The number of knee replacement surgeries is growing steadily each year. Tomorrow's implants will be capable of giving doctors a wealth of information. The FollowKnee implant will be custom-manufactured from each patient's MRIs using 3D printing and will be implanted by surgeons assisted by a virtual-reality system. Most importantly, the implant will be packed with temperature and pH sensors to detect any infections early on, strain gauges to alert doctors to mechanical issues, and motion sensors to help with post-operative rehabilitation.

The sensors will be developed by Leti, a CEA Tech institute, in partnership with Clinatec and several CEA research teams. The sensors and associated electronics will have to be made much, much smaller before they can be integrated into the implant during the 3D printing process, which is under development. And, of course, the sensors must not shorten the implant's lifespan. The sensors on the surface of the implant (to detect infection) will be designed to withstand exposure to the extracellular environment. A specially-developed surface treatment and coating will keep cells from colonizing the sensors, for instance. Last, but not least, the implant will have communicating capabilities and will be remotely powered by antennas designed not to be disturbed by metal or water in the environment.