BOSTON, Massachusetts—Foot-friendly clogs and shock-absorbing stability shoes may be bad for the knees in patients with knee osteoarthritis (OA), said Najia Shakoor, MD, assistant professor of internal medicine in the section of rheumatology at Rush Medical College in Chicago during the annual meeting of the American College of Rheumatology in Boston.

"What may be good for our feet may not be good for our knees," Dr. Shakoor said. "As rheumatologists, many patients ask us what shoes they should wear. We have made recommendations based on what we thought was appropriate, but we must change our approach to footwear and not just think about the foot."

Clogs, stability shoes, walking shoes, bare feet, flip-flops tested for knee effects

Dr. Shakoor and colleagues studied the effects of various types of footwear on 13 women and three men with knee OA. Each participant underwent gait analysis using an optoelectronic camera system and multicomponent force plate either while barefoot, while wearing a Dansko clog, a Brooks Addiction stability shoe, a Puma H-Street (a flat, flexible walking shoe), or flip-flops. After adjusting to the new footwear, each participant was observed walking at normal speed. Researchers calculated the peak external knee adduction moment (AddM) with each shoe type and compared it with those during barefoot gait via a paired t-test.

The stability shoes and the clogs, which are traditionally worn by many physicans and health care workers in hospitals, were associated with significantly higher loading of the knees than walking barefoot.

By contrast, the Puma walking shoes and flip-flops resulted in lower knee loads, which were comparable with walking barefoot. Specifically, clogs and stability shoes were associated with a 16% higher load than walking barefoot, the study showed.

The same team of researchers has previously shown that walking barefoot significantly decreased the AddM compared with walking shoes.

Crocs—those übertrendy, bright colored, lightweight clog-like shoes—probably fall somewhere in the middle of clogs and the walking shoes, she said. "They don't have as thick of a sole as the clog or the Brooks Addiction stability shoe," she said. "If I had to guess, I would say the load is in between the Puma and the clog."

While Dr. Shakoor has no specific recommendations what type of shoes doctors should tell their arthritis patients to wear, "shoes that provide natural foot mobility with arch support may be beneficial for some patients."

Patricia P. Katz, PhD, a professor of medicine and health policy at the University of California in San Francisco, told MSKreport.com that rheumatologists should start paying attention to the feet. "Rheumatologists spend a lot of time looking at the hands and I think they need to spend more time looking at feet and I think they need to bring in some ancillary players like physical therapists and podiatrists to look at some of these problems," she said.

How Your Patients' Shoes Stacked Up Compared With Bare Feet

	Barefoot	Dansko	Brooks	Puma	Flip Flop
AddM (%BW*ht)	2.6 ± 0.7	3.0 ± 0.7	3.0 ± 0.7	2.8 ± 0.7	2.6 ± 0.7
P value		<0.001	0.001	0.096	0.895

Adapted from: Sengupta M, et al. ACR 2007.¹


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