Objective. To determine the benefits and harm of surgery for shoulder osteoarthritis (OA). Methods. We performed a Cochrane Systematic Review of clinical trials of adults with shoulder OA, comparing surgical techniques [total shoulder arthroplasty (TSA), hemiarthroplasty, implant types, and fixation] to placebo, sham surgery, nonsurgical modalities, and no treatment. We also reviewed trials that compared various surgical techniques, reporting patient-reported outcomes (pain, function, quality of life, etc.) or revision rates. We calculated the risk ratio for categorical outcomes and mean differences for continuous outcomes with 95% CI. Results. There were no controlled trials of surgery versus placebo or nonsurgical interventions. Seven studies with 238 patients were included. Two studies compared TSA to hemiarthroplasty (n = 88). Significantly worse scores on the 0-100 American Shoulder and Elbow Surgeons scale (mean difference, -10.05 at 24-34 mo; 95% CI -18.97 to -1.13; p = 0.03) and a nonsignificant trend toward higher revision rate in hemiarthroplasty compared to TSA (relative risk 6.18; 95% CI 0.77 to 49.52; p = 0.09) were noted. With 1 study providing data (n = 41), no differences were noted between groups for pain scores (mean difference 7.8; 95% CI -5.33 to 20.93), quality of life on Medical Outcomes Study Short-Form 36 physical component summary (mean difference 0.80; 95% CI -6.63 to -8.23), and adverse events (relative risk 1.2; 95% CI 0.4 to 3.8). Conclusion. TSA was associated with better shoulder function, with no other demonstrable clinical benefits compared to hemiarthroplasty. More studies are needed to compare clinical outcomes between them and comparing shoulder surgery to sham, placebo, and other nonsurgical treatment options. The Journal of Rheumatology Copyright © 2011. All rights reserved.