Medium-term outcomes following Mathys Affinis Short stemless anatomic total shoulder replacement: clinical and radiologic findings (minimum 5-year follow-up).

Background: Stemless anatomic total shoulder arthroplasty (aTSA) use has increased in recent years. Despite evidence to suggest good midterm results at 2-year follow-up, there is a scarcity of evidence for longer-term follow-up. This study aimed to investigate outcomes at a minimum of 5 years postoperatively following primary stemless aTSA.

Methods: An observational cohort study using prospectively collected data was performed for all patients who underwent a Mathys Affinis stemless aTSA procedure at our institution. The study period ranged from July 2010 to August 2018 (minimum 5-year follow-up). Clinical outcome measures included revision rate, range of motion, and patient-reported outcomes (Oxford Shoulder Score and Numerical Satisfaction Score). Radiologic outcome was an assessment of radiolucency using Lazarus grading.

Results: A total of 105 stemless TSAs were implanted during the trial period. Following exclusions, 75 aTSAs were included in the final cohort for analysis of 5-year outcomes. Five patients underwent revision (4.8%), and the median follow-up time was 6.1 years. The median age was 69 years, and 81% were female. The Oxford Shoulder Score showed a range of 18-48, with a median score of 47. Satisfied or very satisfied was selected in 94.4%. Median range of motion assessments showed forward elevation 160°, abduction 150°, and external rotation 40°, and mode internal rotation was to the lumbar spine. No glenoid lucency was present in 79.7%. There were 9.5% with Lazarus grade 1 lucency, 5.4% with Lazarus grade 2, and 5.4% Lazarus grade 3. No humeral lucency was observed.

Conclusions: This cohort study represents the largest minimum 5-year follow-up data for the Mathys Affinis stemless anatomic total shoulder arthroplasty, demonstrating excellent clinical and radiologic outcomes.