"Currently, knee braces and wedged orthotic shoe inserts are used to relieve the load on the knee joints of patients with osteoarthritis, but everyday footwear is also a factor to consider. The results in our study demonstrate that the reduction in load achieved with different footwear, from 11 to 15 percent, is certainly comparable to reduction in load with braces and shoe inserts ," Shakoor said.
According to Shakoor, several aspects of footwear affect the joint loading.
"Heel height is one factor, and may explain why the stability shoes and clogs in our study, both of which had higher heels, produced greater knee loads," Shakoor said.
"Stiffness is also a factor. We've shown in earlier studies that barefoot walking is associated with lower knee loads than walking with conventional footwear. It may be that the flexible movement of the bare foot is mechanically advantageous. The natural flex of the foot when it contacts the ground probably attenuates the impact on the joint, compared to the artificial 'stomping' movement created by a stiff-soled shoe."
In the present study, Shakoor said, flip-flops and the walking shoe were flat, flexible and lightweight and seemed to mimic the mechanics when walking with bare feet.
"Clogs and stability shoes, conventionally believed to provide appropriate cushioning and support, actually increased the loading on the knee joints, as opposed to shoes with less 'support,' flatter heels and more flexibility," Shakoor said.
Shakoor cautioned, however, that knee loading is not the only consideration in any clinical recommendations based on her study.
"For the elderly and infirm individuals, flip-flops could contribute to falls because of their loose-fitting design. Factors like these need to be taken into account," Shakoor said.
|Contact: Sharon Butler|
Rush University Medical Center