Stiletto shoes for prosthetic legs

Hopkins University students have developed a prosthesis that allows women to put on stilettos again

Dronk.Ru, Geektimes

The loss of limbs is a severe physical and psychological trauma, not everyone can overcome the consequences of which. The rejection of many things that seemed ordinary yesterday becomes inevitable, and the quality of life is inexorably declining. Going to meet the wishes of the forced "eternal patients", engineers in the field of prosthetics create new concepts that every day bring the moment of returning lost opportunities to a person closer. Of course, the level of such a return, the technologies and materials used determine the final cost of the prosthesis.

Taking into account the severity of the problem, the range of offers on the modern market is quite large and covers almost all categories of the population – from the simplest prosthesis – a "continuation" of the stump – to extra-class prostheses that have "learned" to feel touch, to be controlled by the power of thought and even, in addition to the main ones, perform a number of related functions that are not originally peculiar to the native hand or a person's leg.

The vast majority of prostheses are made taking into account the individual characteristics of the patient. If we talk about prosthetic legs, they are designed for the use of shoes, most often a fairly simple, practical, most comfortable model. Almost all the solutions proposed for today are limited to a heel height of 2.5 inches. But an effective solution for women who have lost a leg and wished not only to regain the ability to move on "their" two, but also to look 100% and walk in stilettos has not yet been proposed. Perhaps because of the nature of the injury, this task seemed to prosthetic engineers not just bold, but slightly reckless. And yet…

The first people who thought about how to return a pinch of female happiness to the ladies deprived of fate, as it is not strange, were students from Johns Hopkins University who decided to take on this responsible and difficult mission, and at the same time defend their graduation project. In the team's press release dated May 26, 2016 (Johns Hopkins Students Design Prosthetic Fit for High Heels), the guys reported that one of the driving motives was the situation in the American army, where cases of amputation of limbs among female veterans participating in combat operations in the past are not so rare. This figure is known and amounts to 2,100 people. Of course, the problem is much broader, and its audience is not limited to such a narrow contingent of ladies who have chosen such an extreme lifestyle for themselves – thousands of women of various ages need prosthetics, both in the United States and abroad.

The task that the students set themselves was to create a prosthesis of such a design that would give its owner the opportunity to confidently maintain balance and freely adjust the height of the heel without additional devices. Moreover, the guys decided to complicate the task as much as possible by developing a prosthesis that can withstand the weight of a full person, retains lightness and easily fits in elegant women's shoes with and without heels. "While it took thousands of years of evolution for a human leg to come to such a result, and we had only one year," says one of the team members Luke Brown. Of course, on the key issues of the theory of prosthetics related to medical and some engineering aspects, expert advice was not dispensed with.

The prototype of the design, which the young developers have already been able to demonstrate and test, provided for the adjustment of the heel position due to the movement of two interconnected aluminum discs. The guys note that 23 plates made of durable titanium, which turned out to be heavy, and 20-layer carbon fiber, which brilliantly solved the weight problem, were also tested as the starting material, but did not reach the strength at a significant weight and failed stress tests. The adjustment process itself is carried out by means of a lever attached to the ankle. A hydraulic device is built into the ankle structure, which gives the gait smoothness and ensures that the sole bends to the desired angle in the "automatic" mode.

The first prototype created was tested on four types of shoes, including shoes with a stiletto heel height of almost 14 centimeters. Four volunteers with amputated legs and three healthy people took part in the tests. For healthy people, the task turned out to be surprisingly difficult, since the length of the prosthesis was added to the natural and familiar length of the leg, as a result of which the design had a very stilted appearance.

The prosthesis made an exceptionally favorable impression on the female participants of the experiment who lost a limb. The possibility of changing the height of the ankle was particularly noted, which allows people with disabilities who have different heights and weights to pick up and feel confident in shoes of a variety of styles and purposes – from ballet flats with sneakers to stilettos up to 10 cm high.

According to the creators, the whole mechanism weighs only 1.4 kilograms and is able to withstand the weight of 113 kg ladies. "I had a great walk," Alexandra Capellini, a research participant and a junior researcher at Hopkins University who lost her leg as a result of bone cancer, shared her impressions: "I felt quite stable... adjustable ankles are very comfortable. Ballet flats, sneakers, boots and high heels especially, all differ in height, so adjustable ankles open up opportunities to wear different shoes." And in this sense, the prosthesis created by students is really universal.

Valuable recommendations were also received on making some small but significant changes to the design. So after the end of a series of experimental tests, the participants agreed that it would be nice to slightly lengthen the prosthetic thumb for stability and slightly shift the lever for adjusting the height of the artificial foot.

As the students noted, there is still a lot of work to be done before their prosthesis can act as a commercial product, but the main thing is that the concept called "Prominence" by the students turned out to be successful in general, and was able to successfully pass a series of tough practical tests. Now the team is seriously considering the possibility of patenting its development.

Portal "Eternal youth" http://vechnayamolodost.ru  02.06.2016