Labral-ligamentous complex of the shoulder: evaluation with MR arthrography.

PURPOSE

To determine the usefulness of magnetic resonance (MR) arthrography in assessment of the labral-ligamentous complex and test the hypothesis that the inferior glenohumeral ligament (IGHL) is an important anatomic feature of clinical instability.

MATERIALS AND METHODS

Forty-eight shoulders with labral diagnoses proved with arthroscopy or open surgery were prospectively examined with MR arthrography after intraarticular injection of gadopentetate dimeglumine.

RESULTS

Surgical findings showed that 14 labra were normal, 29 were torn, and six were deficient. (One labrum was torn and deficient in separate locations.) MR arthrographic findings had a diagnostic sensitivity of 91% and specificity of 93%. In 32 patients with proved labral abnormalities, 30 lesions involved the labral-bicipital junction, origins of the glenohumeral ligaments, or both. In 22 of 23 shoulders considered clinically unstable, a labral abnormality involved the origin of the IGHL.

CONCLUSION

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.