Treatment of Irreducible Traumatic Anterior Shoulder Dislocation Caused by Subscapularis Tendon Interposition.

Irreducible shoulder dislocation is an uncommon event. When it does occur, blocks to reduction can include bone, labrum, rotator cuff musculature, or tendon. Concomitant rotator cuff tear at the time of initial dislocation is not an exclusive complication of anterior shoulder dislocation in the older population. Indeed, rotator cuff tear should not be excluded based solely on the patient's age. Rotator cuff interposition is not an uncommon complication after anterior dislocation of the shoulder. It should be suspected when there is incongruency of the joint and persistent subluxation on postreduction radiographs. If such incongruence or subluxation is seen, a computed tomographic (CT) or magnetic resonance imaging (MRI) scan must then be obtained to determine the nature of the interposed soft tissues. The key to treatment is early diagnosis and adequate imaging. Open reduction and repair of the rotator cuff should be performed. We present a technique for treating irreducible anterior shoulder dislocation caused by interposition of the subscapularis tendon. Both CT and MRI observations, along with intraoperative findings and surgical technique, are discussed.