Comparison of reverse total shoulder arthroplasty outcomes with and without subscapularis repair.

BACKGROUND

Repair of the subscapularis with reverse total shoulder arthroplasty (rTSA) is controversial. The purpose of this study is to quantify rTSA outcomes in patients with and without subscapularis repair to determine if there is any impact on clinical outcomes.

METHODS

Three hundred forty patients received rTSA and had the subscapularis repaired, whereas 251 patients received rTSA and did not have the subscapularis repaired. The patients were scored preoperatively and at latest follow-up using the Simple Shoulder Test; University of California, Los Angeles; American Shoulder and Elbow Surgeons; Constant; and Shoulder Pain and Disability Index metrics. Motion was also measured. Mean follow-up was 37 months.

RESULTS

All patients showed significant improvements in pain and function after treatment with rTSA. For both cohorts, American Shoulder and Elbow Surgeons and Constant scores significantly improved, as did range of motion. The repaired cohort had significantly higher postoperative scores as measured by 4 of the 5 metrics and significantly more internal rotation, whereas the non-repaired cohort had significantly more active abduction and passive external rotation. The complication rate was 7.4% (0% dislocations) for the subscapularis-repaired cohort and 6.8% (1.2% dislocations) for the non-subscapularis-repaired cohort.

CONCLUSIONS

Significant clinical improvements were observed for both the subscapularis-repaired and non-repaired cohorts, with some statistical differences observed using a variety of outcome measures. Repair of the subscapularis did not lead to inferior clinical outcomes as predicted by biomechanical models. No difference was noted in the complication or scapular notching rates between cohorts. These clinical results show that rTSA using a lateralized humeral prosthesis delivers reliable clinical improvements with a low risk of instability, regardless of subscapularis repair.