Source: Courtesy of Sandia National Laboratories

Every year tens of thousands of Americans lose limbs to automobile accidents, diabetes and other causes. Yet although prosthetics have come a long way since they emerged three decades ago, today's artificial limbs (right) still leave a lot of room for improvement in terms of functionality and comfort. To that end, researchers from Sandia National Laboratories, the Russian nuclear weapons laboratory Chelyabinsk 70 and the Seattle Orthopedic Group are collaborating to develop the "smart" leg--a prosthetic device that, with the help of a digital control system, hopes to address those concerns.

In order to simulate a real leg's action when walking uphill, downhill or across uneven terrain, scientists plan to install a microprocessor-controlled module in the leg that will respond to signals from sensors placed along the foot and leg. This, according to Sandia's Dave Kozlowski, "will enable a more normal and efficient walking gait." Unlike the so-called passive technologies that form the basis for most prosthetics and require the amputee to expend considerable energy, the smart leg should allow proper limb motion and thus avoid draining the energy of the wearer. The team also aims to create a socket that will self-adjust to the swelling of the residual limb over the course of the day, thus avoiding the pressure sores that can result from rubbing against the prosthetic. Among the challenges that lie ahead will be developing a portable energy source suitable for amputees. But if all goes as planned, smart legs should be on the market in two years.