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FRIDAY, Aug. 8 (HealthDayNews) -- It could be that your osteoarthritis may be caused by something besides the fact that you're getting older and falling apart.

British scientists found that nearly one-third of patients ready to undergo joint replacement surgery for osteoarthritis (OA) had severe inflammation in the synovial fluid that surrounds and protects the joints. This inflammation, already known to cause rheumatoid arthritis, could be a contributing factor in osteoarthritis as well, the researchers suggest.

"Many people with early osteoarthritis have few symptoms, and understanding the role of inflammation in OA may enable markers of inflammation to be used to help decide whether someone with early OA should be offered treatment or not," says study co-author David A. Walsh, a senior lecturer in rheumatology at the University of Nottingham in the United Kingdom.

The finding appears in the August issue of Arthritis & Rheumatism.

"Five to 10 years ago it was thought that osteoarthritis was due to the degeneration of cartilage due to wear and tear, but this is one of a number of studies finding that inflammatory mediators promote more a rapid progression of cartilage to be degraded," says Dr. Steven B. Abramson, chairman of the department of rheumatology and medicine at the New York University-Hospital for Joint Diseases.

As this association becomes clearer, Abramson says, the practice of using magnetic resonance imaging (MRI) in the finding of synovitis will become very common and could serve as a marker for the disease.

Further, he says research will aim to find out whether it would be useful to look at drugs now used to treat rheumatoid arthritis to see if they might have a role in treating osteoarthritis. At present the most powerful drugs that actually modify the progression of the disease have a fair amount of toxicities, Abramson says, so any drug management would have to include a careful risk/benefit analysis.

Osteoarthritis is the most common form of arthritis, especially among older people, affecting some 20 million Americans. By 2030, 20 percent of Americans -- about 70 million people -- will have passed their 65th birthday and will be at risk for osteoarthritis, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Also called degenerative joint disease, osteoarthritis causes the eroding of the cartilage that covers the ends of the bones in the joints, leaving the bones to rub together, which causes pain, swelling and loss of motion in the joint.

For the study, the researchers from the University of Nottingham obtained synovial tissue samples from 104 patients, both men and women of an average age of 69, who were about to undergo joint replacement of hips or knees due to advanced osteoarthritis.

Thirty-two, or 31 percent of the patients, showed evidence of the most severe inflammation, 36 showed evidence of moderate inflammation, 29 had minor inflammation, and seven had none.

"The caveat of this study is that the samples were taken just before surgery, so these were very advanced cases of osteoarthritis," Abramson says, "and critics will question whether this inflammation is important earlier in the disease. But other studies, using arthroscopy, have looked at this in the middle stage of osteoarthritis -- which is about 10 years before surgical intervention -- and about one-third to one-half of those patients will have synovial inflammation."

More information

The National Institute on Aging offers some tips on managing arthritis. Meanwhile, the Arthritis Foundation has information on glucosamine and chrondroitin sulfate, alternative remedies popular among people with arthritis.