Osteoarthritis is a degeneration of one or more bones at the head and adjoining joints. It affects up to 15% of the population, most of them being elderly. The cartilage within joints breaks down, and inflammation of the bone exposed by the damaged cartilage occurs, which is then aggravated by injury and overuse of the joint. There is also a hereditary tendency to develop osteoarthritis.
Symptoms are usually mild at first, but slowly worsen with time and joint abuse. The knees, back, hips, feet, and hands are most commonly affected. Stiffness and pain that are relieved by rest are the initial symptoms, but as the disease progresses, swelling, limitation of movement, deformity and partial dislocation (subluxation) of a joint may occur. A crackling noise may come from the joint when it is moved, and nodules may develop adjacent to joints on the fingers in severe cases.
X-rays show characteristic changes from a relatively early stage, and repeated X-rays are used to follow the course of the disease. There are no diagnostic blood tests.