LABRAL-LIGAMENTOUS COMPLEX OF THE SHOULDER - EVALUATION WITH MR ARTHROGRAPHY

PURPOSE: To determine the usefulness of magnetic resonance (MR) arthro graphy in assessment of the labral-ligamentous complex and test the hy pothesis that the inferior glenohumeral ligament (IGHL) is an importan t anatomic feature of clinical instability. MATERIALS AND METHODS: For ty-eight shoulders with labral diagnoses proved with arthroscopy or op en surgery were prospectively examined with MR arthrography after intr aarticular injection of gadopentetate dimeglumine. RESULTS: Surgical f indings showed that 14 labra were normal, 24 were torn, and six were d eficient. (One labrum was torn and deficient in separate locations.) M R arthrographic findings had a diagnostic sensitivity of 91% and speci ficity of 93%. In 32 patients with proved labral abnormalities, 30 les ions involved the labral-bicipital junction, origins of the glenohumer al ligaments, or both. In 22 of 23 shoulders considered clinically uns table, a labral abnormality involved the origin of the IGHL. CONCLUSIO N: MR arthrography accurately shows the relationship of labral lesions to the origins of the glenohumeral ligaments and helps in distinction between stable and unstable lesions.