Effect of the Design Constraints and the Loading Model on the Geometry of Topology Optimized Acetabular Cages

The treatment of large acetabular bone defects is a challenging task for the clinical experts. One of the most important part is the selection or the design the most appropriate implant. The aim of the study is to explore the potential of topology optimization for the treatment of extensive pelvic bone defects. Using a finite element method, the authors investigate different design spaces and load cases. Sensitivity tests for the material characteristic of the bone and the constraint of the applied volume-fraction were performed. The results are topology-optimized acetabular cage concepts with similar designs. The conceptual designs are not sensitive to the changing of the elastic modulus of the bone and the volume-fraction constraint. The reason for the similarity between the designs is the close connections, they have a special role in maximizing the stiffness. With the use of our design space, a lot of bone grafts can be put behind the cage and it can give an idea for sheet metal conceptual designs. Due to the close connections, similar conceptual variants are generated under normal walking load, which can be used for faster calculations in similar cases.