Devices, systems and methods for monitoring knee replacements

A monitoring system comprising:

• a tibial plate configured to be secured to a tibia of a patient at least in part by bone cement between the tibial plate and the tibia, the tibial plate having a first contact sensor;
• a tibial liner having a second contact sensor paired with the first contact sensor of the tibial plate during surgical placement, which pairing is indicative of an accurate fitting of the tibial liner with the tibial plate, and a plurality of additional sensors, each at a different depth relative to an articular surface of the tibial liner, and each configured to activate upon exposure at the articular surface of the tibial liner;
• at least one additional sensor in or on the bone cement and configured to provide one of a measure of contact or a measure of pressure indicative of contact between the tibial plate and the tibia;
• an accelerometer and a motion sensor positioned within the tibial plate, where the accelerometer is an acceleration sensor that measures acceleration and the motion sensor is a rotation sensor that measures rotation;
• an electronic processor positioned within the tibial plate, where the electronic processor is electrically coupled to the acceleration sensor and to the rotation sensor;
• a memory chip positioned within the tibial plate, where the memory chip is coupled to the electronic processor and is configured to store the measures of acceleration from the acceleration sensor and the measures of rotation from the rotation sensor;
• an antenna configured to transmit the measures of acceleration and rotation from the memory chip to a location outside of the tibial plate;
• and
• an interrogation module configured to communicate with one or more of:
• the accelerometer to obtain measures of acceleration,
• the motion sensor to obtain measures of rotation,
• the first contact sensor of the tibial plate and the second contact sensor of the tibial liner to monitor changes in the accurate fitting,
• the plurality of additional sensors of the tibial liner to detect wear in the tibial liner, and
• the at least one additional sensor in or on the bone cement to monitor contact between the tibial plate and the tibia.