ROLE OF CRUCIATE LIGAMENTS IN THE KNEE JOINT IN FLEXION UNDER DRAWER LOADS

摘要

A validated non-linear 3-D finite element model of the human tibiofemoral joint was utilized to investigate the role of cruciate ligaments in the knee joint response under drawer loads at different flexion angles. This model consisted of two bony structures and their articular cartilage layers, menisci and four principal ligaments. Kinematics and forces in cruciate ligaments in the fully unconstrained joint were computed in the intact joint and in the joint following transection of or alteration in a cruciate ligament. The results showed that the anterior cruciate ligament is the primary ligament to resist the 100N posterior femoral load throughout the range of flexion considered and that the joint primary and coupled laxities could substantially increase in its absence. On the other hand, the posterior cruciate ligament has a minor contribution at full extension under 100N anterior femoral load. With joint flexion up to 90°, however, posterior cruciate ligament force substantially increased. Comparisons between the primary laxity in the intact and cruciate-deficient joints indicate the 30° as the optimal flexion angle for the detection of anterior cruciate ligament rupture in drawer tests whereas the diagnosis of a posterior cruciate ligament tear should be done at larger flexion angles (preferably at 90° flexion).