Irreducible anterior dislocation of the shoulder due to soft tissue interposition of subscapularis tendon

The shoulder joint is the most unstable joint in the body and is easily dislocated. Anterior shoulder dislocation is the commonest and can be associated with glenoid and humeral fractures. Anterior shoulder dislocations are not infrequently associated with cuff tendon tears; however, anterior shoulder dislocation is easily reducible. Irreducible anterior dislocation of the glenohumeral joint is uncommon, and this could be due to bony as well as soft tissue causes. Persistent anterior dislocation due to torn subscapularis interposition in the glenohumeral joint is very rare, and only a few operative cases have been reported in the literature. We present MR features of one such case and a literature review. (orig.)