Knee osteoarthritis is caused by cartilage breakdown in the knee joint. Factors that increase the risk of knee osteoarthritis include being overweight, age, injury or stress to the joints, and family history can increase the risk of knee osteoarthritis.
In knee OA, there is abundant evidence that patients with unusually high loading knees (high amounts of stress on part or all of the knee joint) are at increased risk of both injury and disease progression.
The study, conducted by Rush Medical College researchers, found that shoes that allowed natural foot motion and flexibility are more beneficial in terms of knee loading.
For the study, the researchers examined the effects of various types of footwear on 13 women and 3 men with knee OA. Each participant underwent gait analysis (evaluation of the way they walk and load their knees) while barefoot and while wearing a clog, a stability shoe (designed to limit foot movement), a flat, flexible walking shoe (designed to allow significant foot movement), and flip-flops.
After having time to adjust to their new footwear, each participant was observed walking at normal speed, following which, the researchers calculated the load on the knee.
They found that clogs and stability shoes were associated with significantly higher loading of the knees, while the walking shoes and flip-flops resulted in lower knee loads similar to those occurring when walking barefoot. Therefore, shoes that allowed natural foot motion and flexibility appeared to be more beneficial in terms of knee loading.
"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," said Najia Shakoor, MD, assistant professor of internal medicine, Section of Rheumatology, Rush Medical College, and an investigator in the study.
"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.
"Results from this study suggest that shoes can significantly affect the amount of load on osteoarthritic knees—with flat, flexible shoes providing the greatest degree of benefit in terms of knee loading," she added.
The findings were presented at the American College of Rheumatology Annual Scientific Meeting in Boston, Mass.