Pectoralis major and pectoralis minor transfer for irreparable subscapularis tendon tears.

OBJECTIVE

Irreparable rotator cuff injuries in young patients with moderate to high levels of physical activity remain a challenging pathology for shoulder surgeons. Irreparable anterior rotator cuff injuries require treatment that seeks to restore the dynamic anterior forces of the glenohumeral joint. Among surgical treatment options, transfer of the pectoralis major and minor muscle, have shown good functional outcomes. This technique attempts to reproduce the vector of the subscapular muscle in cases with irreparable tear. Restoration of the dynamic external and internal couple forces to maintain the humeral head in the center of rotation.

INDICATIONS

Pectoralis major transfer (PMa): Irreparable subscapularis tendon (SSC) tear in active patients without osteoarthritis. Pectoralis minor transfer (PMi): Irreparable superior SSC tear with concomitant irreparable supraspinatus tendon (SSP) tear in active patients with no osteoarthritis.

CONTRAINDICATIONS

Primary osteoarthritis Samilson grade C, cuff tear arthropathy Hamada III-V, infection, axillary nerve palsy, older patients with low physical demand, combination with irreparable SSP/infraspinatus tendon (ISP) tear for PMa or combination with irreparable ISP tear for PMi.

SURGICAL TECHNIQUE

General anesthesia and beach-chair position with the arm freely mobile in an arm holder. Deltopectoral approach. Exposure of the humeral head and confirmation of the irreparability of the subscapularis tendon. PMa: Detachment of the tendon to be transferred from the humeral insertion, blunt anatomic dissection medially. Exposure of the conjoined tendon and coracoid process. PMi: Detachment of the tendon with an osteotomy at the coracoid process. Passing the PMa or PMi tendon under the conjoined tendon. The PMa tendon is fixed in a 2-row configuration, the PMi in a single row with suture anchors to the lesser tuberosity.

POSTOPERATIVE MANAGEMENT

Shoulder abduction sling (30°) for 6 weeks. Assisted range-of-motion (ROM) exercises with abduction/adduction 60-0-0°, internal/external rotation free-0-0° for 6 weeks. Free active ROM exercises after 6 weeks, muscle strengthening after 12 weeks.

RESULTS

The pectoralis major and minor transfer shows an improvement in strength and range of motion in young active patients and an improved Constant score (CS) in long-term follow-up examinations.