Biomechanical Comparison of Titanium and CFR-PEEK Intramedullary Nails Using Finite Element Analysis

This study analyzes the biomechanical performance of intramedullary nails made of titanium alloy (Ti-6Al-4V) and carbon fiber-reinforced polyetheretherketone (CFR-PEEK) for the treatment of proximal femoral fractures, with a focus on their effects under different bone density conditions representing young and osteoporotic bone. Using finite element models and analyses simulating mid-stance gait loading and incorporating muscle forces adjusted for age-related reduction, the load transfer and stress distribution were evaluated, along with the osteogenic index (OI) as a measure of biological stimulus for bone healing. Results showed that titanium nails produced lower bone stresses but caused significant proximal stress shielding, particularly in osteoporotic bone, which could impair healing. In contrast, CFR-PEEK nails exhibited higher and more uniformly distributed stresses along the femoral diaphysis and shifted the osteogenic stimulus into a range promoting more mature bone formation in both young and elderly femora. The composite material’s elastic modulus closer to bone and its orthotropic fiber arrangement contributed to these effects. The study concludes that CFR-PEEK nails offer a promising alternative to titanium by reducing stress shielding and enhancing the biomechanical environment favorable for fracture healing, especially in osteoporotic patients. Future work will include dynamic loading conditions and experimental validation to optimize implant design.