Evaluation of New Normal After Shoulder Arthroplasty: Comparison of Anatomic versus Reverse Total Shoulder Arthroplasty.

Background: Reports of equivalent patient reported outcomes between anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) have contributed to a continued preference of rTSA. While many surgeons believe the best aTSA outcome can outperform the best rTSA outcome, this has not yet been demonstrated in the literature. The purpose of this study is to investigate the outcome characteristics of aTSA and rTSA patients who perceive their shoulder is close to normal, with the hypothesis that aTSA patients will outperform rTSA patients.

Methods: A retrospective query of our institution's data repository from 2006 to 2021 identified primary anatomic and reverse total shoulder arthroplasty patients with minimum 2-year follow-up and who have achieved a 'new normal,' defined as a most recent Single Assessment Numeric Evaluation (SANE) score ≥ 95. Anatomic and reverse shoulder arthroplasty patients were compared based on patient-reported outcome measures (PROM), range of motion (ROM), and satisfaction. Specific PROM questions representative of higher functional demands were analyzed and a subset analysis of patients treated for osteoarthritis with an intact rotator cuff was performed.

Results: The query identified 849 aTSA and 745 rTSA patients with minimum 2-year follow-up. Of these, 40% (337) of aTSA and 26% (193) of rTSA patients reached a SANE score > 95 at most recent follow-up. aTSA significantly outperformed rTSA in total American Shoulder and Elbow Surgeons (ASES) score (p<.001), ability to reach a high shelf (p<.001), lift 10 pounds (p<.001), perform usual work and perform usual sport (p<.001), total Simple Shoulder Test (SST) score (p<.001), ability to lift 8 pounds and carry 20 pounds (p<.001), ROM including clinician measured elevation, abduction, external rotation, and internal rotation (p<.001). A subanalysis among patients treated for osteoarthritis with an intact rotator cuff produced similar results, with aTSA patients outperforming rTSA patients in many higher demand functions.

Conclusion: ATSA patients have a 40% chance of perceiving their shoulder as normal. Among shoulder arthroplasty patients who perceive their shoulder as normal, aTSA patients outperform rTSA patients with better motion and greater ability to return to work, return to sport, and perform higher demand activities without difficulty.