Intelligent remote monitoring of knee implants
The aim of the project is to develop a magnetic-based sensing technology that can monitor contact stress in knee implants using a non-contact methodology.
This project is advertised as part of the EPSRC Doctoral Training Partnership. It is currently not available to self-funded applicants. Find out more information about the DTP including how to apply.
The number of total knee replacement (TKR) surgeries worldwide is increasing each year. In 2014, the National Health Service in England and Wales recorded 70,000 total knee replacement procedures. Unfortunately, existing knee implants have limited lifespans due to excessive wear. Early detection of high wear rates, through monitoring of mechanical stress levels, can ensure the implementation of preventative measures to reduce the chances of premature implant failure. This PhD project will use magnetic sensing principles to monitor the degradation of knee implants through measurement of mechanical stress. This is based on embedding a magnetostrictive material (where stress is coupled to the magnetic properties) into the polyethylene component of the implant. Stress can be measured by detecting changes in magnetic permeability using a pick-up coil. The key advantage here is that the measurement requires no contact and in principle maybe incorporated into a wearable knee brace for monitoring stress levels in the implant. A correlation of coil impedance with changing contact pressure within a model implant has demonstrated the proof of principle as evidenced by the supervisor’s recent publications. The PhD student will further develop this methodology and incorporate it into a real knee implant (in vitro). To simulate knee forces, a mechanical test rig will be constructed and used to evaluate the performance of the monitoring system using a real implant. By the end of the project, the student will have demonstrated a working prototype system that could be adapted for use in future clinical studies.