Bipolar implant shoulder arthroplasty. Long-term results.

The bipolar shoulder implant (BSI), designed by the senior author in 1975, has an unfixed metal glenoid cup with a polyethylene liner that articulates with a cemented titanium humeral component. The BSI was inserted in 35 shoulders of 33 patients with severe rheumatoid arthritis (20 cases), degenerative arthritis (ten cases), and posttraumatic lesions (five cases). The follow-up period ranged from 24 to 140 months (average, 63 months). Pain relief was good to excellent in 31 shoulders; four experienced some pain during daily activities