Tissue-integrated bionic knee prosthesis restores natural leg function

A new bionic prosthesis that directly links to the body’s muscles and nerves enables above-knee amputees to move with greater agility, precision, and sensory awareness than traditional devices, researchers report. Prosthetic limbs are widely used to help restore mobility for individuals living with limb amputations. However, their design and use have remained largely unchanged for more than a century. While modern prostheses can be tailored to an individual's needs, they still fall short in enabling a dynamic range of movement and in providing users with sensory feedback. Advancements in traditional lower-limb prostheses have focused on mechanical enhancements that improve repetitive walking, overlooking the full range and complexity of natural leg movement, especially when there is a need to change gait or balance. As a result, amputees often struggle with tasks like navigating uneven terrain or climbing stairs. Here, Tony Shu et al. present a tissue-integrated prosthetic knee that uses implanted neural interfaces to directly connect the device to the body’s physiology. According to Shu et al., the system – called the osseointegrated mechanoneural prosthesis (OMP) – combines three core innovations: direct neuromuscular control that allows fluid and adaptive movement; (2) a bone-anchored implant; and (3) agonist-antagonist myoneural interfaces (AMI) that replicate natural muscle interactions to reestablish a sense of limb position and movement. Clinical trials involved 2 above-knee amputees.  For each, the OMP system enabled superior mobility across diverse, real-world leg movements, such as terrain navigation and sit-to-stand transitions. While some limitations remain, Shu et al. suggest that greater prosthetic embodiment and function can be achieved through biologically integrated systems like the OMP, potentially yielding transformative gains in rehabilitation, mobility, and user experience following limb loss. In a related Perspective, Lee Fisher discusses the study in greater detail.