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Abstract
The human knee is the largest and the most complex joint in the human body supporting large loads while undergoing finite displacements in different planes. Due to these loads and motions, it is a common place for various disorders and injuries. In some sport activities, these loads/displacements may exceed the failure limits of its components causing serious traumatisms, dislocations, sprains, ruptures, degenerative processes, etc. Effective prevention, evaluation, and treatment programs require an adequate knowledge of the role of various components and their interactions in knee joint biomechanics under various loading conditions in normal and perturbed conditions. In this context, numerous experimental in vitro and in vivo studies have been undertaken leading to a considerable improvement in existing comprehension of the knee joint biomechanics.
Towards these objectives, a detailed non linear 3-D finite element model of the entire knee including tibiofemoral and patellofemoral joints was developed. The knee joint model consists of three bony structures (tibia, femur, and patella) and their articular cartilage layers, menisci, six principal ligaments (collaterals LCL/MCL, cruciates ACL/PCL, and medial/lateral patellofemoral ligaments MPFL/LPFL), patellar tendon PT, quadriceps muscle force vectors (divided into three components; vastus lateralis, VL/rectus femoris-vastus intermidus medialis, RF-VIM/vastus medialis obliqus, VMO) and hamstrings muscle force vectors (divided into three components; biceps femoris, BF/sartorius-gracilis-semitendinosus, SR-GR-ST (TRIPOD)/semimembranosus, SM). Adequate boundary conditions were used to preserve stability and free unconstrained mobility of the knee joint during the loadings and movements considered in this work. The effect of changes in the boundary conditions on results was also investigated.
The bony structures were represented by rigid bodies due to their much greater stiffness as compared with joint soft tissues. Menisci are modelled as nonhomogeneous composites of a bulk material reinforced by radial and circumferential collagen fibres. Ligaments are each modeled by a number of uniaxial elements with different prestrain (or pretension) values and nonlinear material properties (no compression). (Abstract shortened by UMI.)
