Biomechanical and Clinical Evaluation of a Novel Lesser Tuberosity Repair Technique in Total Shoulder Arthroplasty

Abstract

A s with arthroplasty of other large joints, shoulder replacement reliably improves a patient's quality of life1-8. However, although shoulder replacement is frequently successful, complications do occur9-15. Injury to the subscapularis can lead to weakness, decreased motion and stability, and diminished satisfaction following shoulder arthroplasty. Compromise or dysfunction of the subscapularis resulting from routine division and repair during the arthroplasty is a complication that is being recognized more frequently16,17. Subscapularis dysfunction may lead to a loss of active terminal internal rotation with an abnormal belly-press or lift-off test or the inability to perform a shirt-tuck test18. In a recent study, >65% of patients had subscapularis dysfunction following shoulder arthroplasty with a soft-tissue subscapularis repair17. While dysfunction is sometimes subtle, resulting in minor functional disabilities, rupture of the subscapularis is a devastating problem that can lead to gross anterior instability. Anterior instability following arthroplasty is typically secondary to rupture of the repaired subscapularis13,19. Reported rates of subscapularis rupture following primary arthroplasty have ranged from 3% to 11%19-22. Instability is the most frequent complication following shoulder arthroplasty and is the most common indication for revision surgery9,11,19,23-25. While the etiology of instability is often multifactorial, the greatest cause is soft-tissue imbalance13,19,24,26,27. In order to strengthen our subscapularis repairs and to prevent rupture, we have been performing a lesser tuberosity osteotomy to reflect the subscapularis and expose the joint in shoulder arthroplasties. The lesser tuberosity osteotomy does not violate the subscapularis tendon, and its repair provides a strong, secure closure that allows bone-healing. The strength of the repair is due …