Wrist Injuries. Part 2: Spotting and Treating Troublemakers
Eric W. Honing, MD
The Recreational Athlete
THE PHYSICIAN AND SPORTSMEDICINE - VOL 26 - NO. 10 - OCTOBER 98
This is the second of two articles on wrist injuries. The first, on the workup, appeared in September.
In Brief: Injuries of the wrist, a complex joint, are common in recreational sports. Often, the clinical diagnosis made is the vague "wrist strain or sprain" unless a fracture is seen on x-ray. A thorough assessment, however (as described in part 1), may reveal any of various injuries and syndromes, including scaphoid fractures, scapholunate dissociation, ganglion cysts, or ligamentous or tendon injuries. Treatment ranges from immobilization to corticosteroid injections to surgical repair of a fracture or underlying cause.
The wrist and hand are the most common sites for upper-extremity injuries in sports activities (1), and the wrist joint can be daunting in its complexity. Until recently, unless a fracture was seen on an x-ray, clinicians too often resorted to the vague diagnosis "wrist strain or sprain" in active patients. Now, however, a greater understanding of specific injuries has led to greater sophistication in the diagnosis and treatment of wrist injuries. Accurate diagnosis of wrist pain will most often allow a safe and speedy return to sports activity.
Most of the recreational athlete's wrist injuries (other than scapholunate dissociation and displaced scaphoid fractures) can be treated by the primary care physician, with referral if conservative treatment fails.
For those patients who have wrist pain, a thorough assessment including a detailed history, palpation of the wrist, diagnostic maneuvers, initial radiographic series, and, possibly, diagnostic corticosteroid injections are the first steps toward making a diagnosis (see "Wrist Injuries: Part 1: Pinpointing Pathology in a Complex Joint," September, page 40). Following is a discussion of various wrist injuries and their management.
Fractures of the wrist are common, and most involve the radius and ulna. Treatment is usually closed reduction, if necessary, and cast immobilization for 4 to 6 weeks. Scaphoid and hamate hook fractures, however, are difficult to diagnose and are associated with a high rate of complications.
Scaphoid fractures. The scaphoid is more susceptible to injury than any of the other carpal bones because of its unique position bridging the proximal and distal rows of the carpal bones (figure 1a: not shown). Unrecognized scaphoid fractures can be a physician's nightmare. The high frequency of nonunion and avascular necrosis in the scaphoid make early diagnosis essential. This frequency is due to a tenuous blood supply, with only one dorsoradial artery to the proximal pole, which results in a nearly 100% incidence of avascular necrosis in proximal fractures and a 30% incidence in distal fractures (1).
Acute scaphoid fractures are frequently missed because initial radiographs can be unremarkable. Any tenderness in the anatomic snuffbox over the dorsal scaphoid (figure 1b) should prompt treatment as for a fracture. Treatment involves immobilization in a thumb spica splint or cast and reexamination in 10 to 14 days. If the patient remains symptomatic, radiographs should be repeated. If the radiographs are negative, a bone scan should be obtained. A negative bone scan any time more than 72 hours after injury rules out an occult fracture of the scaphoid.
Treatment of nondisplaced scaphoid fractures is usually determined by location. Seventy percent of scaphoid fractures are through the waist, 20% are proximal, and 10% are distal (figure 1c) (1). Distal fractures heal rapidly and require 4 to 6 weeks of immobilization in a short arm cast. Proximal and waist fractures require immobilization, first in a long arm thumb spica cast for 6 weeks, then in a short arm thumb spica cast with cast changes every 2 to 3 weeks to prevent loosening of the cast and loss of fixation. Immobilization should continue for 4 to 6 months or until at least 50% bridging or healing is demonstrated by x-ray or, more typically, by computed tomography (CT) scans.
Displaced scaphoid fractures require open reduction and internal fixation with a Herbert compression screw or a smooth (Kirschner) wire fixation. This technique has also been used by some hand surgeons to treat in-season athletes when a playing cast is not feasible. Time to return to sport averages about 6 weeks (2).
Hamate hook fractures. Hamate fractures are uncommon, making up only 2% of all carpal fractures (3), and diagnosis is often delayed. Patients usually do not seek immediate attention because symptoms are often vague. Persistent pain, especially with range of motion and grasping, prompts the patient to seek medical attention. The clinician should be suspicious when a patient presents with a painful grip, pain with deep palpation over the hook, and pain with dorsoulnar deviation (3). Also, resisted distal interphalangeal flexion of the ring and little fingers with an ulnar deviated wrist will cause pain because the hook of the hamate acts as a pulley for the flexor tendons of the ulnar digits.
A complication to be aware of in an undiagnosed hamate fracture is rupture of the flexor digitorum profundus tendon of the little finger, which lies in the radial aspect of the hook of the hamate. Rupture of the tendon will result in absent distal interphalangeal joint flexion of the little finger.
Routine wrist films frequently fail to show fractures of the hook of the hamate, and these are usually the only studies obtained initially. If a fracture of the hamate is suspected, oblique views and a carpal tunnel view must be obtained to help identify the fracture. If these views are noncontributory and suspicion is still high, a bone scan should be obtained. Most fractures can be visualized on a bone scan by 3 to 5 days postinjury (3). CT scanning is probably the best method for diagnosing hamate hook fractures (3,4).
Excision of the fractured hook has been a mainstay of treatment, although it can leave the patient with reduced grip strength (3). Acute fractures that are seen within 3 weeks of injury and are nondisplaced, however, may be treated nonoperatively with short arm casting for 6 to 8 weeks (5). A thumb spica cast has also been used acutely to further limit movement of the hamate. Some surgeons treat younger patients and those who have displaced fractures with open reduction and internal fixation for preservation of grip strength.
Although wrist fractures are common, most injuries to the wrist involve the soft-tissue structures. Following are some of the soft-tissue injuries that can occur in sports, either as a result of a single episode of trauma or from repetitive stresses.
Carpal tunnel syndrome. Carpal tunnel syndrome is the most common overuse injury of the wrist. The Phalen test, a diagnostic maneuver described in part 1 (September, page 48), indicates the presence of this condition. Initial conservative treatment consists of cock-up wrist splints, nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy, avoidance or limitation of aggravating activities, and corticosteroid injection.
Triangular fibrocartilage complex injuries. The triangular fibrocartilage complex (TFCC) functions as a cushion for the ulnar carpus as well as a sling support for the lunate and triquetrum (6). The usual mechanism of injury is compression of the TFCC between the lunate and the head of the ulna, as in breaking a fall with the hand, or from rotational forces as in racket and throwing sports (6).
Patients often have ulnar-side wrist pain, swelling, loss of grip strength, and an inability to perform manual activities (7). There also may be a "click" with active ulnar deviation (8). Physical examination reveals point tenderness distal to the ulnar styloid in the area of the TFCC. Pain with passive pronation and supination as well as ulnar deviation is also suggestive of TFCC injuries.
It is important to assess the stability of the distal radioulnar joint (DRUJ). This can be done using the piano key test and the shuck test. The piano key test is performed with the patient's hand pronated. The examiner presses down on the distal ulna as if pressing on a piano key. If little resistance occurs as the ulna moves volarly, the test is positive. For the shuck test, the examiner holds the radius with one hand and the ulna with the other and moves the distal radius dorsally against the head of the ulna. Laxity should be compared with that of the other wrist.
For patients who have TFCC injuries with an unstable DRUJ, initial treatment is surgical.
Plain film radiography is used only to determine positive ulnar variance, in which the ulna is longer than the medial portion of the radius. This variance affects the axial load borne by the ulna. A normal load distribution is approximately 82% across the radius and 18% across the ulna. A negative ulnar variance of 2.5 mm reduces the axial force across the ulna to 4%, while a positive ulnar variance of 2.5 mm increases the ulnar load to 42% (9). Also, the thickness of the TFCC varies inversely with positive ulnar variance. Therefore, in positive ulnar variance, the TFCC is thinner and has more forces directed through it, making it more susceptible to injury (8).
TFCC injuries traditionally have been diagnosed with wrist arthrography, but high-resolution magnetic resonance imaging (MRI) and wrist arthroscopy are being used increasingly for this purpose.
Initial treatment for the acute TFCC injury without distal radial joint instability is immobilization for 4 weeks in slight flexion and ulnar deviation. Injection of the ulnar carpal space with a corticosteroid and a local anesthetic may be helpful for both diagnosis and treatment.
If a stable wrist remains symptomatic and the condition becomes chronic, arthroscopy is indicated. Surgical options for the degenerative perforation of the TFCC include debridement of localized defects and decompression of the ulnar carpal space (10), as well as arthroscopic repair. For the active patient with a long-standing tear and positive ulnar variance, ulnar shortening should be incorporated into the operative procedure.
Dorsal ganglion cysts. Occult dorsal wrist ganglia can produce chronic wrist pain, which may be constant or may be associated only with activity (10). A history of trauma is often missing in these patients.
The ganglion originates from the dorsal scapholunate ligament. Localized tenderness and maximum aggravation of pain occurs during flexion, with limitation of motion and weakness of grip. For patients who have occult ganglia, the initial examination should include evaluation for scapholunate instability.
Initial treatment includes one corticosteroid injection followed by immobilization in a cock-up wrist splint for 7 to 10 days. If this conservative therapy fails, operative treatment should be initiated.
De Quervain's tenosynovitis. Inflammation or relative narrowing of the extensor pollicis brevis and abductor pollicis longus tendons, which make up the first dorsal compartment, is known as de Quervain's tenosynovitis (figure 2). Repetitive ulnar deviation is most commonly implicated as the cause of this syndrome (8).
On examination, localized tenderness is present over the first dorsal compartment, and symptoms are reproduced by performing the Finkelstein test, a diagnostic maneuver described in part 1 (September, page 47), in which the patient folds the thumb under the fingers and the examiner ulnarly deviates the wrist.
Treatment consists of thumb spica splinting, NSAIDs, and physical therapy for 2 to 4 weeks. A corticosteroid injection into the first dorsal compartment should be considered after 10 to 14 days if there has been no significant improvement. Surgical decompression may be required for chronic symptoms that do not respond to conservative treatment.
Intersection syndrome. Intersection syndrome is similar to de Quervain's tenosynovitis and involves inflammation at the junction of the first dorsal compartment with the second, which consists of the extensor carpi radialis longus and brevis tendons (figure 2). The syndrome is caused by overuse of the radial extensor of the wrist. Signs and symptoms include tenderness, crepitus, and swelling over the dorsal radial aspect of the forearm 2 to 3 fingerbreadths proximal to the wrist joint. Crepitation or squeaking can be heard with passive or active motion, which has led to the term "squeaker's wrist."
Treatment is similar to that for de Quervain's tenosynovitis: avoidance of aggravating activity, splinting, NSAIDs, and, if necessary, local corticosteroid injection. (See "Wrist Pain From Overuse: Detecting and Relieving Intersection Syndrome," December 1997, page 41.)
Extensor carpi ulnaris tenosynovitis and subluxation. The sixth dorsal compartment, which houses the extensor carpi ulnaris (ECU) tendon, is the second most common site of tenosynovitis following de Quervain's disease (11). This is a common injury in racket sports and rowing because of the repetitive ulnar deviation involved.
Patients who have ECU tenosynovitis have pain and tenderness over the tendon, especially with ulnar deviation. Treatment consists of avoiding aggravating activities, using a cock-up wrist splint, taking NSAIDs, and receiving physical therapy for 2 to 4 weeks. A one-time local corticosteroid injection after 10 to 14 days should be considered. Also, attention should be paid to modifying sports technique by limiting excessive ulnar-radial deviation and flexion of the wrist.
With ECU tendon subluxation, for which symptoms and causes are similar to those for tenosynovitis, disruption of the compartment sheath allows the ECU tendon to sublux. This should be suspected when the patient has clicking on the ulnar side of the forearm. On examination, the tendon can be felt to sublux as the supinated wrist is actively taken from radial to ulnar deviation.
In the acute stage of ECU tendon subluxation, treatment consists of immobilization for 6 weeks in a long arm cast, with supination and radial deviation (8,11). With chronic ECU subluxation, surgical reconstruction is indicated.
Scapholunate dissociation. When diagnosing and treating wrist injuries, physicians need to be on the lookout for scapholunate instability. Unfortunately, this diagnosis is often missed, and the best opportunity for restoring alignment with open reduction and internal fixation to allow ligamentous healing is lost.
The patient usually has a history of a fall or a motor vehicle accident, along with pain, swelling, and decreased motion. The greatest pain typically is over the dorsal scapholunate area, and is accentuated with dorsiflexion. Usually, swelling is minimal, and pressure applied over the scaphoid tuberosity will elicit further pain. A diagnostic maneuver such as the Watson, or scaphoid shift, test (see part 1 of this article, September, page 47) is helpful when the condition is subacute or chronic.
Radiographs are especially helpful in making this diagnosis. Views that should be obtained are bilateral unstressed AP and lateral views with the wrist in neutral, and posteroanterior (PA) views with the wrist in radial and ulnar deviation (12). For the lateral radiograph, the x-ray technician should make sure that the third metacarpal is aligned with the radius. As with any x-rays, comparison views can be very helpful and should be obtained.
Abnormal carpal alignment and scapholunate gapping can be reproduced by stressing or loading the wrist, as with the AP clenched-fist view (figure 3). A scapholunate gap of more than 3 mm or a space greater than in the opposite wrist may indicate disruption of the scapholunate interosseous ligament.
The alignment of the scaphoid and lunate can be observed on a lateral radiograph. On a normal lateral view (figure 4: not shown), the radius, lunate, and capitate should be colinear, the scapholunate angle between 30° and 60°, and the capitolunate angle less than 30°. With scapholunate instability, the scaphoid tilts volarly and the lunate tilts either dorsally or volarly (figure 5). Depending on the position of the lunate, dorsal intercalary segment instability (DISI) or volar intercalary segment instability (VISI) is present.
If the patient has extreme tenderness over the scapholunate joint with no radiographic evidence of separation or carpal malalignment, the injury should be treated as a severe ligament sprain with a splint or short arm cast for 6 weeks (12). However, if evidence of scapholunate dissociation (ie, an increased scapholunate gap or signs of malalignment on plain lateral radiographs) exists or there are any other concerns, the patient should be referred to a hand surgeon.
With prompt diagnosis and appropriate referral, the success rate for treating scapholunate dissociation is high. However, reduction is often possible even as long as 3 months after injury (12).
Awareness Averts Chronicity
The complexity of the wrist makes diagnosis difficult, but knowledge of the wrist joint and awareness of these common injuries will help in making a specific diagnosis. Treatment that is tailored to the injury will allow the patient to return to sports activity in a timely manner, and help prevent chronic, debilitating wrist pain.
Dr Honing is the head team physician at Utah State University and director of sports medicine and occupational medicine at Western Orthopaedics and Sports Medicine, both in Logan, Utah. He is a member of the American College of Sports Medicine (ACSM) and the American Medical Society for Sports Medicine (AMSSM). Dr Moeller is an assistant residency director and director of sports medicine at the William Beaumont Hospital Family Practice Residency Program in Troy, Michigan, a member of the ACSM and the AMSSM, and a member of the editorial board of The Physician and Sportsmedicine. Address correspondence to Eric W. Honing, MD, Western Orthopedics and Sportsmedicine, 850 E 1200 N, Logan, UT 84341; e-mail to [email protected].
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