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The device, which is under development at Binghamton University in New York, will harvest energy from friction between two surfaces to power pressure sensors.
Knee replacement surgery is the most common joint replacement procedure, the researchers said, with the number of surgeries increasing every year. Increasingly it is being done for young, active people, and many are done to replace older or worn out implants. Young patients often stay active after the surgery, but exercise can wear down new implants and require replacements after several years.
To tackle the issue, the team led by assistant professor Sherry Towfighian are working on a knee implant with built-in sensors to monitor pressure being put on it, so doctors can gain a clearer understanding of how much activity can negatively affect it.
Sensors require power, however, and batteries need charging or replacing. Instead, the implant will use an energy harvesting mechanism powered by walking. The mechanism uses triboelectric energy, with the friction of two ‘micro-surfaces’ powering the sensors as they rub against each other during movement. The circuit will reportedly require 4.6 microwatts to work, with the average person generating 6 microwatts during walking.
The smart implants will not only give feedback to doctors on optimum use, but they will also help with the development of future implants. “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,” said Towfighian.
The lead investigator said the combination of sensors and self-sufficiency could increase the lifespan of knee implants and reduce the need for follow-up surgeries. It could be “life-changing” for patients facing multiple surgeries, he said.
The research is supported by the National Institutes of Health in the US.
Content published by Professional Engineering does not necessarily reflect the views of the Institution of Mechanical Engineers.