#bionic leg

one of my favourite fic writers wrote about connecting prosthetics to peoples bones over ayear ago.

MIT Engineer Builds Bionic Leg That Feels Sensation

Bionic Leg

Olafsson can move his right ankle by thinking about it. When the electrical impulse from his brain reaches the base of his leg, a pair of sensors embedded in his muscle tissue connect the neural dots, and wirelessly transmit that signal to the Proprio Foot. Since the command reaches the foot before the wearer's residual muscles actually contract, there's no unnatural lag between intention and action. That makes Olafsson part of a highly exclusive club. Along with David Ingvasson, a fellow Ossur tester, he's one of the only people on the planet who owns a brain-controlled bionic limb. Ossur unveiled its implanted myoelectric sensor (IMES) technology today at an event in Copenhagen, and is now preparing large-scale clinical trials, in the hopes of reaching the market in three to five years. And the surgery to implant the sensors was minimal. According to Thorvaldur Ingvarsson, an orthopedic surgeon and head of R&D at Ossur, the procedure took 15 minutes, and each sensor required a single-centimeter-long incision. The tiny sensors (3 millimeters-by-80 millimeters) are powered by magnetic coils embedded in the socket -- the cushioned, hollow component that fits over a user's residual limb, and connects to the prosthesis. Since there are no integrated batteries to deal with, there's no need to replace the sensors (unless they fail for other reasons). “We believe this is a lifelong sensor,” says Ingvarsson. Another thing that differentiates this mind-controlled prosthesis is its simplicity. The sensors, which were provided to Ossur by the Alfred Mann Foundation, don't have to be attached to specific nerves. That also means that tissue doesn't have to be harvested from other, more nerve-dense parts of the subject's body. The prosthesis moves based on which sensor—the front or rear—picks up an impulse in local muscle tissue. If Olafsson moves his calf muscles, the robotic foot follows suit. “It's really surreal,” he says. “The first time, to be honest, I started to cry. You are moving the ankle, and I basically haven't had one in 11 years.” But the biggest benefit he's seen is a surprising one. “You have to learn how to use those muscles again,” says Olafsson. “How to tighten them up, in front and back. And that's the main thing. Those muscles start getting bigger, so you get better at walking. I have more stamina. My gait is better. I don't limp as much.” By forcing the wearer to actively use muscles that were previously ignored, sensor-connected limbs could halt or reverse their deterioration. It's a reminder that, despite the urge among the able-bodied to obsess over cybernetic enhancements, bionic limbs are chiefly medical devices for now, designed to restore function. That a brain-controlled bionic leg would also promote muscle growth is stranger, and more exciting, than all of the superpowered cyborgs that science fiction has to offer.