Compensation and decompensation of articular cartilage in osteoarthritis.

Although contemporary descriptions of the pathology of osteoarthritis emphasize the loss of articular cartilage, in the earlier stages a marked increase in synthetic activity of the chondrocytes can lead to an increase in proteoglycan concentration and commonly, to cartilage hypertrophy. Thus, osteoarthritis exhibits a biphasic course, with an initial "compensatory" phase, during which homeostatic mechanisms may maintain a reasonable articular surface until the second phase, "decompensation" (joint failure), develops. Salicylates interfere with homeostatic repair mechanisms and can markedly truncate the compensatory phase. Polysulfated glycosaminoglycans and tetracyclines prolong the compensatory phase, thereby protecting against joint breakdown.