Devices, systems and methods for using and monitoring medical devices

A knee prosthesis comprising:

• a tibial implant comprising a tibial plate, the tibial plate comprising a stem, the stem comprising an inner canal, where an implantable sensing device is located within the inner canal of the stem, the sensing device comprising:
• a. a sensor channel comprising a sensor and a sensor interface, where the sensor is selected and configured to sense a physical quantity of a subject into which the prosthesis has been implanted, where the sensor interface comprises an oscillator configured to generate a clock signal;
• and where the sensor interface is configured to generate a digitized signal that represents a magnitude of the sensed physical quantity,
• b. a sensor-module controller coupled to the sensor channel, the sensor-module controller comprising a non-volatile memory and a microcontroller, where the microcontroller is configured to i) generate sensor data from the digitized signal, where the sensor data comprises a data stamp and a time stamp that are both associated with the digitized sensor signal, and ii) provide the sensor data to the non-volatile memory for storage;
• c. a communication interface comprising a wireless interface and an antenna, where the wireless interface is i) coupled to the sensor-module controller and the antenna, and ii) is configured to modulate one or more carrier signals with the sensor data from the sensor module-controller in order to generate a transmission signal that is transmitted to a remote receiver;
• and
• d. a single implantable housing, wherein the sensor channel, the sensor-module controller and the wireless interface are disposed within the implantable housing, wherein the implantable housing is located at least partially within the inner canal of the stem.