Those Who Exercise Now May Pay Later With Arthritis

High-impact aerobics is out for Lori O’Koon. She suspects that was probably what got her into trouble in the first place.

O’Koon damaged cartilage in an ankle and believes she is on the road to osteoarthritis.

“When you damage the cartilage that protects the bone, that’s when the process begins,” said O’Koon, a 34-year-old surgical equipment saleswoman in Phoenix. Surgery to clean out the joint helped but hasn’t cured the problem, she said.

“I can’t do any high-impact aerobics,” O’Koon said. “I can’t run.” If she does run, she has to “limp around for the next three days.”

O’Koon is part of a growing group whose good deed, working out, has not gone unpunished. The results were joint injuries--mostly in the knee or hip--especially ones that need surgical repair.

Affecting 21 million people, osteoarthritis is the most common form of arthritis in the United States, according to the Arthritis Foundation. And doctors say it’s afflicting baby boomers, who should be too young for a disease that commonly hits older people. Osteoarthritis can wait for decades.

Osteoarthritis has many causes, including ones that involve exercise. They center on unusual stress or wearing away of cartilage in a joint. This can create friction and inflammation, which can lead to osteoarthritis.

The damage grows worse with time. “We are seeing middle-aged people who had injuries early in life,” said Dr. David Fox of the University of Michigan.

It wasn’t only bad tackles, poor landings after layups, or endless miles of running that did them in, said Fox, a medical spokesman for the arthritis group.

The disease often had help from the sufferers’ doctors. Trying to fix a torn meniscus, the cartilage cushion between the leg bones at the knee, the doctors took out much of the cartilage, and taking out the cushioning left the joint prone to osteoarthritis, he said.

Growing older in itself can make things worse, especially if a person doesn’t stay in shape, said Dr. David Felson of Boston University. “Our strength is diminished, the nervous system that provides information on how we protect our joints is diminished, and the cartilage doesn’t respond as well to stress,” he said.

That’s why the age at which the injury occurs is important, Felson said. Younger people have more muscle strength to hold the knee in place, and better nervous system input to tell the muscles how to react to stress, he said. “It isn’t the high school athlete who messed up his knee; it’s more the baby boomer who ran around 35 and messed up his knee that’s at risk,” he said.

Nor does it have to be only athletics--other physical activity will do, Felson said. A study in which Felson was senior author found a three- to sevenfold higher risk of knee osteoarthritis among seniors who had done repeated lifting when they were younger. The study was in the American Journal of Medicine’s February edition.

These people hadn’t been doing weight training, Felson said--they had been factory workers who had to move objects on their jobs. Other studies have found that simply being overweight may be enough to bring on osteoarthritis, he said.

And because the damage is cumulative, more cases of osteoarthritis should occur as the population ages, according to an arthritis foundation publication, Arthritis Today.

Just the same, this is no reason to be afraid of exercise, the experts said. Instead, they advise it.

Some studies have shown that exercise is good for osteoarthritic joints, said Dr. Peter Lynch of Boston University in the American Journal of Sports Medicine, which he edits. Exercise can keep the muscles around the joint strong, helping to absorb more energy and providing some protection.

People with osteoarthritis simply should find exercises, such as swimming and cycling, that don’t put weight on the joint, Fox said. And people who are worried about developing osteoarthritis can switch to those exercises, because reducing impact reduces risk, he said.

That’s what O’Koon does. She does weight training, in-line skating and bicycling.

And, while she takes pain medication as needed, O’Koon keeps her options open on further surgery. New techniques let doctors take cartilage from areas in which it is not as urgently needed, and implant it in afflicted joints. The trouble is that the surgery has been done more in the knee than the ankle, and it’s “a pretty invasive procedure,” she said.