AAOS Comprehensive Orthopaedic Review

Section 2 - General Knowledge

Chapter 22. Neuro-Orthopaedics and Rehabilitation

I. Spinal Cord Injuries

A. General principles


1. Approximately 400,000 people in the United States have spinal cord damage.


2. Leading causes of spinal cord injury are motor vehicle accidents, gunshot wounds, falls, and sports and water injuries.


3. Patients are generally categorized into two groups:


a. Younger individuals who sustained the injury from significant trauma


b. Older individuals with cervical spinal stenosis caused by congenital narrowing or spondylosis; these patients often sustained the injury from minor trauma and commonly have no vertebral fracture spinal injury.


B. Definitions


1. Tetraplegia—Loss or impairment of motor or sensory function in the cervical segments of the spinal cord with resulting impairment of function in the arms, trunk, legs, and pelvic organs.


2. Paraplegia—Loss or impairment of motor or sensory function in the thoracic, lumbar, or sacral segments of the spinal cord. Arm function is intact, but, depending on the level of the cord injured, impairment in the trunk, legs, and pelvic organs may be present.


3. Complete injury—An injury with no spared motor or sensory function in the lowest sacral segments. Patients with complete spinal cord injury who have recovered from spinal shock have a negligible chance for any useful motor return (

Table 1).


4. Incomplete injury—An injury with partial preservation of sensory or motor function below the neurologic level and includes the lowest sacral segments.


C. Neurologic impairment and recovery


1. Spinal shock


a. Diagnosis of complete spinal cord injury cannot be made until spinal shock has resolved, as evidenced by the return of the bulbocavernosus reflex. To elicit this reflex, the clinician digitally examines the patient's rectum, feeling for contraction of the anal sphincter while squeezing the glans penis or clitoris.


b. If trauma to the spinal cord causes complete injury, reflex activity at the site of injury does not return because the reflex arc is permanently interrupted.


c. When spinal shock disappears, reflex activity returns in the segments below the level of injury.


[Table 1. ASIA Impairment Scale]

2. Recovery


a. The International Standards for Neurologic and Functional Classification of Spinal Cord Injury, published by the American Spinal Injury Association (ASIA) and the International Medical Society of Paraplegia (IMSOP), represents the most reliable instrument for assessing neurologic status in the spinal cord. These standards provide a quantitative measure of sensory and motor function.


b. Assessment


i. The change in ASIA Motor Score (AMS) between successive neurologic examinations should be determined. The AMS is the sum of strength grades for each of the 10 key muscles tested bilaterally that represent neurologic segments from C5 to T1 and L2 to S1.


ii. In a neurologically intact individual, the total possible AMS is 100 points.


D. Spinal cord syndromes


1. Anterior cord syndrome


a. Anterior cord syndrome results from direct contusion to the anterior cord by bone fragments or from damage to the anterior spinal artery.


b. Depending on the extent of cord involvement, only posterior column function (proprioception and light touch) may be present.


c. The ability to respond to pain and light touch signifies that the posterior half of the cord has some intact function.


2. Central cord syndrome


a. Central cord syndrome can be understood on the basis of the spinal cord anatomy. Gray matter in the spinal cord contains nerve cell bodies and is surrounded by white matter consisting primarily of ascending and descending myelinated tracts. Central gray matter has a higher metabolic requirement and is therefore more susceptible to the effects of trauma and ischemia.


b. Central cord syndrome often results from a minor injury such as a fall in an older patient with cervical spinal canal stenosis.


c. Most patients can walk despite severe paralysis of the upper limb.


3. Brown-Sequard syndrome


a. Brown-Sequard syndrome is caused by a complete hemisection of the spinal cord.


b. This results in a greater ipsilateral proprioceptive motor loss and greater contralateral loss of pain and temperature sensation.


c. Affected patients have an excellent prognosis and usually will ambulate.


4. Mixed syndrome


a. Mixed syndrome is characterized by a diffuse involvement of the entire spinal cord.

b. Affected patients have a good prognosis for recovery.


c. As with all incomplete spinal cord injury syndromes, early motor recovery is the best prognostic indicator.


E. General management strategies


1. Prevention of contractures and maintaining range of motion should begin immediately following the injury.


2. Maintaining skin integrity is crucial to spinal injury care. Only 4 hours of continuous pressure on the sacrum is sufficient to cause full-thickness skin necrosis.


3. Intermittent catheterization has been the factor most responsible for decreasing urologic problems and for providing an increased life span of patients with spinal cord injuries.


F. Complications


1. Autonomic dysreflexia


a. Splanchnic outflow conveying sympathetic fibers to the lower body exits at the T8 region.


b. Patients with lesions above T8 are prone to autonomic dysreflexia.


c. Signs and symptoms include episodes of hypertension that may be heralded by dizziness, sweating, and headaches.


2. Heterotopic ossification (HO)


a. HO occurs between the muscles and joint capsule in 20% of patients with spinal cord injury, with a higher incidence in 20- to 30-year-olds.


b. HO is more common in cervical and thoracic-level injuries than in lumbar injuries.


c. A higher incidence of HO is seen in patients with complete lesions.


d. HO is most common at the hip, but it can occur at the knee.


e. If the functional range of motion of a joint is limited, the HO should be surgically excised.


G. Management of tetraplegia


1. C4 level function


a. The key muscles are the diaphragm and the trapezius and neck muscles.


b. Head control is present.


c. With a functioning diaphragm, long-term ventilatory support is generally not needed.


d. Tracheostomy and mechanical ventilatory assistance may be required initially.


2. C5 level function


a. Key muscles are the deltoid and biceps, which are used for shoulder abduction and elbow flexion.


b. Surgical goals are to provide active elbow and wrist extension and to restore the ability to pinch the thumb against the index finger.


c. Transferring the posterior deltoid to the triceps muscle provides active elbow extension.


d. Transferring the brachioradialis to the extensor carpi radialis brevis provides active wrist extension.


e. Attaching the flexor pollicis longus tendon to the distal radius and fusing the interphalangeal joint of the thumb provides for key pinch by tenodesis when the wrist is extended.


3. C6 level function


a. Key muscles are the wrist extensors, which enable the patient to manually propel a wheelchair, transfer from one position to another, and even live independently.


b. Surgical goals are to restore lateral pinch and active grasp.


c. Lateral pinch can be restored either by tenodesis of the thumb flexor or by transfer of the brachioradialis to the flexor pollicis longus.


d. Active grasp can be restored by transfer of the pronator teres to the flexor digitorum profundus.


4. C7 level function


a. The key muscle is the triceps.


b. All patients with intact triceps function should be able to transfer and live independently, if no other complications are present.


c. Surgical goals are active thumb flexion for pinch, active finger flexion for grasp, and hand opening by extensor tenodesis.


d. Transfer of the brachioradialis to the flexor pollicis longus provides active pinch.


e. Transfer of the pronator teres to the flexor digitorum profundus allows for active finger flexion and grasp.


f. If the finger extensors are weak, tenodesis of these tendons to the radius provides hand opening with wrist flexion.


5. C8 level function


a. Key muscles are the finger and thumb flexors, which enable a gross grasp.


b. A functioning flexor pollicis longus enables lateral pinch between the thumb and the side of the index finger.


c. Intrinsic muscle function is lacking, and clawing of the fingers usually is present.


d. Capsulodesis of the metacarpophalangeal joints corrects clawing and improves hand function.


e. Active intrinsic function can be achieved by splitting the superficial finger flexor tendon of the ring finger into four slips and transferring these tendons to the lumbrical insertions of each finger.

II. Stroke and Traumatic Brain Injury

A. Demographics


1. The annual incidence of stroke (cerebrovascular accident, or CVA) in the United States is 1 in 1,000.


a. Cerebral thrombosis causes nearly 75% of cases.


b. More than half of stroke victims survive; of those, 50% have hemiplegia.


2. In the United States, 410,000 new cases of traumatic brain injury can be expected each year.


a. Injury resulting from multiple traumatic injuries is twice as common in men as in women.


b. Most commonly, 15- to 24-year-olds are affected.


c. Half of all traumatic brain injuries result from motor vehicle accidents.


B. Management during neurologic recovery


1. Spasticity must be managed aggressively to prevent permanent deformities and joint contractures.


2. Spasmolytic drugs such as baclofen can be administered either orally or intrathecally.


3. Dantrolene is the drug of choice for treating clonus.


4. Casting and splinting have been shown to temporarily reduce muscle tone and are used to correct contractures. Dynamic splints must be monitored closely for skin effects.


5. Botulinum toxin injections into the spastic muscle provide a focal but temporary decrease in muscle tone.


C. Definitive management


1. Most motor recovery occurs within 6 months of onset in both types of patients.


2. Surgery can be considered to correct residual limb deformities at this time.


3. Surgical lengthening of musculotendinous units permanently decreases muscle tone and spasticity.

III. Lower Limb Deformities

A. Limb scissoring


1. Limb scissoring is a common problem caused by overactive hip adductor muscles.


2. It results in an extremely narrow base of support while standing and causes balance problems.


3. Surgical treatment options


a. If there is no fixed contracture of the hip adductors, transection of the anterior branches of the obturator nerve denervates the adductors, which allows the patient to stand with a broader base of support.


b. If there is a fixed hip contracture, surgical release of the adductor muscles is indicated.


B. Stiff-knee gait


1. Characteristics—Inability to flex the knee during swing phase, unrestricted passive knee motion, and a limb that appears to be functionally longer, but no difficulty sitting.


2. Inappropriate activity in the rectus femoris from preswing through terminal swing blocks knee flexion.


3. Abnormal activity is also common in the vastus intermedius, vastus medialis, and vastus lateralis muscles.


4. Circumduction of the involved limb, hiking of the pelvis, or contralateral limb vaulting may occur as compensatory maneuvers.


5. Surgical treatment options


a. Transfer of the rectus femoris to the gracilis tendon not only removes it as a deforming muscle force but also converts the rectus into a corrective flexion force.


b. When any of the vasti muscles are involved, they can be selectively lengthened at their myotendinous junction.


C. Hip and knee flexion deformity


1. Hip and knee flexion occur in concert and result in a crouched posture, which increases the physical demand on the quadriceps and hip extensor muscles, which must continually fire to hold the patient upright.


2. Surgical treatment options


a. Simultaneous surgical correction of the hip and knee flexion deformities is preferred.


b. The hip is approached through a medial incision, and the adductor longus and pectineus muscles are released.


c. The iliopsoas is recessed from the lesser trochanter.


d. Hamstring tenotomy eliminates the deformity, generally resulting in a 50% correction of the contracture at the time of surgery.


3. The residual joint contracture is then corrected by physical therapy or serial casting.


D. Equinus or equinovarus foot deformity


1. Surgical correction of an equinus deformity is achieved with Achilles tendon lengthening or a Strayer procedure.


2. Surgical correction of a claw toe deformity is achieved with release of the flexor digitorum longus and brevis tendons at the base of each toe. Transfer of the flexor digitorum longus tendon to the calcaneus offers additional support to the weakened calf muscles.


3. Surgical correction of a varus deformity


a. The tibialis anterior, tibialis posterior, and extensor hallucis longus are potentially responsible for the deformity.


b. Tendon transfers are indicated to rebalance the foot (

Figure 1).


i. A split anterior tibial tendon transfer diverts the inverting deforming force of the tibialis anterior to a corrective force. In this procedure, half of the tendon is transferred laterally to the cuboid.


ii. When the extensor hallucis longus muscle is overactive, it can be transferred to the dorsum of the foot.


iii. Lengthening of the tibialis posterior is indicated when this muscle exhibits increased activity.


c. After healing, 70% of patients can walk without an orthosis.

IV. Upper Limb Deformities

A. Shoulder deformities


1. Shoulder adduction and internal rotation deformities


a. These deformities are caused by spasticity and


[Figure 1. Equinovarus is the most common musculoskeletal deformity seen following a stroke or traumatic brain injury. A, Patient with an equinovarus foot deformity after a stroke. B, Same patient after surgery to correct the equinovarus foot deformity.]

   myostatic contracture of four muscles: the pectoralis major, the subscapularis, the latissimus dorsi, and the teres major.


b. Muscle contractures in a nonfunctional arm are surgically released through an anterior deltopectoral incision.


c. The subscapularis muscle can be released without violating the glenohumeral joint capsule.


2. Limited shoulder flexion


a. Antagonistic activity of the latissimus dorsi, teres major, and long head of the triceps muscles can obscure the fact that there is volitional control of the agonist muscles, the shoulder flexors.


b. Diminishing the increased muscle activity by fractional lengthening of the antagonist muscles can improve shoulder flexion.


B. Elbow flexion deformities


1. The patient has active movement.


a. Myotendinous lengthening of the spastic elbow flexors is indicated to correct the flexion deformity and improve function.


b. Surgical technique


i. The long and short biceps are lengthened proximally in the arm.


ii. The brachialis is lengthened at the elbow.


iii. The brachioradialis is lengthened in the forearm.


c. The patient can begin active motion immediately after surgery.


2. The patient has no active movement and a fixed elbow flexion contracture.


a. For fixed contracture in a nonfunctional arm, release of the contracted muscles is done through a lateral incision.


b. The brachioradialis muscle and biceps tendon are transected.


c. The brachialis muscle is released.


C. Wrist and finger flexion deformities in a functional hand


1. With active movement, myotendinous lengthening of the spastic wrist and finger flexors is indicated in the forearm.


2. The pronator teres and pronator quadratus also can be lengthened.


D. Clenched-fist deformity in a nonfunctional hand (

Figure 2)


1. Characteristics—Palmar skin breakdown and hygiene problems, recurrent infections of the nail beds, and compression of the median nerve when combined with a wrist flexion contracture.


2. Adequate flexor tendon lengthening to correct the deformity cannot be attained by fractional or myotendinous lengthening without causing discontinuity at the musculotendinous junction.


3. Recommended surgical technique is a superficialis-to-profundus tendon transfer.


a. This technique provides sufficient flexor tendon lengthening and preserves a passive tether to prevent a hyperextension deformity.


b. The wrist deformity is corrected by release of the wrist flexors.


c. Wrist arthrodesis maintains the hand in a neutral position and eliminates the need for a permanent splint.


[Figure 2. A, Patient with a clenched-fist deformity and no active function of the hand. B, Same patient after a superficialis-to-profundus transfer and wrist arthrodesis to correct the clenched-fist deformity.]

d. Because intrinsic muscle spasticity occurs in conjunction with severe spasticity of the extrinsic flexors, a neurectomy of the motor branches of the ulnar nerve in the Guyon canal also is routinely performed to prevent postoperative development of intrinsic deformities.


e. A neurectomy of the recurrent median nerve is also routinely performed to prevent a thumb-in-palm deformity.

V. Heterotopic Ossification

A. Characteristics


1. HO is characterized by formation of bone in non-skeletal tissue, usually between the muscle and joint capsule (

Figure 3).


2. HO usually develops within 2 months after a neurologic injury such as traumatic brain or spinal cord injuries.


a. In patients with spinal cord injuries, the hip is the site most commonly involved, followed by the knee, elbow, and (least commonly) the shoulder.


b. In patients with traumatic brain injury, the hip is most often affected, followed by the elbow, shoulder, and knee.


3. HO is generally visible on plain radiographs.


4. The etiology of HO is unknown, but a genetic predisposition is suspected.


B. Risk factors


1. Trauma greatly increases the incidence of HO in brain-injured patients.


2. Patients with massive HO usually have severe


[Figure 3. A, Radiograph of the pelvis showing HO of both hips associated with trauma in a brain-injured patient. B, Radiograph of an elbow with posterior HO. C, Radiograph demonstrating HO of the medial knee in a brain-injured patient.]

   spasticity and a higher recurrence rate following resection.


3. The completeness of a spinal cord lesion seems to be more predictive than the level of injury, although cervical and thoracic lesions seem to produce HO more often than lumbar lesions.


4. Soft-tissue damage, as occurs with decubitus ulcers, can be a predisposing factor.


5. Prolonged coma and young patient age (20 to 30 years) appear to increase the likelihood of HO formation.


C. Complications


1. Significant functional impairment, which can lead to a decline in a patient's ability to perform activities of daily living


2. Decreased joint range of motion, which increases the likelihood of pathologic fractures of osteoporotic bone during transfers or patient positioning and can lead to peripheral neuropathy by impinging adjacent nervous structures


3. Soft-tissue contractures of the surrounding skin, muscles, ligaments, and neurovascular bundles, which can contribute to the formation of decubitus ulcers


4. Skin maceration, often resulting in significant hygiene problems


5. Complex regional pain syndrome, which is more prevalent in patients with HO


6. Joint ankylosis, which frequently occurs as a result of HO


D. Treatment


1. Early treatment and prophylaxis


a. Although there is no proven prophylaxis, bisphosphonates and nonsteroidal anti-inflammatory drugs (NSAIDs) are the mainstays of early treatment.


b. Radiation is thought to inhibit HO formation by disrupting the process whereby mesenchymal cells differentiate into osteoblasts; however, no data support this.


c. Maintaining joint motion by treating spasticity and gentle physical therapy is the goal of early treatment.


2. Surgical treatment


a. Surgical excision is indicated when the HO interferes with function.


b. Preoperative assessment and planning are essential.


i. Radiographs—The maturity of HO can be assessed by the appearance of a bony cortex on radiographs. Judet views of the pelvis are useful to assess hip HO. Limited mobility and ability to position the patient makes radiographic studies difficult.


ii. CT is used in planning the surgical approach, with three-dimensional reconstructions particularly helpful in complex cases.


3. Surgical techniques


a. Wide exposure and identification of major vessels and nerves are important because HO often encases neurovascular tissues and can displace and/or compress adjacent tissues, which distort the normal anatomy.


b. Meticulous hemostasis and elimination of dead space decrease the risk of infection.


4. Complications


a. Hematoma and infection


b. Fractures of osteoporotic bone, either during surgery or later with physical therapy


c. Intraoperative bleeding requiring transfusion


d. Recurrence


e. Late development of osteonecrosis in patients who require extensive dissection


5. Postoperative management


a. Early gentle joint mobilization


b. Passive limb positioning for function


c. Prophylaxis for recurrence with bisphosphonates, NSAIDs, radiation, or a combination of these treatments. NSAIDs must be used with caution because of the risk of increased bleeding and hematoma formation.

VI. Physical Therapy and Occupational Therapy

A. Muscle weakness and physiologic deconditioning


1. Prolonged immobilization of extremities, bed rest, and inactivity lead to pronounced muscle wasting and physiologic deconditioning in a short period of time.


2. Disabled patients expend more energy than normal individuals in performing activities of daily living.


B. Aerobic metabolism


1. During sustained exercise, metabolism is mainly aerobic.


2. The principal fuels for aerobic metabolism are carbohydrates and fats.


3. In aerobic oxidation, substrates are oxidized through a series of enzymatic reactions that lead to the production of adenosine triphosphate (ATP) for muscular contraction.


4. A physical conditioning program can increase aerobic capacity by improving cardiac output, increasing hemoglobin levels, enhancing the capacity of cells to extract oxygen from the blood, and increasing the muscle mass by hypertrophy.


C. Areas of concern


1. Patient positioning


2. Mobility


3. Performance of activities of daily living


4. Making it possible for bedridden patients to sit can significantly improve quality of life and greatly enhance the opportunities to interact with other people.


5. For some patients, casts or orthotic devices may be required to maintain desired limb positions.


6. Aggressive joint motion exercises are necessary to prevent contractures.


D. Factors influencing a patient's ability to walk


1. Limb stability


2. Motor control


3. Good balance reactions


4. Adequate proprioception


E. Equipment and devices to aid in movement (eg, canes, walkers, wheelchairs)


1. These aids should always be of the least complex design to accomplish the goal.


2. They should be selected based on the patient's cognitive and physical levels of function.


F. Developing appropriate exercises and activities


1. Considerations include joint range of motion, muscle tone, motor control, and cognitive function of the patient.


2. Cognitive function considerations


a. Even confused and agitated patients may respond to simple, familiar functional activities such as face washing and teeth brushing.


b. Patients with higher cognitive function should be encouraged to carry out hygiene, grooming, dressing, and feeding activities.


G. Physical therapy prescription


1. Components include the diagnosis, functional deficits to be addressed, treatment goals, and any precautions or restrictions.


2. The prescription also should specify whether modalities can be used, the need for orthoses, and the weight-bearing capacity of the arm or leg.


3. The frequency and duration of the therapy also should be specified.

Top Testing Facts

1. A diagnosis of a complete spinal cord injury cannot be made until spinal shock has resolved as evidenced by return of the bulbocavernosus reflex.


2. Neurologic recovery after spinal cord injury is assessed by determining the change in AMS (the sum of strength grades for each of the 10 key muscles tested bilaterally that represent neurologic segments from C5 to T1 and L2 to S1) between successive neurologic examinations. (Review C4 through C7 levels of function.)


3. Management of the spinal cord-injured patient includes prevention of contractures and maintaining range of motion, maintaining skin integrity, and intermittent catheterization.


4. The incidence of HO is approximately 20% in patients with spinal cord injury. Surgical excision is indicated when the HO interferes with function.


5. A crouched posture increases the physical demand on the quadriceps and hip extensor muscles, which must continually fire to hold the patient upright. Simultaneous surgical correction of the hip and knee flexion deformities is the most desirable treatment.


6. Surgical correction of claw toe deformity requires release of the flexor digitorum longus and brevis tendons at the base of each toe.


7. Surgical correction of an equinovarus deformity is achieved with tendon transfers to rebalance the foot, including a split anterior tibial tendon transfer.


8. Wrist and finger flexion deformities in a functional hand are treated with myotendinous lengthenings.


9. The recommended surgical treatment for clenched-fist deformity in a nonfunctional hand is a superficialis-to-profundus tendon transfer.


10. Factors that influence a patient's ability to walk include limb stability, motor control, balance reactions, and adequate proprioception.


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