MAGNETIC-RESONANCE-IMAGING OF THE GLENOID-LABRUM IN ANTERIOR SHOULDERINSTABILITY

Detachment of the anterior inferior labrum and inferior glenohumeral l igament complex from the glenoid is a common lesion encountered in ant erior shoulder instability while other types of labral lesions are ass ociated with symptoms that mimic instability. Accurate delineation of labral lesion is, therefore, key in managing shoulder problems. In a p rospective double-blinded fashion, we compared the magnetic resonance imaging findings with those noted at surgery in 33 patients with possi ble anterior shoulder instability. Of 28 surgically confirmed labral l esions, 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 classification of glenoid labra according to the type and severity of the lesions. Method of tre atment correlated with clinical outcome, using this system, to a stati stically significant level. Unfortunately, this system enabled accurat e classification with magnetic resonance imaging in only 7 of 33 (21%) labra, with the precision necessary to affect surgical planning in ou r series. We conclude that magnetic resonance imaging is not useful in the surgical planning for most patients with obvious anterior shoulde r instability.