Long-Term Results of Anatomic Stemless Shoulder Prosthesis in Patients With Primary Osteoarthritis

Shaft-anchored prostheses have long been the gold standard in shoulder arthroplasty, but there is a growing trend toward bone-preserving, stemless designs. Despite promising short- and midterm results, long-term data remain limited. This study aims to report the long-term outcomes of a stemless anatomic shoulder prosthesis in patients with primary osteoarthritis and seeks to answer the question of whether it is comparable to other prostheses.

This retrospective single-center study included 27 shoulders in 24 patients (mean age 75 ± 8.3 years), who were operated from 2009 to 2011. Outcomes assessed were Constant-Murley score, range of motion, patient satisfaction, revision rate, and radiological findings. Mean follow-up was 142 ± 12.2 months. Twenty-one shoulders underwent total shoulder arthroplasty; six hemiarthroplasty. For the analysis of continuous variables, the Wilcoxon test was used following normality testing. Dichotomous variables were evaluated using the chi² test, with a significance level set at p < 0.05.

The Constant-Murley score improved significantly from 23.1 ± 9.4 (27.5% age-adjusted) preoperatively to 58.8 ± 18.6 (72.3% age-adjusted) postoperatively (p < 0.001). Range of motion increased in flexion (89.5°-137.2°), abduction (70.9°-117.2°), and external rotation (10°-36.8°), all statistically significant. Overall, 85% of patients were (very) satisfied. Four revisions were performed: two with conversion to alternative treatment, two within the same system due to loosening and infection. Ten- and 12-year survival rates were 89% and 85%, respectively. A 30% risk of loosening was observed (per Molé), though no glenoid loosening occurred; humeral loosening was seen in one case.

The clinical, functional, and radiological outcomes of the investigated stemless shoulder arthroplasty system remain satisfactory even in long-term follow-up. High patient satisfaction was observed. The data, which are unique in terms of the length of follow-up, are comparable to those of other stemless anatomic shoulder arthroplasty designs.