Carpal instability in rheumatoid arthritis.

The authors examined prospectively the prevalence of and relations among patterns of carpal instability in 52 patients with proven rheumatoid arthritis. Posteroanterior, lateral and oblique radiographs of both wrists were obtained. Nineteen patients exhibited one or more patterns of instability. The most common isolated pattern was volar intercalated segmental instability, apparent in six patients. Five patients showed more than one pattern, most commonly a combination of ulnar translocation and volar carpal subluxation. Patients with active erosions or changes in the distal radioulnar joint were more likely to exhibit instability than those without such findings. Carpal instability is a frequent mechanical complication of rheumatoid arthritis. The radiologist should be aware of this possibility, so that a diagnosis can be made promptly and appropriate clinical management begun.