Bionic leg restores natural walking speeds and steps: ‘I didn't feel like my leg had been amputated'

Amy Pietrafitta has learned to walk seven times. First as a child and then after an industrial burn led to the amputation of her left leg in 2018. Since then, she’s had ‘first steps’ in prosthetic legs for running, water, high heels, rowing, and everyday walking. Her latest ‘first steps’ were different – she was fitted with a bionic leg that was fully connected to her brain, allowing her to walk and move like anyone else. Pietrafitta was part of a study of a new neuroprosthesis that’s fully controlled by the nervous system. The study indicated that participants who had the specialized amputation and neuroprosthesis increased their walking speed 41%, matching the ranges and abilities of people without leg amputations. The results also suggested that the bionic limb could be controlled using just 18% of natural proprioception. This is the first bionic leg fully controlled by the human nervous system to demonstrate natural walking speeds and gait patterns. The technology also allows users to switch between speeds without changing prosthetics. An estimated 1.9 million Americans live with limb loss, a figure expected to double by 2050, largely due to increasing rates of diabetes. The team aims to make fully neuro-controlled prosthetics commercially available within five years.