EMERGENCY DEPARTMENT EVALUATION AND TREATMENT OF WRIST INJURIES

ORTHOPEDIC EMERGENCIES, PART I

073%8627/99 $8.00

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EMERGENCY DEPARTMENT EVALUATION AND TREATMENT OF WRIST INJURIES James V. Ritchie, MD, and David W. Munter, MD, MBA

Evaluating wrist injuries in the emergency department (ED) is facilitated by a thorough working knowledge of surface and functional anatomy, injury mechanism, and radiologic nuances as well as an understanding of the limitations of the physical examination and radiographic studies. The physical examination can be more reliable than radiographs in some conditions, although swelling and generalized pain often limit the examination’s reliability. Knowing the pattern of injury associated with mechanisms frequently helps in interpreting unusual radiographs. Special radiographic views can be crucial in disclosing an occult fracture or ligamentous injury. ANATOMY OF THE WRIST

The bony components of the wrist include the distal radius and ulna, the carpals, and the proximal metacarpals. The distal radius ends in a smooth articulation with the scaphoid and lunate, as well as the distal radioulnar joint. The ulna has no direct articulation with any of the carpals; instead, a triangular fibrocartilagenous disk cushions the lunate and triquetrium and prevents an ulnar migration of the carpals. The ulnar styloid is prominent on the dorsal aspect of the wrist. The radial styloid is also prominently palpable, and the distal radius forms the proximal border of the anatomic snuffbox. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, the Department of Defense, or the US government.

From the Department of Emergency Medicine, Naval Medical Center, Portsmouth, Virginia

EMERGENCY MEDICINE CLINICS OF NORTH AMERICA VOLUME 17 * NUMBER 4 * NOVEMBER 1999

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Figure 1. The wrist and articulations. A, Metacarpals and phalanges. B, Trapezium. C, Carpals. D, Scaphoid. €, Distal radius. Lunate. G, Triquetrium. H, Pisiform. /, Capitate. J, Hamate. K, Trapezoid.

The carpals are arranged into two functional arches (Fig. 1). The proximal row, from radial to ulnar, comprises the scaphoid, lunate, triquetrium, and pisiform. The distal row, in like manner, is composed of the trapezium, trapezoid, capitate, and hamate. Three substantial extrinsic bands of ligament support the carpals. Two are volar, the proximal band supporting the lunate, and the distal band supporting the capitate. The third is dorsal and is less substantial. In addition, smaller intercarpal ligaments stabilize each carpal articulation. Bearing the largest radial articulation as well as bridging and connecting the two carpal arches, the scaphoid is the most often stressed and most often fractured carpal. Dorsal Landmarks The radial styloid defines the most radial aspect of the wrist’s dorsal surface (Fig. 2). Immediately adjacent, the anatomic snuffbox is bordered by the distal radius, extensor pollicis brevis tendon, and extensor pollicis

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Figure 2. Dorsal anatomic landmarks. A, Radial styloid. B,Extensor pollicis brevis tendon. C, Anatomic snuffbox. D, Extensor pollicis longus. €, Lister’s tubercle. F; Dorsal wrist depression. G, Ulnar styloid.

longus tendon. The scaphoid is palpable deep in the anatomic snuffbox, which can be obscured by edema if the scaphoid is injured. Lister’s tubercle on the surface of the edge of the radius is palpable ulnar to the extensor pollicis longus tendon. Distal to the radial edge, ulnar to Lister’s tubercle, and proximal to the second and third metacarpal rays lies a depression. The capitate is palpable deep in this depression when the wrist is held in a neutral position. In palmar flexion, the lunate becomes palpable here superficially. The triquetrium is palpable distal to the ulnar styloid. Palmar Surface Landmarks

Proximal to the base of the hypothenar eminence lies the readily palpable pisiform, a sesamoid bone (Fig. 3). Immediately distal and radial to the pisiform lies the less palpable hook (or hamulus) of the

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Figure 3. Palmar anatomic landmarks from radial to ulnar margins. A, Radial styloid. 6, Scaphoid tubercle. C,Carpal tunnel. 0,Hamulus. f,Pisiform.

hamate. Radial to the pisiform at the distal palmar crease at the most ulnar base of the thenar eminence lies the scaphotrapezial ridge. The scaphoid tubercle forms the more proximal and ulnar aspect of this palpable ridge, and the trapezium tubercle forms the more distal and radial aspect. Bridging the gap between the pisiform and hamulus on the ulnar side and the scaphoid and trapezium on the radial side is the flexor retinaculum, which covers the carpal tunnel. Note that ulnar deviation of the wrist results in a rotary motion of the scaphoid, diminishing the prominence of the scaphoid tubercle but bringing the scaphoid into a more superficial and immediately palpable location in the snuffbox. Vascular supply to the wrist is through the radial and ulnar arteries. Arterial supply to the scaphoid and lunate is counterintuitive, entering the bones distally. Consequently, proximal fractures of these carpals are more predisposed to nonunion. The median nerve courses along with the flexor tendons through

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the carpal tunne2 (Fig. 4), bordered by the pisiform and hamate on the ulnar side and the scaphoid and trapezium on the radial side and roofed by the flexor retinaculum. The ulnar nerve passes to the radial side of the pisiform, then to the ulnar side of the hamulus, through Guyon's canal (Fig. 5). CLINICAL EVALUATION OF THE WRIST

Knowing the mechanism of injury is a useful but often ignored aspect of evaluating a wrist injury. Most wrist injuries are caused by a fall-on-the-outstretched-hand (FOOSH) mechanism. Some specific injuries, however, should be suspected when a different mechanism caused the injury. Extreme dorsiflexion can result in a perilunate or lunate dislocation. Smith fractures (i.e., volar-displaced distal radius fractures) follow a palmar flexion or blow to the dorsum of the wrist. Triquetrium chip fractures also follow a dorsal blow. Careful inspection for a pisiform or hamate fracture should be performed after a blow to the hypothenar base.l' The patient's age predisposes for certain types of injury. Children more often injure the radial epiphysis, as the cartilaginous carpals are fractured infrequently. Young adults tend to injure the scaphoid and stabilizing ligaments. Older adults, especially those with osteoporosis, more frequently fracture the radius." Inspection reveals focal swelling, ecchymoses, or deformity, al-

Figure 4. Carpal tunnel. A, Pisiform. B,Hamulus. C,Flexor retinaculum. D, Scaphotrapeziai ridge.

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Figure 5. Guyon’s canal. The ulnar nerve (B) passes superficial to the flexor retinaculum (A) and radial to the pisiform and ulnar to the hamulus.

though generalized swelling is commoner. Comparison with the uninvolved extremity can expose subtle signs such as snuffbox swelling and distal radioulnar joint dislocation. The patient often points to a specific site of pain, which can be exacerbated by active motion. Neurologic symptoms can offer clues as well. Paresthesias in the median nerve distribution after an acute injury suggest a lunate dislocation into the carpal tunnel. The same symptoms with a gradual onset and nocturnal exacerbation are seen with carpal tunnel syndrome. Ulnar paresthesias suggest compromise along Guyon’s canal from a fractured pisiform or hamate. Wrist components should be palpated systematically (Table 1). The radius and ulna should be firmly palpated, with special attention directed to the radial and ulnar styloid. The scaphoid, which is the most commonly injured carpal, can be evaluated in a variety of ways. Pressure to the anatomic snuffbox usually produces pain with scaphoid fracture; however, as branches of the radial nerve traverse the snuffbox, overly firm pressure will produce pain even with no injury.2 Snuffbox pain is nonspecific and does not diagnose fracture.2s Ulnar deviation of the wrist produces a rotation in the scaphoid and moves it into a more superficial position in the snuffbox. ”Pinching” the scaphoid between the scaphoid tubercle on the palmar surface and the snuffbox can localize the pain further. Compression of the scaphoid by longitudinal axial loading of the thumb has been found to be 70% to 100% sensitive but nonspecific for scaphoid fracture.6,l2 Resisted supination often exacer-

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Table 1. WRIST EXAMINATION MANEUVERS Maneuver

Finkelstein’s test Longitudinal thumb compression Resisted supination

Palmar flexion with dorsal palpation Longitudinal long finger compression Ulnar nerve function Median nerve function Tinel’s sign Phalen’s sign Carpal compression test

Description

Condition Evaluated

Flex thumb fully, then ulnar deviate the wrist. Produces pain at the EPB and APB tendons. Thumb is grasped, then pushed inline toward the wrist. Hand of injured extremity is held by examiner with patienfs forearm in neutral position. Patient attempts supination, which examiner resists. Wrist is fully palmar flexed while examiner palpates dorsal wrist depression. Pain as h a t e becomes exposed. Long finger is grasped, then pushed in-line toward the wrist.

DeQuervain’s tenosynovitis

Paresthesias in small finger and ulnar surface of ring finger. Paresthesias in index, long, and radial surface of ring finger. Lightly tap flexor retinaculum producing paresthesias in median nerve distribution. Dorsum of both hands held in apposition, with wrists palmar flexed for 1 minute. Hold moderate pressure over carpal tunnel, reproducing symptoms:

Pisiform or hamulus injury

Scaphoid injury Scaphoid injury

Lunate injury

Lunate injury

Carpal tunnel syndrome, lunate dislocation Carpal tunnel syndrome Carpal tunnel syndrome Carpal tunnel syndrome

bates scaphoid fracture pain and is more reliable than pain from resisted pronati~n.~~ The h a t e can be palpated in the dorsal wrist depression with the wrist in palmar flexion. Injury to the scapholunate ligaments should be suspected with tenderness distal to Lister’s tubercle. Forming a tight fist moves the capitate proximally and can exacerbate the pain from a scapholunate ligamentous injury. RADIOLOGY OF THE WRIST

PA and lateral views of the wrist are essential for evaluating most wrist injuries, but special views greatly increase sensitivity in detecting occult injury (Table 2). The PA view should be obtained with the wrist in a neutral position. The radius and ulna should not overlap distally, and the index metacarpal should align with the radius (Fig. 6). The scaphoid is captured in an oblique projection in this view, and fractures can be obscured. A relatively uniform 2-mm intercarpal joint space should be found. Increase in this distance suggests ligamentous interrup-

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Table 2. NONSTANDARD RADIOGRAPHIC VIEWS Clinical Findings

Snuffbox pain, scaphoid tubercle pain, suspect scaphoid injury Hypothenar eminence pain Pain at Lister’s tubercle Global wrist pain

Recommended Views

Benefit

Scaphoid view

Elongates scaphoid, exposes waist fractures

Carpal tunnel, 30-degree semisupinated Clenched first view

Displays pisiform and hamulus

Six-view motion study

Pushes capitate into proximal carpal row, exposes scapholunate ligament injury Exposes occult ligamentous injury or instability

Figure 6. Posteroanterior view of a normal wrist. Note the second metacarpal in alignment with the radius, the short appearance of the scaphoid, and the square appearance of the lunate. The navicular fat pad is visible parallel to the radial surface of the scaphoid and distal to the radial styloid.

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tion. The navicularfut stripe, a small linear or triangular collection of fat distal to the radial styloid and parallel to the radial border of the scaphoid, should be visible. Its absence suggests acute bony or ligamentous injury.'4 The lateral view (Fig. 7) should demonstrate parallel radial and ulnar cortices, with respective processes superimposed. The radius, lunate, capitate, and long-finger metacarpal should align. Standard views provide inadequate visualization of many wrist injuries. When clinical findings suggest a significant injury, special views are helpful. Some authors advocate routine use of these "nonstandard views in evaluating all significant wrist injuries.2,21 Although the scaphoid is most commonly fractured at the waist, standard views provide only an oblique projection of this injury. Ulnar deviation of the wrist rotates the scaphoid with the long axis parallel to the palmar surface. A 60-degree pronated film obtained in this position, the Scaphoid View (Fig. 8), much more readily demonstrates scaphoid waist fractures and should be obtained whenever scaphoid injury is suspected.

Figure 7. Normal lateral radiograph. Note the linear arrangement of the radius, lunate, capitate, and metacarpals. Figure 8. Scaphoid view. The wrist is in ulnar deviation and the forearm is in 60" of pronation.

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Scapholunate ligament disruption might not be apparent on standard views. Clenching the fist drives the capitate proximally into the scapholunate joint, accentuating any ligamentous laxity. Hence, the ”clenched fist view” is a useful tool in evaluating this injury. The hook of the hamate and pisiform are often poorly defined in standard films. Thirty-degree semisupinated and carpal tunnel views (Fig. 9) can elucidate injuries to these structures and should be considered when there is trauma or pain in the hypothenar base. Other injuries can be exposed with a ”motion study,” PA films with the wrist in full radial and ulnar deviation, and lateral films in full flexion and extension, or with semipronated and semisupinated oblique views. SPECIFIC INJURIES

Scaphoid Fractures Scaphoid fractures compose 60% to 70% of all traumatic injuries to the wrist.” Most occur with the wrist in hyperextension, with failure at

Figure 9. Thirty-degree sernisupinated view (A) and carpal tunnel view (B). Note the clear projection of the harnulus on the carpal tunnel view and the pisiform in both views, neither of which are clearly seen on standard views.

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the scaphoid waist, the point of greatest stress, as the commonest site. Only approximately 3% occur with a flexion mechanism? Blood supply to the scaphoid from a branch of the radial artery enters from the distal (radial) pole. Subsequently, proximal, oblique, and displaced fractures have a greater risk for nonunion and avascular necrosis of the proximal fragment. Because proper immobilization decreases the odds of nonunion, and because at least 10% of scaphoid fractures are not apparent on initial radi0graphs2~suspected scaphoid injuries must be thoroughly evaluated and immobilized in the ED. A variety of clinical maneuvers and findings can increase suspicion for scaphoid injury, although none are pathognomonic. The anatomic snuffbox can be obscured by edema, which may be more apparent when compared with the uninvolved extremity. Patients often point specifically to the snuffbox or scaphoid tubercle as the site of pain, or even “pinch the scaphoid via those two structures. Pronation and ulnar deviation usually exacerbates the pain, although this finding is very n0nspecific.2~Longitudinal ”loading” of the scaphoid (by grasping the patient’s thumb and pressing it ’in-line’ toward the radius) should exacerbate pain from a scaphoid fracture. Authors variably endorse or condemn the reliability of this maneuver, although most find it sensitive.’ 6, l2,27 Grasping the patient’s hand and having him or her pronate and supinate against resistance often exacerbates the pain, with supination being more sensitive and specific for scaphoid injury.” 27 Vibrating the bone with a device used in physical therapy (Intrasound device, producing 200- to 8500-Hz vibrations at 100 mW) was found to be 100% sensitive and 95% specific for detecting scaphoid fracture.I3 Radiographic evaluation with standard and scaphoid views is mandatory, obtaining further views as clinically indicated. The scaphoid view elongates the scaphoid and lunate, allowing easier detection of fractures (Fig. 10). Unfortunately, at least 10% to 20% of scaphoid fractures are not apparent on the first set of films.= Radiographs were shown in one study to have low interobserver agreement, even between radiologists and between trauma surgeons. The authors advocated abandoning radiographs and instead using clinical examination and bone scan.26 Bone scan is very sensitive although nonspecific and can detect radiologically occult injury. This modality has been variably recommended anytime from 24 hours to 2 weeks after occult injury.13,23 CT and MRI can detect fracture unequivocally, and MRI can demonstrate marrow edema or fracture in a child‘s cartilaginous wrist.9These studies are not normally employed in the ED evaluation of wrist injuries, however. Nondisplaced scaphoid fractures are treated with casting, but the specific methods are debated. Traditional teaching, based on older cadaver studies, suggests that a long-arm thumb spica cast is the treatment of choice; however, newer studies show questionable benefit from either extending the cast above the elbow, or including the thumb? Many now advocate a short-arm cast, leaving the thumb free. The position of the

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Figure 10. Scaphoid fracture. This radiograph was taken with the wrist in ulnar deviation, and clearly displays a waist fracture that is less apparent on a standard posteroanterior view.

wrist in immobilization is also controversial, with some arguing variably for flexion, extension, radial, or ulnar deviation. Almost all advocate neither pronation nor supination, but a neutral position? Prudence suggests contacting the referral orthopedist and learning his or her preference. Displaced (> 1mm) or comminuted fractures benefit from prompt orthopedic referral. Because a large number of scaphoid fractures are not apparent on initial radiographs, and because nonunion and avascular necrosis of the scaphoid occur more often when the joint is not immobilized, splinting the wrist is mandatory when this injury is suspected. Approximately 15% of suspected occult scaphoid injuries will be confirmed in followand therefore, follow-up should occur within a week. up Fractures of Other Carpals

Triquetrium fractures, the second commonest fracture of the carpals, are usually sustained by a direct blow to the dorsum or ulnar aspect of the wrist, or by hyperextension injuries. Most are chip fractures, which are minor and of little long-term significance. More significant injuries, such as transverse fractures, are uncommon but can be seen especially in association with other injuries such as perilunate dislocations. Clinical evaluation is straightforward. Palpation of the triquetrium on the dor-

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sum of the wrist distal to the ulnar styloid elicits pain. Chip fractures are usually apparent on the lateral or oblique radiograph, and special studies rarely are needed (Fig. 11). Simple chip fractures and nondisplaced fractures are treated with immobilization for 3 to 6 weeks. Fractures associated with other injuries could require surgical repair.ll The pisiform, superficially palpable at the hypothenar base, is most commonly injured by a FOOSH mechanism. Again, clinical evaluation is straightforward but should include an assessment of the ulnar nerve. Fractures can impinge on Guyon’s canal, resulting in ulnar nerve injury. Paresthesias in the ulnar distribution as well as hand clumsiness from intrinsic muscle dysfunction can be seen. Unfortunately, plain radiographs most often do not allow visualization of a fracture. Thirty-degree semisupinated and carpal tunnel views should be obtained (see Fig. 9).

Figure 11. Triquetrium fracture. A small chip fracture is apparent dorsal to the triquetrium on a lateral view. Figure 12. Radial deviation of the wrist produces a signet ring sign, which is also observed with scapholunate dissociation.

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If no ulnar nerve injury is present, fractures of this sesamoid bone can be treated with immobilization for 4 to 6 weeks. If evidence of nerve compromise exists, orthopedic consultation for possible surgical decompression is indicated. Hamate fractures are similar in mechanism and evaluation to pisiform fractures. Hamulus fractures are commoner than hamate body fractures and are especially associated with the use of handheld tools or sports equipment. The base of the hammer, racquet, bat, or other implement injures the hamulus on impact. Clinical examination findings, including ulnar nerve association, radiologic evaluation, and ED treatment are similar to those noted earlier for the pisiform. The carpal tunnel view is most helpful.’l Plaster immobilization results in healing in approximately one half of these fractures. If symptomatic nonunion occurs, excision of the fragment may be indicated? Lunate fractures compose about 3% of carpal fractures. Resulting from FOOSH or dorsiflexion mechanisms, the pain of a lunate fracture typically is exacerbated by firm palpation in the dorsal wrist depression with the wrist in palmar flexion. Axial loading by grasping the patient’s third finger and pushing it in line toward the forearm elicits pain. As in the scaphoid, fractures may not be apparent on plain films.” Also as in the scaphoid, vascular supply enters distally, and proximal fractures can result in avascular necrosis, termed Kienboch’s disease. This disabling disease can result in scaphoid instability and subluxation and migration of the capitate into the proximal carpal row. ED treatment for lunate fractures parallels that for scaphoid fractures.

CARPAL DISLOCATIONS Scapholunate Dissociation

The scapholunate ligament can be ruptured with forceful hyperextension of the wrist. Pain is noted dorsally, especially immediately distal to Lister’s tubercle. Additionally, the patient can experience clicking with wrist motion. On PA radiograph, a diastasis of at least 3 mm between the scaphoid and lunate is diagnostic and is termed the Terry Thomas sign.15 If the ligament is completely torn, the scaphoid can undergo rotary subluxation, producing the ”signet ring sign” on PA view. This finding can also be demonstrated with radial deviation of the hand, as seen in Figure 12. A scapholunate angle greater than 60 degrees on lateral radiograph suggests scapholunate dissociation. Finally, the grip compression view can disclose a scapholunate dissociation (SLD) injury not apparent on plain PA; the capitate is pressed into the proximal row, accentuating the diastasis. SLD is treated surgically, so prompt orthopedic consultation is necessary.

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Perilunate Dislocation

Perilunate and h a t e dislocations result from similar hyperextension mechanisms, lunate dislocations being more severe. The commonest wrist dislocation, perilunate dislocations usually involve a dorsal dislocation of the base of the capitate on the lunate. For the capitate to dislocate, either the scaphoid (which bridges the carpal rows) must fracture, or the scapholunate ligament must be disrupted.20On PA radiograph, the normal 2-mm gap between the capitate and lunate is lost, and on lateral views the lunate is palmar flexed and the capitate base is dorsally dislocated, interrupting the usual radius-lunate-capitate-metacarpal line (Fig. 13). Lunate Dislocation

Lunate dislocations occur with the same mechanism but more force than perilunate dislocations. The lunate dislocates in a palmar direction,

Figure 13. A, Perilunate dislocation. The lunate is firmly seated in its radial fossa, but the capitate is dorsally displaced. B, Lunate dislocation. The lunate is displaced completely in a palmar direction on the lateral view (i.e., the tipped teacup sign).

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resembling a "tipped teacup" on lateral radiographs (Fig. 13B). Because the dislocated h a t e enters the carpal tunnel, median neuropathy can be apparent with this injury. Associated injuries frequently occur with both lunate and perilunate dislocations, with scapholunate ligament, radial styloid, scaphoid, capitate, and triquetrium most often involved.", l8 DISTAL RADIUS FRACTURES Chauffeur (Hutchinson) Fractures Chauffeur fractures occur from a twisting or torque mechanism. The eponym resulted from noting these fractures in early motorists whose starting crank forcefully reversed direction. This avulsion fracture involves the radial styloid area and the scaphoid fossa.' Because many extrinsic and intrinsic stabilizing ligaments of the wrist originate at the radial styloid, this often unimpressive-appearing fracture is considered unstable." Other ligamentous injuries should be sought, especially scapholunate dissociation, perilunate, and lunate dislocation.20Nondisplaced fractures can be treated with casting or splinting and orthopedic referral, but any displacement requires prompt orthopaedic consultation for possible open fixation. Smith Fractures The "reverse Colle's fracture" usually results from a blow to the dorsum of the wrist or hand, or a hyperflexion injury. The radial metaphysis is fractured with volar displacement. Examination discloses a volar displacement deformity and pain in the distal radius. The head of the ulna is prominent. Median nerve injury should be assessed. Standard PA and lateral radiographs are adequate to demonstrate the fracture

Figure 14. Smith's fracture. Palmar angulation is apparent on a lateral radiograph.

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(Fig. 14). An ulnar styloid fracture is often found as well. Stable fractures respond well to closed reduction and casting for 6 to 8 weeks, but unstable fractures require open fixation." Colle Fractures

The commonest distal radius fracture, Colle's fractures result from a FOOSH injury. The radial metaphysis is disrupted, with dorsal displacement. Radiocarpal or radioulnar intra-articular involvement is common, especially in young adults. Ulnar styloid fractures are also commonly associated. Examination discloses the typical "dinner fork" deformity, with dorsal displacement of the distal fragment (Fig. 15). Median nerve function should be assessed. PA and lateral radiographs demonstrate Colle's fractures well. Comminuted and unstable fractures require prompt orthopedist attention, as do open fractures or those

Figure 15. Colle's fracture. A, Angulation deformity is obvious on examination. (Courtesy The , lateral view demonstrates complete displacement of the Douglas Landry, MD) €I distal fragment.

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with neurologic or vascular compromise. Closed reduction and plaster immobilization is appropriate for most Colles fractures. Ensuring proper radius length and tilt after reduction is important. DISTAL RADIOULNAR JOINT DISLOCATIONS Distal radioulnar joint (DRUJ) dislocations are often missed owing to subtle physical and radiographic findings. The injury usually occurs from a hyperpronation or hypersupination injury. The patient perceives a palpable ”pop” and notes pain and crepitus especially with pronation and supination of the wrist. Ulnar styloid palpation leads to suspicion of this injury during examination; an overly prominent styloid suggests dorsal dislocation, and loss of any prominence suggests palmar dislocation. Examining the patient facing you with both elbows flexed and ulnar surfaces vertical and toward you often demonstrates a change in ulnar contour.22Although DRUJ dislocation can be associated with fractures (e.g., a radius fracture in the Galeazzi fracture/dislocation), it can occur in isolation. Radiographs can be misleading because no fracture is apparent. The radiology technician may report difficulty in obtaining a true lateral radiograph. This articular disruption must be reduced. If it is reduced at the time of original injury, lasting reduction is likely.22When associated with a radius fracture, the DRUJ injury usually relocates as the radius is r e d u ~ e d If . ~ inadequately relocated, the injury often results in chronic disabling pain4 Open reduction and repair may be necessary. Because delayed repairs of this lesion are not often successful, early recognition is SOFT TISSUE CONDITIONS OF THE WRIST Carpal Tunnel Syndrome Ten structures-the flexor pollicis longus, four flexor digitorum superficialis and four flexor digitorum profundus tendons, and the median nerve-all traverse the carpal tunnel. A variety of conditions or traumas such as repetitive use, diabetes mellitus, hypothyroidism, amyloidosis, and pregnancy can result in edema or infiltration of the carpal tunnel. A dislocated lunate intrudes on the carpal tunnel. Pain and median nerve paresthesias and weakness can ensue. The pain and paresthesias are often exacerbated by use of the wrist and by sleep (fluid redistribution). Pain frequently is referred to the forearm and shoulder. Clinical evaluation of carpal tunnel syndrome (CTS) depends on history and a few controversial tests. Tinel’s and Phalen’s tests, the classically taught tests for carpal tunnel syndrome, have been evaluated in many clinical trials, with widely disparate reports of sensitivity and specificity. Tinel’s sign has been reported to have a sensitivity ranging

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between 8% and loo%, with Phalen’s sensitivity reported from 10% to 88%.19 If both tests are positive and history is suggestive, however, the diagnosis is 85% certain.” Tinel’s sign is elicited by light tapping over the carpal tunnel; paresthesias in the median nerve distribution define a positive test. Phalen’s sign is found by reproducing symptoms when the patient’s hands are palmar flexed, dorsal surfaces against each other with forearms parallel to the floor for 1 minute. Another test, merely delivering moderate manual pressure to the carpal tunnel to reproduce symptoms, was found to be 87% sensitive and 95% specific.16 Nerve conduction studies have a sensitivity and specificity of about 85% and are useful when the clinical examination is equivocal and symptoms are persistent despite conservative treatment. Initial treatment is conservative, using nonsteroidal anti-inflammatory agents and a dorsal wrist splint in neutral position.” Neutral positioning has been shown to be significantly better than 20-degree extension in treating CTS.3 If conservative treatment is unsuccessful, steroid injection or surgery may be indicated.” TENOSYNOVlTlS

Tenosynovitis is an inflammation of the tendon synovial sheath. In the wrist, the commonest sites are on the radial surface. DeQuervain’s tenosynovitis involves the extensor pollicis brevis and abductor pollicis longus tendons as they traverse the radial styloid. The patient‘s pain is exacerbated by performing Finkelstein‘s test, or fully flexing the thumb of the affected hand and adducting (ulnar deviating) the wrist. The extensor pollicis longus tendon also can be affected where it crosses Lister’s tubercle. Treatment of tenosynovitis is begun with NSAIDs and a thumb-spica splint. CONCLUSION

The wrist is too often viewed as a confusing ”bag of bones” with too many articulations and overlapping shadows for confident acute evaluation; however, an understanding of topical anatomy and radiographic positioning greatly facilitates accurate diagnoses in wrist complaints. When a precise diagnosis is nevertheless not forthcoming, immobilization and appropriate follow-up care most often results in an excellent outcome. ACKNOWLEDGMENT Special thanks to Jean L. Bonnette, medical illustrator.

References 1. Bamaby W Fractures and dislocations of the wrist. Emerg Med Clin North Am 10:133-149. 1992

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2. Barton NJ: Twenty questions about scaphoid fractures. J Hand Surg 178:289-310,1992 3. Burke DT, Burke MM, Stewart GW, et al: Splinting for carpal tunnel syndrome: In search of the optimal angle. Arch Phys Med Rehabil75:1241-1244, 1994 4. Buterbaugh GA, Palmer AK Fractures and dislocations of the distal radioulnar joint. Hand Clin 4361, 1988 5. Carroll RE, Lakin JF: Fracture of the hook of the hamate: Acute treatment. J Trauma 3480-05, 1993 6 . Chen SC: The scaphoid compression test. J Hand Surg 14:323-325, 1989 7. Chin HW,Vitsotsky J: Wrist fractures. Emerg Med Clin North Am 11:70>715, 1993 8. Chin HW, Vitsotsky J: Ligamentous wrist injuries. Emerg Med Clin North Am 11:718737, 1993 9. Cook PA, Yu JS, Wiand W, et al: Suspected scaphoid fractures in skeletally immature patients: Application of MRI. J Comput Assist Tomogr 21:511-515, 1997 10. Cooney WP 111, Linscheid RL, Dobyns J H Fractures and dislocations of the wrist. In Rockwood CA Jr, Green DP, Bucholz RW et a1 (eds): Fractures in Adults, ed 4. Philadelphia, Lippincott-Raven, 1996, pp 745867 11. Eisenhauer MA: Wrist and forearm. In Rosen P, Barkin R (eds): Emergency Medicine: Concepts and Clinical Practice. St. Louis, CV Mosby, 1998, pp 669-683 12. Esberger DA: What Value the Scaphoid Compression Test? J Hand Surg 19:748-749, 1994 13. Finkenberg JG, Hoffer E, Kelly C, et al: Diagnosis of occult scaphoid fractures by intrasound vibration. J Hand Surg 18A:4-7, 1993 14. Freeland I? Scaphoid tubercle tenderness: A better indicator of scaphoid fractures? Arch Emerg Med 646-50, 1989 15. Frankel VH: The Terry Thomas sign. Clin Orthop 135:311, 1978 16. Gonzalez del Pino J, Delgado-Martinez D, Gonzalez Gonzalez I, et al: Value of the carpal compression test & the diagnosis of carpal tunnel syndrome. J Hand Surg 22B33841, 1997 17. Gunnarsson LG, Amilon A, Hellstrand P, et al: The diagnosis of carpal tunnel syndrome: Sensitivity and specificity of some clinical and electrophysiological tests. J Hand Surg 22833437,1997 18. Herzberg G, Comtet JJ, Linscheid RL, et al: Perilunate dislocations and fracturedislocations: A multicenter study. J Hand Surg 18A768-779, 1993 19. Kuschner SH, Ebramzadeh E, Johnson D, et al: Tinel's sign and Phalen's test in carpal tunnel syndrome. Orthopedics 15:1297-1302, 1992 20. Mayfield JK, Johnson Rp, Kilcoyne RK: Carpal dislocations: Pathomechanics and progressive perilunar instability. J Hand Surg 5A:226-241, 1980 21. Mehta M, Brautigan Mw: Fracture of the carpal navicular-efficacy of clinical findings and improved diagnosis with six-view radiography. Ann Emerg Med 19:255-257, 1990 22. Morrissy RT, Nalebuff E A Dislocation of the distal radioulnar joint: Anatomy and clues to prompt diagnosis. Clin Orthop 144954-158, 1979 23. Murphy D, Eisenhauer M The utility of a bone scan in the diagnosis of clinical scaphoid fracture. J Emerg Med 12:709-712, 1994 24. Terry DW Jr, Ramin JE: The navicular fat stripe: A useful roentgen feature for evaluating wrist trauma. Am J Roentgen01 124:25-28, 1975 26. Tiel-van Buul MMC, van Beek EJR, Nooitgedacht EA, et a1 Diagnosing scaphoid fractures: Radiographs cannot be used as a gold standard! Injury 23:77-79, 1992 27. Waizenegger M, Barton NJ, Davis TRC, et a1 Clinical signs in scaphoid fractures. J Hand Surg 19B:74>747, 1994 28. Waeckerle JF: A prospective study identifying the sensitivity of radiographic findings and the efficacy of clinical findings in carpal navicular fractures. Ann Emerg Med 16:73>737, 1987 Address reprint requests to James V. Ritchie, MD Department of Emergency Medicine Naval Medical Center 620 John Paul Jones Circle Portsmouth, VA 23708-2197