"There are two types of osteoarthritis:
Primary Osteoarthritis*- Primary Osteoarthritis*occurs when there is no obvious reason for the arthritis, although you may have some of the risk factors. Generally, primary osteoarthritis occurs in many joints, such as the fingers, base of the thumbs, spine and big toes.Secondary Osteoarthritis*- Secondary osteoarthritis*occurs when there is a likely cause for OA. The most common cause of secondary OA is prior injury to the joint, although there still may be other risk factors. Secondary OA is very common in professional athletes (football and hockey players), but can occur in anyone.Risk Factors For Developing OA
Age -*As we get older, so do our chances of developing osteoarthritis. If we live long enough, many of us will experience OA. Age alone, however, doesn't mean the disease is inevitable.
Family History -*It is becoming clear that genetics plays a role in the development of osteoarthritis. This seems to be more of a factor with arthritis affecting the small joints in the hands (nodal OA). Researchers are not sure how genetics plays a role, but it may be due to the shape of your bones and the way they fit together or your ability to make and repair cartilage.
Excess Weight -*If you weigh too much, your feet, knees and hips have to carry more weight than they should. The good news is that losing weight, even just 10 pounds (4.5 kilograms), can help reduce strain on your knees. Even if you have OA in your knees, losing weight can make you feel better and delay or may be even prevent the need for surgery in the future. Less body weight means less stress on your joints and often less pain.
Joint Injury -*Osteoarthritis can occur in joints that have been "damaged" by a previous injury. The initial injury may have damaged the cartilage or affected the way the joint moves, resulting in secondary OA.
Complications of Other Types of Arthritis -*Osteoarthritis can occur in joints that have been "damaged" by other types of arthritis. For example, people with rheumatoid arthritis or gout can develop secondary osteoarthritis in those joints in which the inflammation has caused damage.
Wear and Tear -*Wear and tear on the joints alone does not lead to OA. For example, some people with similar jobs and lifestyles develop OA in the small joints of the hands and others do not. Research now shows that normal wear does not actually cause the joints to degenerate. Normal activity and exercise is good rather than bad for joints and does not cause osteoarthritis."
http://www.arthritis.ca/page.aspx?pid=941
