Finite Element Analysis Of Intertrochanteric Fracture With Intramedullary Fixation

Intertrochanteric fracture(ITF) is a common fracture to femur. Along with aggravation of osteoporosis and degeneration of reaction, femoral ITF occurs in a high rate among the old men, ITF shows an upward tendency recent years facing the coming aging society. For the high blood levels and physiological structure of intertrochanteric part, the treatment of ITF along with much more complications, leads to a high morbidity and mortality, decrease the quality of life of patients and their family.The object of this study is to construct an effective finite element(FE) model of femur, FE models of ITF, and FE models of intramedullary fixation system(IFS), discuss the methods of element generation for FE models, investigate the influence of element type and element size on material distribution and computational accuracy when material assignment is based on gray value of CT images. The therapeutic efficacy of fixation system can be investigated by comparing the mechanical behavior and of ITF models fixed by different IFS models.In this research, FE models of ITF and IFS are constructed based CT images, and the numerical simulations were conducted in software ABAQUS. Set the same BCs and Loads, totally fixed for the distal femur and a downward load of 1000 N for femur head, for all the models, then compare the stress and strain of all the models. Investigate the influence of IFS material on stress state.Comparing the mass and volume of materials in the model and analysis the computational results, Illustrate that the influence of element size and element type on material distribution was exist when material assigned based on the gray value of CT images, and the hexahedral element model with element size close to voxel size achieved a relatively accuracy result. According to the stress and strain of ITF models under different IFS, IFS with a short nail are more common used for ITF, and the stress level in ITF models under A-Int-d is a little higher than Int-s, ZNNCM could reduce the stress level effectively since its’ anterior arch structure.The model constructed in this research is accuracy in its geometry shape and is high quality for its element. The ITF models assembled with IFS models can be used for quantitative analysis of treatment effect to supplement the result of specimen experiment. The result of this research can be a guidance for IFS selection and design.