Where does OA occur?

• OA can occur in any joint and may occur only on one side of the joint. Usually it is seen in the joints of the fingers, spine, hips, and knees. These joints fall into three common types of osteoarthritis⁽¹⁾. The first and usually mildest is the OA which affects the hands, causing knobby enlargement of the finger joints. When this occurs at the end joints of the fingers, these enlargements are called Heberden's nodes. Growths in the middle of the fingers are called Bouchard's nodes. This type of OA may cause stiffness and changes in the cosmetic appearance of the hand.
• The second type of OA involves the spine. This can involve the neck area as well as the back. Bone spurs are a typical accompaniment.
• The third type of OA commonly seen involves the weight-bearing joints, most frequently the hips and knees. This form of OA can become quite severe and limiting, or may only periodically cause symptoms. In extreme cases walking may become extremely difficult or impossible. This type of OA frequently involves both sides of the body, and may cause a deformity in the lower extremity due to the degeneration process.

When does OA occur?

• OA can develop as a natural process of aging or it may occur as a result of a traumatic injury such as a fracture. Patients who have a congenital malformation of a joint also tend to develop OA at an earlier age than normally seen.
• A common idea in past years was that osteoarthritis developed because of "wear and tear" or over-use of a joint. Research studies of people who participate in strenuous activities have failed to show a relationship between these activities and the development of arthritis. Furthermore, most experts agree that a patient, even when diagnosed with OA, needs to continue a program of exercise to maintain optimal function of the joint.

Why does OA occur?

• No one knows for sure what causes osteoarthritis. Some experts believe that people are born with defective cartilage or abnormalities in their joints which lead to the changes seen in OA. Others believe that OA develops as a result of over-using an already injured joint or because of joint damage caused by other arthritic conditions. Research into the causes, prevention, and treatment of OA as well as other types of arthritis continue to provide improved methods for the relief of symptoms and will continue to aid in the understanding of these disease processes.