Innovative therapies in osteoarthritis.

Until recently, osteoarthritis (OA) was classified as a mechanical wear-and-tear disorder of articular cartilage, for which only pain-modifying therapies such as nonaddictive analgesics were prescribed. Little scientific attention had been focused on the patient with OA, who typically was seen as a frail elderly person hobbling down the street with a cane. With the demographic change that is facing medical policy makers, musculoskeletal disability will decrease the quality of life of the elderly population. By way of analogy, the medical establishment viewed osteoporosis as a similar disease paradigm. However, because of huge commitments of funding and drug development effort, new drugs that reduce the frequency of fractures in postmenopausal women are available. OA and the area of cartilage biology will undoubtedly follow a similar course. Recently, new research identified interleukin 1-beta, collagenase and other matrix metalloproteinases, and signal transduction pathways as important pathobiologic targets in OA. Cartilage agonists such as recombinant human growth factors and gene therapy constructs that stimulate the chondrocyte are being studied in animal models and in humans. Orthopedic approaches, including cartilage regeneration and joint resurfacing techniques with or without biomaterials, are being developed. During the next decade, new efforts will modify the structure and function of the joint, which will be layered onto the drugs, devices, and strategies in use that reduce the pain and suffering in patients with this disease.