Researchers have developed the first non-custom prosthetic foot to help women who have lost a leg to disease or injury adapt to heels up to four inches high.
Women adjusting to life with a prosthetic limb face the same challenges as men, with perhaps one added complication: how to wear high-heels.
A team of researchers at the Johns Hopkins University in the US has developed "Prominence," the first prosthetic foot on the market that is not custom made that adapts to popular fashion for heels up to four inches high.
"High heels have become an integral part of the female lifestyle in modern society, permeating through all aspects of life - professional and social," researchers said.
Scores of prosthetic feet are available on the market, but most are built to fit men's shoes, and none can adjust to a heel more than two inches high. That is less than the average women's heel height in the US.
With some 2,100 American women who lost a leg or foot in military service, and more women entering combat assignments, the demand for a prosthesis that accommodates women's fashion footwear is sure to grow, researchers said.
The challenge was creating a foot that adjusts without a separate tool to a range of heel heights, holds position without slipping, supports up to 113 kg, weighs less than over 1kg and is slender enough to accommodate a woman's shoe.
The researchers' work unfolded as a mix of mathematical calculations on paper and trial and error involving tests by machines and people.
They built a heel-adjustment mechanism with two interlocking aluminium disks that opens and closes with an attached lever at the ankle.
For the ankle, they used an off-the-shelf hydraulic unit that enables a smooth gait and flexing at the sole.
Using four types of women's shoes - including a gold five-and-a-half inch stiletto - the team had the foot tested by seven people.
James K Gilman, executive director of the Johns Hopkins Military and Veterans Health Institute and advisor to the group, said it will take time to assess the commercial appeal and potential of the Prominence, including the question of whether anything the team created could qualify for a patent.