The biomechanical role of the collagen fibril ultrastructure of articular cartilage

Abstract

The modeled behavior of articular cartilage was found to differ from that found by other investigators studying homogeneous isotropic models of articular cartilage. The inhomogeneous cartilage on bone structure prevented the creation of tensile stresses on the articular surface. However, tensile strains were induced by the inhomogeneous structure at the articular surface under the load, the most common area of xiv osteoarthritic degeneration. It is suggested that strain rather than stress is the cause of the mechanical insult involved in the etiology of osteoarthritis. While decreased stiffness of the middle and deep zones of articular cartilage and increased stiffness of the subchondral bone had detrimental effects on the deformation of the tissue, the most drastic effects were caused by changes in the area over which the load was distributed. The unique fibrous structure of the superficial tangential zone decreased the magnitudes of the stresses and strains to which the articular surface was exposed. The sole mechanical function of articular cartilage is to provide an efficient bearing surface for the joint.