The Usefulness of Computed Arthrotomography and MR imaging for the Diagnosis of Reccurent Anterior Dislocation of the Shoulder.

Imaging of glenoid labrum pathology in cases with reccurent dislocation of the shoulder is useful for diagnosis and help in planning surgical repair. We compared magnetic resonance (MR) imaging with computed arthrotomography (CAT), and investigated the usefulness of MR and CAT for diagnosis in nine patients with reccurent anterior dislocation of the shoulder and 5 patients with reccurent anterior subluxation of the shoulder. All patients underwent arthroscopy and modified Bristow's operation. There were 10 males and 4 females, ranging in age from 14 to 59 years (mean: 24.4 years at the time of operation).CAT and MR imaging demonstrated 100per cent sensitivity, specificity and accuracy in the diagnosis of Hill-Sachs lesion, bony Bankart and anterior labral defects. In the diagnosis of anterior labral tears or cracks, CAT demonstrated 75per cent sensitivity, 100per cent specificity and 93per cent accuracy, and MR imaging demonstrated 100per cent sensitivity, 90per cent specificity and 93per cent accuracy. CAT findings of the labrum were almost the same as MR images, but CAT was easier than MR to determine the shape of the labrum. CAT could disclose detachment of the anterior capsule which was not detected by MR. In two cases with anterior subluxation, MR displayed high intensity of the anterior labrum but a normal shape was seen in CAT. Pathologic finding of one of the cases showed degenerative change and inflammation. It was suggested that MR is also capable of displaying pathologic conditions of the labrum in anterior subluxation of the shoulder.