Targeted melting or melting of bone cement through local heating for tissue-friendly explantation of knee prostheses

• Applicants: Dr.-Ing. Sven Hübner; Professor Dr.-Ing. Hans Jürgen Maier; Professor Dr. Henning Windhagen
• Subject Area: Biomaterials ; Medical Physics, Biomedical Technology ; Orthopaedics, Traumatology, Reconstructive Surgery ; Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566031639

The aim of the project is to develop a fundamental understanding of the processes at the metal/PMMA interface in order to later be able to develop a reliable routine for the tissue-sparing explantation of cemented knee prostheses as part of revision surgery. As much as possible of the bone will be preserved by employing a novel method for the targeted softening or melting of bone cement by locally heating the prosthesis. The low thermal conductivity of the bone cement leads to melting and loss of contact in the interface without high heat transfer to the surrounding tissue. The feasibility was demonstrated through preliminary tests on a simple surrogate model. To more intense loosen the bond between implant and bone cement cyclic tensile stresses will be applied on the implant during heating. This should act at the interface between the implant and bone cement and promote crack growth there, which should further reduce the pull-out forces. First, basic analyses of the materials and the explantation behavior of protheses from artificial bones are carried out. For this purpose, suitable temperature-time regimes will be developed that will make it possible to represent different circumstances like room temperature and cooling by rinsing. Subsequently, the results will be transferred to the explantation from human bones. It will also be analyzed, which temperature-time profiles the bone tissue can endure without damage and how high the actual material loss during explantation with the new approach will be.

• DFG Programme: Research Grants