Research on prosthetics takes its greatest strides during or just after wartime, and the past several years have sadly been no exception. Todd A. Kuiken of the Rehabilitation Institute of Chicago and his team have pioneered “targeted reinnervation,” which jacks an artificial arm into the nervous system. They transplant nerves from the shoulder of a lost arm to a patch on the chest. In trying to move the arm, the person causes chest muscles to flex, which electrodes pick up and transmit to the prosthesis. The researchers have begun to experiment with two-way connections, relaying signals from sensors on the arm to sensory nerves.

Details about the prosthetic arm by Segway inventor Dean Kamen of DEKA Research & Development Corporation are limited to a YouTube video ( Rja9eunY), but it is jaw-dropping. In a demonstration that looks like a scene from Bionic Woman, an engineer wearing a prototype arm grasps a water bottle, picks up a pen and scratches his nose. One can only hope that, unlike the Segway, it will be priced at a level affordable to all.

Every year more than 200,000 Americans tear their knee ligaments, which, as the Mafia knows, is a painful and hard-to-treat injury. Cato T. Laurencin of the University of Virginia and his team have developed polymers that serve as tissue scaffolding, promoting the growth of brand-new ligaments. In tests on rabbits’ knees, the regenerated ligament supported a third as much tension as a fresh one. To be sure, half the bunnies suffered new ruptures, but Laurencin attributed this to the difficulty of convincing them to go through physical therapy.
—George Musser