Osteoarthritis, also called degenerative joint disease, is the most common form of arthritis. It occurs most often in older people. This disease affects the tissue covering the ends of bones in a joint called cartilage. In a person with osteoarthritis, the cartilage becomes damaged and worn out, causing pain, swelling, stiffness and restricted movement in the affected joint. Although osteoarthritis may affect various joints, including the hips, knees, hands and spine, the hip joint is most commonly affected. Rarely, the disease may affect the shoulders, wrists and feet.