Pectoralis major tendon transfer for management of subscapularis failure after anatomic total shoulder arthroplasty: technique and results

Background: Subscapularis tendon failure after anatomic total shoulder arthroplasty can lead to pain, dysfunction, and early component failure. The purpose of this study was to report on the results of pectoralis major tendon transfer for treatment of irreparable subscapularis tendon failure in the setting of prior shoulder arthroplasty. Methods: Patients who underwent pectoralis major muscle transfer for treatment of subscapularis failure in the setting of prior total shoulder arthroplasty or hemiarthroplasty were included in the study. The entirety of the pectoralis major tendon was transferred superficial to the conjoined tendon and placed lateral to the bicipital groove. Results: Eight patients were included in the study. All 7 patient who experienced pain in their shoulder had improvement in their pain postoperatively. Those patients with preserved active motion were able to regain that motion postoperatively. Radiographically, anterior translation was found to be temporarily improved; however, anterior instability would later recur in most cases, though this did not correlate with increased pain or decreased function. Discussion: Management options ranging from continued observation, revision repair, pectoralis muscle transfer, or revision to reverse total shoulder arthroplasty should be considered in a setting of subscapularis failure after shoulder arthroplasty. Decision-making should be based on physiological age of the patient as well as symptoms present as well as the position and stability of the arthroplasty components. Conclusion: Pectoralis muscle transfer can provide pain relief, improve subjective instability, and preserve function in physiological young patients with an irreparable subscapularis who have well-positioned and well-fixed anatomic shoulder arthroplasty components.