Ask Your Doctors: To save your knees, stay slim

EDITOR'S NOTE: This weekly column by reporter Bill Kettler answers readers' questions about topics of general medical interest with information provided by doctors from PrimeCare, Jackson County's independent practice association.


I just turned 66, and I've noticed that a lot of people about 10 years older are having knee-replacement surgery. I'm wondering if there are things I can do to avoid being in the same boat when I'm in my mid-70s. Are there stretches I should do, or exercises I should do, or activities I should avoid to preserve my knees?

— Mary S., Medford

Total knee replacement has become increasingly common as a way for people who have deteriorating joints to stay physically active well into their 70s and beyond, says Dr. Hal Townsend, an Ashland orthopedic surgeon.

Townsend says as many as 600,000 "TKRs" are performed annually in the United States. The vast majority are done for people over age 60, although a growing number are being done for people in their 40s and 50s.

Most people who opt for knee replacement suffer from osteoarthritis in the knee joint. Over time, the cartilage that allows the bones to move smoothly over each other breaks down, or it can be damaged in an athletic injury. Eventually there's enough pain associated with ordinary activities such as walking that people seek relief through surgery.

Knee-replacement surgery, however, is a major procedure that shouldn't be chosen without careful thought. The surgeon makes a large incision, removes damaged cartilage and bone, installs new metal and plastic joint surfaces and closes the incision. Recovery can take many weeks, so orthopedists often encourage their patients to try other less invasive treatments (such as injections of artificial lubricants) before resorting to surgery.

Townsend says the single most important thing anyone can do to prevent or lessen the likelihood of having to undergo knee replacement is to maintain proper weight.

"It's been clearly documented that increased weight puts more pressure on the knee joint and increases osteoarthritis," he says.

People who already have some knee damage and want to postpone or avoid knee surgery may also want to consider reducing "impact loading" exercise such as running or jogging, where the full weight of the body must be absorbed by the knee joint.

That doesn't mean giving up exercise — it just means choosing activities that reduce wear and tear on the joint. Townsend recommends cycling or swimming, or using exercise equipment such as treadmills, elliptical trainers and stair climbers to get the aerobic exercise that's so important for proper cardiovascular health.

Strengthening the muscles that hold the knee together will also help preserve the joint. Townsend says most people need to build up their quadriceps (the big muscles in the front of the thigh) to strengthen their knee joints. One simple way to build quad strength is to "sit" with your back against a wall, as though sitting in a chair, but without the chair. Hold this position for 10 to 20 seconds, rest and repeat, gradually increasing the time and number of repetitions as the legs get stronger.

It sounds paradoxical, but people who want to avoid knee replacement should stay active. Townsend says joints stay better lubricated when they move regularly..

The good news about knee replacement is that the technology has improved dramatically since the first transplants were performed in the 1960s. Better adhesives and metal hardware that allows the bone to grow into it make today's artificial joints much stronger and longer-lasting. Townsend says more than 90 percent of artificial knees can be expected to last at least 15 to 20 years.

Call Bill Kettler with your medical questions at 776-4492, or e-mail them to: or send them to: Mail Tribune, Ask Your Doctors, P.O. Box 1108, Medford OR 97501.

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