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- Osteoarthritis facts
- What is osteoarthritis?
- What is the difference between osteoarthritis and rheumatoid arthritis?
- What causes osteoarthritis?
- What are osteoarthritis symptoms and signs?
- How do health care professionals diagnose osteoarthritis?
- What is the medical treatment for osteoarthritis?
- "If I have minimal or no symptoms with early signs of osteoarthritis, what should I do?"
- What is the prognosis for patients with osteoarthritis?
- Is it possible to prevent osteoarthritis?
- What specialists treat osteoarthritis?
- What does the future hold for osteoarthritis?
- Where can people get more information about osteoarthritis?
Quick GuideOsteoarthritis (OA): Treatment, Symptoms, Diagnosis
What causes osteoarthritis?
Primary (idiopathic) osteoarthritis, osteoarthritis not resulting from injury or disease, is partly a result of natural aging of the joint. With aging, the water content of the cartilage increases, and the protein makeup of cartilage degenerates as a function of biologic processes. Eventually, cartilage begins to degenerate by flaking or forming tiny crevasses. In advanced osteoarthritis, there is a total loss of the cartilage cushion between the bones of the joints. Repetitive use of the worn joints over the years can mechanically irritate and inflame the cartilage, causing joint pain and swelling. Loss of the cartilage cushion causes friction between the bones, leading to pain and limitation of joint mobility. Inflammation of the cartilage can also stimulate new bone outgrowths (spurs, also referred to as osteophytes) to form around the joints. Osteoarthritis occasionally can develop in multiple members of the same family, implying a hereditary (genetic) basis for this condition. Osteoarthritis is therefore felt to be a result of a combination of each of the above factors that ultimately lead to a narrowing of the cartilage in the affected joint.
Secondary osteoarthritis is a form of osteoarthritis that is caused by another disease or condition. Conditions that can lead to secondary osteoarthritis include obesity, repeated trauma or surgery to the joint structures, abnormal joints at birth (congenital abnormalities), gout, diabetes, and other hormone disorders.
Obesity causes osteoarthritis by increasing the mechanical stress on the joint and therefore on the cartilage. In fact, next to aging, obesity is the most significant risk factor for osteoarthritis of the knees. The early development of osteoarthritis of the knees among weight lifters is believed to be in part due to their high body weight. Repeated trauma to joint tissues (ligaments, bones, and cartilage) is believed to lead to early osteoarthritis of the knees in soccer players and army military personnel. Interestingly, health studies have not found an increased risk of osteoarthritis in long-distance runners.
Some people are born with abnormally formed joints (congenital abnormalities) that are vulnerable to mechanical wear, causing early degeneration and loss of joint cartilage. Osteoarthritis of the hip joints is commonly related to structural abnormalities of these joints that had been present since birth.
Hormone disturbances, such as diabetes and growth hormone disorders, are also associated with early cartilage wear and secondary osteoarthritis.