Clogs, Stability Shoes Put More Stress on Knees Than Flat, Flexible Shoes and Flip-Flops, Study Finds
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In a comparison study that evaluated the force or "load" on arthritic knees while wearing clogs, athletic shoes with stability features, flat walking shoes, flip-flops, and going barefoot, the flat and flexible shoes won out, says study lead author Najia Shakoor, MD, an associate professor of internal medicine at Rush Medical College and an attending physician at Rush University Medical Center in Chicago.
Her study is published online in Arthritis Care & Research.
"We know barefoot is good for your knee load from previous studies," Shakoor tells WebMD. "Then we thought, do different shoes have different effects on the knee?" So they compared the four shoe types with going barefoot.
The surprise? "The shoes that we intuitively recommend to our patients [with knee arthritis] and thought might be best -- stability shoes and clogs -- were associated with the highest load."
Best Shoes for Knee Pain: Study
Arthritis of the knee is common and a major source of disability and impaired quality of life, the researchers say. Shakoor's team evaluated 31 men and women who had knee arthritis, evaluating their gait as they wore:
- An athletic shoe that promises to minimize inward rolling of the foot
- Flat walking shoes
The study was supported by the National Institutes of Health.
Shakoor measured what's known as a knee adduction moment, "which measures the extent of the force upon your knee as you walk."
"Flat walking shoes, barefoot, and flip-flops were essentially the same in load on the knee," she says. "But clogs and stability shoes result in a 15% higher load."
"These are just initial studies, and it's too early to recommend [changes]," she says. "But several studies are suggesting that perhaps flat, flexible footwear may help decrease loads on the knee compared to footwear that is less flexible and has higher heels. Stability shoes have higher heels [than other athletic shoes]."
"We think it's the flatness and the flexibility that may provide the benefit."
And, she cautioned: "We are definitely not advocating flip-flops. A flat walking shoe would be better than a flip-flop for other reasons -- stability and the risk of falling."
Shakoor will continue her research. With Rush University and a podiatrist, she hopes to develop a walking shoe for people with knee arthritis. She says Rush will hold the patent.
Best Shoes for Knee Pain: Other Views
"This finding [about the best shoes for knee pain] came as absolutely a surprise to me," says Jeffrey A. Ross, DPM, MD, a spokesman for the American College of Sports Medicine, associate clinical professor of medicine, and chief of the diabetic foot clinic at Ben Taub Hospital in Houston.
"I would have expected the running shoe to be the best, but it didn't turn out to be," he says.
But Ross says he wishes the researchers had studied more than one type of athletic shoe. Even with the new study results, he says, "I probably would still suggest [people with knee arthritis] wear a low-heel running shoe with a flexible sole."
For people with knee arthritis, the shoe should bend easily, he says, resulting in less stress on the forefoot.
A "neutral" athletic shoe -- one that does not offer motion control or stability features, may also work to reduce load on the knee, he says.
Choosing footwear for people with knee arthritis can be a trial-and-error experience, says James Christina, DPM, director of scientific affairs for the American Podiatric Medical Association. "A lot of foot doctors would say a cushioned shoe, rather than a stability shoe or a rigid control category of shoe," he says.
Christina says the APMA does not have shoe guidelines for people with knee arthritis.
The new study is a valid one, he says, but the shoe that works for one person with knee arthritis may not work for another person.
The foot specialists say that flip-flops, although they didn't increase the forces on the knee, aren't the best shoe type, especially for older adults with knee arthritis. As balance declines, flip-flops can be hazardous and increase the risk of falling, they say.
SOURCES: Najia Shakoor, MD, associate professor of internal medicine, Rush Medical
College; attending physician, Rush University Medical Center, Chicago.
James Christina, DPM, director of scientific affairs, American Podiatric Medical Association, Bethesda, Md.
Jeffrey A. Ross, DPM, MD, spokesman, American College of Sports Medicine; associate clinical professor of medicine and chief of the diabetic foot clinic, Ben Taub Hospital, Houston.
Shakoor, N. Arthritis Care & Research, published online Feb. 26, 2010.
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