Anterior cruciate ligament tears: evaluation of multiple signs with MR imaging

Abstract

Purpose: To assess the accuracy and reliability of multiple signs of anterior cruciate ligament (ACL) tears with magnetic resonance (MR) imaging.

Materials and methods: Two independent reviewers retrospectively evaluated 103 sets of ACL MR images for the presence of 22 signs of ACL tears. There were 43 patients with ACL tears and 58 patients whose ACLs were proved to be intact at surgery. Although variable imaging protocols were used, T1- and T2-weighted images were obtained in nearly all patients. Direct nonvisualization, intrinisc ACL abnormalities, associated osseous and cartilage abnormalities, and other indirect signs were evaluated.

Results: Discontinuity of the ACL in the sagittal and axial planes and failure of the fascicles to parallel the Blumensaat line were the most accurate signs of a tear. Discontinuity of the ACL, disruption of fascicles, a posterolateral tibial bruise, a buckled posterior cruciate ligament, positive posterior cruciate ligament line sign and positive posterior femoral line sign were the best predictors of an ACL tear at logistic regression analysis.

Conclusion: Signs other than nonvisualization of the ACL are good predictors of an ACL tear.