Age is the most powerful risk factor for osteoarthritis (OA) in the United States. It is estimated that 68% of individuals older than 55 years have radiographic evidence of OA. The US is growing older--the over-65 age group represented only 4% of the population in 1900, but accounted for 12.4% in 1988, and is projected to account for 22% by the year 2030. As the age of our population has increased, so has the prevalence of arthritis. About 43 million individuals (1 in 6) have arthritis, and most are older than 45 years. By the year 2020, 59.4 million persons in the US will be affected by arthritis, thus increasing chronic disability and costs by more than 25%. The annual cost to society in medical care and lost wages is currently estimated to be $65 billion, and is projected to escalate to $95 billion by the year 2000. Physicians who provide care for the increased number of patients with arthritis in the 21st century must be aware of improved therapeutic modalities to reduce arthritis related disabilities, hospitalizations, and complications related to therapy, to minimize the risk of adverse drug reactions, and to preserve function.