Kinematics of the Anterior Cruciate Ligament During Gait

Background: The function of the anteromedial (AM) and posterolateral (PL) bundles of the anterior cruciate ligament (ACL) during gait has not been reported.Hypothesis: The AM and PL bundles have distinct functional behavior during the stance phase of treadmill gait.Study Design: Descriptive laboratory study.Methods: Three-dimensional models of the knee were created by magnetic resonance images from 8 healthy subjects. The contour of the 2 bundle attachments were constructed on each model. Each bundle was represented by a straight line connecting its tibial and femoral attachment centroids. Next, the knee kinematics during the stance phase of gait was determined with a dual fluoroscopic imaging system. The relative elongation, sagittal plane elevation, coronal plane elevation, and transverse plane deviation of the 2 bundles were measured directly from heel strike to toe-off.Results: At heel strike, the AM and PL bundles had first peak elongation of 9% ± 7% and 9% ± 13%, respectively. At 50% progress of the...