Wearing flat and flexible shoes that allow your feet to move more naturally results in self-reported improvements in pain, function and quality of life among people with knee osteoarthritis (OA), according to a study presented at the American College of Rheumatology’s annual meeting in San Diego this week. Patients who wore these so-called mobility shoes for up to 48 weeks also appeared to have less force put on their knee joints.

OA is a chronic condition in which the material that cushions the joints, called cartilage, breaks down, causing the bones to rub against each other, resulting in stiffness, pain and loss of joint movement. About 27 million people in America have osteoarthritis; the knee is one of the most common joints affected. Knee OA can affect the kneecap (called patellofemoral OA), the inside edge of the knee

(called medial compartment OA) and/or the outside edge (called lateral compartment OA).

“When you have knee osteoarthritis and you wonder what kind of shoes would be best for your knees, maybe there should be a shift in thinking from going with supportive and cushioned footwear to a lightweight flexible shoe,” says lead study author Najia Shakoor, MD, a rheumatologist and associate professor of medicine at Rush University Medical Center in Chicago.

To find out if the mobility shoe helps in patients with knee OA, Dr. Shakoor conducted a randomized, placebo controlled trial. In the first part of the study (which lasted six months), 22 patients were given a flexible shoe with a sole that had cuts in it designed to allow feet to bend as they naturally do barefoot. Twenty-eight other participants were given a control shoe that appeared identical, but had a much stiffer sole made of denser material and a metal plate to decrease its ability to bend. The study was “double-blinded,” which means that neither researcher nor participant knew who got which shoe.

Eleven mobility-shoe participants and 13 control-shoe participants continued with the study for an additional 18 months. The results presented at the conference are an analysis of the first 48 weeks.

After 48 weeks, researchers reported participants wearing the mobility shoes were nearly two times more likely to show self-reported improvements compared to the control group:

  • 73 percent improvement in pain with mobility shoes compared to 37 percent with control shoes
  • 70 percent improvement in function with mobility shoes compared to 40 percent improvement with control shoes
  • 42 percent improvement in quality of life with mobility shoes compared to 11 percent with control shoes.

Some of these results are not what scientists call “statistically significant” – which means that they could occur by chance; the researchers say this may be due to the small sample size. However, a statistically significant greater number of participants in the mobility group (10 out of 11) were considered “responders” to treatment compared to the control group (6 out of 13).  

Earlier results from a subset of participants in this same group were published in the May 2013 issue of Arthritis & Rheumatism. That analysis did not feature a control group but focused instead on 16 patients with knee OA who wore the mobility shoes at least six hours a day, six days a week for six months. After 24 weeks patients had an 18 percent reduction in the load on their inner (medial) edge of their knee – the place where most people develop knee OA.

Not only did those participants see improvements when wearing the mobility shoes, but when they were tested throughout the study period in their old shoes or barefoot, they continued to walk with an improved gait that reduced the load on their knees.