Structure-modifying agents for osteoarthritis: an update

The terms "chondroprotective" and "structure-modifying" were coined to identify a class of drugs capable of preventing, stabilizing, or repairing joint damage caused by osteoarthritis. The method of reference for evaluating structure-modifying effects in knee or hip osteoarthritis is the measurement of joint space loss on serial plain radiographs. Joint space width can be measured manually or by a computer. Several radiological techniques have been described for measuring joint space width in the medial femorotibial compartment of the knee and the superolateral part of the hip. Most studies of potentially structure-modifying effects evaluated slow-acting drugs for osteoarthritis, which are currently used for their delayed symptomatic effect in osteoarthritis. Although most of these agents have shown promising effects in vitro, none has been proven to produce clinically meaningful structure-modifying effects in humans with osteoarthritis.