Opera-glass hand in rheumatoid arthritis.

Characteristic deformities occur in the fingers, thumb, and wrist in the opera-glass hand in rheumatoid arthritis. Shortening and instability are the result of bone resorption and dislocation and can be severely disabling. Early spontaneous fusion of the proximal interphalangeal joint preserves digital length. Functional improvement can be obtained in the fingers by interphalangeal joint arthrodesis and metacarpophalangeal prosthetic arthroplasty and in the thumb with metacarpophalangeal and/or interphalangeal arthrodesis. With interphalangeal arthrodesis, interposition grafts often are required in order to restore length and secure fusion. "Prophylactic" arthrodesis of interphalangeal joints should be considered when resorption seems imminent.