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Major osteoarthritis review reveals disease's complexities -- and new solutions

By Brian Fitzgerald

Pitching a baseball -- and Advil, the product he sponsors -- 53-year-old Nolan Ryan is featured on a television commercial talking about something he has in common with many aging baby boomers: osteoarthritis (OA).

David Felson

Some 21 million Americans have OA, and the number of cases is expected to reach 30 million by 2020. "Until about seven or eight years ago, osteoarthritis didn't get the attention it deserved in the scientific community," says David Felson, MED professor of medicine and lead author of a major report released last year on OA, the most common form of arthritis. "We finally woke up and said we have to put more resources into it because it's such a prevalent problem."

The report, a review by 28 researchers from 17 academic and government institutions, declares OA to be "surprisingly complex," but outlines a number of new approaches to understanding, prevention, and treatment. Funded by the National Institutes of Health (NIH), it was presented in two parts in the October 17 and November 7, 2000, issues of the Annals of Internal Medicine.

The researchers found that OA can result from an inherited vulnerability to the disease combined with a joint injury. Regular runners, for example, have almost no additional risk of OA, but football and soccer players and baseball pitchers are at increased risk.

OA has been receiving much media attention lately, including a cover story in the September 3 issue of Newsweek. In August, the NIH joined with four pharmaceutical companies to look for biomarkers of the disease -- chemical substances in joint fluid, blood, or urine whose presence can serve as a reliable measure of the progress of OA by indicating changes in bone or cartilage.

Why are some athletes more prone to OA? Felson says that previous studies have led scientists to appreciate the role of simple joint trauma. Sure enough, Ryan developed OA in his right elbow -- the same one where he tore a ligament during his last professional baseball game, in 1993.

"Some have a genetic predisposition -- the joints that are injured get osteoarthritis," says Felson. "Someone who isn't predisposed might sustain an particular injury, maybe not a serious one, and would never get arthritis from that. But the combination of serious injuries -- some due to repetitive action such as throwing a baseball, or some type of occupation that uses the joint over and over again -- plus the predisposition somehow appears to increase the risk of osteoarthritis."

Certain enzymes seem to play a part, and these may be affected by hormone levels: women are three times as likely to suffer from OA than men.

And then there are injuries serious enough by themselves to pave the way for osteoarthritis in a person who doesn't have any genetic predisposition to it. For example, former Patriots running back Robert Edwards, who tore three out of four knee ligaments and suffered nerve damage in a Pro Bowl flag football exhibition game in 1999, "doesn't need to have any genetic predisposition to get osteoarthritis," says Felson. "He's going to get it in that knee almost certainly."

In OA there is a focused, progressive loss of cartilage, the slippery material that acts as a shock absorber between bones, along with changes in the bone below the cartilage leading to bony overgrowth. The tissue lining of the joint can become inflamed, the ligaments become looser, and the associated muscles weaken.

The review that Felson led concludes that although a cure is not in the immediate future, there is reason to be hopeful, even for people who already have the disease. Exercise can lessen disability if OA has developed. Strengthening thigh muscles can reduce risk of OA of the knee -- a relatively small increase in quadriceps muscle strength (20 percent for men and 25 percent for women) can lead to a 20 to 30 percent decease in risk of developing the disease. In one major study cited by the review, people who lost 11 pounds cut their risk in half. High intakes of vitamins C and D are associated with lower rates of OA.

Those who develop osteoarthritis can also benefit from a combination of treatment approaches, including new medications. The study found that acetaminophen can help mild or moderate joint pain. Other drugs of choice are tramadol and nonsteroidal anti-inflammatory drugs such as ibuprophen -- Nolan Ryan's favorite.

"This review shows that arthritis research is a vibrant area, yielding new means of preventing the disease and slowing its progression, as well as new and effective combinations of drug and behavioral treatments," says Stephen Katz, director of the National Institute of Arthritis and Musculoskeletal and Skin Diseases. "People with osteoarthritis and those at risk for the disease should be encouraged that there is much that they and their doctors can do about it."

14 September 2001
Boston University
Office of University Relations