From: Effect of ACL Deficiency on MCL Strains and Joint Kinematics Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Effect of ACL Deficiency on MCL Strains and Joint Kinematics J Biomech Eng. 2006;129(3):386-392. doi:10.1115/1.2720915 Figure Legend: (A) Internal tibial axial rotation from neutral to peak anterior translation, 30deg knee flexion, before and after ACL transection. (B) Average MCL strains at peak anterior translation, 30deg knee flexion, with fixed and unconstrained tibial axial rotation, before and after ACL transection. In the ACL-intact knee, unconstraining tibia axial rotation significantly reduced strain along the anterior MCL. After ACL transection, internal tibial rotation was significantly decreased and MCL strain was unaffected when tibial axial rotation was unconstrained. Thus, in the intact knee, the ACL promoted internal tibial rotation during anterior translation, which relieved strain in the MCL. This also occurred at 60deg and 90deg flexion. *p<0.05.