New Robotic Advances Promise Artificial Legs that Emulate Healthy Limbs

Patients who have lost their limbs face a constant struggle during day-to-day activities. Prosthetics can help with these challenges, but the robotic limbs are nowhere near as dexterous as biological ones. Now, recent advances in robotics technology may have helped. Scientists have managed to make it possible to create prosthetics that can duplicate the natural movement of human legs, allowing patients to negotiate stairs, slopes and uneven ground.

For years, researchers have worked on lower-limb prosthetics. Actually creating prosthetic legs that can manage rough terrain is extremely important since it can reduce the risk of falling. Now, the scientists have managed to develop the first robotic prosthesis with both powered knee and ankle joints. This design has now also become the first artificial leg controlled with thought via a neural interface.

So how does this prosthetic limb work? It uses lithium-ion batteries, powerful brushless electric motors with rare-Earth magnets and miniaturized sensors built into semiconductor chips. More specifically, the size and weight of these components is small enough so that they can be combined into a package comparable to that of a biological leg and they can duplicate all of its basic functions. In fact, the robotic legs have the capability of moving independently and out of sync with its user's movements.

Actually identifying the user's intent requires some connection with their brain, though. There are currently several different approaches for establishing this connection. The least invasive method, though, uses physical sensors that divine the user's intent from his or her body language. Another method uses electrodes implanted into the user's leg muscles and the most invasive method involves implanting electrodes directly into the patient's brain.

So how does this limb stack up against others? Scientists have shown that users equipped with the lower-limb prostheses with powered knee and heel joints naturally walk faster with decreased hip effort while expending less energy than when they are using passive prostheses. In addition, amputees using conventional artificial legs experience more falls linked to hospitalization than those who employ the other prostheses.

The findings and the new limb are a huge leap forward for amputees. More specifically, scientists could eventually produce a limb that could be used by patients on a regular basis. This could help reduce the risk of falling while at the same time giving patients more freedom of movement.

The findings are published in the journal Science Translational Medicine.