Who is at risk for arthritis? It depends on the type of arthritis that the patient may have. One type of arthritis is post-traumatic arthritis. In other words, if a patient has had an injury to a joint or a fracture or any sort of injury that may affect the articular cartilage of the joint and damage that cartilage, then the joint may wear out and go on to post-traumatic arthritis. So that group is anybody who has had an injury to the joint is at risk. Another type of arthritis is osteoarthritis, which is the wear and tear that occurs on the joint lining. Patients as they age and gain weight may be at risk for this. Inactivity, lack of exercise also may predispose someone to develop osteoarthritis. Another type of arthritis is rheumatoid arthritis, and there seems to be some autoimmune risk with this type of arthritis in which the body itself perceives the joint as a foreign body and the lining of the joint has an inflammatory response against the joint which then damages the articular cartilage within the joint. The reasons for developing rheumatoid arthritis are not fully known but there appears to be autoimmune component to that type of arthritis.