Recurrent Dislocation of the Shoulder: MR Imaging and MR Arthrographic Findings

ABSTRACT

PURPOSE: To evaluate and compare the diagnostic findings and usefulness of MRI and MR arthrogram in recurrent anterior dislocation of the shoulder. MATERIALS AND METHODS: MRI and MR arthrogram of thirty-two cases of thirty patients with recurrent anterior dislocation of the shoulder were retrospectively analyzed to evaluate glenohumeral ligaments, pattern of labral injury, bony Bankart lesion, capsular stripping, Hill-Sachs lesion, and loose body. RESULTS: Labral abnormalities was detected on MRI in 23 cases(72%) and MR arthrogram in 22 cases(69%) as labral tear, detachment, and deficiency. All cases involved anteroinferior labrum. On MR arthrogram, labral abnormalities was confined to anteroinferior portion in 4 cases(18%), extended into midglenoid level in 13 cases(59%), and that into anterosuperior portion in 5 cases(23%). Capsular stripping was noted on MRI in 6 cases(19%) and MR arthrogram in 12 cases(38%). Loose body was detected only on MR arthrogram in 5 cases (16%). Bony Bankart lesion and Hill-Sachs lesion was detected equally on MRI and MR arthrogram in 2 cases (6%) and 21 cases(66%) respectively. We obtained identical findings on both MR arthrogram and operation field in 6 patients. CONCLUSION: MRI with its excellent soft tissue contrast resolution and multiplanar imaging capafility helps detection of labral injury in recurrent anterior dislocation of the shoulder. MR arthrogram is slightly invasive, but shows good artatomic details of labral-ligamentous-capsular relationship and thus provides accurate detec- tion of pattern of labral injury, capsular stripping, and loose body.