HUMERAL AVULSION OF THE ANTERIOR SHOULDER STABILIZING STRUCTURES AFTER ANTERIOR SHOULDER DISLOCATION - DEMONSTRATION BY MRI AND MR ARTHROGRAPHY

Objective. To demonstrate the MRI findings of an anterior shoulder cap sular avulsion from the humerus, with or without subscapularis rupture , after anterior dislocation or severe abduction external rotation inj ury. Design and patients. We retrospectively reviewed the MRI and MR a rthrographic examinations of seven patients who were identified at sur gery with avulsion of the anterior shoulder stabilizers from the humer us. MRI was correlated with clinical history and surgical results. Res ults. MRI findings included: inhomogeneity or frank disruption of the anterior capsule at the humeral insertion (all), fluid intensity anter ior to the shoulder (six patients), tear of the subscapularis tendon ( six patients), dislocation of the biceps tendon (four patients), and a Hill-Sachs deformity (four patients). MR arthrography additionally fo und extravasation of contrast through the capsular defect (two patient s). Conclusions. Our findings suggest that MRT is helpful for diagnosi ng humeral avulsion of the anterior glenohumeral capsule, especially w hen a tear of the subscapularis tendon insertion is present. MR arthro graphy may be of benefit for diagnosing capsular avulsion without asso ciated subscapularis tendon abnormality.