Thin, Flexible Shoes Reduce Stress on OA Knees

Janis C. Kelly

April 11, 2013

Shoes that mimic walking barefoot may reduce mechanical stress and help protect the knees of patients with osteoarthritis (OA).

Najia Shakoor, MD, associate professor of internal medicine in the Section of Rheumatology at Rush Medical College in Chicago, Illinois. and colleagues report in an article published online April 10 in Arthritis & Rheumatism that patients with knee OA who wore the "mobility shoe" for at least 6 hours per day for up to 6 months had improved gait and reduced knee loading.

The lightweight, flat, flexible shoes do not have to be customized for each patient. They have grooves at major flexion points to allow for natural, "barefoot-like" movement.

"This is a very well conducted study which comes to valid conclusions. I think in particular the gait analysis and stress analysis are very well done. One aspect that is strongly favorable is that they asked the patients to compare walking with the special shoes to their normal shoes, which patients with arthritis buy precisely because they regard them as comfortable. Yet, the special shoes and even barefoot walking were better for their legs and feet," Eric L. Matteson, MD, told Medscape Medical News. Dr. Matteson, who was not involved in the study, is chair of the Department of Rheumatology at the Mayo Clinic in Rochester, Minnesota.

The sole cuts allow the mobility shoe to bend where the foot would naturally bend during barefoot gait. Photo courtesy Dr. Comfort Footwear.

The researchers recruited 16 patients with knee OA who had at least 30 mm of pain (on a 100-mm scale) while walking (corresponding to question 1 of the visual analog format of the knee-directed Western Ontario and McMaster Universities Arthritis Index), had moderate OA (Kellgern-Lawrence grade 2 or 3), and were willing to wear the mobility shoes as their main footwear for at least 6 hours per day, 6 days per week.

All participants had medial compartment disease and a peak external knee adduction moment (KAM) of 2% or more of body weight times height, as measured by gait analyses. Gait was evaluated at 6, 12, and 24 weeks.

Twelve of 16 patients completed the study. After 24 weeks, patients had an 18% reduction in KAM compared with their own shoes at baseline (P < .001), KAM was the same with the mobility shoes as with barefoot walking, and patients had an 11% reduction in KAM when in their own shoes (P = .002) and a 10% reduction in KAM during barefoot walking (P = .002) compared with baseline.

The researchers conclude, "This study demonstrates that 6 months of use of a mobility shoe, intended to mimic the beneficial biomechanical effects of barefoot walking, can result in significant reductions in knee loads in participants with medial compartment knee OA. Furthermore, after chronic usage of the mobility shoe, this unloading effect becomes durable when the mobility shoes are replaced by conventional shoes; this suggests the presence of a gait adaptation with reductions in loading present even once the mobility shoes are removed."

Dr. Matteson commented, "Humans are, after all, not born with shoes, and for the greatest part of the history of mankind, we have had either no, or simple, flat shoes, even in cold climates. Yet we must think about protecting our feet from trauma, like rocks and thorns and cold, and so we are in need of wearing protective footwear. Patients with arthritis also often have foot and toe deformities, which make walking barefoot impossible."

The study was supported by the Arthritis Foundation. Dr. Shakoor and one coauthor are coinventors of the shoe used in this study. The invention resulted in a patent owned by Rush University Medical Center. Dr. Matteson has disclosed no relevant financial relationships.

Arthritis Rheum. Published online April 10, 2013. Abstract