Smart knee implants designed to monitor changes in activity as they happen may soon be a reality, thanks to research conducted by a team including faculty at Binghamton University, State University of New York.

“We are working on a knee implant that has built-in sensors that can monitor how much pressure is being put on the implant so doctors can have a clearer understanding of how much activity is negatively affecting the implant,” says Sherry Towfighian from Binghamton University.

She is the lead principal investigator on the study, published in Smart Materials and Structures, which has been supported by the National Institutes of Health (NIH).

The sensors allow doctors to tell patients when a certain movement has become too much for the implant so patients can quickly adjust and avoid further damage to the implant. It also helps them find the sweet spot of activity for each particular patient, according to a media release from Binghamton University.

The researchers did not want to power the sensors with a battery that might need to be replaced periodically and therefore, defeat the purpose of a smart implant. Instead, they worked on an energy harvesting mechanism that can power the knee implant from motion.

Wathiq Ibrahim, a postdoc in Towfighian’s group, developed a prototype of the energy harvester and tested that under a mechanical testing machine to examine its output under equivalent body loads.

Triboelectric energy, a type of energy that is collected from friction, was used. Once someone walks, the friction of the micro-surfaces coming into contact with one another can be used to power the load sensors.

Associate Professor Emre Salman from Stony Brook University designed the circuit and determined that it would need 4.6 microwatts. The preliminary testing showed the average person’s walk will produce six microwatts of power, which they note is more than enough to power the sensors.

This part of the research was complemented by Assistant Professor Ryan Willing from the University of Western Ontario, who worked on the implant design and the package of the sensor, the release continues.

These smart implants could not only give feedback to doctors but could help researchers in the development of future implants, the researchers note.

“The sensors will tell us more about the demands that are placed on implants, and with that knowledge, researchers can start to improve the implants even more,” Towfighian adds.

Towfighian is hopeful that the combination of activity sensors and a self-powered system will increase the life span of knee implants and reduce the need for follow-up surgeries, according to the release.

[Source(s): Binghamton University, Science Daily]