Osteoarthritis is a common joint disease that involves the breakdown of cartilage and formation of new bone at joint surfaces. It affects over 21 million Americans and prevalence increases with age. Symptoms include joint pain, stiffness, and loss of function. Treatment involves lifestyle changes like exercise and weight loss as well as medications like acetaminophen, NSAIDs, or COX-2 inhibitors for symptomatic relief. COX-2 inhibitors are preferred for some patients due to a reduced risk of gastrointestinal side effects compared to non-selective NSAIDs.