Irreparable subscapularis tendon tears are uncommon rotator cuff injuries that are difficult to manage. These injuries result in anteroposterior force-couple imbalance around the glenohumeral joint, with pain and loss of active internal rotation. Insufficiency as a result of a tendon tear, muscle injury, or neurologic alteration leaves the humeral head unbalanced and may lead to weakness, anterior shoulder pain, and dysfunction. Various musculotendinous transfers, such as pectoralis major, pectoralis minor, and latissimus dorsi transfers, have been performed in active or young patients without glenohumeral arthritis to substitute for subscapularis muscle function. Pectoralis major tendon transfer is the most common procedure to manage an irreparable subscapular tear; however, the pectoralis major has a force vector to the chest wall and cannot pull the humeral head posteriorly in the same manner as the native subscapularis. Variable outcomes have been reported after pectoralis major tendon transfer for management of irreparable subscapularis tendon tears. Compared with the pectoralis major, the latissimus dorsi has a force vector better in line with that of the subscapularis muscle. Cadaver model studies and case series have demonstrated that latissimus dorsi transfer is a safe and feasible procedure for subscapularis reconstruction, resulting in improved pain relief and functional outcomes. Orthopaedic surgeons must understand the anatomy of the muscles and nerves in the anterior and posterior shoulder to avoid complications.

This video shows the gross anatomy of the anterior and posterior shoulder, with an emphasis of the anatomy of the muscles and nerves. The video demonstrates latissimus dorsi transfer for management of an irreparable subscapularis tendon tear in a cadaver model and in a 50-year-old patient who sustained a rerupture of the subscapularis tendon 11 months after repair. Latissimus dorsi transfer is an effective and safe salvage procedure for the management of irreparable subscapularis tears.