Once an arthrodesis, always an arthrodesis?

Background: An arthrodesis of the shoulder is historically a solution for severe shoulder joint problems, for which no prosthetic solution is deemed possible. With the introduction of the reverse shoulder arthroplasty (RSA), which is intrinsically stable at the glenohumeral joint, it seems logical to consider conversion of a painful arthrodesis into a RSA, provided that the deltoid was not destroyed during the arthrodesis.

Methods: Four patients (2 men, 2 women; age 46-66 years) with a longstanding arthrodesis (5-11 years) visited our clinic with a painful shoulder (mainly around the scapula) with the request to provide more mobility. In all, the shoulder was fused in 60° to 80° of abduction, 20° to 40° of flexion, and 40° to 50° of internal rotation. All patients refused an osteotomy as treatment for the pain. A preoperative electromyelogram showed activity in at least the posterior or middle parts of the deltoid, or both. They were offered revision of arthrodesis to a reverse prosthesis. All complications, especially instability, were discussed. Surgery was performed through the previous deltopectoral scar. In 3 cases, the osteotomy was lateral to the original joint line, providing some lateralization.

Results: Follow-up was 22 to 60 months. The Constant-Murley score improved from 15-21 to 30-60. No dislocations occurred. All patients were satisfied, especially with the increased, although not impressive, rotations. Pain did not disappear but decreased considerably, from visual analog scale 8-10 to 0-4.

Conclusion: Conversion into a RSA is a safe procedure in patients with a painful arthrodesis and grossly intact deltoid, providing better glenohumeral mobility (especially rotations), leading to improved patient satisfaction.