OBJECTIVETo investigate the diagnostic value of MRI and MR arthrography in the detection of injuries of anterior labrum in shoulder and to evaluate the accuracy of MR arthrography in the classification of anterior labrum lesion.

METHODSSeventy-eight patients with arthroscopically proved anterior labrum lesions(study group) and 75 patients with arthroscopically proved intact anterior labrum (control group) from January 2007 to December 2010 were included to the study. All patients underwent MRI and MR arthrography at our institution prior to shoulder arthroscopy. All MRI and MR arthrography were analyzed by one musculoskeletal radiologists and one sports medicine surgeon who had no knowledge of the clinical histories and arthroscopic results. The same classification system of labrum lesions based on arthroscopy was used in image analysis. Imaging findings and arthroscopic findings were compared in all patients. With arthroscopy used as the standard of reference, the sensitivities, specificities and accuracies of MRI and MR arthrography in the detection of anterior labrum lesions were compared, and the sensitivities, specificities and accuracies of MR arthrography in the correct classification of anterior labrum lesions were calculated.

RESULTSIn arthroscopy, 78 anterior labrum lesions, 67 rotator cuff lesions and 8 SLAP lesions were diagnosed, for the detection of anterior labrum lesions, the sensitivity of MRI and MR arthrography was 80.8% and 92.3%,the specificity was 89.3% and 97.3%,the accuracy was 85.0% and 94.8% respectively. Seventy-eight patients with arthroscopically proved anterior labrum lesions included 39 Bankart lesions, 32 ALPSA lesions and 7 Perthes lesions, with MR arthrography, Bankart, ALPSA, and Perthes lesions were correctly classified in 84.6%, 84.4%, and 57.1% of cases, respectively.

CONCLUSIONMR arthrography has a higher sensitivity, specificity and accuracy than MRI in the detection of anterior labrum injuries. MR arthrography was useful in the classification of different variants of anterior labrum injuries before operations. It may directly influence the surgeon's strategy and is useful in preoperative planning of arthroscopic reconstructions.