Researchers from Rush Medical College conducted a study into the effects of various types of footwear on knee osteoarthritis (OA). What they found was that shoes which allowed natural foot motion and flexibility are more favorable on the knees.
Much research points to unusually high loading of the knees (high amounts of stress on part or all of the knee joint) as a significant factor in risk of injury and OA disease progression.
In this investigation, presented at the American College of Rheumatology Annual Scientific Meeting in Boston, the team studied 13 women and 3 men with knee OA. They evaluated the participants gait (evaluation of the way they walk and the load on their knees) while barefoot and wearing several different types of shoes. The shoes included clogs, a stability shoe (designed to limit fool movement), a flat, flexible shoe (designed to allow significant foot movement), and flip-flops.
The participants were given time to adjust to each type of footwear before the knee load analysis, based on walking at normal speed, was completed.
The researchers found that the stability shoes and clogs resulted in significantly higher loading of the knees. They also found that walking shoes and flip-flops resulted in lower loads that were similar to walking barefoot.
According to Najia Shakoor, MD, assistant professor of internal medicine, Section of Rheumatology, Rush Medical College, and an investigator in the study: “These results highlight the importance of re-evaluating the design of modern day shoes in terms of their effects on knee loads and knee OA”.
“Knee loads play an important role in the progression of knee osteoarthritis. Shoes have traditionally been engineered to provide foot comfort and little previous attention has been directed to the effects that shoes may have on loading of osteoarthritic knees.”
An earlier study, published in the September, 2006 issue of Arthritis & Rheumatism, also found that walking barefoot provided lower loading on the knees than walking shoes.
In that study, 75 participants with knee osteoarthritis underwent gait analysis while walking barefoot and in their walking shoes.
Walking barefoot reduced the loads on the knee by 11.9%. Additionally, significant reduction was also found in the hips, as well as reductions in hip rotation.
These researchers also concluded that shoes may increase knee loads and increase risk of joint damage on the lower extremity joints in patients with knee osteoarthritis.
An even earlier study from 2003, conducted by Dr. D. Casey Kerrigan, chair of the University of Virginia Department of Physical Medicine and Rehabilitation also found a link between shoes and OA disease progression. Her research suggested that high-heel shoes may be a primary reason why osteoarthritis is twice as common in women as in men.
Her research found that walking in 2 inch, narrow-heeled shoes increases the strain on the parts of the knee most vulnerable to osteoarthritis by 23% compared to walking barefoot. And surprisingly, wide-heeled shoes increased the loads by an even greater 30%.