The effects of contact area and surface curvature on biomechanical behavior of articular cartilage

Understanding the mechanical behavior of contact mechanics in human joints is crucial in order to characterize its biomechanical properties. In previous studies, cartilage surface of axisymmetric models was assumed to be flat in order to investigate the cartilage behavior. However, this assumption was inappropriate since the synovial joint possessed curvature geometrical shape and may lead to the inaccurate results. Thus, the aim this study is to investigate the effects of contact area and surface curvature on the cartilage contact stress and pore pressure using finite element analysis. Axisymmetric biphasic poroelastic finite element model was developed in order to investigate possible effect of contact area and surface curvature to the contact stress and pore pressure of the cartilage. The results show that the smaller cartilage surface of 40 mm radius produced 65% and 68% difference of pore pressure and contact pressure respectively compared to the flat surface. The effects of the cartilage curvature became more crucial when the radius was decreased. Based on these results, it could indicate that contact pressure and pore pressure give the affect on the cartilage behavior characterization.