Subscapularis function after total shoulder arthroplasty: electromyography, ultrasound, and clinical correlation

Background The literature lacks electromyographic (EMG) examination of subscapularis function in the postoperative period after total shoulder arthroplasty (TSA). The primary purpose of this study was to document EMG activity of the subscapularis after TSA and to correlate it with clinical and ultrasound findings. Methods The study included 30 patients who were at least 1 year (average, 2.1 years) from surgery, status post TSA approached through a standard subscapularis tenotomy. Patients returned for a physical examination, ultrasound evaluation, and EMG evaluation. Patients also completed postoperative surveys: the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and the 12-Item Short Form Health Survey. Results The American Shoulder and Elbow Surgeons, Simple Shoulder Test, and physical 12-Item Short Form Health Survey scores improved from preoperatively to postoperatively, respectively, 45.3 to 76.8 ( P = .0002), 3.9 to 9.0 ( P