Predictors of Internal Rotation-Dependent Activities of Daily Living Performance and Favorable Satisfaction Despite Loss of Objective Internal Rotation After Reverse Shoulder Arthroplasty

Introduction: Previous research has determined that objective and subjective internal rotation (IR) may be discordant. The purpose of this study was to identify predictors of patient-reported ability to perform IR-dependent activities of daily living (IRADLs) and favorable patient satisfaction after reverse shoulder arthroplasty (RSA) despite the loss of objective IR.

Methods: A single, institutional, shoulder arthroplasty database was queried for patients undergoing primary RSA with a minimum 2-year follow-up. Patients who were wheelchair bound or had a preoperative diagnosis of infection, fracture, or tumor were excluded. We first identified patients in the overall cohort that lost objective IR from pre- to postoperative assessment, defined as a one-point reduction in the eight-point Flurin scale. In this cohort, we identified patient characteristics that were predictive of patient-reported ability to perform IRADLs and overall patient satisfaction and thresholds in postoperative objective IR.

Results: Out of 599 RSAs initially identified, 107 RSAs lost objective IR (45% female, mean age 70 years). On average, patients lost 1.7 IR score points pre- to postoperatively. Greater preoperative IR and lesser loss of objective IR pre- to postoperatively were associated with greater patient-reported ability to perform all 4 IRADLs (odds ratio 1.54 to 2.5), whereas female sex was associated with worse patient-reported ability to perform 3 IRADLs (odds ratio 0.26 to 0.36). We identified that patients with postoperative IR below the sacrum were unlikely to be able to perform IRADLs and those with postoperative IR at or above L4-L5 were likely to be satisfied.

Conclusion: Despite losing objectively assessed IR after RSA, many patients are still able to perform IRADLs and report favorable satisfaction as long as objective IR reaches L4/5. Female sex and postoperative IR below the sacrum were associated with the inability to perform IRADLs, whereas postoperative IR to or above L4-L5 was associated with subjective ratings of satisfaction.