Technical Guide and Tips to Arthroscopic Trans-scapular Transfer of Lower Trapezius for Irreparable Subscapularis Tears.

The efficacy of tendon transfers in the treatment of irreparable subscapularis tears has been inconsistent, with frequently unsatisfactory outcomes. We describe a technique for transfer of the lower trapezius tendon to the lesser tuberosity using an Achilles tendon allograft through a trans-scapular route after a scapular osteotomy. The surgical procedure begins with the preparation of the lower trapezius tendon via an open posterior incision. After splitting the infraspinatus muscle, the osteotomy of the scapular body is performed inferior to the scapular spine and medial to the glenoid vault. Then, the arthroscopic dissection of the anterior space of the glenohumeral joint and subscapular fossa is performed. The axillary and radial nerves are visualized and protected. The anterior dissection is completed by debridement of the subscapularis remnant as well as the subscapular fossa. A shuttle relay is placed, and the allograft is shuttled from the posterior scapula to the anterior compartment of the glenohumeral joint following the subscapular fossa. After debridement of the lesser tuberosity, the graft is fixed with 2 lateral anchors and 1 medial anchor. The shoulder is immobilized in internal rotation for a period of 6 weeks, after which physiotherapy can be started.