Mayo Clinic Radio: Osteoarthritis Osteoarthritis is the most common form of arthritis, affecting millions of people worldwide. It occurs when the protective cartilage on the ends of your bones wears down over time. Although osteoarthritis can damage any joint in your body, the disorder most commonly affects joints in your hands, knees, hips and spine. Although the underlying process cannot be reversed, osteoarthritis symptoms usually can be managed effectively. Staying active, maintaining a healthy weight and other treatments may slow progression of the disease and help improve pain and joint function. Medications, physical therapy and surgical procedures are used to treat osteoarthritis.