ACCURACY OF DIRECT SIGNS OF TEARS OF THE ANTERIOR CRUCIATE LIGAMENT

OBJECTIVE: To evaluate the accuracy of direct magnetic resonance imagi ng (MRI) signs of tears of the anterior cruciate ligament. PATIENTS AN D METHODS: Over the period April 1991 to February 1994, 92 consecutive MRI studies of the knee were obtained for which arthroscopic data wer e also available. The MRI studies were retrospectively evaluated for c ourse, continuity, signal intensity, morphologic features, contour and visualization of the anterior cruciate ligament. Arthroscopic finding s were correlated with individual primary signs and the overall MRI di agnosis. RESULTS: Among the cases studied were 4 partial and 32 comple te tears of the anterior cruciate ligament (as determined by arthrosco py). Because of the low number of partial tears, it was not possible t o draw any meaningful conclusions about the MRI diagnosis of this type of tear. For complete tears, the criteria with the highest accuracy w ere abnormal course of the ligament (96.0%) and high signal intensity (89.3%), The overall diagnostic accuracy of MRI was 98.8%, CONCLUSIONS : The most accurate direct MRI finding in patients with a complete tea r of the anterior cruciate ligament was abnormal course of the ligamen t, followed by abnormally high signal intensity.