Mid-term clinical and radiographic outcomes at minimum five-year follow-up after stemless reverse shoulder arthroplasty.

Abstract

Background: Stemless reverse total shoulder arthroplasty (rTSA) was developed to preserve humeral bone stock and facilitate revision surgery. While short-term outcomes are promising, mid-term data beyond five years remain limited. The purpose of this study was to evaluate clinical and radiographic outcomes at a minimum follow-up of five years after implantation of a stemless reverse shoulder prosthesis. We hypothesized that metaphyseal fixation would demonstrate sustained clinical function and stable radiographic integration at mid-term follow-up.

Methods: This retrospective case series included 44 consecutive patients who underwent stemless rTSA. At minimum five-year follow-up, 35 patients were available for clinical and radiographic evaluation (follow-up rate 79.5%). Clinical assessment included the Constant Score (CS), age-adjusted Constant Score, American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and Visual Analog Scale (VAS) for pain. Radiographic evaluation was performed using standardized two-plane radiographs and assessed for humeral and glenoid radiolucency, implant subsidence, loosening, and scapular notching.

Results: At a median follow-up of 69 months, patients demonstrated sustained functional outcomes with a median Constant Score of 74 (IQR 71-78), ASES score of 85 (IQR 80-95), SST score of 9.1 ± 2.0, and VAS pain score of 1 (IQR 0-2). The absolute Constant Score decreased slightly between the two- and five-year follow-up; however, this difference was not statistically significant (p = 0.264). Incomplete humeral radiolucent lines < 1 mm were observed in 3 patients (10.7%) and glenoid radiolucent lines in 2 patients (7.1%). No progressive loosening or implant migration was detected.

Conclusion: Stemless reverse shoulder arthroplasty demonstrated favorable clinical outcomes and stable radiographic metaphyseal fixation at a minimum follow-up of five years. No progressive radiographic changes or implant-related complications were observed beyond the initial two postoperative years. While these findings support the mid-term performance of this implant concept, further studies with larger patient cohorts are warranted to confirm these results.

Level of evidence: IV.