Osteoarthritis is a type of joint disease that results from breakdown of cartilage and underlying bone. It commonly affects the hands, feet, spine and weight-bearing joints like the hips and knees. Risk factors include mechanical stress, excess weight, hereditary factors and other medical conditions like diabetes. Symptoms include joint pain and stiffness, with diagnosis typically made based on medical history and x-rays. Treatment involves lifestyle changes, physical therapy, medications like acetaminophen or NSAIDs, and sometimes alternative therapies.