MRI Accuracy in Diagnosis of Traumatic Intra-articular Knee Lesions

MRI is widely used for diagnosis of traumatic intra-articular knee lesions. Its accuracy is variable in different studies and also accuracy of MRI in diagnosis of traumatic intra-articular knee lesions in our country is not clear. This study was performed to evaluate the accuracy of MRI in one of imaging centers in our country in detecting traumatic intra-articular knee lesions by comparing the results of MRI with subsequent arthroscopy as a gold standard. In a case series study, 33 patients with clinical diagnosis of traumatic intra-articular knee lesions underwent prearthroscopic MRI. The sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio and negative likelihood ratio of MRI were calculated relative to the findings during arthroscopy. The Measure of agreement of MRI with arthroscopy was calculated as well. The accuracy of MRI for medial meniscus was 73%, lateral meniscus 82%, ACL 82%, PCL 97% and articular cartilage 85%. The agreement of MRI with arthroscopy in meniscal lesions was moderate and in ACL and articular cartilage was good. In this study, the accuracy of MRI for medial meniscus and ACL, the sensitivity of MRI for medial meniscus, and the specificity of MRI for lateral meniscus and ACL were significantly lower than the most of the studies. The result of MRI for articular cartilage is the similar to other studies. This issue should be considered by physicians that request MRI.