Reliability of magnetic resonance imaging versus arthroscopy for the diagnosis and classification of superior glenoid labrum anterior to posterior lesions.

PURPOSE: The physical examination of the shoulder is usually not reliable for the true diagnosis of superior glenoid labrum anterior to posterior (SLAP) lesions. Magnetic resonance imaging (MRI) has been routinely used for the diagnosis. This prospective study investigates the radiological diagnosis of the SLAP lesions and compares accuracy of arthroscopic and MRI classifications.

METHODS: One hundred thirty-two patients with positive physical examination signs using O'Brien, Yergason, resistance supination external rotation and Krank tests and MRI findings are included in the study. Shoulder MRIs were obtained for all patients within three months prior to the surgeries. SLAP lesion is detected in 90 and 102 patients according to MRI and arthroscopy, respectively. Arthroscopic and MRI classifications of the patients were performed according to modified Snyder classification.

RESULTS: Sensitivity and specificity of the MRI were found as 70.59 and 40%, respectively. No difference was detected between MRI and arthroscopy classifications in 52 (39%) patients. Although the diagnosis was compatible with arthroscopy in 34 (25%) patients, the classification was incompatible. In 46 (34%) of patients the diagnosis was incompatible with the MRI.

CONCLUSION: Although MRI is a good diagnostic tool for SLAP lesions, its use for the classification is limited. Level of evidence Level III, Diagnostic study.