rare injuries. They cannot be reduced by closed methods. If open reduction, with or without bone grafting, is elected, prolonged protection from weight bearing is the best means of preventing collapse of the healing area.
Other Talar Fractures
Other rare fractures include those of the lateral (snowboarders' fracture) or posterior process (Shepherd's fracture) or its lateral or medial tubercles. These fractures may be difficult to demonstrate. Special radiographs and radionuclide imaging can be very helpful.
Conservative treatment usually gives excellent results; however, consideration should be given to open reduction and fixation or fragment excision of displaced fractures and those involving the articular surface.
Subtalar dislocation, also called peritalar dislocation, is the simultaneous dislocation of the talocalcaneal and talonavicular joints. Inversion injuries result in medial dislocations (85%), whereas eversion injuries result in lateral dislocations (15%). Anterior and posterior dislocations are rare.
Prompt gentle closed reduction is usually successful. Immobilization in a non-weight–bearing short leg cast for 6 weeks is usually satisfactory. Soft-tissue interposition, particularly of the posterior tibial tendon, may prevent closed reduction. Open reduction, with or without internal fixation, is then indicated.
Total Dislocation of the Talus
This injury usually results from high-energy trauma, and most are open dislocations. Despite adequate prompt reduction and thorough wound debridement, the complication rate is extremely high, including persistent infection and avascular necrosis. Talectomy and tibiocalcaneal fusion is a frequent final outcome.
The calcaneus (os calcis) functions to provide support for body weight, maintains the lateral column of the foot and acts as a lever arm for the calf muscles. A fracture causing an impairment of any of the above functions will result in significant gait abnormalities. The most common mechanism of fracture is high-energy axial loading driving the talus downwards (e.g. a fall from a height). Ten percent of calcaneal fractures are associated with compression fractures of the thoracic or lumbar spine, and 5% are bilateral. Comminution and impaction are common features.
SYMPTOMS AND SIGNS
Pain is usually significant but may be masked by associated injuries. Swelling, deformity, and blistering of the skin occur frequently during the first 36 hours as a result of the severe damage to surrounding soft tissues. The heel pad in particular is a highly specialized fatty structure that acts as a hydraulic cushion. Major disruptions of the heel pad lead to persistent pain and deformity and can produce poor functional results in spite of adequate bony healing.
Initial radiographs include three views: anteroposterior, lateral, and axial projection (Harris view). Disruption of Böhler's angle and the angle of Gissane can be determined from initial radiographs (Figure 3–20). Oblique or Broden's views are useful to demonstrate subtalar joint incongruity. CT scanning is the diagnostic tool of choice and will further delineate fracture patterns and occult injuries. Bone scanning may be useful to diagnose a stress fracture.
Various classifications have been advocated. Sanders has developed a classification system based upon coronal CT images (Figure 3–21). This classification has been found to be useful in both treatment and prognosis. Type I fractures are nondisplaced articular fractures. Type II fractures are two-part fractures of the posterior facet and are divided into A, B, and C based upon the location of the fracture line. Type III fractures are three-part fractures with a centrally depressed fragment, also divided into A, B, and C. Type IV fractures are four-part articular fractures with extensive comminution. To simplify classification, calcaneus fractures can be divided into intraarticular and extraarticular fractures. Intraarticular fractures occur frequently (75%), have a poorer prognosis, and are further subdivided into nondisplaced, tongue-type, joint depression and comminuted. Extraarticular fractures are rare (25%) and generally have a better prognosis.
The subtalar joint is almost always involved, and occasionally the fracture line extends into the calcaneocuboid joint. Isolated fractures of the calcaneocuboid joint are rare.
TYPES OF FRACTURES
These fractures are successfully treated by protection from weight bearing, for 4–8 weeks, until clinical and radiographic signs of healing are present.
This fracture pattern (Figure 3–22) involves the subtalar joint with a posterior extension in the transverse plane, creating a dorsal fragment.
This fracture pattern (Figure 3–23) creates a separate fragment of the posterior facet with joint incongruity.
Some fracture patterns create such comminution and impaction that they defy classification. They all have in common significant soft tissue injury and subtalar joint incongruity.
Treatment of displaced intraarticular fractures remains controversial. As already stated, the final outcome is much dependent on soft-tissue as well as bony healing. For the severely displaced fracture, the bursting nature of the injury may defy anatomic restoration.
Some surgeons still advise conservative treatment.
Other surgeons advocate early closed manipulation of displaced intraarticular fractures, to at least partially restore the external anatomic configuration of the heel region. Internal fixation with percutaneous pins may be performed. This is particularly successful for non-comminuted tongue-type fracture patterns. An axial pin is inserted in the tongue fragment, which is then disimpacted and reduced. The pin is then pushed further to stabilize the fracture (Essex-Lopresti technique). Open reduction and internal fixation with pins, screws, or plates, with or without bone grafting, has gained acceptance. The aim of ORIF is to restore Böhler's angle and improve heel alignment through stable fixation. A recent study has demonstrated a correlation between restoration of Böhlers angle and clinical outcome. Some authors advocate primary subtalar arthrodesis for severely comminuted fractures.
The most significant complication is posttraumatic degenerative arthritis. When only the subtalar joint is involved, talocalcaneal fusion is recommended. When the calcaneocuboid joint is also involved, triple arthrodesis should be performed. The rate of wound complications after ORIF has been reported to range from 0 to 12%. Other complications include compartment syndrome, neurovascular and tendon injury, heel pad pain and exostosis and, malunion. Compartment syndrome features in 10% of patients and should be excluded during the examination.
Because posttraumatic joint disease is usually not a complication of these fractures, the final outcome is usually much better than that for intraarticular fractures. Fractures can affect any part of the bone.
TYPES OF FRACTURES
Fracture of the Tuberosity
Isolated fractures of the calcaneal tuberosity are rare.
These fractures may be limited to the superior portion of the region of the former apophysis (avulsion type) or extend toward the subtalar joint in the substance of the tuberosity (beak type). A pull from the Achilles tendon may displace the fragment proximally, and reduction may be indicated. If the fragment is big enough, the application of skeletal traction can reduce it to the plantar-flexed foot, and the pin is incorporated in a long leg cast with the knee flexed at 30 degrees. For smaller fragments or when closed reduction is unsuccessful, ORIF with screws, wires, or pullout sutures is indicated.
Vertical fracture occurs in the sagittal plane somewhat medially through the tuberosity. Because the minor medial fragment normally is not widely displaced, plaster immobilization is not required but may reduce pain. Limitation of weight bearing with crutches will also be helpful.
Non-Articular Fracture of the Body
Comminuted fractures of the entire tuberosity, sparing the subtalar joint, are rare. Proximal displacement of the fragments may decrease the subtalar joint angle, but symptomatic degenerative arthritis is not an important sequela, even though some joint stiffness may persist permanently. Marked displacement may benefit from closed reduction to improve heel contour.
Fracture of the Sustentaculum
A rare injury, fracture of the sustentaculum tali should be suspected in the patient with a history of eversion injury and pain below the medial malleolus, which is often accentuated by passive hyperextension of the great toe. Interposition of the flexor hallucis longus tendon may even prevent reduction. Conservative treatment is usually successful. In the rare instance of symptomatic nonunion, careful excision is indicated.
Fracture of the Anterior Process
Usually caused by forced inversion of the foot, it must be differentiated from midtarsal and ankle sprains. The firmly attached bifurcate ligament avulses a bony flake from the anterior process. Maximal tenderness and swelling occurs midway between the tip of the lateral malleolus and the base of the fifth metatarsal. A lateral oblique radiograph will demonstrate the fracture line.
Treatment is by a non-weight–bearing short leg cast in neutral position for 4 weeks.
Fracture of the Medial Process
This process gives origin to the abductor hallucis and part of the flexor digitorum brevis muscle and can be avulsed in eversion-abduction injuries. Conservative treatment with a well-molded short leg walking cast is usually successful.
Posttraumatic arthritis of the subtalar joint has already been mentioned as the most frequent complication of calcaneal fractures. Other complications include peroneal tendinitis, bone spurs, calcaneocuboid arthritis, and nerve entrapment syndromes (medial or lateral plantar branches and sural nerve, either from posttraumatic or postsurgical scarring).
ANKLE FRACTURES & DISLOCATIONS
Fractures and dislocations of the ankle are among the most common injuries treated by orthopedic surgeons. This injury is seen in all age groups, with a slightly different fracture pattern in children and adolescents than with adults. The ankle joint itself is limited to one plane of motion: plantarflexion and dorsiflexion in the sagittal plane. With incorporation of the motion of the subtalar joint (which allows for inversion and eversion in the coronal plane), the foot is able to move in a complex and varied arc in relationship to the leg.
Anatomy & Biomechanical Principles
The distal tibia and fibula are structures easily palpable because of their minimal soft-tissue coverage. The muscles, tendons, and neurovascular structures in the leg are generally grouped into anterior, lateral, and posterior compartments. In the distal leg, the compartments are predominantly tendinous, with little muscle being present. The tibia has a tubular diaphysis with wide flaring metaphyses both proximally and distally. The shape and size of the bone are markedly different in the proximal versus distal metaphysis. A cross-section of the midshaft tibia is approximately triangular, whereas a cross-section of the distal metaphysis is rounder and smaller in diameter. The inner and distal articular surfaces of the distal tibia and fibula form the ankle mortise (a uniplanar hinge joint). The ankle mortise serves as the "roof" over the talus. The articular portions of the lateral and medial malleoli serve as constraining buttresses to allow for controlled plantarflexion and dorsiflexion in the ankle mortise. This geometric configuration resists rotation of the talus in the ankle mortise. Further constraint and stability are provided by the interosseous membrane, the ankle capsule, the deltoid ligament medially and the lateral ligamentous complex (composed of the anterior talofibular, calcaneofibular, and posterior talofibular ligaments). The syndesmotic ligament connects the tibia to the fibula at the level of the tibial plafond. It allows for 1–2 mm of mortise widening, with ankle plantarflexion and dorsiflexion, accommodating the geometry of the talar dome. The bony architecture of the mortise also provides some constraint to posterior subluxation of the talus. This is provided by the cup-shaped tibial plafond and the slightly increased width of the talar dome anteriorly as compared with posteriorly.
The distal tibia also serves to absorb the compressive loads and stress placed on the ankle. The internal trabecular pattern of the bone helps transmit, diffuse, and resorb the compressive forces. Cross-sectional studies have shown that reduced activity and old age lead to resorption of cancellous bone, thereby decreasing the compressive resistance of the distal tibia.
Fracture-dislocations of the ankle are frequently referred to as bimalleolar (fractures of the medial and lateral malleoli) or trimalleolar (fractures of the medial, lateral, and posterior malleoli). Fracture of the lateral malleolus with complete rupture of the deltoid ligament (Dupuytren's fracture) or fracture of the medial malleolus with complete disruption of the syndesmosis and a proximal fibular shaft fracture (Maisonneuve's fracture) are also considered bimalleolar fractures on a functional basis.
The purpose of any classification scheme is to provide a means to better understand the extent of injury, describe an injury, and determine a treatment plan. Presently, the two most widely used classification schemes for describing ankle fractures are the Lauge-Hansen and Weber classifications.
In 1950, Lauge-Hansen described a classification system based on mechanism of injury that described over 95% of all ankle fractures (Figure 3–24). By stressing freshly amputated limbs in combinations of supination, pronation, adduction, abduction, and external rotation, he was able to describe nearly all fracture patterns. Pronation and supination refer to the position of the patient's foot at the instance of injury, while adduction, abduction, and external rotation refer to the vector of the force that is applied. Thus, four mechanisms of injury were described for ankle fractures: (1) supination adduction, (2) supination-external rotation, (3) pronation abduction, and (4) pronation-external rotation. Lauge-Hansen later added a fifth type of injury, the pronation dorsiflexion injury, in order to include a mechanism for tibial plafond fractures. This fifth type is caused by a compression-type injury.
The Weber classification is much simpler, and is based on the level at which the fibular fracture occurs.
Type A: Fracture in which the fibula is avulsed distal to the joint line. Thesyndesmotic ligament is left intact, and the medial malleolus is either undamaged or is fractured in a shear-type pattern, with the fracture line angulating in a proximal-medial direction from the corner of the mortise.
Type B: Spiral fracture of the fibula beginning at the level of the joint line and extending in a proximal-posterior direction up the shaft of the fibula. Parts of the syndesmotic ligament complex can be torn, but the large interosseous ligament is usually left intact so that no widening of the distal tibiofibular articulation occurs. Complete syndesmotic disruptions, however can result from this fracture pattern.
The medial malleolus can either be left intact or sustain a transverse avulsion fracture. If the medial malleolus is left intact there can be a tear of the deltoid ligament. Avulsion fracture of the posterior lip of the tibia (posterior malleolus) can also occur.
Type C: Fracture of the fibula proximal to the syndesmotic ligament complex, with consequent disruption of the syndesmosis. Medial malleolar avulsion fracture or deltoid ligament rupture is also present. Posterior malleolar avulsion fracture can also occur. Figure 3–23 shows a comparison of the Weber and Lauge-Hansen schemes.
Many studies have stated that the above classification systems have failed to encompass all possible types of fracture. Furthermore, reproducibility is moderate and the fracture configuration is not predictive of prognosis. In fact, initial talar displacement and number of malleoli injured seem to be important for determining prognosis.
The AO classification system has better reproducibility as it is based on radiographic findings. However, it too cannot clearly separate fracture configurations to identify those that require surgical treatment.
Four criteria should be met for the optimal treatment of ankle fractures: (1) dislocations and fractures should be reduced as soon as possible; (2) all joint surfaces must be precisely restored; (3) the fracture must be held in a reduced position during the period of bony healing, and (4) joint motion should be initiated as early as possible.
If these treatment goals are met, a good outcome can be expected, keeping in mind that disruption of the articular cartilage results in permanent damage.
Previous studies have demonstrated that the ankle has the thinnest articular cartilage but the highest ratio of joint congruence to articular cartilage thickness of any of the large joints. This suggests that loss in congruity of the ankle joint following fracture will be poorly tolerated and lead to posttraumatic arthritic changes. Thus, it is important to obtain anatomic reduction of the articular surfaces of the ankle after a fracture. A lateral talar shift of as little as 1 mm will decrease surface contact at the tibiotalar joint by 40%.
Initial treatment of ankle fractures should include immediate closed reduction and splinting, with the joint held in the most normal position possible to prevent neurovascular compromise of the foot. An ankle joint should never be left in a dislocated position. If the fracture is open, the patient should be given appropriate intravenous antibiotics and taken to the operating room on an urgent basis for irrigation and debridement of the wound, fracture site, and ankle joint. The fracture should also be appropriately stabilized at this time.
With the advent of excellent results obtained from the techniques of open reduction and rigid internal fixation as developed by the AO group, the standard of care for displaced ankle fractures has become operative intervention. Exceptions to this rule are nondisplaced, isolated Weber type B lateral malleolar fractures (supination eversion stage 2), distal fibular avulsion fractures, fractures in nonambulatory (ie, paraplegic) patients, and fractures in patients for whom the surgical risks are greater than the consequences of non-anatomic reduction of the fracture. The isolated previously described lateral or medial malleolar fractures may be treated in a well-molded short leg walking cast for 6 weeks. Unstable ankle fractures treated by immobilization should be placed in a long leg cast with the knee flexed to prevent weight bearing on the involved limb. Most non-displaced medial malleolar fractures should be treated with internal fixation because of the risk of nonunion, when these fractures are treated non-operatively.
When performing ORIF of ankle fractures, several principles must be followed. It is important to gently handle the soft tissues about the ankle so as to minimize the risks of infection and wound-healing problems. In the treatment of bimalleolar and trimalleolar fractures, the lateral malleolus should usually be reduced and internally fixed first. This has two benefits: (1) it helps to correctly restore the original limb length, and (2) because of the strong ligamentous connections between the lateral malleolus and talus (anterior and posterior talofibular ligaments), initial fixation of the lateral malleolus will correctly position the talus in the mortise. If a long oblique fracture of the lateral malleolus is present, fixation can sometimes be adequately obtained with two interfragmentary screws. More commonly, however, further fixation, in the form of a neutralization plate and screws, is required.
When performing ORIF of the medial malleolus, it is important to remove any soft tissue or periosteum interposed in the fracture site. It is also preferable to fix the medial malleolus with either two cancellous-type screws or a screw and a K-wire to provide rotational control of the medial malleolar fragment.
The necessity for fixation of the posterior malleolar fragment is dependent on several factors. After the lateral and medial malleolar fractures have been internally fixed, ligamentotaxis often will anatomically reduce the posterior malleolar fragment. If this fragment represents less than 25% of the articular surface of the tibial plafond and there is less than 2 mm of displacement, internal fixation is not always required. If the fragment does not reduce on the intraoperative radiograph with ligamentotaxis, or if the fragment represents more than 25% of the articular surface, most authors agree that it should be internally fixed. Several methods have been described for this, utilizing either direct fixation posteriorly via the lateral or medial incisions, or a lag screw from anterior to posterior.
Following surgery, the limb is placed in a bulky sterile dressing with plaster splints from the ball of the foot to the proximal calf to allow for wound healing. The ankle is kept in neutral position to prevent equinus deformity. After the sutures are removed at 1–2 weeks, the surgeon must decide whether to begin early mobilization of the ankle joint. If the patient is reliable and stable fixation was achieved at the time of surgery, then early range of motion may be initiated, keeping the patient on crutches and not allowing weight bearing. If there is a question about patient reliability or stability of fixation, the limb can be placed in a short leg cast for added protection. Usually at 6 weeks all immobilization is discontinued and weight bearing is slowly advanced. Physical therapy often helps promote ankle motion, strengthening, and regained ankle proprioception.
TIBIA & FIBULA INJURIES
The tibial diaphysis is straight and triangular in cross-section. Its anteromedial border and anterior crest are palpable throughout the entire length of the bone, and are useful landmarks for closed reduction techniques and cast molding with pressure relief, as are the palpable fibular head, distal third of the fibula, medial malleolus and patellar tendon. The distal half of the leg has more tendons and less muscle than the proximal half, and thus soft tissue coverage and blood supply of the distal tibia is more precarious than its proximal portion. The fibula transmits approximately one sixth of the axial load from the knee to the foot and the tibia five sixths.
From a surgical standpoint, the leg has been divided into four compartments. A compartment is defined by the unyielding boundaries, such as bone and fascia, enclosing a given content. The anterior compartment is limited medially by the tibia, posteriorly by the interosseous membrane, laterally by the fibula, and anteriorly by the crural fascia. It contains the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius muscles, as well as the anterior tibial artery and the deep branch of the peroneal nerve. It is responsible for ankle and toe extension. The lateral compartment contains the peroneus brevis and longus muscles responsible for ankle flexion and foot eversion and the superficial branch of the peroneal nerve. The superficial posterior compartment contains the gastrocnemius, soleus, plantaris, and popliteus muscles and the sural nerve. It is responsible for plantar flexion of the foot and ankle. The deep posterior compartment is enclosed by the tibia, the interosseous membrane, and the deep transverse fascia. It contains the tibialis posterior, flexor hallucis longus, and flexor digitorum longus muscles, and also the posterior tibial and peroneal arteries and the tibial nerve.
Fractures of the tibial or fibular diaphysis are the result of direct or indirect trauma, with some of these injuries being open fractures. A thorough assessment of the surrounding soft tissues is mandatory. One must remember that the size of the skin wound does not necessarily correlate with the amount of underlying soft tissue damage. A 1 cm skin laceration can be associated with an extensive muscle and periosteal injury, making the fracture a Gustilo grade 3 instead of 1, with a much poorer prognosis. Also, closed tibia fractures can be associated with significant soft tissue injury. Tscherne and Oestern in 1982 classified the soft tissue injury in ascending order of severity (grades 0 to 3):
Grade 0: soft-tissue damage is absent or negligible.
Grade 1: there is a superficial abrasion or contusion caused by fragment pressure from within.
Grade 2: a deep contaminated abrasion is present associated with localized skin or muscle contusion from direct trauma. Impending compartment syndrome is included in this category.
Grade 3: the skin is extensively contused or crushed and muscular damage may be severe. Also, subcutaneous avulsions, compartment syndrome and rupture of a major blood vessel associated with a closed fracture are additional criteria.
When the fracture is displaced, the clinical diagnosis is usually evident. All compartments should be palpated, and a thorough distal neurovascular examination should be recorded.
Radiographs in the anteroposterior and lateral projections are taken of the entire leg, including the knee and ankle joints. Oblique views are sometimes necessary. Fractures of the distal end of the tibia (pilon or plafond fractures) can be better visualized with CT scanning.
Fibula Diaphysis Fractures
Isolated fibula fractures can be associated with other injuries of the leg, such as fracture of the tibia or fracture-dislocation of the ankle joint. One should pay particular attention to the medial malleolus to rule out deltoid ligament rupture or medial malleolus fracture. Isolated fibula fracture can be the result of a direct or "tapping" mechanism; however, it can also coincide with syndesmosis disruption. If reduction of the mortise is congruent, radiographic follow-up needs to be careful to ensure maintenance of reduction.
Tibia Diaphyseal Fractures
Isolated fractures of the tibial diaphysis are usually the result of torsional stress. There is a tendency for the tibia to displace into varus angulation because of an intact fibula.
Fractures of both the tibia and fibula are more unstable, and displacement can recur after reduction. The fibular fracture usually heals independently of the reduction achieved. The same does not apply to the tibia. There is some controversy as to what is an acceptable reduction of a tibial shaft fracture in the adult. The following criteria are generally accepted: apposition of 50% or more of the diameter of the bone in both anteroposterior and lateral projections, no more than 5 degrees of varus or valgus angulation, 5 degrees of angulation in the anteroposterior plane, 10 degrees of rotation, and 1 cm of shortening. It is assumed that fracture healing in an unacceptable position (ie, malunion) will affect the mechanics of the knee or ankle joint and possibly lead to premature degenerative joint disease.
Acceptable reduction can be obtained in one of many ways, and this is another area of ongoing controversy: closed versus open treatment. The goal of any treatment is to allow the fracture to heal in an acceptable position with minimal negative effect on the surrounding tissues or joints. Closed reduction is obtained under general anesthesia if necessary, and the patient is immobilized in a long leg non-weight–bearing cast. Weekly radiographs for the first 4 weeks will help ensure that displacement does not occur. If it does, angulation can be corrected by "wedging" the cast. This involves dividing the plaster circumferentially and inserting wedges in the appropriate direction after corrective manipulation. At 6 weeks, some shaft fractures are stable enough to be put in a short leg weight-bearing cast, usually a patellar tendon-bearing cast or brace as recommended by Sarmiento. Protected weight bearing should be continued until clinical and radiologic healing is evident.
If acceptable and stable reduction cannot be obtained by closed means, other methods are required. Skeletal traction via a calcaneal transfixing pin is rarely used, although it is an acceptable short-term option in the polytraumatized patient. An external fixator with an outer frame is extremely useful for open fractures, as it provides rigid fixation and still allows access for wound care. This is still the initial treatment for some Gustilo type 3 injuries and in the hemodynamically unstable patient. A reamed intramedullary nail is the recommended treatment for most displaced closed and possibly Gustilo type 1-3a fractures. Intramedullary nails are introduced from a proximal starting point anterior to the tibial tubercle and across the fracture site under fluoroscopic control without opening the fracture site. Dynamic or static interlocking can be achieved with transfixing screws on both ends of the nail, and this maintains length and provides rotational control.
Open reduction and internal fixation with plates and screws using minimally invasive percutaneous plate osteosynthesis (MIPPO) techniques, avoids direct exposure of the fracture site and decreases soft-tissue dissection, devascularization of the bone, risk of infection, and delayed union. This technique is useful in periarticular fractures with diaphyseal extension.
Recent studies comparing tibia fractures treated with cast immobilization with those treated with intramedullary nailing indicate that the intramedullary nail group has a shorter time to healing, a better rate of healing, and an improved functional score. Disadvantages of operative treatment include infection, wound problems, and possible contractures. The advantages of closed treatment are early mobilization with or without weight bearing and a short hospital stay, with less risk of infection from the operative approach. Closed treatment does not preclude further surgical treatment. Disadvantages include residual deformity, knee or ankle joint stiffness, and more difficult wound care. Sound clinical judgment is needed in the decision-making process. An isolated closed tibial fracture in a compliant patient is a much different problem than the same tibial injury in a polytraumatized comatose patient.
Fracture of the Distal End of the Tibia
Also referred to as pilon or plafond fractures, these fractures involve the distal articular surface of the tibia at the tibiotalar joint. Ruedi and Allgower classified these injuries into I, II, and III based upon the amount of articular displacement and comminution, which represents a wide spectrum of injury (Figure 3–25).
As for any intraarticular fracture, the goal of treatment is to restore an anatomic articular surface. This can be difficult and sometimes impossible. Closed reduction of displaced fractures is almost never successful and external fixation spanning the injury, with or without ORIF of the fibula can be initially performed. Once soft-tissue swelling subsides, minimally invasive open reduction and percutaneous techniques should be attempted. Bone graft can be added to metaphyseal defects to support the articular surface. When the fracture is so comminuted that internal fixation is impossible, an attempt at indirect reduction by ligamentotaxis should be done: ORIF of the fibular fracture to restore length, and closed reduction and external fixation of the tibia. This can usually restore normal contours and alignment of the distal leg and make an eventual tibiotalar fusion easier should disabling posttraumatic arthritisoccur.
These fractures are notorious for associated soft-tissue damage. Swelling can be impressive, and prolonged leg elevation is often necessary, especially to prevent surgical wound problems after open reduction. If open surgical treatment of the tibial pilon is planned, the surgery should be deferred until the soft tissue condition improves, usually 7 to 14 days, once the "wrinkle" sign appears. Surgical incisions through hemorrhagic blisters should be avoided. Healing is likely to be slow, and weight bearing should be carefully started only when radiologic evidence of bone healing is present.
Compartment syndrome is a frequent concern in tibia fractures and is caused by increased pressure in any of the four closed osteofascial spaces, compromising circulation and perfusion of the tissues within the involved compartment. Nerves and muscle tissue are particularly susceptible.
Fasciotomies are performed through a lateral and a medial incision in the skin and fascia of all four compartments. Compartment pressure measurements are taken after decompression to ensure adequate pressure reduction. Tissue debridement is kept to a minimum. The wounds are left open, sterilely dressed, and then treated by delayed primary closure or split-thickness skin grafting 5 days later. Delaying treatment of any compartment syndrome by more than 6–8 hours can lead to irreversible nerve and muscle damage.
Complications are common after tibia and fibula fractures and may be related to the nature of the injury itself or to its management.
DELAYED UNION OR NONUNION
Because of its relatively poor soft-tissue coverage, the tibia, particularly its distal third, is prone to delayed union or nonunion. This occurs more frequently in high-energy, open, and segmental fractures. Pain and motion at the fracture are noted to be present more than 6 months after the injury. Radiographs show the persistence of the fracture line without bridging callus. Sclerosis and flaring of the bone ends characterize the hypertrophic nonunion, whereas osteopenia and thinning of the fragments are seen in atrophic nonunions. Early weight bearing is thought to stimulate bone healing. If nonunion develops in spite of this, rigid fixation (hypertrophic nonunion) or bone grafting (atrophic nonunion) may be required in order for the nonunion to heal. Electrical stimulation, ultrasound, and shock waves have limited efficacy but may achieve union in selected cases.
Malunion may lead to premature degenerative joint disease. Corrective osteotomies may be required. When associated with shortening, multiple-plane correction and lengthening can be obtained after corticotomy and external fixation with Ilizarov-type devices, which allow progressive correction of the deformity.
Infection of the tibia following open fracture or surgical treatment remains the most severe complication, especially when associated with nonunion. Perioperative prophylactic antibiotic therapy and adequate debridement and irrigation of open fractures are not always successful in preventing this dreaded complication. Recently, the generous utilization of free muscle flaps to increase the local blood supply has significantly improved the overall results of treatment, although amputation is still occasionally required.
COMPLEX REGIONAL PAIN SYNDROME (REFLEX SYMPATHETIC DYSTROPHY)
Complex regional pain syndrome is a fortunately rare complication of unknown cause. It is characterized by pain out of proportion to the original injury. Swelling, pain, and vasomotor disturbances are the hallmarks of this syndrome. Gradual increase in weight bearing and early joint mobilization will minimize the occurrence of this complication. Chemical or surgical sympathetic blockade may be helpful for the more severe forms of this disease.
Posttraumatic arthritis is a frequent occurrence after pilon fractures or as a complication of tibial shaft malunion. Joint stiffness and ankylosis may occur after prolonged immobilization. Soft-tissue injuries, including those of nerve, vessels, or muscles, have been discussed in the compartment syndrome section. Sequelae may include dropfoot and claw toe deformities and may require further soft-tissue or bone procedures.
Injuries Around the Knee
Anatomy & Biomechanical Principles
The knee is a modified synovial hinge joint formed by three bones: the distal femur, the proximal tibia, and the patella. It is often divided into three compartments: medial, lateral, and patellofemoral.
The distal femoral diaphysis broadens into two curved condyles at the metaphyseal junction. Each condyle is convex and articulates distally with its corresponding tibial plateau. Their articular surfaces join anteriorly to articulate with the patella. Posteriorly, they remain separate to form the intercondylar notch. The lateral condyle is wider in the sagittal plane (preventing lateral patella displacement) and extends further proximally. The medial condyle is narrower but extends further distally. This difference in length of both condyles allows for the distance between both knees, when weight bearing, to be smaller than the distance between both hips. Both condylar surfaces form a horizontal plane parallel to the ground and create an anatomic angle (physiologic valgus position) of 5–7 degrees with the femoral shaft. Normally, the centers of the hip, knee, and ankle joints are all aligned to form a mechanical angle of 0 degrees. The supracondylar area of the femur is defined as the distal 9 cm. Fractures proximal to this are considered femoral shaft fractures and carry a different prognosis.
As for the distal femur, the proximal tibia widens proximally at the diaphyseal-metaphyseal junction to form the medial and lateral tibial plateaus (condyles). There is a 7–10 degrees slope from anterior to posterior of the tibial plateaus. The tibial eminence, with its medial and lateral spines, separates both compartments and is the attachment for the cruciate ligaments and the menisci. Distal to the joint itself, the tibia has two prominences: the tibial tubercle anteriorly, where the patellar tendon attaches, and Gerdy's tubercle anterolaterally, where the iliotibial band inserts. Posterolaterally, the under surface of the tibial condyle articulates with the fibular head to form the proximal tibiofibular joint.
The patella is the biggest sesamoid bone in the body. It lies within the substance of the quadriceps tendon. The distal third of the under surface is nonarticular and provides attachment for the patellar tendon. The proximal two thirds articulates with the anterior surface of the femoral condyles and is divided into medial and lateral facets by a longitudinal ridge. The area of contact at the patellofemoral joint varies according to the degree of knee flexion. On each side of the patella are the medial and lateral retinacular expansions formed by fibers of the vastus medialis and vastus lateralis muscles. These expansions bypass the patella to insert directly on the tibia. When intact, they can allow active knee extension even in the presence of a fractured patella. The blood supply to the patella is derived from anastomosis of the genicular vessels from the distal pole proximally. Avascular necrosis of a proximal fracture fragment is not uncommon.
The main plane of motion of the knee is flexion and extension, but physiologically, internal and external rotation, abduction and adduction (varus and valgus), and anterior and posterior translations also occur. The intrinsic bony configuration of the joint affords little stability. A complex soft-tissue network provides joint stability under physiologic loading. It includes passive stabilizers such as medial and lateral collateral ligaments, medial and lateral menisci, anterior and posterior cruciate ligaments, joint capsule, and active stabilizers such as the extensor mechanism, the popliteus muscle, and the hamstrings with their capsular expansions. All these soft tissue components work together in an extremely complex and finely tuned way to prevent excessive displacement of the joint surfaces throughout the full arc of motion under physiologic loading. When abnormal stresses that exceed the soft tissues' ability to resist them are transmitted across the joint, an infinite range of injuries can occur. These may be isolated or combined, partial or complete, and may or may not be associated with bony injuries. An accurate diagnosis, although sometimes difficult, is essential before the appropriate treatment can be decided upon.
As already stated, a wide spectrum of ligamentous injuries, from partial sprain of an isolated ligament to major soft-tissue disruption are seen in knee dislocations. Associated injuries to bone, cartilage, and menisci are common.
Knowledge of the mechanism of injury is of paramount importance, as certain injury patterns may be anticipated. Dashboard injuries may cause posterior translation of the tibia under the femur with posterior cruciate ligament damage. Hyperextension injuries, as seen in skiers, volleyball players, or basketball players, often involve the anterior cruciate ligament. Tackles at knee level in football often create a valgus flexion external rotation injury with damage to the medial collateral ligament, medial meniscus, and anterior cruciate ligament (The Terrible Triad). A good clinical examination is sometimes difficult, particularly in a young muscular athlete with a large lower extremity, but it is essential and will usually provide key diagnostic information.
Plain radiographs are of limited benefit. They will show fractures, bony avulsions at ligament attachment sites, or capsular avulsion signs such as the lateral capsular sign (Segond fracture), which is diagnostic of anterior cruciate ligament disruption (Figure 3–26).
Tomograms and contrast arthrograms have only limited indications because MRI has become so widely accepted. MRI is now by far the imaging tool of choice for ligamentous injuries of the knee, with an accuracy rate above 95%. Diagnostic arthroscopy is now reserved for cases when MRI is inconclusive or the surgeon is fairly sure that surgical treatment of a lesion will be necessary.
Medial (Tibial) Collateral Ligament Injury
This ligament normally resists valgus angulation at the knee joint. A history of abduction injury, often with a torsional component, is usually obtained. Examination reveals tenderness over the site of the lesion and often some knee effusion. When compared with the contralateral knee, valgus stressing with the knee flexed at 20–30 degrees will show exaggerated laxity at the joint line, signaling a complete tear. Stress radiographs can, on rare occasions, be useful in confirming the diagnosis.
Grade 1 and 2 sprains (incomplete) are treated with protective weight bearing in a hinged brace or cast to prevent further injury while healing progresses. Grade 3 sprains (complete) are rarely isolated. Known associated injuries, such as medial meniscus damage, anterior cruciate ligament tear, or lateral tibial plateau fractures, should be systematically ruled out. Most surgeons now favor conservative treatment of isolated grade 3 medial collateral ligament tears in a long leg hinged-knee brace for 4–6 weeks because surgical repair has not proved to provide any long-term benefit.
Lateral (Fibular) Collateral Ligament Injury
This ligament originates from the lateral femoral condyle and inserts on the fibular head. It resists varus angulation at the knee joint. Isolated injuries are extremely rare. Most often, there is a combination of varying degrees of injury to the posterolateral corner, which includes the biceps tendon, posterolateral capsule, popliteus tendon, and iliotibial band. Injury to the peroneal nerve is not uncommon. Pain and tenderness are present over the lateral aspect of the knee, usually with some intraarticular effusion. In severe injuries, there is abnormal laxity on varus stressing compared with the other knee.
Radiographs often show avulsion of the fibular head. When this fragment is of sufficient size, internal fixation with a screw gives excellent results. Conservative management involves protected weight bearing in a long leg hinged-knee brace for 4–6 weeks. Most injuries require operative treatment, although conservative treatment may be indicated for the low-demand patient with mild laxity.
Anterior Cruciate Ligament Injury
This ligament originates at the posteromedial aspect of the lateral femoral condyle and inserts near the medial tibial spine. Because it is composed of at least two distinct fiber bundles, part of it remains taut throughout the normal flexion-extension arc of motion. It prevents anterior translation (gliding) of the tibia under the femoral condyles. Isolated injuries are frequent, especially with hyperextension mechanism, but associated medial collateral ligament, medial meniscus, posteromedial capsule, and even posterior cruciate ligament injuries are more common. When the tear is complete, it most often occurs within the substance of its fibers. Rarely, bony avulsion at the femoral or tibial attachment will be seen on plain radiograms.
The patient usually recalls the mechanism of injury, and classically feels a popping or snapping sensation in the knee. A moderate effusion usually accumulates during the first few hours is usually the rule. The only clinical finding in acute anterior cruciate ligament deficiency may be a positive Lachman's test, which is the anterior drawer test performed with 20–30 degrees of knee flexion. The classic drawer test, done with the knee flexed at 90 degrees and the foot resting on the table, is not as reliable. The injured knee should always be compared with the uninjured contralateral knee. In chronic anterior cruciate ligament deficiency, secondary restraints have stretched out and other clinical signs, such as the pivot shift and the active drawer sign, become more apparent.
Treatment remains controversial despite the abundance of literature on this topic over the last 20 years. Most surgeons feel that surgical reconstruction affords the best long-term results. Non-operative treatment may have a role in the stable knee without signs of quadriceps wasting. When bony avulsions from the femur or tibia are present, surgical repair is indicated as bone-to-bone healing and good long-term results have been demonstrated.
Primary repair of the ligament stumps without reconstruction is likely to fail. The trend presently seems to reserve surgical reconstruction for young high-demand athletes. For others, conservative management with rehabilitation therapy and bracing can give satisfactory results. Those patients who remain unacceptably unstable after conservative treatment can still benefit from delayed reconstructive surgery. Favored techniques at the present include the arthroscopically assisted use of the middle third of the patellar tendon or harvest of an autogenous hamstrings graft.
Posterior Cruciate Ligament Injury
The posterior cruciate ligament is a broad thick ligament that extends from the lateral aspect of the medial femoral condyle posteriorly and inserts extraarticularly over the back of the tibial plateau approximately 1 cm below the joint line. It resists posterior translation (gliding) of the tibia under the femoral condyle. It usually ruptures after a posteriorly directed force on the proximal tibia as is sometimes seen in dashboard injuries. Posterior cruciate ligament ruptures can also occur as the end stage of severe hyperextension injuries.
The posterior drawer test will be positive, as will the sag test, showing posterior sagging of the tibia with the knee flexed to 90 degrees compared with the opposite side. As for the anterior cruciate ligament, the rupture may be at the bone-ligament junction or more often in the middle substance of the ligament.
Reattachment of bony avulsions should restore functional competency of the ligament. Repair of the middle substance tear alone is of no value. Complex reconstructions have been described but remain of unproved value for non-athletic patients. Conservative treatment with rehabilitation (particularly of the extensor mechanism), and even bracing, of isolated posterior cruciate ligament injuries is currently recommended.
The meniscus is a fibrocartilage that allows a more congruous fit between the convex femoral condyle and the flat tibial plateau. Both medial and lateral menisci are attached peripherally and have a central free border. They are wedge-shaped and thicker at the periphery. The medial meniscus is C-shaped and the lateral meniscus is O-shaped, with both anterior and posterior horns almost touching medially. They are vascularized only at their peripheral third. Tears involving that vascularized portion have a better repair potential. The menisci spread the load more uniformly on the underlying cartilage, thus minimizing point contact and wear. They are secondary knee stabilizers but are more important in the ligament-deficient knee.
Tears can be secondary to trauma or attrition. The medial meniscus is more often involved. Symptoms include pain, swelling, a popping sensation, and occasionally locking and giving way. Examination usually reveals nonspecific medial or lateral joint-line pain, and occasionally grinding or snapping can be felt with tibial torsion and the knee flexed to 90 degrees (McMurray's sign). Radiographs are of minimal value but may rule out other disorders; MRI has replaced contrast arthrography as the diagnostic tool of choice.
Initial conservative management with immobilization, bracing, protective weight bearing, and exercises can give good results. Arthroscopic evaluation and treatment is recommended for recurrent or persistent locking, recurrent effusion, or disabling pain. If the tear is large enough and in the vascularized portion, repair should be attempted. For other tears, the affected area should be removed, leaving as much as possible of the healthy meniscus. Routine total meniscectomy has been abandoned because of the high incidence of subsequent arthritis.
Chondral & Osteochondral Injuries
The hyaline articular cartilage is avascular and has no intrinsic capability to repair superficial lacerations. Deep injuries involve the bone in the subchondral plate, and extrinsic repair occurs first with a fibrin clot replaced by granulation tissue, which is then transformed to fibrocartilage. Repetitive injury can cause abnormal motion with shearing stresses that can loosen chondral or osteochondral fragments. Compression injuries to the cartilage can lead to posttraumatic chondromalacia.
Chondral injuries usually give nonspecific symptoms that mimic meniscal injury. Plain radiographs will often reveal a loose body if the osteochondral fragment is big enough. Tunnel views and patellar tangential views can be helpful in visualizing fragments. Pure chondral fragments will only be seen with contrast arthrograms or MRI, both of which can easily miss the smaller fragments. Arthroscopy remains the most accurate diagnostic procedure.
Treatment is controversial. The age of the patient, skeletal maturity and the presence of adequate subchondral bone all play an important part in guiding treatment.
Removal of the free fragment, debridement of the donor site, and drilling of the underlying subchondral bone to promote fibrin clot formation is the most accepted treatment. Rarely, an osteochondral fragment involving weight-bearing cartilage is large enough to warrant reduction and internal fixation.
Traumatic dislocation of the knee is a rare injury that often results from high-energy trauma, but may occur from low energy injuries in the elderly. It is classified according to the direction of displacement of the tibia: anterior, posterior, lateral, medial, or rotatory. Complete dislocation can occur only after extensive tearing of the supporting ligaments and soft tissues. Injury to the neighboring neurovascular bundle is common and should be looked for systematically.
Knee dislocations require prompt reduction. This is most easily accomplished in the emergency room by applying axial traction on the leg. Rarely, reduction can only be obtained under general anesthesia. The role of angiography is controversial. If pulses and ankle-brachial pressure index are normal, the limb is closely observed. Studies have shown that the isolated presence of abnormal foot pulses is not sensitive enough to detect a surgical vascular injury. Furthermore, one study demonstrated no vascular injury in any of their traumatic knee dislocations with initial normal vascular examination. Angiograms can be useful in the limb with obvious vascular injury, but should not delay treatment. Any vascular injury should be repaired as soon as possible. Ischemia of more than 4 hours implies a poor prognosis for salvage of a functional limb. Prophylactic fasciotomies should be performed at the time of vascular repair to prevent compartment syndrome caused by post-revascularization edema.
The timing of the treatment of the ligamentous damage is also controversial. Most authors now agree that surgical repair of all ligaments is indicated in relatively young (<50 years) active patients. Others still prefer closed management in a cast or braces. Whatever method is used, close follow-up is essential, especially at the beginning, to prevent subluxation, usually posteriorly. If subluxation occurs, the knee should be maintained in a reduced position using a femorotibial external fixator. After 6–8 weeks of immobilization, the knee is protected in a long leg brace and motion is started. Intensive quadriceps and hamstring rehabilitation is necessary to minimize functional loss. The need for a brace for strenuous activities may be permanent.
PROXIMAL TIBIA FRACTURES
Tibial Plateau Fractures
Proximal tibia fractures account for 1% of all fractures. There is a wide spectrum of fracture patterns that involve the medial tibial plateau (10–23%), the lateral tibial plateau (55–70%), or both (11–31%). These fractures occur through metaphyseal bone. Like all metaphyseal fractures, the spongiosa is impacted and once reduced, there can be a void with functional bone loss. These fractures usually result from axial loading, as seen in falls from a high place, combined most often with some varus and valgus forces. It is reported that at least 20% of unilateral tibial plateau fractures are associated with ligament rupture of the opposite compartment. The bone fails in compression and shear, with the ligament in tension. This is not easy to determine clinically, because of pain and motion at the fracture site. A thorough neurovascular evaluation should be recorded.
Many different classification systems have been proposed, none with universal acceptance. The system most widely used today is the Schatzker classification; type I: split fracture of the lateral plateau, type II: split-depression of the lateral plateau, type III: depression of the lateral plateau, type IV: medial plateau fracture, type V: bicondylar fracture, and type VI: a fracture with metaphyseal-diaphyseal dissociation (Figure 3–27). Proper classification is based on quality radiographs, including oblique views if necessary. If fat is present in the knee aspirate and plain films fail to show any obvious fractures, occult injury needs to be ruled out. CT and more recently, MRI have all been used successfully for this purpose. MRI has also been useful to reduce inter-observer disparities in fracture classification, which in turn can affect management.
The goal of treatment is to restore anatomic contours to the articular surface, to prevent posttraumatic degenerative joint disease, allow soft-tissue healing in optimal position, and prevent knee stiffness. Both closed and open treatment can achieve these goals. The choice will depend on multiple factors, including the patient's age and general medical condition, the degree of displacement and comminution of the fracture, associated local soft-tissue and bony injuries, local skin condition, residual knee stability, and fracture configuration.
Closed treatment with a cast or fracture brace is appropriate for minimally displaced fractures with no ligament instability. Definite varus and valgus laxity at full extension is a poor prognostic sign for closed treatment. Articular step-off of 3 mm or less and condylar widening of 5 mm or less can be treated conservatively. Lateral or valgus tilt up to 5 degrees is well tolerated. Medial plateau fractures with any significant displacement should be surgically stabilized. Articular step-off >3 mm should be anatomically fixed. Bicondylar fractures with any medial displacement, valgus tilt >5 degrees or with significant articular step-off should be surgically stabilized. Range of motion is usually allowed after 6 weeks and weight bearing after 3 months. Non-comminuted fractures can undergo closed reduction with fluoroscopic imaging and percutaneous pinning with cannulated screws.
Recently, reduction of the articular fragment under arthroscopic visualization has become more popular, particularly for Schatzker type I, II, III, and IV injuries. The depressed fragment is elevated and bone graft packed underneath to prevent loss of reduction.
Open reduction and internal fixation with plates and screws remains the traditional approach of operative treatment. Reduction should be as anatomically precise as possible, and fixation should be solid enough to allow early mobilization. More recently, Minimally Invasive Plate Osteosynthesis (MIPO) and the Less Invasive Stabilization Systems (LISS) are being used in the treatment of these injuries. Bone defects should be grafted with either autograft, allograft or structural graft substitutes. Early range of motion is allowed according to the stability of the construct. Weight bearing is occasionally allowed at 6–8 weeks but more frequently after 12 weeks.
An external monolateral or ring fixator can be used for provisional and definitive treatment depending upon the clinical situation and experience of the surgical team.
Hybrid and ring external fixators have been found to be useful for bicondylar injuries with severe soft tissue trauma.
Early complications include infection, deep vein thrombosis, compartment syndrome, loss of reduction, and hardware failure. Late complications include residual instability and posttraumatic degenerative joint disease that may require total knee replacement arthroplasty or arthrodesis.
Tibial Tuberosity Fracture
Tibial tuberosity fractures can occur with a violent quadriceps muscle contraction causing avulsion of the tibial tuberosity. When the fracture is complete, the extensor mechanism is disrupted and active knee extension is impossible.
Although conservative treatment of a nondisplaced avulsion fracture with a cylinder cast in extension for 6–8 weeks will allow it to heal, rigid fixation with percutaneous screws allows much earlier knee mobilization. Closed or open reduction and solid internal fixation is recommended for all fractures displaced by 5 mm or more.
Tibial Eminence (Spine) Fracture
A tibial eminence fracture occurs as an isolated injury or as part of the comminution of tibial plateau fractures. The isolated type of injury occurs mostly in the pediatric age group before physeal closure and is believed to be an avulsion fracture at the tibial attachment of the anterior cruciate ligament.
Myers has classified this lesion into three stages and has recommended open reduction for the displaced type 3 fractures. Type 1 and 2 fractures should be treated with a cylinder cast with the knee in extension for 4–6 weeks. When associated with other fractures of the tibial plateau, the tibial eminence fragment usually keeps its attachment to the anterior cruciate ligament, and anatomic reduction with rigid fixation should be obtained.
DISTAL FEMUR FRACTURES
These fractures involve the distal metaphysis and epiphysis of the femur. The incidence of distal femoral fractures has been estimated between 4 and 7% of all femoral fractures. It is important to distinguish between extraarticular (supracondylar) and intraarticular (condylar or intercondylar) fractures, and low energy fractures (usually in the elderly) and high energy fractures (young patient). The distal fragment is usually rotated into extension from traction by the gastrocnemius muscle. The distal end of the proximal fragment is apt to perforate the overlying quadriceps and may penetrate the suprapatellar pouch, causing hemarthrosis. The distal fragment may impinge on the popliteal neurovascular bundle, and an immediate thorough neurovascular examination is mandatory. Absence or marked decrease of pedal pulsations is an indication for immediate reduction. If this fails to restore adequate circulation, an arteriogram should be obtained immediately and the vascular lesion repaired as indicated. Injuries to the tibial or peroneal nerves are less frequent. Treatment should be aimed at restoring the mechanical axis, anatomic reduction of the articular surface and early knee range of motion.
A temporary spanning external fixation can be used to stabilize the fracture in polytrauma patients. Two pins can be rapidly allocated in the femoral shaft and two additional pins in the Tibial shaft. ORIF can be safely done in the first 2 weeks when the patient has been hemodynamically stabilized without increasing the risk of infection, provided that no infection at the pin sites has occurred. Complex Trauma of the Knee encompasses a distal supra or intercondylar femoral fracture combined with a proximal tibial fracture (floating knee); a supra or intercondylar femoral fracture with a second or third degree closed or open injury; or a complete knee dislocation and possible associated neurovascular injuries. Because of the complexity of injury and multidisciplinary team approach, this subset of patients is better treated in level 1 trauma centers.
Most of these fractures, are best treated with internal fixation, which allows early mobilization of the patient and of the neighboring joints. Most fractures are best treated with fixed-angle plates, locking plates using MIPPO techniques, or retrograde intramedullary nailing. Skeletal traction treatment is reserved for patients for whom surgery is contraindicated and is fraught with all the previously mentioned complications that can accompany prolonged recumbency.
As for any intraarticular fracture, maximal functional recovery of the knee joint requires anatomic reduction of the articular components and restitution of the mechanical axis. Closed reduction of displaced fragments is almost never successful. Displaced intraarticular fractures usually require open reduction and internal fixation with a variety of methods including Dynamic Compression Screws (DCS), AO buttress plating, LISS, with or without a percutaneous or minimally invasive plate osteosynthesis (MIPPO). For combined intercondylar and supracondylar fractures, or condylar fractures, the transarticular approach and retrograde plate osteosynthesis (TARPO) facilitates anatomic articular reconstruction and percutaneous plate insertion (Krettek et al., 1997).
A comminuted fracture of the distal femoral epiphysis is classically described as a T or Y fracture, according to the configuration of the articular fragments. Displaced fractures are best treated by open reduction, to restore anatomic alignment of the articular surface, and by internal fixation using screws and condylar plates or screws. Even if the fracture heals in anatomic position, joint stiffness, pain, and posttraumatic arthritis are not uncommon outcomes.
Isolated fractures of the lateral or medial femoral condyles are rare. They usually result from varus or valgus stress to the knee joint, and associated ligament injuries should be looked for systematically. Fractures of the posterior portion of one or the other condyle in the frontal plane can also be seen (Hoffa fracture).
Closed reduction of displaced fragments is rarely successful. Open reduction and internal fixation is usually indicated and requires anteroposterior lag screws. Associated ligamentous ruptures are repaired as needed. If fixation is solid, postoperative immobilization is kept at a minimum, and the patient can start moving the knee joint early. Weight bearing is usually allowed at 3 months when clinical and radiologic evidence of bone healing is present.
Transverse Patellar Fracture
Transverse fractures of the patella (Figure 3–28) are the result of an indirect force, usually with the knee in flexion. Fracture may be caused by sudden voluntary contraction of the quadriceps muscle or sudden forced flexion of the leg with the quadriceps contracted. The level of fracture is commonly in the middle. Associated tearing of the patellar retinacula depends upon the force of the initiating injury. The activity of the quadriceps muscle causes upward displacement of the proximal fragment, the magnitude of which depends on the extent of the retinacular tear.
Swelling of the anterior knee region is caused by hemarthrosis and hemorrhage into the soft tissues overlying the joint. If displacement is present, the defect in the patella can be palpated, and active extension of the knee is lost. A straight leg raise may be preserved if the retinacula is intact.
Nondisplaced fractures can be treated with a walking cylinder cast or brace for 6–8 weeks followed by knee rehabilitation. Open reduction is indicated if the fragments are displaced >3 mm or if articular step-off is >2 mm. The fragments must be accurately repositioned to prevent early posttraumatic arthritis of the patellofemoral joint. If the minor fragment is small (no more than 1 cm in length) or severely comminuted, it may be excised and the quadriceps or patellar tendon (depending upon which pole of the patella is involved) sutured directly to the major fragment. Whenever possible, internal fixation of anatomically reduced fragments should be done, allowing early motion of the knee joint. This is best achieved by figure-of-eight tension banding over two longitudinal parallel K-wires.
Accurate reduction of the articular surface must be confirmed by lateral radiographs taken intraoperatively.
Comminuted Patellar Fracture
Comminuted fractures of the patella are usually caused by a direct force. Most often, little or no separation of the fragments occurs because the quadriceps retinaculum is not extensively torn. Severe injury may cause extensive destruction of the articular surface of both the patella and the opposing femur.
If comminution is not severe and displacement is insignificant, immobilization for 8 weeks in a cylinder extending from the groin to the supramalleolar region is sufficient.
Severe comminution can often be treated with ORIF with addition of a cerclage wire, but on rare occasions excision of the patella and repair of the defect by imbrication of the quadriceps expansion is the only viable alternative. Excision of the patella can result in decreased strength, pain in the knee, and general restriction of activity. No matter what the treatment, high-energy injuries are frequently complicated by chondromalacia patella and patellofemoral arthritis.
Acute traumatic dislocation of the patella should be differentiated from episodic recurrent dislocation, as the latter condition is likely to be associated with occult organic lesions. When dislocation of the patella occurs alone, it may be caused by a direct force or activity of the quadriceps, and the direction of dislocation of the patella is almost always lateral. Spontaneous reduction is apt to occur if the knee joint is extended. If so, the clinical findings may consist merely of hemarthrosis and localized tenderness over the medial patellar retinaculum. Gross instability of the patella, which can be demonstrated by physical examination, indicates that injury to the soft tissues of the medial aspect of the knee has been extensive.
Reduction is maintained in a brace or cylinder cast with the knee in extension for 2–3 weeks. Isometric quadriceps exercises are encouraged. Physical therapy should be initiated to maximize the strength of the vastus medialis. Dynamic bracing may be helpful. Recurrent episodes require operative repair for effective treatment.
Tear of the Quadriceps Tendon
Tear of the quadriceps tendon occurs most often in patients over the age of 40. Apparent tears that represent avulsions from the patella occur in patients with renal osteodystrophy or hyperparathyroidism. Preexisting attritional disease of the tendon is apt to be present, and the causative injury may be minor. The tear commonly results from sudden deceleration, such as stumbling or slipping on a wet surface. A small flake of bone may be avulsed from the superior pole of the patella, or the tear may occur entirely through tendinous and muscular tissue.
Pain may be noted in the anterior knee region. Swelling is caused by hemarthrosis and extravasation of blood into the soft tissues. The patient is unable to extend the knee completely. Radiographs may show a bony avulsion from the superior pole of the patella.
Operative repair is recommended for complete tear. Postoperative immobilization should be encouraged in a walking cylinder cast or brace for 6 weeks, at which time knee mobilization is started.
Tear of the Patellar Tendon
The same mechanism that causes tears of the quadriceps tendon, transverse fracture of the patella, or avulsion of the tibial tuberosity may also cause the patellar ligament to tear. The characteristic finding is proximal displacement of the patella. A bony avulsion may be present adjacent to the lower pole of the patella if the tear takes place in the proximal patellar tendon.
Operative treatment is necessary for a complete tear. The ligament is resutured to the patella, and any tear in the quadriceps mechanism is repaired. The extremity should be immobilized for 6–8 weeks in a cylinder cast extending from the groin to the supramalleolar region. Guarded exercises may then be started.
Fracture of the shaft of the femur usually occurs as a result of severe trauma. Indirect force, especially torsional stress, is likely to cause spiral fractures that extend proximally or, more commonly, distally into the metaphyseal regions. Most are closed fractures; open fracture is often the result of compounding from within.
Extensive soft-tissue injury, bleeding, and shock are commonly present with diaphyseal fractures. The most significant features are severe pain in the thigh and deformity of the lower extremity. Hemorrhagic shock may be present, as multiple units of blood may be lost into the thigh, though only moderate swelling may be apparent. Careful radiographic examination in at least two planes is necessary to determine the exact site and configuration of the fracture pattern. The hip and knee should be examined and radiographs obtained to rule out associated injury. A femoral neck fracture may occur in association with a femur fracture and if overlooked can increase patient morbidity.
Injuries to the sciatic nerve and the superficial femoral artery and vein are uncommon but must be recognized promptly. Hemorrhagic shock and secondary anemia are the most important early complications. Later complications include those of prolonged recumbency, joint stiffness, malunion, nonunion, leg-length discrepancy, and infection.
No classification is universally accepted for fractures of the femoral diaphysis. Classically, the fracture is described according to its location, pattern, and comminution. Winquist has proposed a comminution classification that is now widely used.
Type 1: Fracture that involves no, or minimal, comminution at the fracture site, and does not affect stability after intramedullary nailing
Type 2: Fracture with comminution leaving at least 50% of the circumference of the two major fragments intact
Type 3: Fracture with comminution of 50–100% of the circumference of the major fragments. Nonlocked intramedullary nails do not afford stable fixation.
Type 4: Fracture with completely comminuted segmental pattern with no intrinsic stability
Treatment depends upon the age and medical status of the patient as well as the site and configuration of the fracture.
This remains a treatment option for some skeletally immature patients. Depending on the age of the pediatric patient and the amount of initial displacement at the fracture site, treatment may consist of immediate immobilization in a hip spica cast, or skin or skeletal traction for 3–6 weeks, until the fracture is "sticky," and then spica casting.
Closed treatment of femoral shaft fractures in the adult is rarely indicated. Acceptable alignment may be difficult to maintain, and joint stiffness is frequent. Other rarer complications of prolonged recumbency, like pressure sores and deep vein thrombosis, can have disastrous consequences.
Most fractures in the middle third of the femur can be internally fixed by an intramedullary rod. Intramedullary fixation of femoral shaft fractures allows early mobilization of the patient (within 24–48 hour if the fracture fixation is stable), which is of particular benefit to the polytraumatized patient; more anatomic alignment; improved knee and hip function by decreasing the time spent in traction; and a marked decrease in the cost of hospitalization.
Although open nailing procedures have been described, intramedullary fixation is routinely performed closed.
In closed nailing, the fracture is reduced by closed manipulation on a fracture table under fluoroscopic control. An small incision is made proximal to the greater trochanter, and the nail is inserted through the piriformis fossa down into the intramedullary canal, after reaming to the appropriate size. The fracture site is not opened. Closed nailing decreases the chance of infection by decreasing the amount of soft-tissue dissection necessary and by limiting access to the fracture site to the medullary canal. It also does not disturb the periosteal circulation. Some authors feel that bone reamings at the fracture site further promote bone healing. Interlocking nails are the standard of treatment. Screws are inserted percutaneously through holes in both ends of the nail. Dynamic interlocking using screws at only one end of the nail, relies on interference friction of fracture fragments and muscle action to prevent rotation of the unlocked fragment. It allows axial compression at the fracture site. However, up to 10% of dynamic interlocking may undergo secondary rotation or shortening due to unseen fracture lines. Static interlocking (screws at both ends of the nail) provides rotational control and prevents shortening of the bone at the fracture site; this is the recommended technique. Reamed interlocked nailing is recommended for most grade 1, 2, and 3a open fractures. When associated with extensive soft-tissue loss, as in grade 3b and 3c open fractures, temporary bony stability may be achieved with external fixation devices.
Complications of this procedure can arise from technical problems at the time of surgery (eg, choice of a rod that is too short or too narrow) and result in malalignment or shortening. Comminution of the fracture can occur during placement of the rod. Late bone fracture (weeks or months) can occur through interlocking screws, and severely comminuted fractures with weight bearing can suffer rod or screw breakage. Infection can occur after any open procedure but is uncommon with closed nailing. Occasionally, a painful bursa or heterotopic calcification may develop over the proximal end of the nail, causing discomfort when the patient sits or walks. The rod may be removed after healing is complete, usually at 12–16 months. The healing rate of femoral shaft fractures in general is high and approaches 100% after closed nailing techniques.
Other fixation devices are seldom used. Flexible intramedullary rods of the Ender type do not provide sufficient stability in the adult; however, they are routinely used in the pediatric population. Plates and screws require significant soft-tissue dissection and opening of the fracture hematoma and are usually reserved for special cases such as ipsilateral femoral neck and diaphyseal fractures. External fixation remains indicated in some open fractures. In polytrauma patients, initial external fixation may be indicated when early intramedullary nailing (first 24 hours after trauma), can be potentially hazardous due to hemodynamic instability, head or chest trauma. It has also recently gained acceptance as treatment for closed femoral shaft fractures in children to allow earlier mobilization and decreased hospital stays. The distal fragment pins should always be inserted with the knee in flexion to avoid quadriceps tenodesis that will prevent knee flexion. Superficial pin tract infection is common but rarely involves the bone. A course of oral antibiotics, proper pin care, and eventual pin removal, when the fracture is sufficiently healed, are usually all that are needed to control this problem.
Subtrochanteric fractures occur below the level of the lesser trochanter and are usually the result of high-energy trauma in young to middle-aged adults. They are often comminuted, with distal or proximal extension toward the greater trochanter. Associated soft-tissue damage can be extensive.
The Russell and Taylor classification (Figure 3–29) is a treatment based classification system that incorporates involvement of the piriformis fossa. Type Ia Russell-Taylor fractures do not involve the piriformis fossa, with the lesser trochanter attached to the proximal fragment. These fractures may be treated with a first-generation intramedullary nail. Type Ib fractures do not involve the piriformis fossa; however, the lesser trochanter is detached from the proximal fragment. These fractures require a second-generation nail, with screw fixation into the head and neck. Type II fractures have fracture extension into the piriformis fossa and are best treated with a sliding hip screw or fixed angle plate. The patient usually presents with a swollen painful proximal thigh with or without shortening or malrotation. If the lesser trochanter is intact, the proximal fragment will tend to displace in flexion, external rotation, and abduction because of the unopposed pull of the iliopsoas and abductor muscles.
In the vast majority of cases, internal fixation (by closed or open methods) is now widely favored. Temporary skeletal traction will maintain femoral length until the definitive surgical procedure can be performed. A variety of devices are available.
Closed intramedullary interlocking nails have gained more popularity recently. Devices with cephalic proximal interlocking are available for those cases where conventional intertrochanteric proximal interlocking is contraindicated. Fixation can be obtained with first-generation intramedullary nails, "gamma nails," intramedullary hip screws, or with a variety of cephalomedullary nails or blades and long sideplates based upon the fracture pattern.
Postoperative activity depends on the adequacy of internal fixation. If fixation is solid, an agile cooperative patient can be out of bed within a few days after surgery and ambulating on crutches with toe-touch weight bearing on the affected side. The fracture is usually healed at 3–4 months, but delayed union and nonunion are not uncommon. Hardware failure in these cases are frequent. Repeat internal fixation with autogenous bone grafting is then the treatment of choice.
Hip Fractures & Dislocations
Epidemiology & Social Costs
Hip fractures include intertrochanteric fractures and femoral neck fractures and constitute a major problem in the United States because of the disabling nature of these injuries. Ambulation is almost impossible in all fractures except femoral neck fractures until they have been treated surgically. These fractures primarily occur in older patients (>55 years), unable in many cases to care for themselves. The incidence of hip fractures sharply rises after menopause in women and the age of 70 in men. Fourteen billion dollars are spent yearly to take care of one million affected Americans. Of these, approximately a quarter regain pre-fracture function. Further, prompt and effective care is necessary to avoid the all too frequent occurrence of death in the elderly (>70 years) patient with a hip fracture (20–30% of patients in the first year after fracture). Thus, this injury justifies state-of-the-art care to minimize not only the societal cost but also the human suffering.
Anatomy & Biomechanical Principles
The hip joint is the articulation between the acetabulum and the femoral head. The trabecular pattern of the femoral head and neck, and that of the acetabulum, is oriented to optimally accept the forces crossing the joint. The total force across the joint is the vector sum of body weight and active muscle force. When the concept of lever arm is factored in, surprising forces across the hip joint are attained: 2.5 times body weight when standing on one leg, five times body weight when running, and 1.5 times body weight when lifting the leg from the supine position with the knee in extension. Using a cane in the opposite hand reduces the force to body weight when standing on that leg. For the same reasons, forces across the joint when the ipsilateral leg is kept in the air are significantly greater than when toe-touch weight bearing is allowed.
The hip capsule is a strong thick fibrous structure that attaches on the intertrochanteric line anteriorly and somewhat more proximally posteriorly. The intracapsular portion of the neck is not covered with periosteum, and fractures of the intracapsular part of the neck cannot heal with periosteal callus formation, only with endosteal union. Interposition of synovial fluid between fracture fragments, as in any joint, can delay or altogether prevent bony union.
The vascular supply of the femoral head is also of paramount importance. There are three main sources of vascular supply: (1) the retinacular vessels arising from the lateral femoral circumflex artery and the inferior metaphyseal artery and then running beneath the synovium along the neck, which they penetrate proximally both anteriorly and posteriorly; (2) the interosseous circulation crossing the marrow spaces from distal to proximal; and (3) unreliably, the ligamentum teres artery. Fractures of the femoral neck always disrupt the interosseous circulation; the femoral head then relies only on the retinacular arteries, which may also be disrupted or thrombosed. Secondary avascular necrosis of part or all of the femoral head can result. Union of a fracture can occur in the presence of an avascular fragment, but the incidence of nonunion is higher. Revascularization of the necrotic fragment occurs through the process of creeping substitution. Part of this process involves replacement of necrotic bony substrate with a "softer" granulation tissue and sets the stage for delayed segmental collapse.
Intertrochanteric fractures usually do not suffer this same fate. The capsule (and vessels) are still attached to the proximal fragment after fracture, and thus the blood supply remains patent.
Femoral Neck Fractures
Femoral neck fractures are intracapsular fractures. Because of the already mentioned unusual vascularization of the femoral head and neck, these fractures are at high risk of nonunion or avascular necrosis of the femoral head. The incidence of avascular necrosis increases with the amount of fracture displacement and the amount of time before the fracture is reduced.
Fractures of the femoral neck occur most commonly in patients over age 50. The involved extremity may be slightly shortened and externally rotated. Hip motion is painful, except in the rare cases of nondisplaced or impacted fractures, where pain may be evident only at the extremes of motion. Good quality anteroposterior and lateral radiographs are mandatory.
The Garden classification for acute fractures is the most widely used system:
Type 1: Valgus impaction of the femoral head
Type 2: Complete but nondisplaced
Type 3: Complete fracture, displaced less than 50%
Type 4: Complete fracture displaced greater than 50%
This classification is of prognostic value for the incidence of avascular necrosis: The higher the Garden number, the higher the incidence. The benefits of either skeletal or skin traction are unclear prior to definitive treatment. Traction may offer comfort in some patients but do not improve overall outcome.
Stable Femoral Neck Fractures
These include stress fractures and Garden type 1 fractures. Stress fractures may be difficult to diagnose. Physical examination, as well as the initial radiographs, may be normal. Repeat radiographs, radionuclide imaging, and MRI may be necessary to confirm the diagnosis. Reviews have shown that age, walking ability, and degree of impaction on the radiographs are important factors influencing fracture healing, and may guide the choice of treatment (conservative management versus internal fixation).
Toe-touch weight bearing (with crutches) until radiologic evidence of healing is usually successful for the compliant patient. Healing is usually complete in 3–6 months. Prophylactic internal fixation may be necessary and is indicated by failure of pain resolution with toe-touch weight bearing or by displacement.
The Garden type 1 fracture is impacted in valgus position and is usually stable. Impaction must be demonstrated on both anteroposterior and lateral views. The risk of displacement is nevertheless significant; most surgeons recommend internal fixation to maintain reduction and allow earlier ambulation and weight bearing. If surgery is contraindicated, closed treatment with toe-touch crutch ambulation and frequent radiographic follow-up until healing can be successful.
Unstable Femoral Neck Fractures
Although undisplaced, a Garden type 2 femoral neck fracture is unstable because displacement is probable under physiologic loading. Garden type 3 and 4 fractures are displaced and often comminuted. They can be life-threatening injuries, especially in elderly patients.
Treatment is directed toward preservation of life and restoration of hip function, with early mobilization. This is best attained by rigid internal fixation or primary arthroplasty as soon as the patient is medically prepared for surgery. Closed treatment in a spica cast is almost always bound to fail. Definitive treatment using skeletal traction requires prolonged recumbency with constant nursing care and is associated with numerous complications, including malunion, nonunion, pressure sores, deep vein thrombosis and pulmonary embolus, osteoporosis, and hypercalcemia, to name a few. If for some reason surgery is not possible, it is better to mobilize the patient as soon as pain permits. Subsequent nonunion can be treated at a later stage, electively. Surgical options are internal fixation or primary arthroplasty. In general, the younger the patient, the greater the effort is justified to save the femoral head.
The goal of internal fixation is to preserve a viable femoral head fragment and provide the optimal setting for bony healing of the fracture while allowing the patient to be as mobile as possible. Because persistent displacement and motion at the fracture site may further jeopardize the femoral head blood supply, surgery should be performed as soon as possible. General or spinal anesthesia is used. The fracture is reduced under fluoroscopic imaging as anatomically accurately as possible. Gentle manipulation is usually sufficient. Rarely, open reduction may be necessary before fixation. Open reduction, if performed, should be approached anteriorly as this results in less disruption of blood supply than a posterior approach. Rigid internal fixation is obtained using multiple parallel partially threaded screws, a dynamic hip screw and plate, or a combination of both. The patient can usually be mobilized the following day, and weight bearing is allowed according to the stability of the construct.
This procedure is indicated in the elderly patient for Garden type 4 fractures, in which avascular necrosis is highly probable, and for Garden type 3 fractures that cannot be satisfactorily reduced or for femoral heads with preexisting disease. The femoral head is sacrificed, but a definitive procedure is performed, whereas internal fixation of Garden type 4 fractures frequently fails and repeat surgery is required. When the acetabulum is undamaged, the most commonly accepted technique is hemiarthroplasty, using a femoral stem stabilized with methyl methacrylate or a surface that allows biologic fixation with bony ingrowth. If the hip joint itself is already damaged by preexisting disease, total hip replacement may be indicated. Primary head and neck resection (Girdlestone arthroplasty) may be rarely indicated in the presence of infection or local malignant growth.
The most common sequelae of femoral neck fractures are loss of reduction with or without hardware failure, nonunions or malunions, and avascular necrosis of the femoral head. This latter complication can appear as late as 2 years after injury. According to different series, the incidence of avascular necrosis for Garden type 1 fractures varies from 0 to 15%, for type 2 fractures 10–25%, for type 3 fractures 25–50%, and for type 4 fractures 50–100%. Secondary degenerative joint disease appears somewhat later. The most disabling complication, infection, is fortunately rare.
Lesser Trochanter Fracture
Isolated fracture of the lesser trochanter is rare. When it occurs, it is the result of the avulsion force of the iliopsoas muscle. Rarely, a symptomatic nonunion may require fragment fixation or excision.
Greater Trochanter Fracture
Isolated fracture of the greater trochanter may be caused by direct injury or may occur indirectly as a result of the activity of the gluteus medius and gluteus minimus muscles. It occurs most commonly as a component of intertrochanteric fracture.
If displacement of the isolated fracture fragment is less than 1 cm and there is no tendency to further displacement (as determined by repeated radiographic examinations), treatment may be bed rest until acute pain subsides. As rapidly as symptoms permit, activity can increase gradually to protected weight bearing with crutches. Full weight bearing is permitted as soon as healing is apparent, usually in 6–8 weeks. If displacement is greater than 1 cm and increases on adduction of the thigh, extensive tearing of surrounding soft tissues may be assumed, and ORIF is indicated.
By definition, these fractures usually occur along a line between the greater and the lesser trochanter. They typically occur at a later age than do femoral neck fractures. They are most often extracapsular and occur through cancellous bone. Bone healing within 8–12 weeks is the usual outcome, regardless of the treatment. Nonunion and avascular necrosis of the femoral head are not significant problems.
Clinically, the involved extremity is usually shortened and can be internally or externally rotated. The degree of displacement and comminution will determine the instability of the fracture. A wide spectrum of fracture patterns is possible, from the nondisplaced fissure fracture to the highly comminuted fracture with four major fragments (head and neck, greater trochanter, lesser trochanter, and femoral shaft). The Muller/AO system is useful in classifying intertrochanteric femur fractures and has gained more popularity in recent years (Figure 3–30).
The selection of definitive treatment depends upon the general condition of the patient and the fracture pattern. Rates of illness and death are lower when the fracture is internally fixed, allowing early mobilization. Operative treatment is indicated as soon as the patient is medically able to tolerate surgery. Overall mortality decreases if surgery can be performed within 48 hours. Initial treatment in the hospital should be by gentle skin traction to minimize pain and further displacement. Skeletal traction as the definitive treatment is rarely indicated and is fraught with complications such as pressure sores, deep vein thrombosis and pulmonary embolus, deterioration of mental status, and varus malunion. When surgery is contraindicated, it may be preferable to mobilize the patient as soon as pain permits and accept the eventual malunion or nonunion.
The great majority of these fractures are amenable to surgery. The goal is to obtain a fixation secure enough to allow early mobilization and provide an environment for sound fracture healing in a good position. Reduction of the fracture is usually accomplished by closed methods, using traction on the fracture table, and monitored using fluoroscopic imaging. Some surgeons do not attempt to anatomically reduce comminuted fractures but instead prefer to keep the distal fragment medially displaced, to enhance mechanical stability. Internal fixation is most widely obtained with a dynamic screw and sideplate. The screw can slide in the barrel of the sideplate, allowing the fracture to impact in a stable position. The patient can be taken out of bed the next day, and weight bearing with crutches or a walker is begun as soon as pain allows. The fracture usually heals in 6–12 weeks. Other devices used to treat intertrochanteric fractures include second-generation interlocked nails and prosthetic replacement. Recent results of series have shown more complications of fracture fixation with intramedullary techniques compared to the dynamic hip screw.
General complications include infection, hardware failure, loss of reduction, and irritation bursitis over the tip of the sliding screw.
Traumatic Dislocation of the Hip Joint
Traumatic dislocation of the hip joint may occur with or without fracture of the acetabulum or the proximal end of the femur. It is most common during the active years of life and is usually the result of high-energy trauma, unless there is preexisting disease of the femoral head, acetabulum, or neuromuscular system. The head of the femur cannot be completely displaced from the normal acetabulum, unless the ligamentum teres is ruptured or deficient because of some unrelated cause. Traumatic dislocations are classified according to the direction of displacement of the femoral head from the acetabulum.
Posterior Hip Dislocation
Usually, the head of the femur is dislocated posterior to the acetabulum when the thigh is flexed, for example, as may occur in a head-on automobile collision when the knee is driven violently against the dashboard. Posterior dislocation is also a complication of hip arthroplasty.
The significant clinical findings are shortening, adduction, and internal rotation of the extremity. Anteroposterior, lateral and, if fracture of the acetabulum is demonstrated, oblique radiographic projections (Judet views) are required. Common associated injuries include fractures of the acetabulum or the femoral head or shaft and sciatic nerve injury. The head of the femur may be displaced through a tear in the posterior hip joint capsule. The short external rotator muscles of the femur are commonly lacerated. Fracture of the posterior margin of the acetabulum can create instability.
If the acetabulum is not fractured or if the fragment is small, reduction by closed manipulation is indicated. General anesthesia provides maximum muscle relaxation and allows gentle reduction. Reduction should be achieved as soon as possible, preferably within the first few hours after injury, as the incidence of avascular necrosis of the femoral head increases with time until reduction. The main feature of reduction is traction in the line of deformity followed by gentle flexion of the hip to 90 degrees with stabilization of the pelvis by an assistant. While manual traction is continued, the hip is gently rotated into internal and then external rotation to obtain reduction.
The stability of the reduction is evaluated clinically by ranging the extended hip in abduction and adduction and internal and external rotation. If stable, the same movements are repeated in 90 degrees of hip flexion. The point of redislocation is noted, the hip is reduced, and an anteroposterior radiograph of the pelvis is obtained. Soft tissue or bone fragment interposition will be manifested by widening of the joint space as compared to the contralateral side. Irreducible dislocations, open dislocations, and those that re-dislocate after reduction despite hip extension and external rotation (usually because of associated posterior wall fracture of the acetabulum) are indications for immediate open reduction and internal fixation if necessary. Most authors agree that a widened joint space on radiograph, despite a stable reduction, is also an indication for immediate arthrotomy. Others prefer obtaining a CT scan first, to further delineate the incarcerated fragments and associated injuries before surgery. Recently, hip arthroscopy has gained popularity, but it remains controversial.
Minor fragments of the posterior margin of the acetabulum may be disregarded, but larger displaced fragments are not usually successfully reduced by closed methods. Open reduction and internal fixation with screws or plates is indicated.
Postreduction treatment will vary according to the type of initial surgery. A strictly soft-tissue injury with a stable concentric reduction may be treated with light skin or skeletal traction for a few days to a week before exercises are begun. A motivated patient can then start crutch ambulation, progressing to full weight bearing at 6 weeks. An unstable reduction can be immobilized in a spica cast or abduction brace for 4–6 weeks. Securely fixed fractures are treated as soft-tissue injuries, but weight bearing is allowed when radiologic signs of bone healing are present. When fixation is tenuous, skeletal traction for 4–6 weeks or hip spica immobilization may be necessary.
Complications include infection, avascular necrosis of the femoral head, malunion, posttraumatic degenerative joint disease, recurrent dislocation, and sciatic nerve injury. Avascular necrosis occurs because of the disruption of the retinacular arteries providing blood to the femoral head. Its incidence increases with the duration of the dislocation. It can occur as late as 2 years after the injury. MRI studies enabling early diagnosis and protected weight bearing until revascularization has occurred are recommended. Sciatic nerve injury is present in 10–20% of patients with posterior hip dislocation. Although usually of the neurapraxia type, these lesions leave permanent sequelae in about 20% of cases. The rare patient who is neurologically intact before reduction but has a deficit after reduction should be explored surgically to see if the nerve has been entrapped in the joint. Associated injuries also, on rare occasions, include fracture of the femoral head. Small fragments or those involving the non-weight–bearing surface should be ignored if they do not disturb hip mechanics; otherwise they should be excised. Large fragments of the weight-bearing portion of the femoral head should be reduced and fixed if at all possible.
Anterior Hip Dislocation
Anterior dislocation of the hip is rare compared to its posterior counterpart. It usually occurs when the hip is extended and externally rotated at the time of impact. Associated fractures of the acetabulum and the femoral head or neck occur rarely. Usually, the femoral head remains lateral to the obturator externus muscle but can be found rarely beneath it (obturator dislocation) or under the iliopsoas muscle in contact with the superior pubic ramus (pubic dislocation).
The hip is classically flexed, abducted, and externally rotated. The femoral head is palpable anteriorly below the inguinal flexion crease. Anteroposterior and transpelvic lateral radiographic projections are usually diagnostic.
Closed reduction under general anesthesia is generally successful. Here also the surgeon must make sure of a concentric reduction comparing both hip joints on the postreduction anteroposterior radiograph. The patient starts mobilization within a few days when pain is tolerable. Active and passive hip motion, excluding external rotation, is encouraged, and the patient is usually fully weight bearing by 4–6 weeks. Skeletal traction or spica casting may rarely be useful for uncooperative patients.
Rehabilitation of Hip Fracture Patients
There has been an increased interest in the psychosocial outcome issues of patients with hip fractures. The goal of rehabilitation after hip injuries is to return the patient as rapidly as possible to the pre-injury functional level. Factors influencing rehabilitation potential include age, mental status, associated injuries, previous medical status, myocardial function, upper extremity strength, balance, and motivation.
For the rare patient treated conservatively, rehabilitation focuses early at preventing stiffness and weakness of the other extremities, and at eventually mobilizing the patient out of bed when pain is tolerable. Because the great majority of these injuries are now treated with internal fixation or prosthetic replacement, rehabilitation efforts are focused toward early range of motion, muscle strengthening, and weight bearing. Early full weight bearing as tolerated is encouraged for patients with prosthetic replacements, cemented or not, and for patients with stable fixation of an intertrochanteric fracture to allow compression of the fracture fragments. Most authors now agree that the same applies for femoral neck fractures with stable internal fixation, although some still prefer partial weight bearing until radiologic evidence of bone healing is present to prevent hardware failure. When internal fixation does not provide stable fixation of the fracture fragments, supplemental protection may be added with a spica cast or brace However, it is highly undesirable in elderly patients. Otherwise, restricted range of motion or weight bearing may be allowed according to the surgeon's specifications.
PELVIC FRACTURES & DISLOCATIONS
The innominate bones articulate with the sacrum through the sacroiliac joints and between themselves through the symphysis pubis. Upper body weight is transmitted across the hip joint to the lower limbs via the sciatic buttress and the acetabulum. The mechanism and severity of trauma will determine the pattern of injury. Osteoarticular structures and adjacent soft tissues will be involved to varying degrees depending upon the direction and magnitude of applied forces. Pelvic fractures are potentially life threatening with high mortality. A multidisciplinary team approach is necessary to reduce the likelihood of death and disability.
Mechanism of Injury
Four patterns of injury are responsible for pelvic fractures. Anteroposterior compression results in external rotation of the hemipelvis and rupture of the pelvic floor and anterior sacroiliac ligaments. Lateral compression creates compression fractures of the sacrum and disruption of the posterior sacroiliac ligament complex. The sacrospinous and sacrotuberous ligaments remain intact limiting the instability. In high energy lateral compression injuries, the contralateral hemipelvis can be pushed in external rotation, as seen in rollover or crush injuries. Combined external rotation-abduction is common in motorcycle accidents and the deforming forces are transmitted through the femur. The fourth pattern is a shear force vector resulting from fall from heights, where the grade of translational instability is variable.
Knowledge of the injury mechanism is of prime importance and should be assessed either by patient history or discussion with the prehospital provider. The physical examination includes inspection of the skin, perineum and rectum. Closed degloving injuries (Morel-Lavallée) should be properly identified. Palpation of the pelvic bony landmarks, including posterior palpation of the sacrum and sacroiliac joint, should be done. Rectovaginal examination is mandatory in all cases to identify open fractures. Bony spikes protruding through the mucosa contaminates the fracture hematoma. Anteroposterior and lateral iliac wing compression maneuvers to assess stability should be performed only once or avoided in hemodynamically unstable patients as excessive manipulation can increase bleeding. Associated injuries should also be systematically sought: lower urinary tract injuries, distal vascular status, and a thorough recorded neurologic examination.
An initial anteroposterior pelvic radiograph as per ATLS protocol is examined to evaluate the pelvic ring as a possible cause of shock. Following successful resuscitation, inlet and outlet views should be obtained. CT scan is essential to further define the fracture pattern Vascular and urologic imaging may also be required.
Open Pelvic Fractures
Open pelvic fractures account for 2–4% of all pelvic fractures. Because a higher energy is required to fracture the immature pelvic ring, the incidence of open pelvic fractures is increased among children. Motorcycle accidents are in part responsible for the increase in open pelvic fractures. Mortality has decreased from 50% in the 80s to 10–25%, probably because of the application of multidisciplinary protocols, including aggressive fracture management, selective fecal diversion and advances in critical care.
Significant forces, either directly or indirectly through the lower extremities, are required to destabilize the pelvic ring. A systematic search for associated injuries is mandatory. Hemorrhage and shock are the primary causes of death due to pelvic fracture. The cornerstones of successful treatment include: identification of a significant pelvic injury; rapid resuscitation; hemorrhage control (using angiography or pelvic packing); assessment and treatment of associated injuries, and mechanical stabilization and in selected cases. In the hemodynamically unstable patient the ATLS® protocol should be followed. A pelvic binder or sheet can be used to stabilize the unstable pelvis temporarily. Antiseptic pressure dressings should be applied to bleeding sites. If there is continued hemodynamic instability after initial resuscitation (2 liters of IV fluids), a decision needs to be made in consultation with the trauma surgeon to perform pelvic packing with or without external fixation. If the patient's hemodynamic status stabilizes, the need for definitive versus temporizing mechanical fixation of the pelvis should be determined. This may involve anterior plating of the pubic symphysis, or the application of an external fixation device (pelvic clamp and /or anterior external fixator). Posterior fixation (either surgical or computed tomography guided percutaneous fixation) is usually deferred until a later time. When used to control pelvic fracture motion, the pelvic external fixator is a useful tool to manage volume depletion. It does not provide stable enough fixation to treat complex fractures or most unstable pelvic fractures. It usually resists stresses imposed by sitting but not those from weight bearing, and further internal fixation is often required at a later stage.
In open pelvic fractures, early surgical intervention using a multidisciplinary approach should be undertaken. Seventy-two percent of the open pelvic fractures are grade III open wounds, and should be appropriately treated. Swabs for microbiological examination followed by extensive irrigation and debridement are performed and repeated daily in an attempt to reduce the incidence of pelvic sepsis. Early selective faecal diversion in patients with perineal wounds can reduce sepsis and related mortality. The definitive method of stabilization of open pelvic fractures remains controversial. Internal fixation can be done when no gross contamination is present. Otherwise, external fixation is preferred when faecal or environmental contamination is present.
Bleeding associated with pelvic ring fractures usually comes from the small to medium-sized arteries and veins in the surrounding soft tissues and from the bone itself. After blunt trauma, the most common pelvic arteries injured are the superior gluteal artery, internal pudendal, obturator, and lateral sacral arteries. Occasionally, large vessels such as the femoral artery or the common iliac artery or vein are lacerated or torn. An arteriogram is diagnostic. Alternatively, contrast enhanced CT allows the early diagnosis of arterial bleeding. Arterial injuries causing significant bleeding occur only in about 10% of pelvic fractures, and surgery for repair or bypass is urgently required if there is distal ischemia.
It is now well recognized that patients with pelvic fractures have a high incidence of thrombosis of the pelvic veins and, less frequently, of the femoral vein. Those treated with bed rest compound the risk of deep vein thrombosis and secondary pulmonary embolus. More trauma centers now use intermittent pneumatic compression after trauma and pharmacologic anticoagulation once the acute hemorrhagic phase has passed (24–48 hours). Severely traumatized patients with contraindications for pharmacological anticoagulation may benefit from temporary vena cava filters.
Neurologic injuries are common, with an overall incidence between 10% and 15% in pelvic fractures and are a common cause of disability following pelvic fracture. After unstable vertical shear sacral fractures the incidence rises to 50%. They involve either the roots (L5, S1) as they travel in or around the sacral foramen, or the peripheral nerve itself (sciatic, femoral, obturator, pudendal, or superior gluteal). Neurologic injury following closed or open reduction is not uncommon. Thus it is of paramount importance that a thorough neurologic examination be performed and recorded as soon as possible, searching for sensory or motor deficits in the distribution of all previously mentioned nerves. Peripheral nerve injuries have, overall, a better prognosis than root injuries. Partial nerve injuries also have a better outcome than complete ones. Most of the lesions are of the neurapraxia type, with favorable outcome. It is still accepted that nearly 10% have clinically significant permanent neurologic sequelae.
Urogenital injuries are also common, especially in men. The incidence of bladder rupture and urethral disruption is estimated at 5–10% for each. These injuries should be suspected in the conscious patient who is unable to void or who has gross hematuria. Other signs include bloody urethral discharge, swelling or ecchymosis of the penis or perineum, or a high-riding or "floating" prostate on rectal examination. A retrograde urethrogram should be obtained before attempting to introduce a Foley catheter. If unremarkable, catheterization can be safely undertaken and a cystogram obtained later. When a partial or complete urethral disruption is diagnosed, a suprapubic cystostomy should be performed. Late sequelae are common and include urethral strictures, sexual dysfunction, and impotence.
Injuries to the Pelvic Ring
Pelvic ring fractures account for 3% of all fractures. There is an extremely wide spectrum between the innocuous avulsion fracture and the life-threatening severely unstable pelvic ring disruption. The choice between different treatment modalities revolves around one key issue: Is the fracture pattern stable or unstable?
From the anatomic standpoint, the posterior sacroiliac ligamentous complex is the single most important structure for pelvic stability. Injuries involving the pelvic ring in two or more sites create an unstable segment. The integrity of the posterior sacroiliac ligamentous complex will determine the degree of instability. Inlet and outlet views and CT scanning are necessary imaging techniques to make this determination. When intact, the hemipelvis will be rotationally unstable but vertically stable. When disrupted, the hemipelvis will be both rotationally and vertically unstable.
Classification & Treatment
Tile devised a dynamic classification system based on the mechanism of injury and residual instability (Table 3–4).
Type A: Fractures that involve the pelvic ring in only one place and are stable.
Type A1: Avulsion fractures of the pelvis, which usually occurs at muscle origins such as the anterosuperior iliac spine for the sartorius, anteroinferior iliac spine for the direct head of the rectus femoris, and ischial apophysis for the hamstring muscles. These fractures occur most often in the adolescent, and conservative treatment is usually sufficient. On rare occasions, symptomatic nonunion occurs, and this is best dealt with surgically.
Type A2: Stable fractures with minimal displacement. Isolated fractures of the iliac wing without intraarticular extension usually result from direct trauma. Even with significant displacement, bony healing is to be expected, and treatment is, therefore, symptomatic. On rare occasions, the soft tissue injury and accompanying hematoma may heal with significant heterotopic ossification.
Type A3: Obturator fractures. Isolated fractures of the pubic or ischial rami are usually minimally displaced. The posterior sacroiliac complex is intact, and the pelvis is stable. Treatment is symptomatic, with bed rest and analgesia, early ambulation, and weight bearing as tolerated.
Type B: Fractures that involve the pelvic ring in two or more sites. They create a segment that is rotationally unstable but vertically stable.
Type B1: Open-book fractures occur from anteroposterior compression. Unless the anterior separation of the pubic symphysis is severe (>6 cm), the posterior sacroiliac complex is usually intact and the pelvis relatively stable. Significant injury to perineal and urogenital structures is often present and should always be looked for. One should remember that fragment displacement at the time of injury might have been significantly more than what is apparent on radiograph. For minimally displaced symphysis injuries, only symptomatic treatment is needed. The same applies for the so-called straddle (four rami) fracture. For more displaced fracture-dislocations, reduction is done by lateral compression using the intact posterior sacroiliac complex as the hinge on which "the book is closed." Reduction can be maintained by external or internal fixation. "Closing the book" decreases the space available for hemorrhage. It also increases patient comfort, facilitates nursing care, and allows earlier mobilization, which is beneficial to the polytrauma patient.
Type B2 and B3: Lateral compression fractures. A lateral force applied to the pelvis causes inward displacement of the hemipelvis through the sacroiliac complex and the ipsilateral (B2) or, more often, contralateral pubic rami (B3, bucket-handle type). The degree of involvement of the posterior sacroiliac ligaments will determine the degree of instability. The posterior lesion may be impacted in its displaced portion, affording some relative stability. The hemipelvis is infolded, with overlapping of the symphysis. Major displacement requires manipulation under general anesthesia. This should be done soon after injury because disimpaction becomes difficult and hazardous after the first few days. Reduction can be maintained with external or internal fixation, or both. External fixation alone decreases pain and makes nursing care easier but is not strong enough for ambulation if the fracture is unstable posteriorly.
Type C: Fractures that are both rotationally and vertically unstable. They often result from a vertical shear mechanism, like a fall from a height. Anteriorly, the injury may fracture the pubic rami or disrupt the symphysis pubis. Posteriorly, the sacroiliac joint may be dislocated or there may be a fracture in the sacrum or in the ilium immediately adjacent to the sacroiliac joint, but there is always loss of the functional integrity of the posterior sacroiliac ligamentous complex. The hemipelvis is completely unstable. Three-dimensional displacement is possible, particularly proximal migration. Massive hemorrhage and injury to the lumbosacral nerve plexus are common. Indirect radiologic clues of pelvic instability should be looked for such as avulsion of the sciatic spine or fracture of the ipsilateral L5 transverse process. Reduction is relatively easy, with longitudinal skeletal traction through the distal femur or the proximal tibia. If chosen as definitive treatment, traction should be maintained for 8–12 weeks. Bony injuries heal quicker than ligamentous injuries. External fixation alone is insufficient to maintain reduction in highly unstable fractures, but it may help control bleeding and eases nursing care. Open reduction and internal fixation is often required. The surgical technique is demanding, and there is a significant risk of complications. It is best left to experienced pelvic surgeons.
Long-term complications of unstable pelvic ring disruptions are more frequent and disabling than once thought. Of those patients with residual displacement of more than 1 cm, fewer than 30% are pain free at 5 years. Chronic low back pain and posterior sacroiliac pain is the most frequent long-term complaint, approaching 50% in some series. Nearly 5% of type C injuries are left with a leg length discrepancy of more than 2–5 cm. Residual gait abnormalities are present in 12–32% of cases. The overall nonunion rate is around 3%.
Clinically significant neurologic deficit is present in 6–10% of patients, but abnormal electromyographic findings are present in up to 46%. Long-term urologic complications include urethral strictures in 5–20% of cases and impotence in 5–30% of cases.
Fractures of the Acetabulum
The acetabulum results from the closure of the Y or triradiate cartilage and is covered with hyaline cartilage.
Fractures of the acetabulum occur through direct trauma on the trochanteric region or indirect axial loading through the lower limb. The position of the limb at the time of impact (rotation, flexion, abduction, or adduction) will determine the pattern of injury. Comminution is common.
The acetabulum appears to be contained within an arch. It is supported by the confluence of two columns and enhanced by two walls. The posterior column is the strongest one and where more space is available for fixation. It begins at the dense bone of the greater sciatic notch and extends distally through the center of the acetabulum to include the ischial spine and ischial tuberosity. The inner surface forms the posterior wall, and the anterior surface forms the posterior articular surface of the acetabulum. The anterior column extends from the iliac crest to the symphysis pubis. The anterior column rotates 90° just above the acetabulum as it descends. The medial part of the anterior column is the true pelvic brim. The quadrilateral plate is the medial structure preventing medial displacement of the hip, and is an independent structure between the two columns. The acetabular dome or weight-bearing area extends from the bone posterior to the anterior inferior iliac spine to the posterior column.
Letournel has classified acetabular fractures based on the involved column. Fractures may involve one or both columns in a simple or complex pattern.
Proper fracture classification requires good-quality radiographs. Two oblique views (Judet views) taken 45 degrees toward and away from the involved side complement the standard anteroposterior view of the pelvis. The obturator oblique view is obtained by elevating the fractured hip 45 degrees from the horizontal. This view shows the anterior column and the posterior lip of the acetabulum, and the iliac wing is perpendicular to its broad surface. In this view, the spur sign can be identified in 95% of cases of both-column fractures (Type C), and it corresponds to the area of the iliac wing above the acetabular roof. The Iliac oblique view is obtained by elevating the non-fractured hip 45°. This view best shows the posterior column, including the ischial spine, the anterior wall of the acetabulum, and the full expanse of the iliac wing. In addition, inlet and outlet pelvic views can be complimentary used if any doubt about pelvic ring compromise is present.
CT scanning gives further information on the fracture pattern, the presence of free intraarticular fragments, and the status of the femoral head and the rest of the pelvic ring.
Letournel has classified acetabular fractures into 10 different types: 5 simple patterns (one fracture line) and 5 complex patterns (the association of two or more simple patterns) (Figure 3–31). This is the most widely used classification system, as it allows the surgeon to choose the appropriate surgical approach.
The goal of treatment is to attain a spherical congruency between the femoral head and the weight-bearing acetabular dome, and to maintain it until bones are healed. As with other pelvic fractures, acetabular fractures are frequently associated with abdominal, urogenital, and neurologic injuries, which should be systematically sought and treated. Significant bleeding can be present and should be addressed as soon as possible. Examination of the knee ligaments and vascular status of the extremities is mandatory. A careful neurologic examination is necessary. Sciatic nerve compromise occurs in 20% of cases. The peroneal branch is often involved. Also, the tibial branch of the sciatic nerve, the femoral nerve, and the lateral femoral cutaneous nerve can be involved depending upon the fracture pattern and mechanism. Prophylaxis and surveillance for deep vein thrombosis (DVT) should be started soon after trauma. The reported incidence of DVT in patients with pelvic fractures has been as high as 60%.
The stabilized patient should be put in longitudinal skeletal traction through a distal femoral or proximal tibial pin pulling axially in neutral position. A trochanteric screw for lateral traction is contraindicated, as it will create a contaminated pin tract and thus preclude possible further surgical treatment. Postreduction radiographs are obtained. In general, a displaced acetabular fracture is rarely reduced adequately by closed methods. If the reduction is judged acceptable, traction is maintained for 6–8 weeks until bone healing is evident. Another 6–8 weeks is necessary before full weight bearing can be attempted. Surgical indications include intraarticular displacement of 2 mm or more, an incongruous hip reduction, marginal impaction >2 mm, or intraarticular debris. The choice of approach is of primary importance, and sometimes more than one approach will prove necessary. Acetabular surgery uses extensile approaches and sophisticated reduction and fixation techniques and is best performed by trained pelvic surgeons. Other surgical indications include free osteochondral fragments, femoral head fractures, irreducible dislocations, or unstable reductions.
Complications inherent to the injury include posttraumatic degenerative joint disease, heterotopic ossification, femoral head osteonecrosis, deep vein thrombosis, and other complications related to conservative treatment. Surgery is performed to prevent or delay osteoarthritis, but increases the possibility of complications such as infection, iatrogenic neurovascular injury, and increased heterotopic ossification. When the reduction is stable and fixation is solid, the patient can be mobilized after a few days with non-weight–bearing ambulation, and weight bearing may begin as early as 6 weeks. Most pelvic surgeons now routinely use postoperative prophylactic anticoagulation and heterotopic bone formation prophylaxis with irradiation or indomethacin, or both.