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 one-year postoperatively. The primary outcome of interest was a comparison of subscapularis strength between cohorts relative to preoperative baseline, while secondary outcomes were functional, ROM and PROMs.RESULTS: Sixty-six patients were included in final analysis (32 TR vs 34 SR). There were no statistically significant differences between cohorts at the ICV with regards to demographics, baseline subscapularis strength, functional testing, or PROMs. All postoperative time points demonstrated similar subscapularis strength testing between TR and SR groups (p>0.05). 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 timepoint as compared to baseline ICV values (p<0.05).CONCLUSIONS: Patients undergoing anatomic total shoulder arthroplasty return to baseline internal rotation strength by 3-months postoperatively and demonstrate significant improvements in function, range of motion, 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.