Has it really been four years since we featured smart sockets in Amplitude? Time flies. Way back in our Nov/Dec 2021 issue, we declared: “’The world’s first socket liner that uses AI to adapt and change with the wearer’s residual limb is already making a splash—and it hasn’t even launched yet.”
That device, Roliner, still hasn’t launched—but it’s on the verge. Developed by the startup Unhindr and the Imperial College of London’s engineering school, the product is expected to reach consumers in the UK by the end of this year. And as a recent study in the prestigious journal Nature Communications shows, Roliner could vastly reduce the blisters, sores, rashes, damaged nerves, and other pains that amputees incur from ill-fitting sockets.
A quick refresher: Roliner is a silicone liner that constantly monitors the size and shape of the residual limb. As your limb expands or contracts throughout the day because of weather, activity, food intake, or any other reason, Roliner detects the changes in real time and automatically adjusts to maintain a consistent fit. These adjustments occur via tiny fluid channels embedded within the liner, which empty or fill as needed. A user-controlled interface allows wearers to modify the fit to suit their own comfort, and an AI feature tracks your patterns and preferences over time.
The paper in Nature Communications reports the team’s findings from preclinical human trials. In addition to gathering subjective, user-reported data regarding comfort, the team took objective functional measurements via motion-capture technology and gait analysis. “Roliner was shown to improve various aspects of gait in a number of objective metrics,” the researchers found, while “not imped[ing] the natural gait of the participants in comparison to their usual clinically prescribed liner.” The study also recorded statistically significant improvement in all four relevant domains of user experience: prosthetic utility, ambulation, frustration, and residual limb health. “All participants found Roliner to be more effective as a liner….and their experience to be less frustrating compared to their everyday liner,” the paper notes.
The most profound improvement occurred for a participant who had lost more than 40 pounds since his last socket fitting and “consistently experienced poor fitting everyday with his prosthetic socket. The gap between his residual limb and the socket was on the order of 1.5 cm, and the subject manually filled this gap by wearing additional layers of ply socks to walk. Once the subject wore Roliner, the fitting problem was immediately solved. When actuated, the subject could comfortably move around with confidence within seconds. In fact, Roliner rendered an otherwise unusable prosthetic socket usable, thus extending the usable lifetime of the socket.”
Roliner still has a few regulatory hurdles to clear in the UK, but the research team projects it will be commercially available in the UK before the end of this year. That would make it the first device in this class to reach consumers. A different type of smart socket, under development at the University of Washington, has also performed well in preliminary trials; it will vie with Roliner to reach the US marketplace first.
