Impedance-Based Structural Health Monitoring of Total Knee Arthroplasty

  • Robert Ponder
  • Mohsen Safaei


Total Knee Replacement (TKR) is a medical procedure with high prevalence within the United States. In spite of advanced medical techniques, almost 20% of TKR patients are dissatisfied with their outcomes. This dissatisfaction can result from a number of causes including mechanical failure of the implant. A variety of in vivo techniques have been proposed and implemented to detect and quantify issues such as loosening in TKR. These techniques have largely focused on detecting the intra-joint forces between the tibia and femoral implant components. An alternative to measuring compartmental forces in TKR is to perform active Structural Health Monitoring (SHM) to sense the conditions of the knee implant and its surrounding structures. One form of SHM, which has previously seen little implementation in the biomedical world, utilizes the electromechanical coupling of piezoelectric transducers, called the Electro-Mechanical Impedance Method (EMI). In this work, validation of the EMI method with orthopedic structures is investigated. Validity is determined by testing the effectiveness of the EMI method in materials present in a simulated cemented orthopedic implant system. Various damage conditions are introduced to the system to investigate measurement sensitivity. The final objective of this study is to provide a foundation for research and innovation in the world of orthopedic medicine.