The relationship between the medial collateral ligament and the medial meniscus: a topographical and biomechanical study.

The functional influence of the medial collateral ligament on the medial meniscus is still discussed controversially. Commonly, a strong fixation of the meniscus by the collateral ligament is described. Injury to the medial meniscus is explained by its reduced mobility due to its strong adherence to the medial collateral ligament. The analysis of 10 plastinated series of the medial femorotibial compartment prove that only few fibres of the ligament radiate into the meniscus. To define the possible contribution of these fibers to the stability of the medial meniscus, experiments on two fresh frozen knee joints were performed. The distal femur was separated by cutting the capsule. The medial collateral ligament was detached carefully from its femoral insertion. The tibial head with both menisci was fixed in a clamping system. A translucent, exact acrylic glass copy of the femoral component to which the medial collateral ligament was reinserted, allowed studying the behaviour of the medial meniscus under axial compression (500 N). Firstly, stress was applied while the collateral ligament was proximally fixed and under tension; then the same experiment was performed after femoral detachment of collateral ligament. All plastinated series revealed only some deep and tender fibrous bundles of the medial collateral ligament radiating into the medial meniscus proximally and posteriorly. The behaviour of medial meniscus was exactly the same in both stress experiment series. The conclusion is that there is no relevant influence of the medial collateral ligament on the stability of the medial meniscus.