In-Service Exam
Wrist - 2001





PHOTO

The above radiograph is from a 58-year-old mechanic who has had progressively worsening pain in the dominant right wrist for the past eight months. He reports dull pain and mild swelling over the dorsal and volar midportion of the wrist that progressively worsens during the work day. On physical examination, there is mild tenderness over the capitate and lunate.

These findings are most consistent with

(A) pantrapezial arthritis
(B) radiocarpal arthritis
(C) scapholunate advanced collapse (SLAC) wrist
(D) scaphotrapeziotrapezoidal arthritis
(E) triangular fibrocartilage complex tear

This patient has findings consistent with scapholunate advanced collapse (SLAC wrist), a common pattern of degenerative arthritis of the wrist. This patient's condition developed following an undiagnosed scapholunate injury; other common causes include rotary subluxation or nonunion of the scaphoid, Preiser's disease, and Kienbšck's disease. The radiograph shows a 2.5-mm diastasis of the scapholunate joint, as well as proximal migration of the capitate between the scaphoid and lunate and loss of capitolunate joint space. The capitate will ultimately become wedged between the scaphoid and lunate.

Pantrapezial arthritis is an advanced type of basal joint arthritis of the thumb that involves the carpometacarpal and scaphotrapeziotrapezoid joints. A grind test will be positive. In radiocarpal arthritis, loss of joint space between the scaphoid and its fossa will be visible on radiographs, and the patient will have pain in the region of the anatomic snuff box. In contrast, patients with scaphotrapeziotrapezoidal (STT) arthritis will have loss of the STT joint space and positive findings on grind testing. Ulnar-sided wrist pain is typically the initial symptom of a tear of the triangular fibrocartilage complex; arthrography or arthroscopy should be used to confirm the diagnosis.

References
1. Imbriglia JE. Four-corner arthrodesis. In: Blair WF, ed. Techniques in Hand Surgery. Baltimore, Md: Williams & Wilkins; 1996:865-871.
2. Watson KH, Weinzweig J. Intercarpal arthrodesis. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;1:122-126.