“We think when people wore these flexible shoes they changed the way they walked, so even when they put their old shoes on again, they were walking in a mechanically more advantageous way for their knees than they were before,” says Dr. Shakoor, whose work is supported by funding from the Arthritis Foundation.

Dr. Shakoor and her team of researchers from Rush University also developed the mobility shoe used in these studies. The university has a patent for them and licensed the rights to a company called Dr. Comfort, which produces and sells the shoes. Rush University and the researchers involved receive a small percentage of royalties.

Marian T. Hannan, an associate professor of medicine at Harvard Medical School in Boston, Mass., has done her own research about foot mechanics and pain in the knee. She says it is interesting to look at how a simple, non-surgical change in someone’s footwear can help people dealing with painful OA that doesn’t have a cure.

“It is impressive to think that [footwear] makes a difference. Shoes can be expensive but they are easy to change and it looks to have a training effect, which means it’s not just the shoes but how the person interacts with their shoes,” says Hannan. “Whether it’s their foot or brain or the whole package, it appears to work. As a proof of concept it is very appealing.”

John Hardin, MD, vice president of research for the Arthritis Foundation, agrees. “I am always thrilled when relatively low-cost and safe strategies promise benefit for patients with arthritis. Perhaps there is a subset of patients in whom mobility shoes will be just ‘the thing.’”

Dr. Hardin, who is also professor of medicine and orthopaedic surgery at Albert Einstein College of Medicine, in the Bronx, N.Y., notes that gait mechanics – or how a person walks – clearly has a role in determining the stress on the knees, and it is possible that appropriate footwear might help minimize that stress.

Hannan points out that plenty of questions remain, including how long these benefits will last and how often you have to buy new shoes. And, she says, you do have to look carefully at study results when researchers are also inventors. “They are upstanding people but you wonder about the unseen bias. Obviously they believe in this shoe. If they can prove everyone is blinded that would be key,” Hannan says.

Dr. Shakoor says her researchers are blinded, and while she was involved in analyzing the data for initial pilot studies, she no longer does that for ongoing research. She also stresses that these shoes were designed in order to carry out research in this area and study the biomechanical effects of flexible footwear.

“These studies aren’t meant to say you need this specific shoe, but more broadly to evaluate the biomechanical and clinical effects of flexible shoes versus stiff shoes,” Dr. Shakoor explains.

In general when looking for shoes that will help patients with knee OA, Dr. Shakoor recommends people look for a flat shoe that is lightweight, soft and has a flexible and flat sole that easily bends and has no built in heel.

She and her team are still investigating why this design is beneficial but she believes it may be in part that the average shoe doesn’t let your foot pronate, or turn in, which could increase loads in people with medial knee OA.

Melvyn Harrington, MD, an associate professor of orthopedic surgery at Baylor College of Medicine in Houston, Texas, says it is interesting that researchers are looking at the science and biomechanics of these shoes. But he says larger studies are needed to know if mobility shoes translate into a real improvement for patients. He says for now, weight loss is what’s been shown to make the most difference in decreasing stress across the joints in the knee.

“I don’t think shoes make that much of a difference for most people,” Dr. Harrington says. “You hear that some people can’t tolerate heels because of the loading. Some people like tennis shoes. Some people like their work shoes. Usually I just tell them to wear whatever is the most comfortable. I don’t think it makes that much difference functionally.”