March 13, 2010
A durable, cheap prosthetic knee is tested for developing countries
contributor: Rob Goodier
Updated Dec. 26, 2013 – Roger Gonzalez was nominated as a Global Humanitarian Engineer of the Year at IEEE’s Global Humanitarian Technology Conference in Silicon Valley, Calif. on Oct. 22. The award honored Gonzalez’s work developing low-cost prostheses with his non-profit organization LIMBS.
Prosthetic limbs in the developing world are often expensive, imported, and not always designed for humid climates and dusty fields. This trifecta of cost, maintenance and durability has stymied treatment before, and now thousands of new Haitian earthquake survivors may confront these problems too.
Yet there is a solution. The LIMBS knee (formerly called the LEGS M1 knee) is a rugged prosthesis that’s been tested in developing countries since 2004. It’s designed for local manufacture and maintenance. And it’s amazingly cheap, just $15 to $20 each. (For comparison, please see our coverage of the low-cost Jaipurknee in development now in India).
Dr. Roger Gonzalez developed the knee with his students at LeTourneau University in Longview, Tex. It’s made of plastic – he found that DuPont’s Delrin polyacetyl works well – and standard stainless steel bolts. It’s polycentric, as opposed to a simpler single-axis (hinged) joint, to better mimic the multiple directions that a flesh and bone knee moves. Tested against a commercial knee that costs 30 times more, the LIMBS knee kept pace on 80 to 90 percent of the performance, Gonzalez said. And it conforms to ISO 10328 prosthesis strength standards, maybe the only locally-produced knee in the developing world that can make that claim.
Tested in Kenya
The knee is manufactured internationally at more than a dozen clinics in six countries. For the last six years, clinicians have distributed the knee to children at the CURE International Children’s Hospital in Kijabe, Kenya. About 8,000 children are admitted every year, and a few undergo amputations for infections and injuries from car accidents, animal attacks, falls, and war and violence. Local manufacturers produce the knee and other prostheses.
“The M1 [LIMBS] knee is easy to produce, it is affordable to our clients and has been well researched and tested. It is a low-cost, high quality knee,” the hospital’s director, Jack Muthui, wrote E4C in an email.
That first point, “easy to produce,” is the clincher, Gonzalez points out. “You don’t just need a design – the secret lies in the manufacturability of it,” he said. To improve that, Gonzalez and his team have developed a graphic, wordless instruction manual for distribution in any country.
Also, he only works alongside established enterprises that can train local technicians in the production and use of the prostheses.
A sustainable solution for Haiti
Hewing to that model, he is now working with partners in the Dominican Republic who have already begun manufacturing the knees on their own. The progress there could lead to new partnerships with Haitian clinics, as well. “The issue with Haiti is we want to ensure that we have an appropriate and sustainable response,” Gonzalez said. “Our intention is not to just go in there and hand out knees. We’re about empowering the local entities to be self-sufficient, so the people of Haiti don’t depend on us.”
To reach Haitians in need, Gonzalez and his team partnered with the Institute for Latin American Concern at Creighton University in Omaha, Nebraska. ILAC has a facility near Santiago in the Dominican Republic and connections with a web of clinics throughout the island.
“The plan is actually to teach Dominicans and Haitians how to fabricate this prosthesis,” said Dr. John Tessier, an orthopedic surgeon who works with ILAC. “They would be taught how to repair and fit these, so that ultimately the gift can keep on giving.”
Gonzalez founded the organization LIMBS International to develop the knee and other prostheses. For more information or to donate, please visit the LIMBS site.