New Prosthetic Leg Lets People With A Limb Amputated Feel Their Foot And Knee Again

In the last few years, researchers have been working to give prosthesis wearers and robots a sense of touch; however, most of the effort is focused on the hands. Recently, experts at ETH Zurich have found a way to allow leg amputees feel sensory feedbacks again.

Their research can be found in Nature Medicine, and it details the team’s modification effort to a regular prosthetic leg by giving it electrodes and sensors. What they aim at is to provide the amputee the sense of the sole of the foot as well as knee movements. While they have just tested on two users, the results seem promising.

The researchers have two patients, both with transfemoral or above the knee amputations, participated in the test. What they used was Össur prosthetic leg, which comes equipped with an angle sensor located in the knee joint and a microprocessor.

To the leg, they added seven sensors and an insole, which are capable of real-time signal transmitting. There is a controller at the users’ angle and the transmission process happens via Bluetooth.

The controller’s algorithm then turns the feedback into neural signals, which will be sent to an implant in the tibial nerve of the patient. With this system, the patient’s brain can perceive these signals as foot and knee’s feedback.

The new prosthetic leg can increase the speed at which the users walks. The amount of oxygen needed is also lower, an indication of a less strenuous experience for the patient.

The researchers also tested the possibility of reducing phantom limb pain. The two patients experienced less pain after the electrical stimulation started for a few minutes. However, this kind of treatment is only available at the lab.

The team hopes that future development may bring this technology to more amputees.