Bionic gradient porous titanium rods enhance mechanics, osteogenesis, and osseointegration for load-bearing bone defect repair

Abstract In treating load-bearing bone defects in the lower limbs, implants are required to provide both robust osteogenic potential and adequate mechanical strength. Two types of porous titanium alloy rods are developed in this study, employing triply periodic minimal surfaces (TPMS) as the design basis. While a regular porosity rod (Re-rod) maintains a uniform 80% porosity, a bionic gradient-porosity rod (Bi-rod), with porosity ranging from 30% to 80%, aims to mimic bone microarchitecture. The results show that the Bi-rod has better mechanical properties and more closely replicates the mechanical environment of load-bearing bone defects. in vivo experiments in rabbits demonstrate that Bi-rod enhance osteogenic activity and osseointegration compared to Re-rod, providing a reference for optimising bone-implant designs.