Internal rotation based activities of daily living show limitations following reverse shoulder arthroplasty versus anatomic shoulder arthroplasty

One of the more common limitations after reverse total shoulder arthroplasty (rTSA) is limited internal rotation (IR). Outcomes after rTSA are commonly reported as patient-reported outcome measures (PROMs) but are rarely assessed by specific activities of daily living (ADLs). Analyzing ADLs evaluates for specific motions from PROMs. The purpose of this study is to investigate the deficit in IR following rTSA through ADLs. A retrospective case-control study was conducted using institutional medical records. Patients who underwent total shoulder arthroplasty between 2009 and 2020 were reviewed for demographic and clinical variables (type of arthroplasty, indication, range of motion and strength). PROMs were taken by phone at 2-year minimum follow-up. Statistics were calculated as two-tailed using Chi-square or simple t-tests as appropriate. Among 208 patients, 114 aTSA, and 94 rTSA were identified and included in this study. Both groups reported significant increases in range of motion and strength postoperatively. PROMs were mostly similar between aTSA and rTSA (Single Assessment Numeric Evaluation 83.4 ± 17.1 vs. 82.3 ± 18.4, P = .643; visual analog scale Pain 2.2 ± 2.8 vs. 1.8 ± 2.4, P = .247), while Simple Shoulder Test did show a difference (9.2 ± 2.8 vs. 7.8 ± 3.2, P = .001) with higher scores in the aTSA cohort. The ADLs which showed significant disparity between aTSA and rTSA were toileting (P = .001), donning a coat (P = .017), reaching one's back (P = .017), as well as throwing overhand (0.013) with rTSA patients reporting more difficulty in all these ADLs. Both aTSA and rTSA are safe and efficacious options for shoulder replacement, as evidenced by high Single Assessment Numeric Evaluation and low visual analog scale pain scores and should be used according to their established indications. Surgeons may counsel rTSA patients about potential increased deficits in ADLs reliant on IR such as managing toileting and dressing compared to aTSA recipients.