Tn. Vahey et al., ANTERIOR TRANSLOCATION OF THE TIBIA AT MR-IMAGING - A SECONDARY SIGN OF ANTERIOR CRUCIATE LIGAMENT TEAR, Radiology, 187(3), 1993, pp. 817-819
The authors evaluated measurement of the degree of anterior subluxatio
n (''translocation'') of the tibia in regard to the femur as a predict
or of anterior cruciate ligament (ACL) tear. Eighty-nine magnetic reso
nance (MR) imaging studies of patients with either an arthroscopically
confirmed intact (n = 29), acutely tom (n = 27), or chronically tom (
n = 33) ACL were retrospectively reviewed. The degree of translocation
was measured on hard-copy images by using two methods. Buckling of th
e posterior cruciate ligament (PCL) was also evaluated. Anterior tibia
l 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 disrupti
on. 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 o
r more had torn ACLs. Buckling of the PCL was less sensitive and less
accurate than anterior translocation as an indicator of ACL disruption
.