Stemless reverse total shoulder arthroplasty: a systematic review and meta-analysis.

Background: Stemless reverse total shoulder arthroplasty (rTSA) is one of the many modifications of the original Grammont rTSA design. Much has been made of the debate between stemless and stemmed humeral implants for anatomic reverse shoulder arthroplasty, with less attention awarded to the relatively newer variation in stemless rTSA. Proposed advantages of said design include preserving bone stock, ease of revision, reduced blood loss, and shortening surgical times. Methods: A systematic search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines using search engines in PubMed, EMBASE, and Cochrane to retrieve all relevant studies. Results: Initial search strategies produced 174 studies, of which 15 studies were included for full analysis in this review. This included 657 shoulders in 648 patients (9 bilateral cases). Stemless rTSA led to significant improvement in functional outcomes and range of motion (ROM) across all studies. Meta-analysis of comparative studies including stemless and stemmed rTSA showed no significant difference in ROM measurements across abduction (standardized mean difference [SMD] -0.17, 95% confidence interval [CI]: -1.05, 0.70) or forward flexion (SMD -0.36, 95% CI: -1.23, 0.50). However, there was a statistically significant difference in internal rotation in favor of stemless implants (SMD -0.79, 95% CI: -1.56, -0.03). There was no significant difference in visual analog scale (VAS) between stemmed and stemless designs (SMD -0.31, 95% CI: -2.32, 1.69). Likewise, there was no significant difference in odds ratio (OR) for revision rates (OR: 1.02, 95% CI: 0.92, 1.14) or overall complications (OR: 0.82, 95% CI: 0.2, 3.42). Across all 15 studies, comparative and noncomparative studies, overall complication rates for stemless rTSA stood at 13.4% and revision rates at 5.5%. Conclusion: Stemless rTSA achieves similar functional outcomes to stemmed rTSA designs. Stemless designs achieved superior internal rotation in the comparative studies. Proposed advantages of stemless rTSA including reduced blood loss and lesser surgical times need further research, as does the long-term robustness of this relatively novel design.