Hemi- versus bipolar shoulder arthroplasty for chronic rotator cuff arthropathy

Both bipolar and hemiarthroplasty have been used to treat rotator cuff arthropathy (RCA) of the shoulder in patients with low functional demands. In this study, 41 patients treated with either a bipolar or hemiarthroplasty were selected retrospectively to detect possible differences in the functional outcome and to evaluate radiological properties of the implants. Patients were examined before and 30 +/- 6 months after surgery. There were no differences in the Constant scores between the groups treated with hemiarthroplasty and bipolar arthroplasty, 58.9 +/- 13.1 points and 55.8 +/- 13.5 points, respectively (P = 0.457). We found a significant increase in abduction postoperatively in both groups (P = 0.041 bipolar, P = 0.000 hemiarthroplasty) but without statistical significance between the hemiarthroplasty and bipolar arthroplasty groups (P = 0.124, F = 2.6). This result is related in the bipolar group due to movement between the shell and inner head (P = 0.042) and in the hemiarthroplasty group due to movement between the humeral head component and the glenoid (P = 0.000). In conclusion, we found that both hemiarthroplasty and bipolar arthroplasty are effective treatment options for carefully selected patients with RCA and low functional demands, with no differences between the groups.