Semiconstrained arthroplasty for the treatment of rheumatoid arthritis of the elbow.

Fifty-four patients in whom a total of fifty-eight semiconstrained modified Coonrad elbow implants had been inserted for rheumatoid arthritis were followed for a mean of 3.8 years (range, two to eight years). At the latest follow-up, there was little or no pain in fifty-three elbows (91 per cent). The arc of motion was from an average point in flexion of 20 degrees to an average point in flexion of 129 degrees, representing an average increase of 12 degrees of extension and 11 degrees of flexion. The average arc of pronation was 78 degrees, an increase of 14 degrees, and the average arc of supination was 77 degrees, an increase of 18 degrees. An additional ten patients who had had insertion of ten modified Coonrad implants during the same period were followed for less than two years but were included in the assessment of complications. Fifteen (22 per cent) of the sixty-eight elbows had a complication: four, infection; eight, acute or delayed condylar or ulnar fracture; and one each, ulnar neuritis, avulsion of the triceps, and fracture of the implant. Radiographic evaluation was performed for fifty-four of the fifty-eight elbows; the other four were excluded from this evaluation because of infection. A satisfactory radiographic appearance of the cement--its extent and the absence of skip areas--was noted for all of the ulnar components and for fifty-one (94 per cent) of the humeral components. No patient had radiographic evidence of a loose implant. A reoperation was performed in six elbows (10 per cent of the fifty-eight; 9 per cent of the sixty-eight): four were done for infection; one, for insufficiency of the triceps; and one, for a fractured ulnar component. Of the fifty-eight elbows, forty (69 per cent) had an excellent result; thirteen (22 per cent), a good result; four (7 per cent), a fair result; and one, a poor result.