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Healthy Aging

Healthy Body

Making Knees New Again

Knee replacements are on the rise. Here’s what you should know from Johns Hopkins experts to help boost your knee health—and help decide whether knee replacement is right for you.

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Research Shows
New Hope for an Arthritis Cure

Johns Hopkins researchers report that worn cartilage is not the only culprit in the development of osteoarthritis (OA)—an overgrowth of bone beneath the cartilage wear down the cartilage faster, until eventually the ends of the bones rub together with no cushioning. Testing their theory in mice with an anterior cruciate ligament tear, an injury that can lead to arthritis, researchers found that damaged bone beneath the cartilage triggered a bone-building protein to form new bone. Blocking the action of that protein stopped extra bone growth and prevented further cartilage destruction. “Our results are potentially really good news for patients with OA,” says Xu Cao, M.D., Ph.D., director of the Johns Hopkins Center for Musculoskeletal Research. Next up: a clinical trial in humans. If the same result is seen, we will be closer to a medical treatment for arthritis.

How are your knees? If you’re like many people age 50 and older, they’ve been aching. If you’re 65 or older, you may have some degree of osteoarthritis, in which the cartilage that cushions the ends of the bones in the joints begins to degenerate or wear away.

Symptoms can range from stiffness to severe pain and limited mobility. So it’s probably not surprising that surgeons perform more than 700,000 knee-replacement surgeries in the United States each year.

Total knee replacement is very effective, but implants don’t last forever. Although they can last 20 years, one study found that about 14.9 percent of men and 17.4 percent of women who receive a total knee replacement will need another. The earlier you get your implant, the more likely you’ll be back in surgery at some point.

That’s why knee replacement should only be considered after you’ve tried everything else, says Harpal S. Khanuja, M.D., chief of hip and knee replacement surgery with the Department of Orthopaedic Surgery at Johns Hopkins. That includes following your doctor’s recommendations for losing weight, physical therapy, pain management, and modifying your activities.

“I tell people it’s time for a replacement when they can’t live the life they want to live; it is not a good solution for an occasional pain,” Khanuja says.

To keep knee replacement as a last resort, keep your knees healthy with these smart steps.

Hit a healthy weight.

Weight management is one of the top ways to fight osteoarthritis. Excess weight puts more pressure on your knees. This increases inflammation and likely contributes to disease progression. Every 10-pound loss relieves 30 pounds of force on your knee per step, says Khanuja.

One study found that overweight people who lost just 10 percent of their body weight experienced significantly less knee pain, could walk faster, and moved better. They also had lower levels of inflammation.

Get the right kind of exercise.

Moderate physical activity won’t increase your risk of osteoarthritis. In fact, by helping you maintain a healthy weight, it can actually reduce the risk. If your knees hurt, however, be smart. Don’t start training for a marathon or join a basketball team. Instead, says Khanuja, try lower-impact exercise such as swimming, walking, or using an elliptical machine.

Toss the high heels.

A study published in the journal Arthritis & Rheumatism found that wearing flat, flexible shoes significantly reduced pressure on knees and helped people with osteoarthritis walk better.

Definitions

Cartilage (kahr-ti-lij): Tough, flexible tissue that covers the ends of bones, allowing our joints to move without pain or friction. It also is what gives shape to our noses, ears and windpipe. When cartilage becomes damaged or inflamed, movement can be painful or limited.
Inflammation (in-fluh-mey-shun): The redness and warmth around a cut or scrape is short-term inflammation, produced by the immune system to aid healing. But another type called chronic inflammation, triggered by compounds from abdominal fat, gum disease and other factors, lingers in the body. Research suggests this type increases the risk for heart disease, diabetes, dementia and some forms of cancer.

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