Triply periodic minimal surface scaffolds for large bone defects: mechanical characterisation and bone regeneration potential

Large bone defects remain a major clinical challenge, as current treatments often fail to provide sufficient mechanical stability and regenerative support. This study presents a comprehensive evaluation of Triply Periodic Minimal Surface (TPMS) architectures for scaffolds designed to support bone regeneration in large bone defects. Experimental compression tests and finite element simulations revealed that increasing scaffold porosity reduced elastic modulus and compressive strength, with TPMS architectures exhibiting marked differences: the IWP structure demonstrated superior mechanical performance, while the Primitive exhibited the lowest values. Complementary computational fluid dynamics simulations confirmed that all scaffold designs provided permeability within the physiological range required for bone regeneration. A mechano-driven bone regeneration model further identified the IWP scaffold at 70 % porosity as the optimal design, achieving a balance between mechanical integrity and biological performance. In addition, different fixation systems were analysed, showing that screw arrangement and the inclusion of intramedullary nails or external plates significantly altered stress distribution, cell migration and bone density. These findings underscore the combined importance of scaffold architecture and fixation strategy, and highlight the role of computational modelling in scaffold optimisation. The proposed framework supports the development of patient-specific strategies for enhanced bone regeneration.