Plastic surgery

PART VIII

HAND

CHAPTER 76  MANAGEMENT OF WRIST FRACTURES

SANDEEP JACOB SEBASTIN AND KEVIN C. CHUNG

The wrist is one of the most complex joints in the body and links the forearm to the hand. Anatomically the wrist consists of eight carpal bones, but functionally it extends from the distal forearm to the base of the metacarpals and includes the distal ends of the radius and the ulna, eight carpal bones, and the bases of the metacarpals (Figure 76.1). The distal radius and ulna refer to the distal 2 to 3 cm metaphyseal (cancellous) portion of these two bones.1 The carpal bones are arranged in two rows. The proximal row includes the scaphoid, lunate, and the triquetrum and the distal row includes the trapezium, trapezoid, capitate, and the hamate. The pisiform is a sesamoid bone in the tendon of the flexor carpi ulnaris (FCU) and lies palmar to the triquetrum.2 This complex architecture of the wrist is maintained by the inherent geometry of the bones that are held together by numerous extrinsic and intrinsic ligaments (Chapter 81). This joint configuration maintains stability and allows for transfer of loads from the hand, while providing tremendous mobility. This chapter discusses the management of fractures of the wrist with emphasis on the distal radius and the scaphoid with brief mention of avascular necrosis of the lunate (Kienbock disease).

DISTAL RADIUS FRACTURES

A fracture of the distal radius and/or ulna is the most common fracture seen by physicians accounting for 15% to 20% of all fractures. There is a bimodal age distribution, with peaks of incidence occurring in the youth and in the elderly.3,4 In the younger population, these fractures are most often the result of high-energy trauma such as motor vehicle accidents or falls from a height. In the elderly population, however, these fractures frequently result from falls from a standing height and other low-energy trauma.5 Although the overall gender rates are similar, the fractures in men tend to occur in the younger group, whereas there is a preponderance of females in the elderly group due to osteoporosis. In the United States, approximately 280,000 fractures occur in working-age persons and the economic impact of these injuries is considerable, as patients take an average of 12–16 weeks to return to work. Approximately 10% of 65-year-old white women will experience a distal radius fracture in their lifetime and the annual incidence of distal radius fractures in the US population over the age of 65 has been reported to be 57–100 per 100,000. These numbers will rise in the future because the “Baby Boomers” are aging and individuals are living longer and lead healthier and more active lives compared to previous generations.6

FIGURE 76.1. The bones of the wrist as seen from the volar surface.

Anatomy

The ulna articulates proximally with the humerus and represents the stable unit of the forearm. The radius (with the associated carpus and hand) rotates around the ulna at the proximal and distal radioulnar articulations.3 The volar surface of the distal radius is relatively flat, whereas the dorsal surface is convex and closely related to the overlying extensor tendons. The volar cortex of the distal radius is also considerably thicker than the dorsal cortex. The distal ends of the radius and ulna articulate with the proximal carpal row. The distal end of the radius has three articular fossae (Figure 76.2). The most radial is the triangular scaphoid fossa with the radial styloid at its apex. An anteroposterior ridge (interfacet ridge) separates the scaphoid fossa from the lunate fossa. The sigmoid fossa is located along the distal ulnar surface of the radius and articulates with the ulnar head.7 It has a poorly defined proximal margin, but well-defined distal, volar, and dorsal margins.8 The carpus is separated from the distal end of the ulna by the triangular fibrocartilage complex (TFCC). The TFCC originates on the ulnar border of the lunate fossa and inserts onto the base of the ulnar styloid.9

Biomechanics

Approximately 80% of the axial load across the wrist is transmitted through the distal end of the radius and 20% across the TFCC and the distal end of the ulna.3 Most fractures of the radius occur at the metaphysis because it is mostly spongy cancellous bone. Fractures may be either extra-articular or intra-articular involving the radiocarpal and/or distal radioulnar joint/s (DRUJ). Extra-articular fractures often follow a fall on an outstretched, extended hand. Because the dorsal cortex is thinner compared to the volar cortex, it is frequently comminuted and results in the classic dinner fork deformity (dorsal displacement with dorsal tilt [loss of normal volar tilt], radial tilt [loss of radial inclination], and shortening [loss of height]).10 Intra-articular fractures usually result from higher energy trauma and the fracture pattern depends on the magnitude and direction of force and the quality of bone and soft tissues. The lunate can exert pressure on its fossa causing a die-punch fracture. A multifragmentary intra-articular fracture pattern with four large fracture fragments is often seen. These fragments are the radial styloid, the radial shaft, and volar and dorsal lunate fossa fragments.1Occasionally the articular surface is sheared off to produce a fracture subluxation of the wrist. Other deforming forces around the distal radius include the insertion of the brachioradialis on the radial styloid, associated injuries to the ulnar styloid or the TFCC that can lead to DRUJ instability, and intercarpal injuries that can lead to carpal instability.11

FIGURE 76.2. The distal articular surface of the radius and ulna.

FIGURE 76.3. Standard PA radiograph of wrist. A. Positioning for a wrist PA radiograph. B. A correctly positioned PA view showing the ECU groove radial to the ulnar styloid.

FIGURE 76.4. Standard lateral radiograph of wrist. A. Positioning for a wrist lateral radiograph. B. A correctly positioned lateral view showing the pisiform (white dotted lines) overlying the distal scaphoid (green dotted lines) and the capitate (red dotted lines).

History and Physical Examination

The key elements in the history are the mechanism of injury to determine the energy involved and the direction of force transmission. This information is useful in assessing severity of injury and likelihood of associated ligament and nerve injuries.7 The patient should be questioned about pain in the hand, elbow, and shoulder and sensation in the median nerve distribution. The patient should also be questioned about handedness, occupation, medical history, social history, and recreational activities to determine the functional demands on the injured wrist.2,3

The involved wrist as well as the elbow and the contralateral upper limb are examined. Focal tenderness in the anatomic snuffbox suggests a scaphoid fracture. Tenderness 1 cm distal to the Lister tubercle suggests a scapholunate ligament injury. Median nerve function is evaluated by assessing sensibility at the fingertips. We use the ‘ten test’ to perform a quick assessment.12 A decrease in sensibility compared with the normal side may indicate the need for median nerve decompression.

Radiographic Evaluation

The posteroanterior (PA) and lateral radiographs are routine. The PA view is obtained with the shoulder in 90° abduction, the elbow in 90° flexion, and the wrist and forearm in neutral rotation (Figure 76.3A).13 In a true standard PA view, the groove for the tendon of the extensor carpi ulnaris should be at the level or radial to the base of the ulnar styloid (Figure 76.3B).9 The lateral view is obtained with the shoulder in 90° adduction, elbow in 90° flexion, and the hand positioned in the same plane as the humerus (Figure 76.4A). In a true lateral view, the palmar cortex of the pisiform should overlie the central third of the interval between the palmar cortices of the distal scaphoid and the head of the capitate (Figure 76.4B).

Three radiographic measurements on standard PA and lateral views correlate with patient outcome: radial height, radial inclination, and volar tilt (Figure 76.5).9,11,13 The radial height is measured on a PA radiograph as the distance between a line perpendicular to the long axis of the radius passing through the distal tip of the sigmoid notch at the distal ulnar articular surface of the radius and a second perpendicular line at the tip of the radial styloid. Normal radial height averages 10 to 14 mm. The articular surface of the radius has a radial to ulnar slope (radial inclination) and a dorsal to volar slope (volar tilt).

The radial inclination is also measured on a PA radiograph and represents the angle between one line connecting the tip of the radial styloid and the ulnar aspect of the distal radius and the second line perpendicular to the longitudinal axis of the radius. The normal radial inclination ranges between 20° and 25°. The volar tilt is measured on a lateral radiograph and represents the angle between the line along the distal articular surface of the radius and a line perpendicular to the longitudinal axis of the radius. The normal volar tilt averages 11° and has a range of 5° to 15°. An additional radiographic parameter that is useful is ulnar variance. Ulnar variance refers to the distance between the articular surface of the ulnar head and the ulnar border of the lunate fossa. It is described as neutral when both are at the same level: ulnar plus, when the ulna is longer; and ulnar minus, when the ulna is shorter (Figure 76.6). Normal ulnar variance can range from 0 ± 2 mm.

FIGURE 76.5. Measurement of radiographic parameters of the distal end of the radius [Radial height (red dotted lines), radial inclination (white dotted lines), and volar tilt (green dotted lines)].

FIGURE 76.6. Measurement of ulnar variance.

Plain radiography may be insufficient in the assessment of the comminuted, grossly displaced, and complex intra-articular fractures. Computed tomography (CT) is performed in such cases (Figure 76.7). CT should also be considered when a detailed evaluation of an articular step or gap is required. Magnetic resonance imaging (MRI) is useful when concomitant ligamentous injuries are suspected or fractures are suspected but not visualized on routine radiographs (Chapter 81). A dynamic fluoroscopic examination is also useful for detecting carpal instability.

Classification

Many eponyms and classification systems have been used to describe distal radius fractures. A list of common eponyms has been provided because they are frequently used in clinical practice (Figure 76.8). The commonly used classification systems include the Frykman,14 Melone,15 Fernandez,16 Mayo Clinic,17 and the AO18 (Association for the Study of Internal Fixation) classifications. The Frykman, Melone, Mayo clinic, and the AO classifications focus on the fracture pattern, whereas the Fernandez classification is based on the mechanism of injury. We use the AO classification in our practice. It divides the fractures into three broad groups (A. Extra-articular; B. Partial involvement of articular surface; and C. Involvement of entire articular surface). These are then subdivided into 9 subtypes or 27 distinct fracture patterns (Figure 76.9).

Treatment

The aim of treatment of distal radius fractures is to restore normal anatomy (radial height, volar tilt, and articular congruity) because this is believed to correlate with functional outcome.1,13,19 Based on the radiographic findings, fractures may be classified as stable or unstable. Stable fractures do not displace at presentation or following manipulative reduction.20 They present with minimal displacement, have dorsal angulation less than 5°, and radial shortening less than 2 mm.21 Stable fractures can be managed with cast immobilization. In contrast, unstable fractures cannot be reduced or the reduction cannot be maintained. The factors that have been associated with instability following closed reduction are listed in Table 76.1.22,23 Age of the patient, dorsal comminution, and increased ulnar variance (>3 mm) are the most important predictors of collapse with cast treatment.24 Unstable distal radius fractures require surgical intervention to maintain reduction. Multiple surgical options are available that include percutaneous pin fixation, external fixation, open reduction and plate fixation, intramedullary fixation, and arthroscopically assisted fixation.

FIGURE 76.7. CT images of a comminuted intra-articular distal radius fracture demonstrate the comminuted and impacted “die-punched” articular fragments.

FIGURE 76.8. Common eponyms used to describe distal radius fractures.

While there is no consensus, the current trend is toward internal fixation of unstable fractures.3 Insufficient data exist to support any particular treatment method. Although age is not a contraindication to surgical treatment, one must take into account the functional demands of the patient. Available evidence shows no difference between casting and surgical fixation of unstable distal radius fractures in the elderly, defined by age (>55 years), low functional demand, and poor bone quality with low-energy injuries.6

Closed Reduction and Plaster Immobilization. This is the initial treatment for most distal radius fractures. It relies on ligamentotaxis to pull the fracture out to length, uses the intact soft tissues to reduce the displaced fragments, and requires a three-point pressure splint to maintain the reduction. Closed reduction needs relaxation of the local musculature with adequate analgesia. It can be performed under general anesthesia, axillary, or intravenous regional anesthesia, but usually it is performed under a hematoma block by infiltrating 5 to 7 mL of local anesthetic into the fracture site.

There are a number of ligaments that extend from the distal radius to the carpal bones. By putting longitudinal traction on the hand, these ligaments are stretched and pull the impacted distal radius fragments with them. In the common Colles fracture, the volar periosteum is torn, however the dorsal soft tissue (periosteum and the extensor tendon sheath) is intact. This dorsal soft tissue hinge is the key to the reduction. The traditional reduction maneuver consists of three steps: (1) Longitudinal traction for a few minutes to assist in muscle relaxation; (2) Application of a force in the direction of the deformity to disimpact the fracture fragments; and (3) Application of force opposite to the direction of deformity to reduce the fracture (Figure 76.10).25

We tend not to use the traditional maneuver to reduce Colles fractures as it requires extreme hyperextension and flexion. Instead we apply strong longitudinal traction by pulling on the thumb, index, and the long finger, while an assistant provides counter-traction at the distal arm just proximal to the elbow. Sustained traction is maintained for 5 to 7 minutes. Thereafter pressure is applied in a palmar direction on the dorsum of the distal radius (the distal fracture fragment) along with slight pronation and ulnar deviation to reduce the fracture (Figure 76.11).26,27

Once reduction is complete, it must be maintained by keeping the dorsal soft tissue hinge under tension. This is done by using a three-point pressure splint. Two points of pressure are on the dorsum of the forearm proximal and distal to the fracture site and one point is on the volar side corresponding to the fracture (Figure 76.12). Three-point pressure cannot be given by a simple dorsal splint or a volar splint. It needs a dorsoradial splint or a sugar-tong splint.28 We prefer the use of a sugar tong splint because forearm rotation can be controlled and it immobilizes the DRUJ.27 It is important to avoid extremes of wrist flexion and ulnar deviation (Cotton-Loder position) that can result in iatrogenic median nerve compression, extensor tendon tightness, and weaken flexion from decreased excursion of flexors. The splint should also not extend beyond the proximal palmar crease to allow full flexion of the metacarpophalangeal joint.

A cast is generally not applied after the initial reduction in the emergency room because subsequent swelling may lead to skin breakdown or compartment syndrome. Radiographs are repeated to evaluate restoration of the radiographic parameters, to evaluate articular congruity, and assess severity of comminution. Patients are seen within 1 week after reduction for repeat radiography. If the reduction is maintained, the splint is exchanged for a cast. Patients are typically seen again 1 week after cast placement to ensure that fracture reduction is not lost. Surgical intervention may be needed if there is loss of reduction.9

FIGURE 76.9. The AO classification of distal radius fractures.

Percutaneous Pinning. This technique is suitable for unstable fractures that can be reduced but the reduction cannot be maintained using plaster. Pinning by itself is inadequate for fractures with significant metaphyseal comminution and/or articular instability. The use of intraoperative fluoroscopy has greatly enhanced the accuracy of pin placement and allows confirmation of fracture reduction. 1.6 mm (0.062 inches) Kirschner wires (K-wires) are usually used. After reduction, the K-wire is passed in a distal to proximal direction entering the tip of the radial styloid, across the fracture to the proximal ulnar cortex of the diaphysis. One or two additional K-wires can be placed in a crossed fashion. Another technique popularized by Kapandji is “intrafocal pinning.” Here the K-wire is used to achieve reduction as well as maintain the reduction (Figure 76.13). The initial wire is introduced through the fracture site in a radial to ulnar direction. Once the wire reaches the ulnar cortex, it is used as a lever to elevate the radial fragment to restore radial height and inclination. The wire is then driven through the ulnar cortex to hold the reduction. Another wire is introduced through the fracture site at 90° to the first in a dorsal to volar direction and in a similar manner used to restore volar tilt. A third wire may be passed through the radial styloid across the fracture site for additional stability.29

FIGURE 76.10. The traditional maneuver for reduction of a Colles fracture. A. Fracture disimpaction by longitudinal traction and dorsiflexion. B. Fracture reduction by continued traction, flexion and ulnar deviation.

FIGURE 76.11. Maneuver preferred by the authors for reduction of a Colles fracture. A. Fracture disimpaction by sustained longitudinal traction. B. Fracture reduction by palmar directed pressure on dorsum with slight flexion and ulnar deviation.

FIGURE 76.12. The three point pressure splint. A. Producing and holding the reduction by maintaining the dorsal tissue hinge under tension and compressing the volar cortex (small red arrows). Note the three points of pressure (large red arrows). Two on the dorsum (distal and proximal to the fracture) and one on the volar aspect (at the level of the fracture). B. Maintaining the three points of pressure by using a dorsoradial plaster slab.

Pinning is usually combined with a short arm splint. The K-wires are removed 4 to 6 weeks later and the patient is started on range of motion exercises coupled with a protective splint until the fracture is clinically healed. Pinning is associated with the risk of pin tract infection and impaling the superficial radial nerve that may lead to chronic regional pain syndrome (CRPS). It is important to make a sufficiently long skin incision at proposed pin insertion sites and dissect the soft tissue so that the pin can be placed safely (open pin placement versus percutaneous pin placement).

External Fixation. External fixators work by holding the fracture out to length and neutralizing compressive, bending, and torsional forces across the fracture site. External fixation is useful in patients with highly unstable fractures with significant metaphyseal comminution as they allow alignment of the articular surface with the shaft of the radius (Figure 76.14). They cannot, however, be used to reduce displaced intra-articular fractures. This technique is also useful in cases where the risk of infection is high or significant edema precludes safe open reduction and internal fixation (ORIF).It is usually used in conjunction with other forms of fixation most often with K-wires. Many different types of external fixator frames are available that differ in variation of pin placement, rigidity in different planes, ability to adjust fracture reduction, and whether the fixator frame spans the radiocarpal joint (bridging versus non-bridging). In bridging external fixator, a set of pins are placed in the second metacarpal and another set in the proximal radial shaft, thus spanning the radiocarpal joint. In a non-bridging external fixator, the distal group of pins is placed in the articular fragment of the distal radius. This design prevents stiffness resulting from excessive ligamentotaxis and immobilization of the wrist. However a large and stable distal fragment is necessary for pin placement.10,19 A variation of the external fixator frame is a percutaneously placed dorsal fixator plate (bridge plating) that extends from the diaphysis of the radius to the second or third metacarpal. This “fixator-internal” is especially useful in polytrauma patients, where external fixation makes nursing care difficult.30

FIGURE 76.13. Result of Kapandji technique of “intrafocal pinning” in an extra-articular distal radius fracture in an elderly patient (AO A2 type).

The interval for safe passage of the proximal external fixator pins is between the tendons of the extensor carpi radialis longus and the extensor carpi radialis brevis approximately 10 to 15 cm proximal to the radial styloid. The distal pins are inserted along the dorsal lateral aspect of the index metacarpal. It is important to ensure that the pins are bicortical to prevent subsequent pin loosening.7 The use of external fixators in osteoporotic bone can be challenging due to risk of pin loosening and loss of reduction. Other complications associated with external fixator frames include pin tract infection, superficial radial nerve injury, and CRPS.31

FIGURE 76.14. External fixation combined with percutaneous pinning in a poly-trauma patient with a comminuted intra-articular distal radius fracture (AO C3 type).

Open Reduction and Internal Fixation. Open reduction and plate fixation allows direct reduction of the fracture, maintains the reduction rigidly, and is associated with a decreased period of immobilization and an earlier return of wrist function. Dorsal and volar approaches to the distal radius have been described. The dorsal approach uses a longitudinal incision in line with the Lister tubercle. The 3rd extensor compartment is opened and the extensor pollicis longus (EPL) transposed subcutaneously. The second and fourth compartments are elevated off the distal radius to expose the fracture. The volar approach uses the standard Henry approach between the radial artery and the flexor carpi radialis (FCR) protecting the palmar cutaneous branch of the median nerve on the ulnar aspect of the FCR. The flexor pollicis longus (FPL) is retracted ulnarly, the pronator quadratus (PQ) incised along the radial border of the radius, and elevated as an ulnarly based flap to expose the fracture.32

Traditionally a dorsal approach was used, because this allowed the plate to buttress the dorsally displaced fracture. The dorsal approach permits direct visualization of the articular surface, allows concomitant treatment of intercarpal ligament injuries, and is indispensable in dorsal shearing fractures. It is also easier to bone graft from the dorsum as the metaphyseal bone is thinner and frequently comminuted. However dorsal plating fell out of favor in the late 1990s and early 2000s as earlier generations of dorsal plates were associated with soft tissue complications resulting from the close proximity of the extensor tendons to the distal radius. This resulted in tendon irritation or ruptures and often required routine removal of the plate or other procedures. In addition, early motion following the use of nonlocked dorsal plates could result in loosening of the distal screws, especially in osteoporotic patients with metaphyseal comminution. The newer generation low-profile dorsal locking plates, however, has been shown to be as equally effective in maintaining reduction following fracture fixation without increased risks of complications when compared with volar plates (Figure 76.15).33

Currently, most hand surgeons prefer the volar approach for the majority of distal radius fractures (Figure 76.16). The PQ forms a barrier between the implant and the flexor tendons minimizing the tendon complication rate. The fixed angle plate with locked screws maintains reduction more effectively, providing subchondral support, and resisting secondary displacement even in the presence of osteoporotic bone. The need for bone grafting is reduced compared to dorsal plating. A direct visualization of the articular surface is not possible from the volar approach and one must be careful not to elevate the volar carpal ligaments off the volar rim of the distal radius. Volar plating is not without complications. Improperly placed plates can result in irritation and rupture of the FPL at the distal border of the plate. Overpenetrated screw tips can result in rupture of extensor tendons. There is also risk of the distal subchondral screws penetrating the joint. This is difficult to assess on standard PA and lateral views and a 22° elevated lateral view or a 45° pronated oblique view is often required to rule out joint penetration (Figure 76.17).19

FIGURE 76.15. The use of a low profile dorsal locking plate in a patient with a comminuted intra-articular distal radius fracture (AO C3 type).

FIGURE 76.16. The use of a low profile volar locking plate to address a partial articular distal radius fracture (AO B3 type).

Fragment-specific fixation, which uses small contoured plates on specific components of the fracture, is another. The smaller size of the implants decreases tendon irritation and allows the use of smaller volar and/or dorsal incisions minimizing soft tissue disruption. The distal unstable fragment is reduced and fixed to the proximal shaft. Stable fixation is achieved by smaller implants because they are aligned in an orthogonal fashion.34 Recently, a new class of implants has been introduced that uses a fixed angle subchondral support fixed to an intramedullary stem and locked by metaphyseal screws. Less dissection is required to place the implant and there is no tendon irritation as the device is intramedullary.35 A combined dorsal and volar approach may be occasionally required to achieve reduction and fixation in complex high-energy intra-articular fractures. In such cases it is preferable to stabilize the volar rim first by a volar approach. The volar wound is then closed and a dorsal approach used to reduce and fix intra-articular fracture fragments or place bone grafts. Rarely a bridging external fixator may be required.

Arthroscopic Assisted Fixation. Wrist arthroscopy allows direct visualization of the articular surface, manipulation of individual articular fragments using small pointed probes, and fixation of the fragments with K-wires. Arthroscopy is also valuable in the diagnosis and treatment of concomitant ligament injuries of the wrist especially the scapholunate and lunotriquetral interosseous ligaments and the triangular fibrocartilage complex. The use of arthroscopy has not been associated definitively with superior outcomes. There is a substantial learning curve and it increases the operative time.19,36

FIGURE 76.17. The use of a 22° elevated lateral view to rule out joint penetration by the distal screws. The radiograph on the left represents the fixation in Figure 76.15 (dorsal locking plate) and the radiograph on the right represents the fixation in Figure 76.16 (volar locking plate). 

Associated Injuries

It is important to evaluate the entire upper extremity to identify any associated musculoskeletal or neurovascular injuries such as shoulder dislocation, elbow fracture/dislocations, brachial plexus injuries, or vascular injuries. The following wrist injuries are frequently associated with distal radius fractures.

Ulnar Styloid Fractures. A concomitant ulnar styloid fracture is seen in more than 50% of distal radius fractures but not all ulnar styloid fractures require repair. Operative intervention depends on the stability of the DRUJ. Basal fractures of the ulnar styloid and those with greater than 2 mm of displacement were found to affect DRUJ stability.37,38 When there is suspicion of DRUJ instability based on radiographic appearance, the opposite normal wrist is examined for translational laxity of the DRUJ in neutral, full supination, and full pronation. Once the distal radius fracture has been repaired, the surgeon should examine the injured wrist and compare it with the normal side. If the DRUJ is lax, especially in full supination, the ulnar styloid is repaired. K-wires, tension band wire, or a cannulated headless screw can be used (Figure 76.18). The forearm should be immobilized in neutral rotation for 4 to 6 weeks using a sugar tong or Munster type splint.

Distal Radial Ulnar Joint Instability. In addition to an ulnar styloid/neck/head fracture, DRUJ instability may result from an intra-articular fracture involving the sigmoid fossa or a tear of the TFCC. The stability of the DRUJ should be reassessed after fixation of the fractures. If the DRUJ is stable in full supination, one can consider immobilizing the forearm in supination for 3 weeks, neutral position for the following 3 weeks, and then start mobilization. If the DRUJ is stable only in full pronation, the forearm should not be immobilized in pronation as it is difficult to regain supination postoperatively. In these cases it is preferable to reduce the DRUJ in neutral (mid-prone) position and maintain the reduction using two parallel 0.062 inch (1.6 mm) K-wires passed below the ulnar head into the radius.7 If the DRUJ is unstable in all positions, one must consider a tear of the radioulnar ligaments (RUL), which is usually an avulsion of the RUL from their foveal insertion. Direct bone anchor repair of the RUL is required with pinning of the radius and ulna for 4 to 6 weeks.

Carpal Ligamentous Injuries. They are frequently associated with high-energy trauma especially those resulting in radiocarpal fracture–dislocations and avulsion of the radial styloid. Arthroscopic studies have shown a 30% incidence of scapholunate ligament injury and 15% incidence of lunotriquetral ligament injury following a distal radius fracture.39 All patients with a distal radius fracture should be assessed for associated ligament injuries. This can be done after fixation of the radius by doing a fluoroscopic assessment of the carpus in radial and ulnar deviation and flexion and extension. An arthroscopic assessment is ideal when injury to these ligaments is suspected. Complete interosseous ligament injuries in young and active individuals will need exploration and bone anchor repair, whereas partial ligament injuries can be managed by pinning the respective joints under fluoroscopy. The pins are cut under the skin to prevent pin tract infection and maintained for 4 to 6 weeks.

Median Nerve Dysfunction. The median nerve can be injured by blunt contusion during the injury, by stretch of the nerve over the angulated fracture fragment, or from fracture hematoma within the carpal tunnel. It is important to obtain history of preexisting carpal tunnel symptoms and do a quick ‘ten test’ to assess sensibility in the fingertips. If the nerve symptoms (paresthesias, numbness, etc.) do not improve or worsen within 24 to 48 hours after satisfactory closed reduction, one must perform early carpal tunnel release and surgical stabilization of the fracture. However, there is no evidence to support routine release of the carpal tunnel at the time of operative fixation in patients without preoperative evidence of median nerve dysfunction.40

FIGURE 76.18. Delayed presentation of DRUJ instability with non-union of the ulnar styloid. A. Pre-op radiograph demonstrating dorsal subluxation of the radius relative to the ulna, with displaced ulnar styloid shown by arrow. B. Late postoperative radiograph showing tension band wiring of the ulnar styloid with TFCC re-insertion using a bone anchor.

Complications

The long-term complications reported after distal radius fractures include stiffness of the fingers and wrist, CRPS, attritional rupture of tendons, malunion, ulnar-sided wrist pain, and degenerative arthritis involving the radiocarpal and radioulnar joints.5 Mild forms of CRPS are common with distal radius fractures especially those treated with casting and/or percutaneous pins. Patients with increasing pain, joint stiffness, and paresthesias will need early attention and referral to a pain management service. The use of supplemental vitamin C after distal radius fractures was found to significantly reduce the incidence of CRPS.40 Spontaneous rupture of the EPL is an uncommon complication after distal radius fractures. It is believed to result from ischemia of tendon as a result of compression by fracture hematoma within the third extensor compartment. It is usually associated with an undisplaced or minimally displaced extra-articular fracture when the increased intracompartmental pressure within the third extensor compartment is not released with the surgical procedure. The treatment of choice is a transfer of the extensor indicis proprius to restore thumb extension (Chapter 80). The other cause of tendon rupture is irritation by a plate or screw tip.

Malunion of the distal radius is common and may be extra-articular, intra-articular, or both. Only symptomatic malunion requires operative intervention. Elderly low-demand patients who are pain free and function well despite significant radiographic deformity require no intervention. However, malunion in young adults with higher functional demands can result in pain, loss of motion, and deformity. If there is greater than 25° to 30° of dorsal tilt or 6 mm of discrepancy between the radius and ulna, surgical intervention is required. This may include a corrective osteotomy (lengthening) of the distal radius or a shortening osteotomy of the ulna.9 The distal radius osteotomy aims to restore radial height, volar tilt, and radial inclination and improves the flexion/extension arc of motion (Figure 76.19). The ulnar osteotomy is indicated for ulnar impingement and ulnar-sided wrist pain. The Darrach procedure (resection of the ulnar head) is the procedure of choice in elderly patients with ulnar-sided wrist pain. Limited or total wrist fusion or a Sauve-Kapandji procedure may be indicated in symptomatic patients with radiocarpal and radioulnar arthritis, respectively.

FIGURE 76.19. Osteotomy of the radius for correction of a malunited distal radius fracture. A. Pre-op radiographs showing loss of radial height and inclination and significant dorsal tilt with an ulnar positive variance. B. Early postoperative radiograph demonstrating correction of radiographic parameters after a corrective osteotomy of the radius.

CARPAL FRACTURES

Carpal fractures account for 6% to 7% of all carpal injuries and 18% of hand fractures. The scaphoid and triquetrum are the most frequently fractured accounting for 79% and 14% of all carpal fractures. The incidence of isolated fractures of any of the remaining carpal bones is 1%.41 Carpal fractures are often associated with fractures of other carpal bones, fracture of the distal radius, and ligamentous instability of the carpus. These fractures are a diagnostic challenge because of their infrequency and the difficulty in detecting them on initial conventional radiographs. Missed carpal fractures have a high risk of developing degenerative arthritis resulting in a chronically painful wrist.

Scaphoid Fractures

Scaphoid fracture occurs most often in young men as a result of a fall on an outstretched hand. In the United States, approximately 345,000 scaphoid fractures occur per year.42 These fractures are rare in children because the carpal bones have not completely ossified and the distal radius physis tends to fracture first.

Anatomy. The scaphoid is boat shaped (scaphos [Greek] = skiff) and concave in both the ulnar and palmar directions. It is anatomically divided into three parts, namely the distal pole, waist, and the proximal pole. The tubercle is the distal and palmar protuberance of the scaphoid. Over 80% of the scaphoid is covered with articular cartilage. Approximately 70% to 80% of the blood supply of the scaphoid arises from dorsal branches of the radial artery that enter at the level of the waist. The remaining 20% to 30% of the blood supply is via palmar braches of the radial artery that enter via the distal tubercle. The proximal pole of the scaphoid is vascularized by retrograde flow and explains the slower union and increased tendency for proximal pole fractures to go into avascular necrosis (AVN).41

Biomechanics. The scaphoid links the proximal and distal carpal rows. It assumes a flexed foreshortened posture in radial deviation and wrist flexion and an extended and elongated posture on ulnar deviation and wrist extension. A fall on the outstretched hand causes the proximal aspect of the scaphoid to impact on the dorsal rim of the distal radius resulting in palmar tensile and dorsal compressive forces causing a fracture through the scaphoid waist. Another mechanism of injury is a pure compressive force like in an automobile accident. Approximately 75% to 80% of scaphoid fractures occur at the waist, 10% to 15% occur at the proximal pole, and 5% to 10% occur at the distal pole including the tuberosity.43 The displacement of a scaphoid fracture depends on the direction and degree of force and the plane of the fracture. Scaphoid fractures heal by intramembranous ossification. There is no fracture callus to provide initial stability. If the wrist is loaded before union occurs, it can lead to progressive flexion and pronation of the distal scaphoid, especially in unstable or displaced fractures. The distal scaphoid fragment has a tendency to flex and the proximal fragment extends by virtue of its attachment to the lunate. This combined with the resorption of bone on the volar aspect will lead to a “humpback” or flexion deformity of the scaphoid.9

History and Physical Examination. There will be history of fall on an extended wrist and pain over the scaphoid. There will be swelling and loss of the normal concavity of the anatomical snuffbox and pain on moving the wrist and the thumb. Tenderness can be elicited on deep palpation in the snuffbox or over the scaphoid tuberosity or on axial loading of the first metacarpal thus compressing the scaphoid. Patients presenting subacutely may complain of vague ache in the wrist with loss of motion or strength.

Radiographic Evaluation. In addition to the standard PA and lateral views of the wrist, one should obtain 45° pronated and supinated oblique views, and a PA clenched fist view in ulnar deviation (Figure 76.20). Ulnar deviation places the scaphoid in an extended posture and brings it more completely in view. The clenched fist will accentuate any scapholunate widening and distract any unstable fracture fragments. Approximately 8% to 20% of scaphoid fractures are not evident on initial X-ray. If there is a high clinical suspicion, but no radiographic evidence of a fracture, a thumb spica cast is applied and follow-up radiographs done 10 to 14 days later. This may show bone resorption at the fracture site.41 If the plain radiographs are still negative, one can consider bone scintigraphy, CT scan, or an MRI. Although bone scintigraphy is sensitive, it is nonspecific and increased uptake may indicate arthrosis or synovitis. A CT scan is better for assessing bony anatomy; 2 mm sagittal cuts parallel to the long axis of the scaphoid are ideal. An MRI is useful in detecting occult scaphoid fractures, assessing the vascularity, especially in delayed union or nonunion, and ruling out any associated ligamentous injuries. An acute scaphoid fracture shows a low signal intensity at the fracture line and high signal intensity on the surrounding bone marrow on T2 images. AVN of the proximal pole is evident as dark signal intensity on T1 and T2 images.42 Gadolinium enhancement can improve the MR evaluation of proximal pole vascularity.

Classification. Scaphoid fractures have been classified based on fracture location, plane of the fracture, and stability. Russe classified scaphoid fractures based on the plane of the fracture into horizontal oblique, transverse, and vertical oblique. He felt that vertical oblique fractures were unstable, difficult to control with immobilization, and had a higher risk of nonunion.44 Herbert and Fisher classified fractures based on their stability into stable acute (type A), unstable acute (type B), delayed union (type C), and nonunion (type D) (Figure 76.21). In their opinion all complete fractures of the waist and proximal pole were unstable (type B). The only stable fracture patterns were tubercle fracture (type A1) and an incomplete waist fracture (type A2).45 However neither classification predicts fracture union. We agree with Herbert’s concept of scaphoid fractures and fix all unstable fracture patterns (fracture line traverses the entire scaphoid).

Treatment. A scaphoid fracture with greater than 1 mm displacement, comminution, angulation (intrascaphoid angle greater than 35°; height to length ratio greater than 0.65), open fracture, and/or associated carpal instability (scapholunate angle greater than 60°; radiolunate angle greater than 15°) is considered as an unstable fracture pattern and surgical treatment is indicated.42 In addition surgery is recommended in patients with a proximal pole fracture or where the diagnosis and treatment have been delayed. The proximal pole fracture may heal with prolonged casting (up to 6 months). Complications from disuse of the arm are high with such a long period of immobility, which supports surgical fixation of proximal pole fractures. The indications for conservative treatment with a cast include stable, undisplaced waist and tuberosity fractures that are diagnosed soon after injury. We recommend internal fixation for undisplaced scaphoid waist fractures in the young and active patients in preference to casting. Early internal fixation reduces the problems associated with the long period of cast immobilization such as stiffness of the wrist, decreased grip strength, and delayed return to work.46

Conservative Treatment. A thumb spica cast is applied for 8 to 12 weeks until radiographic union is evident. There is no consensus whether the cast should include the elbow or the thumb interphalangeal joint. Our preference is to give a short arm cast that excludes the thumb interphalangeal joint and the elbow. A union rate of over 95% has been shown in undisplaced scaphoid waist fractures and 70% in undisplaced proximal pole fractures, when treatment is started within 3 weeks of injury. If fracture union is in doubt, healing should be monitored with serial radiographs or CT scans.

FIGURE 76.20. Scaphoid views showing a displaced scaphoid wrist fracture.

FIGURE 76.21. Herbert classification of scaphoid fractures.

Surgical Treatment. The headless compression screw introduced by Herbert and Fisher in 1984 has become the accepted standard surgical treatment of scaphoid fractures. The greatest advantage of this technique is that the screw can be recessed below the articular cartilage. Technological advances using cannulated headless screws and better instrumentation combined with improved intraoperative fluoroscopy have made placement of the screw easier.

The screw can be placed through dorsal or palmar approaches either by an open technique or a percutaneous technique (Figure 76.22). The dorsal open approach provides better exposure of the proximal pole and allows easier screw placement, but has a risk of disrupting the tenuous dorsal blood supply. The palmar open approach preserves the blood supply, but disrupts the radiocarpal ligaments and provides poor exposure of the proximal pole. The palmar approach is needed to reduce humpback deformity by prying open the collapsed scaphoid and inserting a cortical bone graft strut to restore scaphoid length. The percutaneous technique is useful in patients with undisplaced or minimally displaced fractures and avoids damaging the blood supply or the ligaments. It has been combined with wrist arthroscopy to ensure anatomic reduction and detect any concomitant ligament injuries. Irrespective of the approach, the important aspect of screw fixation of the scaphoid is to place the screw in the long axis of the scaphoid. Recognizing that the long axis of the scaphoid tilts approximately 45° palmarly and 45° radially is important when the screw is inserted.47

FIGURE 76.22. Scaphoid fracture. A. Preoperative radiograph showing scaphoid fracture (arrow). B. Open reduction internal fixation of scaphoid fracture with a headless cannulated screw.

Complications. The most important complication of a scaphoid fracture is nonunion. Other complications include malunion and radiocarpal arthritis. Nonunion results from a delay in diagnosis or treatment allowing the two fracture fragments to move independent of each other creating a fibrous interphase between the distal and proximal scaphoid. Other factors that can lead to nonunion include insufficient immobilization, fracture comminution, fracture displacement, and poor patient compliance. Scaphoid nonunion can also occur following operative treatment due to inadequate screw length, eccentric screw placement, or failure to achieve compression across the fracture site. If left untreated, scaphoid nonunion will lead to a predictable pattern of arthritic change beginning at the radial styloid articulation with the distal scaphoid pole, the radioscaphoid articulation, followed by the midcarpal joint, and ultimately by pancarpal arthritis. This sequence of changes has been termed as scaphoid nonunion advanced collapse (SNAC).

The treatment of nonunion depends on the location of the fracture, degree of collapse, vascularity of the proximal pole, and presence of any arthritic change. If there is no collapse or humpback deformity, screw fixation with cancellous bone graft is adequate. Bone graft may be obtained either from the distal radius, the olecranon, or the iliac crest. Iliac crest bone harvested using a trephine is ideal. The use of distal radius bone graft may compromise the use of vascularized bone grafts needed for later reconstruction. If there is associated collapse or a humpback deformity, the fracture should be approached volarly and a corticocancellous wedge-shaped bone graft used to correct the deformity and a screw or K-wires used to immobilize the scaphoid until union is complete.

Scaphoid nonunions with avascular necrosis of the proximal pole require vascularized bone grafting. Many different vascularized bone grafts have been described.48,49 The most widely used is a bone graft from the dorsoradial aspect of the distal radius that is vascularized by the 1, 2-intercompartmental supraretinacular artery (1, 2-ICSRA). Other vascularized bone grafts include the 2, 3-ICSRA and the 4, 5-extracompartmental artery (ECA) from the dorsum of the distal radius and the PQ-based graft from the volar aspect of the distal radius. The use of a vascularized bone graft from the medial femoral condyle as a free flap is becoming increasingly popular. This requires microsurgical anastomosis of the donor vessels to the radial artery and its venae commitantes. The main advantage of this graft is that it can be placed on the volar side and corrects the humpback deformity in addition to revascularizing the proximal pole. A rare cause of AVN of the scaphoid is Preiser disease or idiopathic AVN. There is no history of previous fracture and it is believed to be caused by repetitive microtrauma. Other suggested factors include alcoholism, corticosteroids, chemotherapy, and systemic lupus erythematosus. It is seen more often in women (3:1) and patents present with dorsoradial wrist pain. MRI is the investigation of choice and the treatment options are similar to scaphoid nonunion with an avascular proximal pole.

Patients with arthritic change will need a salvage procedure depending on the extent of the arthritic change and the functional demands of the patient. If the arthritis involves only the radial styloid, radial styloidectomy combined with bone grafting of the scaphoid may be attempted in the young active patient. In the older patient and in patients with more extensive arthritis, the options include scaphoid excision and four-corner fusion (fusion of the lunate-triquetrum-hamate-capitate) or proximal row carpectomy (excision of the scaphoid, lunate, and triquetrum such that the capitate articulates with the lunate fossa of the radius). Proximal row carpectomy (PRC) is useful when the arthritic changes are restricted to the radioscaphoid joint. If there is arthritic change of the capitate, a four-corner fusion is indicated. In advanced SNAC with involvement of the radiolunate joint, the treatment of choice is a wrist arthrodesis.

Lunate Fracture

Fractures of the lunate are quite rare except in association with Kienbock disease (idiopathic avascular necrosis of the lunate discussed in the next section). Dorsal chip fractures of the lunate may be confused with dorsal fractures of the triquetrum on plain radiographs. Patients with lunate fractures have tenderness immediately distal to the Lister tubercle. The suggested treatment is cast immobilization for 4 to 6 weeks for undisplaced and chip fractures and ORIF for large displaced fractures.50

Kienbock Disease. Kienbock disease (avascular necrosis of the lunate) is common in men between the ages of 20 and 40 years. The etiology is unknown and possible causes include abnormalities in blood supply of the lunate and repetitive trauma. Negative ulnar variance, flatter than normal radial inclination, and the geometry of the lunate itself are believed to predispose an individual to Kienbock disease.51

History and Physical Examination. Patients may present with remote history of trauma and complain of wrist pain with limitation of motion. This may range from mild discomfort to constant debilitating pain depending on the stage of the disease. There may be history of fall on an extended wrist. Physical examination may show a swelling suggestive of reactive synovitis over the dorsum of the wrist with weakness of grip and pain on motion. There is also tenderness over the lunate.

Radiographic Evaluation. Standard PA and lateral views of the wrist are obtained. In a young patient with unexplained mid-dorsal wrist pain and normal radiographs, further evaluation with an MRI is indicated. The MRI will be able to pick up early AVN before radiographs show positive findings. There will be evidence of bone marrow edema initially followed by decreased vascularity of the lunate (decreased signal intensity on T1 weighted images limited to the lunate). With progressive disease, the radiographs will demonstrate fractures, sclerosis, collapse, loss of carpal alignment, and progressive degenerative changes of the radiocarpal and midcarpal joints. Lichtman has modified the Stahl classification of Kienbock disease (Table 76.2)52 and this is useful in treatment planning.

Treatment. Patients with stage I disease are managed conservatively with immobilization (cast) and activity modification. The treatment of patients with stage II and stage IIIA disease is directed toward improving the vascularity of the lunate by revascularization procedures or by decreasing the axial load on the lunate or a combination of both procedures. Revascularization procedures include use of pedicled vascularized bone grafts from the base of the 2nd or 3rd metacarpal or from the dorsum of the distal radius. The selection of unloading procedures depends on the ulnar variance. If the patient has positive ulnar variance, a capitate shortening or capitohamate fusion can be considered. If the patient has a negative or neutral ulnar variance, a radial shortening osteotomy is carried out (Figure 76.23).

In patients with stage IIIB disease, one can consider scaphotrapeziotrapezoid (STT) fusion or scaphocapitate fusion to unload the radiolunate and restore carpal height. If there is significant synovitis associated with collapsed lunate, the lunate can be excised. In stage IV disease, the options are limited to PRC and wrist fusion. The radiolunate joint must be evaluated before considering a PRC. If it is grossly arthritic, the only option is a wrist fusion.

Triquetrum Fracture

This is the second most common carpal bone to be fractured after the scaphoid. Fractures of the triquetrum may occur in isolation or be part of a more complex injury like a perilunate fracture–dislocation. Isolated triquetral fractures can either be a dorsal rim chip fracture or involve the body.53 Chip fracture usually represents an avulsion of the dorsal radiotriquetral ligament. Body fractures represent a high-energy injury and one must be suspicious for other associated injuries. Patients present with dorsal hand and wrist edema and restricted range of flexion. They also have tenderness on palpation just distal to the ulnar styloid. The fracture can usually be visualized on an oblique or lateral view radiograph. Occasionally, a CT scan may be necessary to confirm the diagnosis. Dorsal chip fractures and undisplaced body fractures can be managed with 4 to 6 weeks of cast immobilization. The exception to this is the instance where a dorsal chip fracture is associated with flexion of the lunate as a result of complete lunotriquetral dissociation following failure of the lunotriquetral and dorsal radiotriquetral ligamentous restraints. Symptomatic nonunited avulsion fragments may need excision. Displaced body fractures and those associated with carpal instability will need ORIF.

Pisiform Fracture

Pisiform fractures result from a direct blow like a fall on the palm of the hand. Patients present with tenderness over the base of the hypothenar eminence. A carpal tunnel view or a supinated oblique view may be necessary to visualize the fracture. Cast immobilization for 4 to 6 weeks is the treatment of choice. Malunion can lead to pisotriquetral arthritis that may require excision of the pisiform at a later date. Excision usually does not compromise the strength of wrist flexion.

Hamate Fracture

A hamate fracture may involve the body, the dorsal rim, or the hook of the hamate. Body fractures are rare and usually follow a direct injury to the ulnar aspect of the wrist or a dorsopalmar crush. Dorsal rim coronal fractures occur following an axial force, as in a fist fight.54 These injuries are frequently associated with fracture–dislocation/subluxation of the fourth and fifth carpometacarpal joints. The hook of the hamate fracture classically occurs following a stick-handling sport like golf or hockey or following repetitive trauma from holding a handle too tightly. These patients usually do not recall a specific traumatic incident and present with pain and weakness of grip especially of the small and ring fingers. Late cases may even present with attritional rupture of the flexor tendons to the small and ring finger and ulnar nerve dysfunction. It is difficult to pick up this injury on standard radiographs. A carpal tunnel view and a 30° palmar tilted lateral projection are useful in visualizing fractures of the hook of the hamate. The most reliable diagnostic study is a CT scan. Hook of hamate fractures are frequently recognized late, after it has progressed to nonunion. In these cases the treatment is subperiosteal excision of the hook, taking care to protect the motor branch of the ulnar nerve. ORIF with a screw can be attempted if the diagnosis is made acutely.

FIGURE 76.23. Kienbock Disease. A. MRI, with arrow showing avascular lunate. B. Vascularized bone graft (to revascularize the lunate [arrow]) coupled with radial shortening osteotomy (to take pressure off of the lunate) is an effective treatment for advanced stages of Kienbock disease.

Capitate Fracture

Isolated capitate fractures are rare and usually occur along with a perilunate injury. This injury is known as a scaphocapitate fracture syndrome and results in waist fractures of the scaphoid and the capitate. The proximal capitate fragment may end up rotated 180° with the fracture surface pointed proximally. The injury can easily be missed on a routine radiograph and a CT scan is necessary for an accurate diagnosis. Anatomic reduction is required to restore carpal kinematics. ORIF with a cannulated, headless screw is optimal. Fractures of the capitate waist may progress to AVN; however nonsurgical treatment is preferred for AVN of the capitate as patients often remain asymptomatic.55

Trapezoid Fracture

Isolated trapezoid fractures are extremely rare and usually seen along with an injury to the index finger carpometacarpal joint (CMCJ). It is important to achieve anatomic reduction to prevent arthrosis of the CMCJ. Malunited fractures may necessitate arthrodesis at a later date.

Trapezium Fracture

Isolated trapezium fractures are also uncommon and occur in association with first metacarpal or distal radius fractures. The Robert view (hyperpronated AP view) or the Bett view (semipronated hand with ulnar palm resting on the X-ray plate and X-ray beam centered on the scaphotrapeziotrapezoid joint) allow visualization of the injury.9,55 Undisplaced fractures are treated with cast immobilization for 4 weeks. Unstable fractures or those with articular incongruity will need ORIF. Patients with median nerve symptoms will need carpal tunnel release.

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