Osteoarthritis is a disease characterized by defects in articular cartilage with involvement of the tissues about the joint. The disease is frequent in the population over the age of 40 and is a major public health problem. Development of disease is due to cartilagenous, bony, synovial, mechanical, and other factors operating independently, as well as in combination. Therapeutic programs should be an integration of physical measures, medicinal agents, psychosocial interventions, and surgery. Therapy should be directed at the pathophysiologic causes of the patients' symptoms.