The document defines osteoarthritis as a degenerative joint disease characterized by destruction of articular cartilage and new bone formation at joint surfaces. It most commonly affects weight-bearing joints like the hip and knee. Treatment involves a combination of approaches to relieve pain, restore function, and reduce disability, including weight loss, exercises, braces, and medications like acetaminophen, NSAIDs, or opioids. Conservative treatment succeeds for about 50% of patients before considering surgical options.