Despite the widespread use of bone cement in the fixation of hip and knee arthroplasties, loosening is still the main cause of revision surgeries, which account for about 10% of all arthroplasty surgeries in Germany. Conventional methods of revision are often associated with a high level of bone loss during the cement extraction process. Consequently, there is an urgent need for the development of gentler revision procedures, which would preserve the bone tissue and ensure stability of the new implant. For metallic implants, transcutaneous inductive heating has proven to be a possible alternative approach in model tests. Preliminary studies have shown that this procedure softens the bone cement, allowing the implant to be removed with considerably less mechanical stress.
Thus the goal of subproject A08 is to develop a revision method based on transcutaneous inductive heating of the implant, through which an implant can be revised, without causing bone defects.
A model for the numerical simulation of the inductive heating process is being developed and validated. This model will be used to investigate which strategies can be applied to achieve sufficient and homogeneous inductive surface heating on complex implant geometries without damaging the periprosthetic tissues. The mechanisms that reduce pull-out forces and the conditions that allow complete implant removal will also be determined. Pull-out experiments with implants or corresponding replacement models as well as first feasibility studies for a clinical and intraoperative application of the system will be conducted.
