Arthroscopic evaluation of the accuracy of clinical examination versus MRI in diagnosing meniscus tears and cruciate ligament ruptures.

BACKGROUND Magnetic resonance imaging (MRI) of the knee joint has often been regarded as a noninvasive alternative to diagnostic arthroscopy. In day-to-day clinical practice, the MRI scan is routinely used to support the diagnosis for meniscus or ligamentous injuries prior to recommending arthroscopic examination and surgery. On the other hand, rapidly progressing medical technology sometimes obscures the importance of history and physical examination. This study aims to evaluate the accuracy of physical examination and MRI scanning in the diagnosis of knee injury, including meniscus tears and cruciate ligament ruptures. METHODS In a cross-sectional, descriptive analytical study, 120 patients with knee injury who were candidates for arthroscopy were referred to Tabriz Shohada Hospital during a one-year period. Prior history of arthroscopy or knee surgery was considered as exclusion criteria. Before ordering an MRI and arthroscopy, a thorough physical examination of the affected knee was performed and a preliminary diagnosis made. The results of arthroscopy were considered as the definitive diagnosis, therefore the results of the physical examination and MRI were judged accordingly. RESULTS Of the 120 evaluated patients with knee injuries, there were 108 males and 12 females with a mean age of 29.13 ± 7.37 (16-54) years. For medial meniscus injuries, clinical examination had an accuracy of 85%, sensitivity of 94.8%, and specificity of 75.8%. Lateral meniscus injuries had the following results: accuracy (85%), sensitivity (70.8%) and specificity (88.5%). Clinical examination of anterior cruciate injuries had an accuracy of 95.8%, sensitivity of 98.6% and specificity of 91.7%. According to MRI results, for medial meniscus injuries there was an accuracy of 77.5%, sensitivity of 84.2%, and specificity of 71.4%. In lateral meniscus injuries, MRI had an accuracy of 85.8%, sensitivity of 56.5% and 92.8% specificity. MRI evaluation of anterior cruciate injuries was 92.5% for accuracy, 98.6% for sensitivity, and 83.3% for specificity. Both clinical examination and MRI were 100% for posterior cruciate injuries. Overall, in isolated injuries, the accuracy of clinical examination was relatively better than with complicated cases. The opposite results were seen for MRI findings in this regard. CONCLUSION According to our results, both physical examination and MRI scans are very sensitive and accurate in the diagnosis of knee injuries, with a mild preference for physical examination. MRI should be reserved for doubtful cases or complicated injuries.