Validity of magnetic resonance arthrography as a diagnostic tool in femoroacetabular impingement syndrome.

ABSTRACT

INTRODUCTION: Femoroacetabular impingement (FAI) is one of the main causes of hip pain in young adult and a contributory factor for development of early primary osteoarthritis. An accurate clinical diagnosis, supported by imaging studies, is important to determine the best treatment for the patient. The aim of this study is to determine the diagnostic correlation between direct magnetic resonance imaging (MRI) arthrography and the arthroscopic findings. MATERIALS AND METHOD: A review was performed on a series of 36 patients diagnosed with FAI, and who underwent hip arthroscopy surgery between 2009 and 2012. All of them had a direct MRI arthrography performed in our hospital. The presence of labral lesions, CAM deformity, and acetabular and femoral cartilage damage, were evaluated in both imaging techniques. RESULT: After analysing the results and taking the hip arthroscopy as 'gold standard', a sensitivity of 87% and a specificity of 77% were obtained, with a PPV of 87% for the diagnosis of labral lesions by direct MR arthrography. The specificity for CAM deformity was 100%, with a sensitivity of 79% and PPV of 100%. For chondral disorders lower values were found for both acetabulum and femoral head. For acetabular lesions the sensitivity was 78.5%, and specificity was 82% with a PPV of 73% and NPV of 80%. For femoral lesions, there was a sensitivity of 71.5%, a specificity of 73%, with a PPV of 62.5% and NPV of 80%. CONCLUSIONS: Due to the high sensitivity for the detection of labral lesions and the high specificity to detect CAM deformity, hip MR arthrography is a useful diagnostic tool for femoroacetabular impingement.