The effect of subscapularis-specific rehabilitation following total shoulder arthroplasty: a prospective, double-blinded, randomized controlled trial.

Background: Patients undergoing a total shoulder arthroplasty (TSA) through a deltopectoral approach will require repair of the subscapularis tendon. There are no universal postoperative guidelines for rehabilitation of the subscapularis specifically. We hypothesize that the addition of a subscapularis-specific regimen will result in improved subscapularis strength and function.

Methods: Adult patients undergoing anatomic TSA for the treatment of primary glenohumeral osteoarthritis were included. Patients were randomized into either the traditional rehabilitation (TR) control group or the subscapularis rehabilitation (SR) group, which consisted of the traditional therapy along with early and additional subscapularis exercises. Baseline demographics, patient-reported outcome measures (PROMs), range of motion (ROM), provocative tests, and subscapularis strength using a handheld dynamometer were measured preoperatively at the initial clinic visit (ICV) as well as 3 months, 6 months, and 1 year postoperatively. The primary outcome of interest was a comparison of subscapularis strength between cohorts relative to preoperative baseline, whereas secondary outcomes were functional, ROM, and PROMs.

Results: Sixty-six patients were included in the final analysis (32 TR vs. 34 SR). There were no statistically significant differences between cohorts at the ICV with regard to demographics, baseline subscapularis strength, functional testing, or PROMs. All postoperative time points demonstrated similar subscapularis strength testing between TR and SR groups (P > .05). Additionally, peak and average subscapularis strength testing at 3, 6, and 12 months postoperatively were similar to baseline ICV testing in both groups. Both groups demonstrated improvements across several provocative tests, ROM, and PROM outcome metrics at every postoperative time point as compared to baseline ICV values (P < .05).

Conclusions: Patients undergoing anatomic TSA return to baseline internal rotation strength by 3 months postoperatively and demonstrate significant improvements in function, ROM, and several patient-reported outcome measures. The addition of early and focused subscapularis strengthening exercises does not appear to significantly impact any outcomes when compared to traditional rehabilitation programs.