A prosthetic implant for the body having an associated gyroscope, accelerometer and/or magnetometer as the sensor to detect changes in position of the implant. The device incorporates a miniature gyroscope, accelerometer, and/or magnetometer as a permanent part of the prosthesis for navigational information. Alternatively, the magnetometer can be external to the implant when the implant has magnetic elements associated with it. The sensors can be microelectromechanical system (MEMS) sensors placed within a drilled hole and sealed with a screw or a cap (20). The implant can be responsive to an external interrogation and powering systems. The device provides information so as to help to properly place the prosthetic implant during surgery and to assess proper functioning. The gyroscope, accelerometer, and/or magnetometer are used after implantation to provide diagnostic information in situ based upon the changed positioning or motion of the device in the prosthesis. The device can be a total joint replacement, dental implant or other type of prosthetic implant.