A Numerical Model of Mechanics of Osteoarthritis in Human Knee Joint

Articular cartilage is composed of water entrapped in a solid matrix formed by proteoglycans and collagen fibers. Therefore, the mechanical behavior of this tissue is determined by all of these three components. In addition, the properties of articular cartilage vary along the depth and by location. In the human knee joint, the three dimensional geometry as well as the contact between the cartilaginous tissues plays essential roles in the joint mechanics. On the other hand, initiation and progression of osteoarthritis (OA) could be partly caused by contact loads. Consequently, the fibrillar and non-fibrillar matrices, the three dimensional geometry and the contact between the tissues should be considered as essential parameters in the study of the mechanics of osteoarthritis. However, previous studies on OA mechanics were mostly limited to explants geometries [1]. Also, the contact mechanics associated with the fluid pressure have not been considered in the previous OA models. In a recent knee model, fluid was considered in femoral cartilage but not in the menisci [2]. Additionally, the depth-dependent mechanical properties were not included in that model.