The Short-Term Survival of Total Stemless Shoulder Arthroplasty for Osteoarthritis is Comparable to that of Total Stemmed Shoulder Arthroplasty: A Nordic Arthroplasty Register Association Study

To compare the short-term survival rate of total stemless, metaphyseal fixated, shoulder arthroplasty with that of total stemmed shoulder arthroplasty in treatment of osteoarthritis (OA). The stemless humeral component relies on adequate bone quality and the risk of component loosening could be higher than with stemmed components Data was prospectively collected by the national arthroplasty registries in Denmark, Finland, Norway and Sweden and merged into one dataset under the umbrella of the Nordic Arthroplasty Register Association. For the present study we included all patients with OA treated with stemless (n=761) or stemmed (n=4,398) shoulder arthroplasty from 2011 to 2016. 21 (2.8%) stemless and 116 (2.6%) stemmed shoulder arthroplasties were revised. The 6-year cumulative survival rates were 0.953 for stemless shoulder arthroplasty and 0.958 for stemmed shoulder arthroplasty, P = 0.77. The most common indication for revision of both arthroplasty types was infection. Five (0.7%) stemless and 16 (0.4%) stemmed shoulder arthroplasties were revised because of loosening of either the glenoid or the humeral component. In the multivariate cox regression model, which included age category, gender, year of surgery, previous surgery and arthroplasty type, the hazard ratio for revision of the stemless shoulder arthroplasty was 1.00 (95%CI,0.63-1.61), P = 0.99 with the stemmed shoulder arthroplasty as reference. Male gender (HR=1.50(95%CI, 1.06-2.13), P=0.02) and previous surgery (HR=2,70 (95%CI, 1.82-4.01), P<0.001) were associated with increased risk of revision. The short-term survival of total stemless shoulder arthroplasty appears comparable to total stemmed shoulder arthroplasty, but longer observation time is needed to confirm if they continue to perform equally.