Anterior translocation of the tibia at MR imaging: a secondary sign of anterior cruciate ligament tear.

Abstract

The authors evaluated measurement of the degree of anterior subluxation ("translocation") of the tibia in regard to the femur as a predictor of anterior cruciate ligament (ACL) tear. Eighty-nine magnetic resonance (MR) imaging studies of patients with either an arthroscopically confirmed intact (n = 29), acutely torn (n = 27), or chronically torn (n = 33) ACL were retrospectively reviewed. The degree of translocation was measured on hard-copy images by using two methods. Buckling of the posterior cruciate ligament (PCL) was also evaluated. Anterior tibial translocation, when measured at the midsagittal plane of the lateral femoral condyle with regard to a plane parallel to the cephalocaudal axis of the image, was a relatively specific indicator of ACL disruption. Subluxation of 5 mm or more had 58% sensitivity, 93% specificity, and 69% accuracy for an ACL tear. All knees with subluxation of 7 mm or more had torn ACLs. Buckling of the PCL was less sensitive and less accurate than anterior translocation as an indicator of ACL disruption.

Anatomic anterior cruciate ligament reconstruction: reducing anterior tibial subluxation

“…It was found that measuring ATS is an accurate way to diagnose rupture of the ACL and that there is a positive correlation with the duration of ACL deficiency [7,8,17].…”

Altered knee kinematics in ACL‐deficient non‐copers: A comparison using dynamic MRI

“…Tibial subluxation has also been correlated with ACL rupture in diagnostic MRI scans acquired when subjects were supine, relaxed, and in full knee extension. 26 Comparison of goniometer linkage-based studies to medical imaging-based studies such as the current one should be evaluated in this knowledge. Measurement error can also be introduced by relative motion between goniometer linkages and bones during motion.…”

Musculoskeletal MR: knee

“…The PCL curvature value is defined as the length of line ªaº divided by the length of line ªb.º In cases of a normal ACL the value is 0.27 0.06 and for torn ACL 0.40 0.12 [13]. Anterior translocation of the tibia in ACL tear is defined when the distance of the posterior cortex to a line at the midlateral femoral condyle parallel to the edge of the image is greater than 5 mm [14,15]. The posterior horn of the lateral meniscus is uncovered when a vertical line drawn tangent to the posterior cortical margin of the lateral tibial plateau intersects any part of the posterior horn of the lateral meniscus [13].…”