The role of subscapularis repair in reverse total shoulder arthroplasty.

BACKGROUND: Controversy surrounds the role of the sub- scapularis (SSC) in reverse shoulder arthroplasty (rTSA) and the need for repair, if possible, at the conclusion of the procedure. QUESTIONS AND PURPOSE: Some investigators have concluded that an intact SSC is critical for stability; others have found no such correlation. What factors should be part of the decision-making matrix on SSC management for surgeons considering rTSA?

FINDINGS: The data on management of the SSC in rTSA support a design-based approach. Researchers have shown that the SSC is critical to stability when the surgeon uses an implant with a medialized humeral component and medialized glenoid component. However, lateralized designs allow for more stability from horizontal deltoid compression and may not require repair of the SSC. In addition, SSC repair has been shown to increase the workload of the residual posterior rotator cuff and the deltoid in rTSA, both of which may have negative consequences on overall function. Lateralization from the glenoid component increases deltoid work, whereas lateralization from the humeral component maintains deltoid efficiency while improving stability.

CONCLUSIONS: The need for SSC repair in rTSA can vary based on the implant selected. Humeral and glenoid offset influence the stability and kinematics of rTSA.