A New Approach for Diagnostic Investigation of Total Hip Replacement Loosening

Abstract

Diagnosis of total hip replacement (THR) loosening using imaging often fails to provide reliable results. New implants instrumented with sensors shall conform to this challenge. Therefore, a novel concept of an in vivo sensor was tested. This simple mechano-acoustical sensor is integrated inside the total hip stem and enables detection of osseous fixation. The sensor is excited by an external coil and impinges inside the THR. The spring-back of the sensor can be detected by an extracorporeal coil, while the structure-borne sound is measured with a vibration sensor placed at the patient’s leg. Experiments of a THR with one integrated sensor showed the possibility to differentiate between well fixed and loosened implants. The presented in vivo sensor system has a promising potential to detect loosening and to analyze osseointegration.