Abstract
Background: Magnetic resonance imaging (MRI) has been recognized as the imaging method for non-invasive evaluation of knee pathology, particular meniscus and ligaments. Objective: Compare the sensitivity, specificity, and accuracy of MRI in the detection of meniscal tears with arthroscopy. Material and methods: Twenty-seven patients who were diagnosed as meniscal tear on arthroscopy with preoperative MRI were included in this study between January 2003 and June 2008. MRI was performed with a 1.5 Tesla Signa Horizon Echospeed MRI for eight patients between January 2003 and June 2005 and a 1.5 Tesla Signa Excited HD MRI for nineteen patients between July 2005 and June 2008. The location of meniscal tear was evaluated by studying three areas: anterior horn, body and posterior horn. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the anterior horn, body, posterior horn and overall meniscus were calculated. Results: The sensitivity of MRI for detecting meniscal tears at the anterior horn, body, posterior horn, and overall medial meniscus was 42.9%, 87.5%, 94.1%, and 81.3%, respectively. The specificity was 95.0%, 84.2%, 81.8%, and 88.0%, respectively. The accuracy was 81.5%, 85.2%, 89.3%, and 85.4%, respectively. The PPV was 75.0%, 70.0%, 88.9%, and 81.2%, respectively. The NPV was 82.6%, 94.1%, 90.0%, and 88.0%, respectively. The sensitivity of MRI for detecting meniscal tears at the anterior horn, body, posterior horn and overall lateral meniscus was 0%, 100%, 85.7%, and 80.0%, respectively. The specificity was 100%, 100%, 90.5% and 97.2%, respectively. The accuracy was 96.0%, 100%, 90.5%, and 97.2%, respectively. The PPV was 100%, 75% and 80%, respectively. The NPV was 96.3%, 100%, 95.0%, and 97.2%, respectively. Conclusion: MRI is a helpful technique to detect meniscal tear with different sensitivity and accuracy on the meniscal location.