Avulsion of subscapularis muscle tendon leading to recurrent anterior dislocation of the shoulder

Abstract

Fifteen patients, ten males and five females, were identified as having recurrent anterior dislocation of the shoulder after trauma due to avulsion of the subscapularis muscle tendon from its humeral attachment. The usual mechanism of injury was traumatic hyperextension or external rotation of the abducted arm. The right arm was involved in 12 patients and the left arm in only three patients. The presenting symptoms were pain and weakness of the affected shoulder. Physical examination showed reduction of the passive range of joint movement and tenderness on the anterior aspect at the shoulder at the level of the intertubercular groove and a reduced range of internal rotation of the shoulder. The diagnosis was suspected from the history, physical examination and radiographs and was finally confirmed by surgical exploration. The ages of the patients ranged from 20 to 46 years (mean 33 years). The dislocation was found to be due to a complete tear of the subscapularis tendon (12 patients) and partial tears in three patients, without fracture of the lesser tuberosity in any of the patients. The repair consisted of mobilisation of the subscapularis muscle and its reinsertion into an osseous trough created in the humerus. The shoulder was splinted for six weeks in a Velpenu bandage before mobilisation and physiotherapy. In two patients the subscapularis tendon was frayed and could not take sutures and therefore an allograft of tendo Achilles was used. The patients have been followed up for an average of three years postoperatively. All have acceptable functional results but a reduced range of external rotation.