If you’re lucky, you probably only worry about your feet when something goes wrong—if you break a toe or sprain your ankle, say. In daily life, most people don’t marvel at the natural machinery that lets them navigate icy sidewalks, step over obstacles, or go up and down stairs with nary a second thought. (I’ll resist the urge to make a Rex Ryan joke—moving right along.)
But for lower-leg amputees, including the still-growing number of soldiers injured by explosive devices in Iraq and Afghanistan, life isn’t so easy. Conventional artificial limbs are still pretty crude, and walking with a prosthetic foot tends to be painful, tiring, and limiting compared to the real thing.
Enter iWalk, the Cambridge, MA-based company that has been developing a new kind of powered prosthetic foot and ankle for the past five years. Earlier this month, the startup confirmed it had raised a $15 million Series C venture round from new investor Sigma Partners and existing investors General Catalyst and WFD Ventures. (The company declined to comment on how much total investment it has taken, except to say the figure is much less than the “nearly $40 million” reported by the Boston Globe, which broke the news about the latest round.)
The cash infusion marks an important transition for the company, from doing mostly research and clinical testing to building out its technical platform and ramping up product development. “Turning theory into a functional and durable device is a real challenge,” says Tim McCarthy, iWalk’s chief executive. “What our investors see in the technology is the fact that we’ve been able to bridge that gap.”
McCarthy (see photo below) joined iWalk as CEO in December 2009, so he’s been on the job for just over a year. He previously spent seven years as vice president of sales and marketing at Ossur Americas, an orthopedics and prosthetics firm. His leadership seems to be paying off, as iWalk delivered its first five commercial “PowerFoot BiOM” units to the Walter Reed Army Medical Center earlier this month. The prosthetic foot and ankle uses robotics technology (sensors, algorithms, and a spring-like actuator) to help propel an amputee forward while automatically adapting to different types of terrain and walking speeds.
iWalk was founded in 2006 by MIT Media Lab professor Hugh Herr, who is a double amputee (both legs below the knees) from a mountain climbing accident when he was 17. Herr serves as chief scientific officer at the firm and previously worked with McCarthy on a prosthetic knee when the latter was at Ossur. [Disclosure: Herr was my postdoctoral research supervisor at the MIT Artificial Intelligence Lab from 2000-2002; you can read about some of our work on animal locomotion here.]
Knowing Herr’s scientific interests, I can tell that iWalk, which has 20-plus employees, has plans far beyond prosthetic feet. In fact, the company wants to apply its
