Bionic Legs, i-Limbs, and Other Super Human Prostheses You'll Envy

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MIT professor Hugh Herr, 45, who lost his legs in a mountain-climbing accident, says 70% of amputees have hip and back problems. One reason: When walking, there is no "lift" or "push" forward from the prosthetic foot, which leads to a violent, uncushioned impact on the forward foot. For the able-bodied, that lift is "like the hand of God," he says. So Herr invented powered iWalk ankles (shown) that use hydraulics, pulleys, and batteries that can provide a 400-watt boost out of each step. "I don't walk my legs. My legs walk me." | Photograph by Jesse Frohman

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"Last year," says Carrie Davis, "I went down to a clinic and met this lady who saw what I could do with my arm, and she said, 'I want one like that.' She wanted to knit." Davis was born with one forearm missing and has 12 dif-ferent hands, or "terminal devices," each designed for different tasks. Her favorite: the carbon-fiber-sheathed bionic hand (shown) from Touch Bionics. "I get a lot of attention walking into a room with i-Limb. I love it. It's bad-ass looking." The limb uses a battery and a force-sensitive resistor to respond to her muscle contractions and impulses. | Photograph by Jesse Frohman

There are many advantages to having your leg amputated.

Pedicure costs drop 50% overnight. A pair of socks lasts twice as long. But Hugh Herr, the director of the Biomechatronics Group at the MIT Media Lab, goes a step further. "It's actually unfair," Herr says about amputees' advantages over the able-bodied. "As tech advancements in prosthetics come along, amputees can exploit those improvements. They can get upgrades. A person with a natural body can't." Herr lost both his legs below the knee in a Mount Washington climbing accident when he was 17, but says that shouldn't inspire pity. Instead, by donning whirring, whispering, shiny supermachines -- the robotic ankles that can propel him across the room in 400-watt bursts -- Herr has been given: Power. Allure. The strange animal magnetism of the very bad boy.

"When the prosthetic technology doesn't work," Herr says, "and the [amputee] is limping and he can't run and he's hurting, then nobody feels threatened, because that person is labeled as 'cute' and 'courageous.' " He leans forward in his office and crosses his aluminum shins with an audible clink. "But when the technology works, when it can make you stronger or faster than you were, it overnight becomes sexy and powerful and threatening. Overnight."

Anybody who hears "prosthetic" and thinks "peg leg" might wonder about Herr's sunny hubris. The thought that an artificial limb could make anybody stronger or faster, or confer social advantage, is an opinion ripe for skepticism. Wearing one is inconvenient at best. It often hurts. It can break. It is obvious proof of loss. It seems by its very nature to announce a lack of health or vitality.

Yet much of the dissonance in Herr's "prosthetics as progress" thesis stems from the undeniable fact that for years, prostheses were irredeemably ugly, off-putting, scary. Who would call a disembodied limb a "design object" to be lusted after, like an Audi or an iPhone? Who would consider herself better, or more beautiful, than a person without one?

"When I first got this job," says Stuart Mead, CEO of Touch Bionics, a prosthetics and robotics firm based in Scotland, "it struck me how depressing it all was. Prosthetics were at the back of the hospital, the downstairs office, the back room. The look of most of these devices was horrible -- half-human, half-plastic. This frightening pink color."

Just wearing one could induce shame: The Barbie doll cosmesis (a cosmetic cover), tipped with a hook, acted like social repellent, pushing the user and the observer apart. "It was like having a scarlet letter," says Marshall Young, an industrial designer for Otto Bock HealthCare, of the old-style prosthetic limbs. "It was, 'I've got this damn thing and now my life sucks.' "

All that is about to change -- not only because prostheses are being built with materials found in sports cars and jet airplanes; or because designers are giving their creations an exuberant, unapologetic carbon-fiber sparkle; or even because nerve reintegration and myoelectrics are offering some amputees the joy of normal function. The biggest reason for amputees' unlikely rise into a new, socially advantaged class comes from something much more mundane: profit. The prosthetics business is set to explode, and its products will make amputees stronger, faster, and, to some, more desirable than the rest of us.

In the meantime, Herr says, you can dispense with the Tiny Tim pity and the warm fuzzy feeling you get when a little girl struggles to her feet on poorly designed stilts. Because the new machines -- and they are machines -- are becoming so lustrous and so efficient that some people are already willing to chop off a perfectly good limb to get one.

The $2.8 billion orthotics and prosthetics business revolves around a few major players: the German manufacturing company Otto Bock HealthCare; Iceland-based össur; Fillauer in Chattanooga, Tennessee; Ohio Willow Wood in Mount Sterling, Ohio; and patient-services provider Hanger Orthopedic in Bethesda, Maryland. There are also smaller manufacturers that supply components such as motors and microchips.

The industry receives regular media attention for its work with returning American soldiers, but those soldiers represent less than 0.1% of the 1.7 million amputees in the United States. Unfortunately, that customer base is about to get much larger. The Centers for Disease Control and Prevention has predicted that 29 million Americans will be diagnosed with diabetes by 2050 -- increasing their chances of having a lower extremity amputated by a factor of 28. Hanger Orthopedic's CEO, Tom Kirk, points to diabetes and vascular disorders, largely driven by a 37% increase in obesity between 1998 and 2006, as the reason for most amputations. According to the CDC, diabetes-related amputations have risen to as many as 84,000 in a single 12-month period.