PURPOSE: The aim of this study was to conduct a randomised, clinical trial comparing stemmed hemiarthroplasty and resurfacing hemiarthroplasty in the treatment of glenohumeral osteoarthritis.

METHODS: A total of 40 shoulders (35 patients) were randomised to stemmed hemiarthroplasty or resurfacing hemiarthroplasty and evaluated three and 12 months postoperatively using the Constant-Murley score (CMS) and Western Ontario Osteoarthritis of the Shoulder (WOOS) index.

RESULTS: There were no statistically significant differences in age, gender or pre-operative scores except for WOOS at baseline. Two patients were lost to follow-up. Significant improvements in CMS and WOOS were observed at one year after both arthroplasty designs. At one year, the mean CMS was 48.9 (range 6-80) after resurfacing hemiarthroplasty and 59.1 (range 0-88) after stemmed hemiarthroplasty {mean difference 10.2 [95 % confidence interval (CI) -3.3 to 23.6], P = 0.14}. The mean WOOS was 59.2 (range 5.2-100.0) and 79.4 (range 12.8-98.6), respectively [mean difference 20.2 (95 % CI 3.4-36.9), P = 0.02]. No major complications occurred and there were no revisions.

CONCLUSIONS: The effects of resurfacing hemiarthroplasty tended to be inferior to those of stemmed hemiarthroplasty. It is unclear whether this reflects a real difference in effect or baseline differences due to the limited number of randomised patients. We suggest there is a need for a larger, more definitive trial.