Comparison of magnetic resonance imaging (MRI) and arthroscopy in the diagnosis of ligamentous and meniscal tears of the knee

We prospectively studied 20 patients with suspected ligamentous or meniscal tears of the knee. They were examined by both magnetic resonance imaging (MRI) and arthroscopy. The accuracy of the diagnoses from MRI compared with arthroscopy was 90% for the anterior cruciate ligament (ACL), 100% for the posterior cruciate ligament (PCL), 90% for the medial meniscus (MM), and 95% for the lateral meniscus (LM). But there were 2 'false positive' ACL tears, 1 'false positive' MM tear, 1 'false negative' MM tear, and 1 'false negative' LM tear. We thought that we can reduce these 'false positive' and 'false negative' findings by describing the best conditions to take MRI for ligamentous or meniscal tears of the knee, or raising the ability to interpret MRI findings. However it is probable that the MRI findings are different from the arthroscopic findings, because MRI is more sensitive to intermeniscal tears and there is the dead angle of the arthroscope in the knee to be taken into consideration. (author)