The aim was to establish a correlation between the integrity of a suture made in the subscapular tendon (SST), as assessed by an ultrasound examination, and its functionality, as assessed by clinical tests during the postoperative period following reverse shoulder arthroplasty (RSA). A secondary goal is to evaluate the presence and viability of the sutured SST. Methods: This is a retrospective study of 18 RSA patients in whom the SST was repositioned to the anterior face of the humeral osteotomy. The median time of the postoperative evaluation was 31 months. The clinical evaluation consisted of the Gerber lift-off test, the internal rotation (IR) lag sign test, and the abdominal compression test, as well as forward flexion (FF), external rotation (ER), and IR. All patients underwent shoulder ultrasounds to evaluate the SST presence and viability. Results: The SST was visualized in 13 patients (72.2%; 95% confidence interval [CI], 51.5-92.9). Of these 13 patients, the SST presented an altered fibrillar pattern in 5 patients (38.4%; 95% CI, 12.0-64.9) and was considered nonviable. There were no associations between SST viability and a positive Gerber's lift-off test (P ¼.480), a positive IR lag sign test (P ¼.480), or a positive abdominal compression test (P ¼.618). There were no significant differences in FF (P ¼.104), ER (P ¼.196), or IR (P ¼.374) mobility between patients with viable SSTs and those without viable SSTs. Conclusion: It was not possible to demonstrate a correlation between the integrity of the SST repair based on the ultrasound and its functionality as assessed by clinical tests in the postoperative period following an RSA. The SST repair has a high failure rate, as demonstrated by the high incidence of nonviable or absent tendons.