In arthritis, inflammation occurs in the damaged area of a joint. Damage may be caused by any number of conditions, including trauma, infection, neurogenic disturbances, degenerative joint disease, metabolic disturbances, or for unknown reasons. Symptoms of inflammation include redness and warmth in the area of the injury, swelling, and pain. Arthritis is usually chronic, which means that it rarely changes, or it progresses slowly. Specific causes for most forms of arthritis are not yet known.
Joints are the areas where two bones meet.
Most joints are mobile, allowing the bones to move. Cartilage helps reduce the friction of movement. It is a chronic disease involving the joints, particularly the weight-bearing joints such as the knee, hip, and spine. It occurs in most people as they age, but also may occur in young people as a result of injury or overuse. The inflammation often affects the joints of the hands and the feet and tends to occur equally on both sides of the body.