Bipolar shoulder arthroplasty.

Bipolar shoulder arthroplasty was designed as a salvage procedure for the arthritic shoulder with a massive rotator cuff tear. Between 1985 and 1989, 14 patients were treated with a bipolar shoulder arthroplasty and were followed for a mean of 3.3 years (range, 2-4.8 years). Two patient populations were studied, including: (1) rheumatoid patients undergoing a primary shoulder arthroplasty, and (2) reconstructive patients undergoing a secondary reconstructive procedure. The rheumatoid group had overall good pain relief. The average postoperative active forward flexion, abduction, and external rotation was 79 degrees, 66 degrees, and 20 degrees, respectively. The reconstructive group had fair pain relief, with an average postoperative active forward flexion, abduction, and external rotation of 39 degrees, 44 degrees, and 12 degrees, respectively. Six of seven complications were noted in the reconstructive group, including two bipolar cup dislocations, one bipolar cup subluxation, and one loosening of the prosthesis. The factors associated with complications included absence of an intact subacromial arch and deltoid abnormality. The bipolar shoulder arthroplasty appears to be an alternative to a primary arthroplasty for the arthritic rheumatoid shoulder with a massive rotator cuff tear.