Lifelike prosthetic limbs

Materials World magazine
2 Jun 2017

A new surgical technique developed by researchers at the University of Michigan, USA, could allow finer-grained control of a human prosthetic leg by grafting pairs of muscles onto the amputation site, where their limbs can adjust to force, position and speed.

The grafts, which measure 4 x 1.5cm, consist of a pair of muscles that work together to mimic natural muscles. When the brain sends signals instructing a limb to move, one of the grafted muscles will contract, and its agonist will extend. The agonist muscle then sends feedback to the brain about how much the muscle moved and contracts. This allows the brain to quickly learn how much control it has to exert to move the limbs.

The study, published in Science Robotics, demonstrated in seven rats over four months that the technique generates muscle-tendon sensory feedback to the nervous system and could in future reduce the rejection rate of prosthetic limbs. The researchers will now begin human trials with results expected within the next two years.