In the New York Times Personal Health Section, Jane Brody writes about Relief for Joints Plagued by Arthritis:

If you live long enough — that is, beyond 50 or 60 — chances are one or more of your joints, probably your knees or hips, will become arthritic. And if pain or stiffness begin to seriously limit your ability to enjoy life and perform routine tasks, chances are you’ll consider replacing the troublesome joint.

PERSONAL HEALTH

Jane Brody on health and aging.

“People with osteoarthritis are relying more and more heavily on surgery,” Dr. David T. Felson, a rheumatologist and epidemiologist at Boston University School of Medicine, told me. “The rate of knee replacement is just skyrocketing, out of proportion to increases in arthritic changes seen on X-rays, and replacement surgery is contributing greatly to the rising costs of Medicare.”

Between 1979 and 2002, knee replacement surgery rose 800 percent among people 65 and older. Although Dr. Felson described hip replacement as “dynamite” — highly effective in relieving pain and restoring function — knee replacement may be far less helpful.

“For 10 to 30 percent of patients, the improvement never comes,” Dr. Felson said.

How the Trouble Starts

Osteoarthritis results from wear and tear on the joints. (Rheumatoid arthritis, on the other hand, is an autoimmune disorder.) Some 27 million Americans have life-limiting osteoarthritis, and the numbers are rising as the population gets older and fatter.

“With every step, the force exerted on weight-bearing joints is one and a half times body weight,” said Dr. Glen Johnson, who reported on arthritis prevention and treatment at the annual meeting of the National Athletic Trainers’ Association in June. “With jogging, the force is increased seven or eight times. Thus, the most effective way to prevent arthritis in knees and hips is to lose weight if you’re overweight and to pursue non-impact activities for recreation.”

While most people think of osteoarthritis as a breakdown of the cartilage that keeps bones from rubbing together, recent studies have shown it is a far more complicated disease that also involves tissues in and around joints, including bone and marrow. Inflammation can be a contributing factor, and genetics play a role. Three genes have been identified thus far that accelerate the development of arthritis in people who carry them.

Any kind of joint injury or surgery, even if performed arthroscopically, raises the risk that a joint will become arthritic. That is why so many professional and recreational athletes develop arthritis at younger ages.