Factors associated with outcomes after reverse total shoulder arthroplasty at midterm follow-up

Reverse total shoulder arthroplasty has become the preferred treatment for many patients with irreparable cuff tears, osteoarthritis, and complex proximal humeral fractures. While outcomes are generally favorable, the influence of demographic and surgical factors-such as age, sex, previous surgery, and dominance of the operated arm-on post-operative results remains incompletely understood.

After institutional review board approval, a retrospective review of prospectively collected data was conducted for all primary reverse total shoulder arthroplasties performed by a single surgeon between December 2011 and December 2022, with a minimum follow-up of 24 months. Typical characteristics, including sex, age at the time of surgery, previous rotator cuff surgery, and subscapularis repair, were recorded. Patient-reported outcome measures included the American Shoulder and Elbow Surgeons (ASES) score, visual analog scale for pain, Single Assessment Numeric Evaluation (SANE), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), and 12-Item Short Form Health Survey physical and mental component summaries. These were obtained pre- and post-operatively. Minimal Clinically Important Difference and patient acceptable symptom state for ASES were assessed. Additionally, fatty infiltration was assessed pre-operatively according to the Goutallier classification. Multivariable linear regression analyses were used to identify factors associated with post-operative outcomes.

Final follow-up was obtained for 148 of 185 patients (80%) at a mean of 76.1 ± 32.5 months. The mean age at surgery was 66.0 ± 9.8 years; 61.5% were male. Significant post-operative improvements were observed in ASES, visual analog scale, SANE, QuickDASH, and 12-Item Short Form Health Survey Physical Component Summary scores (all P < .05). A total of 90.7% achieved the Minimal Clinically Important Difference for ASES, and 68.9% achieved the patient acceptable symptom state. Male sex and surgery on the dominant arm were associated with superior QuickDASH, and female sex was associated with inferior SANE outcomes (P < .05), while age, subscapularis repair, and fatty infiltration showed no significant influence (P > .05). The overall failure rate was 4.7%, with dislocation being the most frequent cause (2.7%). The complication rate was 1.3% (2 cases of acromial stress fracture).

Reverse total shoulder arthroplasty provides consistent and durable clinical improvement, with high patient satisfaction and low complication and failure rates. Procedures performed on the dominant arm may yield more favorable outcomes, whereas the female sex has been associated with inferior results in select domains, but without influencing overall failure rates.