Surgeons ask exercising baby boomers not to abuse their new knees

WASHINGTON (AP) -- Exercising baby boomers must realize new knees are not like new tires: You can't just wear out one set and buy another.

Active, middle-aged patients with arthritic knees should try switching to lower-impact activities before deciding on surgical replacement of the joint, orthopedic surgeons say. If they have surgery, patients should realize that tennis, basketball and a daily run may be out afterward.

What to do with patients who insist on doing things they love, even if it endangers compromised joints, was the subject of a presentation at the American Academy of Orthopaedic Surgeons' annual meeting in Dallas in February.

"People are healthier and more active into their 60s, and they expect to be more active," said Dr. Arlen Hanssen of the Mayo Clinic, Rochester, Minn., who moderated the program. "You can't do everything, but a lot of people attempt that."

The surgery often is done to relieve pain and improve joint movement that deteriorates due to osteoarthritis. In this condition, cartilage on the bone surfaces inside the joint wears away, and the leg bones rub against each other. Doctors take out the joint, and put in a metal-and-plastic replacement. The joint surfaces are cemented to the bones, or the bones are allowed to grow through mesh surfaces on the replacement.

Potential patients might avoid surgery by switching to activities that put less impact on their damaged joints, Hanssen said. This conservative approach could be the best alternative, potentially preserving their knees while letting them continue activity that is healthful for the rest of their bodies, he said.

Over 300,000 knee replacements are done each year, and most work out quite well, Hanssen said. About 95 percent of first-time knee patients think the results are good or excellent, but the percentage drops 10 percent to 15 percent with each subsequent operation, Hanssen said. The subsequent operations have higher risks of scarring that can lead to stiffness.