A validated three-dimensional computational model of a human knee joint

This paper presents a three-dimensional finite element tibio-femoral joint model of a human knee that was validated using experimental data. The geome try, of the joint model was obtained from magnetic resonance (MR) images of a cadaveric knee specimen. The same specimen was biomechanically tested us ing a robotic/univevsal force-moment sensor (UFS) system and knee kinematic data under anterior-posterior tibial loads (up to 100 N) were obtained. In the finite element model (FEM), cartilage was modeled as an elastic materi al, ligaments were represented as nonlinear elastic springs, and menisci we re simulated by equivalent-resistance springs. Reference lengths (zero-load lengths) of the ligaments and stiffness of the meniscus springs were estim ated using an optimization procedure that involved the minimization of the differences between the kinematics predicted by the model and those obtaine d experimentally. The joint kinematics and in-situ forces in the ligaments in response to axial tibial moments of up to 10 Nm were calculated using th e model and were compared with published experimental data on knee specimen s. It was also demonstrated that the equivalent-resistance springs represen ting the menisci are important for accurate calculation of knee kinematics. Thus, the methodology developed in this study can be a valuable tool for f urther analysis of knee joint function and could serve as a step toward the development of more advanced computational knee models.