Screening for extensor tendon rupture in rheumatoid arthritis

Objective. Surgery can prevent extensor tendon rupture in the rheumatoid wr ist but it is difficult to identify patients at risk. Extensor digiti minim i (EDM) usually ruptures first, but rupture may pass unnoticed because exte nsor digitorum communis (EDC) extends all four fingers simultaneously. We a ssessed the value of screening for EDM rupture by examining for absent inde pendent extension of the little finger in a hospital rheumatoid arthritis p opulation. Methods. The EDM test was performed in 550 previously unoperated wrists. Di sease activity, joint damage, wrist swelling, tenderness and crepitus were recorded. Results. Unsuspected EDM loss was found in nine of the 550 wrists (1.60%): dorsal synovitis was absent or minimal in eight and ulnar tenderness was ab sent in six. EDM loss was not associated with activity, severity or duratio n of disease. Conclusions. The EDM test is simple and cheap. It may identify patients at risk and permit prophylactic surgery before hand function is lost.