Influence of different trabecular bone volume fractions on crack propagation in femoral neck fractures:a finite element analysis

Du Chuanjia; Jiao Jiao; Zhou Jihe; Wang Shuai; Liu Guohui; Wang Yang; Shang Huayu; Wang Huiming; Zhang Xiaopei

doi:10.12307/2025.880

Abstract：BACKGROUND:Femoral neck fractures are among the most common and severe fractures in the elderly,with incidence rates rising sharply as age advances.At present,the injury mechanism of femoral neck fractures remains incompletely understood,specifically regarding the mechanical characterization,crack initiation,and failure mechanisms. OBJECTIVE:To analyze the effect of different trabecular bone volume fractions on femoral neck crack propagation using finite element analysis,and to provide theoretical support for in-depth analysis of the mechanical mechanism of femoral neck fracture. METHODS:CT data of the proximal femur from a healthy volunteer were imported into Mimics 19.0 for three-dimensional reconstruction,creating a model that includes both cortical and trabecular bone.This model was then imported into ABAQUS/CAE 2021,where appropriate material properties were assigned.Subsequently,a Python script for random batch deletion was utilized to generate finite element models of the proximal femur with trabecular bone volume fraction of 35％,30％,25％,and 20％.Cohesive Zone Model analysis was performed to investigate the mechanical response behaviors and damage mechanisms of femoral neck fractures under a 2 mm axial displacement load. RESULTS AND CONCLUSION:(1)Compared with the 35％ trabecular bone volume fraction model,the 20％trabecular bone volume fraction model exhibited a 10.02％ reduction in load-bearing capacity,indicating that a decrease in trabecular bone volume fraction compromises the mechanical integrity of the femoral neck and increases fracture risk.(2)The maximum ratio of shear failure elements to total failure elements exceeded 90％ in all models.Under high-speed axial impact loading,shear failure is the dominant mechanism in the formation of femoral neck fractures.(3)These findings indicate that a decrease in trabecular bone volume fraction significantly weakens the mechanical properties of the femoral neck,thereby increasing the risk of fracture.Furthermore,under high-speed axial impact loading,the mechanism of femoral neck fracture is predominantly characterized by shear failure.