Purpose: To investigate the accuracy of the MRI of the knee for the detection of injuries of the meniscus, cruciate ligaments and articular cartilage, in comparison with the preoperative clinical examination and intraoperative findings.

Material and methods: During 2002 88 patients underwent surgical arthroscopy in our institution, with the diagnosis of meniscal and or cruciate tear. 56 from these patients had preoperative MRI of the affected knee. The accuracy, sensitivity and specificity of the MRI findings were correlated with the lesions identified during arthroscopy. Furthermore, the predictive value of the preoperative MRI was compared with the preoperative clinical evaluation, as well as definitive intraoperative findings.

Results : The accuracy for tears of the medial, lateral meniscus, anterior and posterior cruciate ligaments and articular cartilage was 81%, 77%, 86%, 98% and 60% respectively. The specificity was 69%, 88%, 89%, 75% and 73% respectively. The positive predictive value was 83%, 81%, 90%, 100% and 53% respectively. Finally, the clinical examination had less reliability in the detection of these injuries.

Conclusions: As seen in this retrospective study the accuracy of the MRI in detecting injuries to the knee is superior to the clinical examination. The arthroscopy still remains the gold standard for definitive diagnosis.