Functional internal rotation after shoulder arthroplasty: a comparison of anatomic and reverse shoulder arthroplasty.

BACKGROUND: Recovery of functional internal rotation after primary shoulder arthroplasty is essential to perform many important activities of daily living. Functional internal rotation is typically reported as it relates to clinical examination findings of motion (posterior reach) and lift-off or belly-press tests. A more detailed evaluation of functional recovery of internal rotation after primary anatomic total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA) is needed.
METHODS: A retrospective review of patients treated with primary TSA (n = 132) and RSA (n = 91) with a minimum 2-year follow-up was performed. Subanalysis of revision RSA (n = 24) and primary RSA was performed. Active range of motion, subjective internal rotation motion, manual internal rotation strength, and specific questions related to internal rotation function isolated from the Simple Shoulder Test (SST) and American Shoulder and Elbow Surgeons (ASES) functional questionnaires were reviewed.
RESULTS: Compared with RSA, TSA patients could more likely reach the small of the back (SST) and wash the back/fasten bra (ASES). Active internal rotation motion, SST score, ASES score, and subjective internal rotation were greater after TSA. No significant difference was observed with respect to managing toileting between cohorts. Revision RSA patients were less likely to be able to wash the back/fasten bra (ASES) and easily manage toileting (ASES) compared with primary RSA patients.
CONCLUSION: Primary anatomic shoulder arthroplasty yields greater functional internal rotation than does primary RSA, with either procedure being effective at managing toileting. Patient education regarding activities of daily living related to internal rotation can be predicted.