The knee is one the most vulnerable joints in the human body, hence it has attracted the attention of many researches. Anterior cruciate ligament (ACL), which restrains anterior displacement of tibia with respect to femur, is the most frequently ruptured ligament due to accidental or sport related activities. To quantify the extent of injury to ACL the laxity of knee joint is assessed by clinical tests such as Lachman and Anterior Drawer tests or quantified by arthrometers. A theoretical simplified static 3-D finite element (FE) model of knee was developed to simulate these tests. An arthrometer was also constructed to allow in-vivo measurements of knee laxity model provided force-deformation or stress/strain responses of force ligaments during drawer tests. The results of FE model of normal and injured knee matched the in-vivo measurement of 100 normal and 45 patients suffering from ACL rupture. The response of both FE model and in-vivo measurements illustrated the effect of knee angle and point of application of external force on tibia. The developed arthrometer requires further in-vivo testing patients population while the good agreement with existing literature and FE model studies provides justification for an optimistic outlook of its clinical validity.

D. Soudbakhsh, R. Shirazi , M.Parnianpour , J. Khamsei

Click here to download the Movie