RWTH Aachen Explores New Approaches for Bioresorbable Implants

The Chair of Digital Additive Production (DAP) at RWTH Aachen is collaborating with partners from science and industry to develop a new concept for patient-specific, bioresorbable implants. As part of the reACT alliance, the combination of additive manufacturing, algorithmic design configuration, and innovative zinc-magnesium alloys is being researched as an alternative to conventional implants. This approach could provide new treatment options for critical bone defects in long bones over the long term.

Bone defects often result from accidents, congenital malformations, or tumor resections. Reconstruction is challenging, as traditional implants, such as titanium, can increase the risk of refractures due to stress shielding and often require follow-up surgeries for removal. The goal of this research is to develop implants that degrade in a controlled manner after healing, eliminating the need for a second surgical procedure.

A key component of the project is the design configurator, which generates an optimized implant based on patient-specific parameters, such as defect geometry and biomechanical load. The algorithm first defines the design space using segmented CT data, then incorporates adaptive lattice structures. These structures promote tissue ingrowth and enable the controlled resorption of the implant. The manufacturing process utilizes powder bed fusion laser beam (PBF-LB) technology, allowing for the precise structuring of implants.

At the same time, research is being conducted on an optimized zinc-magnesium alloy. While pure zinc has favorable resorption properties, it lacks the mechanical stability required for implants. Magnesium, on the other hand, has bone-like mechanical properties, but it degrades too rapidly in certain applications. Research findings indicate that an alloy with a magnesium content of less than one percent offers optimal properties for bone implants.

A first demonstrator has already been successfully produced. The structure was adapted to the defect size and allows for flexible variations in cell geometry and strut thickness. This approach could be extended in the future to spinal cages or jaw implants. The project is funded by the German Federal Ministry of Education and Research (BMBF) under the RUBIN program and involves partners such as Fraunhofer ILT, University Hospital Aachen, and various medical technology companies.