Osteoarthritis (OA) of the lower extremity is largely mediated by "aberrant biomechanical forces," note Dr. Najia Shakoor and Dr. Joel A. Block, from Rush Medical College, Chicago, in the journal Arthritis and Rheumatism.

"In knee OA, the most well-studied form, there is evidence that patients with abnormally high dynamic loading of the knees are at greater risk of incident and progressive diseases," they note. "Consequently, strategies that effectively reduce loads on the knee during gait would be of great interest."

The researchers assessed the effects of modern shoes on gait and lower extremity joint loads in 75 patients with knee OA. Their mean age was 59, their mean BMI (body mass index) was 28.4, and 59 of the 75 were women.

Gait analysis was performed while the subjects were wearing their everyday walking shoes and while they were walking barefoot.

Walking barefoot resulted in significant decreases in dynamic loads at the knees and hips, the team reports.

The findings "suggest that modern shoes may exacerbate the abnormal biomechanics of lower extremity OA," the team concludes.

Although the effect of wearing shoes on onset of OA hasn't been studied, they add, "modern shoes, and perhaps our daily walking practices, may need to be reevaluated with regard to their effects on the prevalence and progression of OA."