Histological Changes of Cartilage and Subchondral Bone in Varus Gonarthrosis: Comparison with Radiographic and Macroscopic Findings

Abstract

The initial pathomorphological changes in osteoarthrosis can be located in the joint cartilage (calcified and noncalcified hyaline cartilage), in the subchondral bone, or in the synovial membrane (Fig. 1). Depending on the particular reason, primarily mechanical-induced or an enzyme-induced cartilage damage is produced (Hackenbroch 1992). The reason for the mechanically induced cartilage damage is a pathological load distribution in the knee joint, which leads to local cartilage overload and exceeds the tolerance threshold of the joint cartilage. A varus deviation of the mechanical axis results in a greater overload in the medial compartment of the knee joint, followed by a varus gonarthrosis. It is presumed that the enzyme-induced cartilage destruction, produces an intraarticular release of enzymes and inflammation mediators, which in turn decrease the cartilage resistance below the level necessary for everyday joint loading.