Total knee arthroplasties can be very effective at restoring comfortable, pain-free walking in many patients. One of the downsides of such procedures is that the implants that are used tend to wear out over time, particularly when exposed to too much use.
While there are sensors able to provide information about the status of a knee implant, they can’t last for very long if they rely on a built-in battery. A collaborative group of scientists at Binghamton University, Stony Brook University, and the University of Western Ontario is developing a self-powered knee implant sensor that relies on friction to generate its own electricity.
The team is relying on the triboelectric effect, which involves a material becoming electrically charged when another material rubs against it. They have actually built their own knee sensor, which uses only 4.6 microwatts of electricity, and the new generator that was developed can consistently produce more than that for an average adult patient.
It is believed that since knee implants are prone to failure over time, monitoring their usage and performance can help patients to control their physical activities and the designers of implants to improve their longevity.