An electromechanical generator implanted in human total knee prosthesis

This paper describes an electromechanical generator, implantable in a human Total Knee Prosthesis (TKP), in which the mechanical energy, related to the movement of the knee joint, is converted in electric energy. This device has been designed with the aim of (1) powering an autonomous sensor system integrated in the knee prosthesis, (2) monitoring the loads on the articular surfaces and (3) transmitting the data outside the body. This activity is motivated by the necessity to replace the batteries, which require periodical substitution, with a power harvesting system exploiting the mechanical energy naturally available during day activities. The supplying energy can monitor the working condition of a prosthesis also to support the rehabilitation therapy of the patient and to reduce the radiographic examinations.