New perspectives on osteoarthritis

Osteoarthritis (OA) is the most common rheumatologic disease, afflicting tens of millions of U.S. citizens. It is not an inevitable consequence of aging; rather, it is a degenerative process acquired because of metabolic, mechanical, genetic, and other influences. It is characterized by progressive loss of cartilage and bony overgrowth. Because cartilage is not innervated, the pain of OA arises from secondary effects, such as joint capsule distention, stretching of periosteal nerve endings, and, possibly, synovial inflammation. Psychologic factors, including stress and depression, may influence the perception of pain by OA patients. The risk of OA apparently is not increased by normal joint use, but persons who participate in competitive sports or who play with abnormal or injured joints are at increased risk. Obesity increases OA risk, and weight loss has been found to decrease it. Some forms of premature OA appear to be inherited. The objective diagnosis of OA is made on the basis of radiography. However, many individuals with radiographic evidence of OA are asymptomatic in the affected joint. It is essential to ensure that pain in the affected joint is attributable to OA and not another cause. The management of OA should include physical medicine measures such as heat or cold therapy and often-neglected environmental measures, such as reducing chair height and using shoe orthotics. Therapeutic exercise is beneficial for many patients and includes an initial warmup with range of motion, muscle strengthening, and aerobic activity (such as swimming). A major question in the pharmacologic management of OA is whether nonsteroidal antiinflammatory drugs (NSAIDs) are superior to analgesics in terms of symptomatic relief; studies indicate that they are not. The question is relevant because of the adverse effects of NSAID use, particularly in the elderly population.