Pathogenesis of osteoarthritis

Osteoarthritis involves all of the joint tissues including the menisci in the knee, ligaments, synovium, articular cartilage, and bone. Damage to the menisci and ligament tears not only alter joint mechanics but, along with the inflamed synovium (synovitis), produce proinflammatory factors (cytokines and chemokines) and matrix-degrading enzymes (eg, matrix metalloproteinases [MMPs]). These factors are also produced by chondrocytes and serve to promote joint tissue destruction.