Building a Better Limb
Veterans are inspiring a big push to create thought-controlled prosthetics
James Stuck thinks his newest right foot is "pretty cool"; it can sense when he's headed downstairs or climbing up a slope and angle itself accordingly. A great choice for hiking. But when the 22-year-old Army specialist from New Kensington, Pa., wants to play soccer, this foot's "not quick enough to keep up." For that, he pulls on one of the five others in his arsenal. They're not "smart" like his new foot, but each has a strength, be it springiness or lightness. He chooses depending on what he plans to do: run, snowboard, play basketball, climb a tree.
Stuck lost his right leg below the knee last December, when his armored humvee hit an explosive device near Kirkuk, Iraq. At that moment, he joined a group of wounded soldiers unique in the history of battlefield medicine. Improved body armor and speedy emergency care have reduced the death rate among Americans wounded in Afghanistan and Iraq to a historic low, but the amputation rate is up by 100 percent. The result: an unprecedented wave of research on prosthetics, aimed at bringing a primitive technology into the 21st century.
A market. Until Iraq, companies had little incentive to develop high-performance prosthetics, since most of the country's approximately 1 million people missing a limb are older and often frail victims of diabetes or vascular disease. But Stuck and his comrades are young, athletic, and impatient--and have no intention of quietly retiring on disability. "Our soldiers have really inspired the research community to apply the science to help," says Lt. Col. Paul Pasquina, medical director of the amputee program at Walter Reed Army Medical Center in Washington, D.C. Much of the new research is being funded by the Defense Department--including a $48.5 million program that aims to build a "thought controlled" arm by 2009 that's as strong and agile as Luke Skywalker's in Star Wars.
Stuck is doing his bit to advance prosthetic science. In late June, he became one of two patients at Walter Reed to test the new Proprio foot, a 2.5-pound, motor-powered appendage with sensors that detect terrain changes and "artificial intelligence" that realizes the person is going upstairs, say, and bends the ankle accordingly. Other prosthetics have a fixed ankle, making stair-climbing "like walking uphill in a rigid cast," says Ian Fothergill, prosthetist at Ossur, which created the foot. The Proprio follows the hugely popular Otto Bock C-Leg, featured in Doonesbury, which was the first device to use microprocessors to control the leg's swing, thus making walking less tiring. Last year, Ossur introduced the Rheo Knee, a prosthetic that uses artificial intelligence to remember and adapt to the user's tendencies. And the company is about to unveil the motorized Power Knee, which bends and lifts as if controlled by a well-toned quad muscle. These computer-driven prostheses react too slowly for running but complement innovations such as the Flex-Foot, a spatula-shaped piece of carbon fiber that's light and springy and has some Walter Reed patients running within months of being injured.
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