[Editors] MIT/Artificial legs: Toward a better fit

[Elizabeth Thomson]

MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA  02139-4307
Phone: 617-253-2700
http://web.mit.edu/newsoffice/www

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MIT students develop device to simplify fitting of prosthetics
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For Immediate Release
MONDAY, MAR. 10, 2008
Contact: Elizabeth A. Thomson, MIT News Office -- Phone: 617-258-5402 
-- Email: thomson at mit.edu

PHOTO AVAILABLE

EDITORS: The story below is part of a new feature produced by the MIT 
News Office that explores the ways people from MIT are using 
technology--from the appropriately simple to the cutting edge--to 
help meet the needs of local people in places around the planet.


CAMBRIDGE, Mass.--In the United States, a typical prosthetics 
specialist who fits artificial legs for amputees might handle 15 or 
20 such patients a year, fitting them with custom-built legs that can 
cost upwards of $6,000 apiece. Each patient then gets a series of 
followup visits to make sure the new limb was properly fitted.

But in India, the Jaipur Foot Organization handles that many patients 
every day in each of its local centers. The charity is the world's 
largest provider of prosthetics, and has worked with about a million 
patients since being founded in 1975.

The JFO, also known as Bhagwan Mahavir Viklang Sahyata Samiti, is 
based in Jaipur, a city of more than three million people that is the 
capital of Rajhastan in northern India. The artificial legs they 
provide, based on a locally developed design, cost about $40, and the 
company has little time or funding for followup consultations, or for 
developing new methods.

A team of MIT students has been working on a new device that could 
greatly simplify the process of fitting these legs, producing a 
better fit while eliminating some steps in the process and reducing 
waste materials. The hand-powered system, which requires no external 
power, would also greatly simplify the fitting of legs in rural 
areas, where the present electrically powered fitting system requires 
bringing along a bulky generator.

The first step in fitting a leg is to make a mold of the person's 
stump, to provide a precise fit. This is done by placing the stump 
into a container filled with tiny glass beads and covered with soft 
silicone rubber, and then creating a vacuum so that the beads seal 
tightly around the limb. This "negative" mold is then filled with 
more glass beads (referred to as "sand") to form a positive mold - an 
exact replica of the stump - and the socket of the prosthetic leg is 
made to fit that replica. Alternatively, the two steps can be done 
with plaster of paris instead of the sand - a process that doesn't 
require electricity, but does use up heavy and non-reusable plaster.

The MIT system was designed under the auspices of the D-Lab in the 
Department of Mechanical Engineering. Mechanical engineering students 
Philip Garcia, Maria Luckyanova, and Tess Veuthey, physics student 
Jessica Schirmer, and D-Lab instructor Goutam Reddy have been working 
on the project - some of them for more than a year.

The new fitting system they devised uses a hand-crank to produce the 
vacuum, eliminating the need for electric power. And the same device 
can be used to produce both the initial negative mold, and then the 
positive mold that replicates the shape of the stump.

Garcia, Luckyanova, Reddy and Schirmer spent two weeks at the Jaipur 
facility this January, thanks in part to a grant from MIT's Public 
Service Center and a $7,500 award from last year's IDEAS competition. 
They did one test run of a fitting, and the JFO personnel were very 
impressed.

"They were really pleased with the results," Luckyanova says. They 
liked the fact that the new system produced less waste, required no 
electricity, and seemed to produce a better fit that might lead to a 
longer-lasting prosthetic. That's because the plaster of paris in the 
traditional method shrinks slightly as it hardens, making the fit 
less exact.

The Jaipur technicians also had some useful suggestions for 
simplifying and streamlining the device. "Basically, they wanted a 
black box," Garcia says, a system in which the working parts were 
hidden from view and that was simple to set up and use in the field. 
The students are now hard at work refining the design, partly in a 
seminar class they are conducting this semester that includes about 
20 students from a variety of different disciplines.

After that, "this summer we'll do some field testing" back in Jaipur, 
Luckyanova says.  The Jaipur company is so busy serving patients that 
they don't have much time to work on researching better systems, 
Luckyanova says, so they were delighted to have MIT's help on that 
part of the process.

The trip to India was a big eye-opener for the students. Garcia says 
that "I learned a lot about the world." He's not sure what he intends 
to do after he graduates this spring, but says that it will "probably 
be something involving the developing world."

Luckyanova says this "changed my perspective a lot." While she enjoys 
working on high-tech engineering projects, she says, with this 
project "you feel such a sense of accomplishment when you see that 
something you made can affect people's lives right away. It is very 
gratifying."

--END--

Written by David Chandler, MIT News Office