Self-powered implants for injured knees

Fauzan Baharudin explored the potential for the use of thick-film technology in the development of medical sensors, which could be embedded in the knee during surgery, as part of his final year project in his Masters degree in Electromechanical Engineering which he studied at the University's School of Electronics and Computer Science (ECS).

The sensor, called Serial In-vivo Transducer (SIT), uses thick-film technology and could measure tendon force during anterior cruciate ligament (ACL) reconstruction, the most commonly injured ligament in the knee.

Fauzan’s project was supervised by Prof Neil White at ECS, who, in 1991, developed thick-film piezoelectric material which made it possible to produce a sensor that could power itself if it were installed in a device that vibrates and would be suitable for appliances where physical connections to the outside world were difficult.

“Although this work is still in its infancy, our earlier research in thick-film sensors has shown that it is feasible to apply the technology to medical applications such as prosthetic hands,” White said.

“We have also shown that it is possible to harvest energy from the human body using piezoelectric materials and the knee is subjected to very high levels of force during everyday activities.

“It therefore seems logical to combine the two approaches to deliver a new type of embedded, self-powered sensor,” he said.

In Fauzan’s project, entitled ‘Assessing the use of thick-film technology in knee surgery: along with energy harvesting in-vivo’, he has also incorporated this energy harvesting capability into SIT, which means that it will be self-powered.

Before developing SIT, Fauzan reviewed the existing devices and concluded that due to its flexibility in fabrication, low capital cost, fast lead time and its suitability for use in the body, thick-film technology is the best solution for ACL surgery.

Assessment of the energy harvesting feature revealed that the device could produce more than enough energy to power itself.