Magnetic Resonance Imaging of the Glenoid Labrum in Anterior Shoulder Instability

Abstract

Detachment of the anterior inferior labrum and inferior glenohumeral ligament complex from the glenoid is a common lesion encountered in anterior shoulder insta bility while other types of labral lesions are associated with symptoms that mimic instability. Accurate delinea tion of labral lesion is, therefore, key in managing shoul der problems. In a prospective double-blinded fashion, we compared the magnetic resonance imaging findings with those noted at surgery in 33 patients with possible anterior shoulder instability. Of 28 surgically confirmed labral lesions, 21 were detected by imaging. Sensitivity was 75%, specificity 100%, while positive and negative predictive values were 100% and 41%, respectively. Overall accuracy was 79%. Based on a literature review and our clinical experience, we developed a classifica tion of glenoid labra according to the type and severity of the lesions. Method of treatment correlated with clini cal outcome, using this system, to a statistically signifi cant level. Unfortunately, this system enabled accurate classification with magnetic resonance imaging in only 7 of 33 (21 %) labra, with the precision necessary to affect surgical planning in our series. We conclude that magnetic resonance imaging is not useful in the surgical planning for most patients with obvious anterior shoul der instability.