Osteoarthritis is a degenerative joint disease which is the most common chronic condition of the joints. It can affect any joint, but it occurs most often in knees, hips, lower back and neck, small joints of the fingers and the bases of the thumb and big toe. In OA, the cartilage breaks down, causing pain, swelling and problems moving the joint. In the final stages of Osteoarthritis, the cartilage wears away and bone rubs against bone leading to joint damage and more pain. Mostly affects people older than 65 years.