A review of the histopathological evidence on the pathogenesis of cartilage destruction in rheumatoid arthritis.

These are three ways of cartilage destruction as summarized in Fig. 1. The relative significance of the contribution among them to the pathogenesis of cartilage destruction varies individually. It appears important here to note that chondrocytes themselves are not actively involved in the pannus formation. Chondrocytes only provide a basis for extension of the pannus by proteolytic digestion of cartilage matrix. It is however possible in some individuals that the digestion of cartilage by chondrocytes plays the predominant role in their cartilage destruction. Besides the autonomous proliferative potential of pannus tissue, it seems evident that active synovitis is the main cause of cartilage loss. This is quite important from the therapeutic view point, because we can expect to halt the disease process causing joint deformities by controlling the active synovitis.