Rotation resistance at the knee
The new tip of the day - all thanks to my wonderful student Erika - relates to the ligaments of the knee. Most everyone knows what the ACL/PCL and LCL/MCL limit in the sagittal and frontal planes, respectively. We test ACL/PCL with "drawer" type maneuvers in the sagittal plane and put the knee in valgus and varus strain in the frontal plane for the collateral ligaments. Did you know that each pair of these ligaments also have a resistive or limiting capability in the transverse plane, limiting tibial rotation? Because we rarely test the ligaments in this plane sometimes it can be hard to remember which does what. Here is the tip: The "internal" ligaments - the ACL/PCL will limit internal rotation of the tibia on the femur. The "external" ligaments - the LCL/MCL will limit external rotation of the tibia on the femur.










