Numerical Simulation Of Bone Remodeling Influence Caused By Low Loads Under The Electrical Stimulations

Bone can change the structure of tissue to adapt to changes in external loads by remodeling.When the external load increases,the bone tissue will be stronger;when the external load decreases,the bone tissue will be weaker.Bone remodeling is a hot topic and frontier in the field of bone mechanics,and there are many studies on the interaction mechanism between bone remodeling and external force loading.Bone remodeling is a complex biological process controlled by many factors.In addition to mechanical factors,electromagnetic stimulation also plays an important role in bone remodeling.With the application of computer technology in the field of biomechanics,the study of bone remodeling behavior through numerical simulation plays an increasingly important role in bone mass prediction,prosthesis evaluation and postoperative rehabilitation training.This paper is based on the bone remodeling model proposed by Hazelwood et al.,in which cancellous and cortical bone structures are considered simultaneously,and the coupling effects of electric field and mechanical stimulation on bone remodeling process are considered.In this paper,the CT value is established as a function relationship with density,and material parameters such as different densities and elastic moduli of elements in the model are given by CT value.Using ANSYS parametric design language(APDL)to write iterative program to simulate the whole process of disuse.In this paper,the density loss of the proximal femur at a low-load stimulation frequency and the active resistance process of electrical stimulation are simulated by using the above-mentioned finite element analysis method,and various parameters of the disuse model are discussed.The simulation results show that low load stimulation frequency will lead to a certain degree of density loss,and the greater the reduction of load frequency,the more serious the density loss.There is a three-stage process of bone density loss.In the early stage of remodeling,the bone density loss rate is low because the effect of disuse stimulus is less accumulated;with the gradual accumulation of disuse stimulation,the density loss rate gradually increased until the maximum value;as osteoblasts in bone remodeling began to fill bone tissue,the rate of change in density began to decrease gradually and finally remained at a constant value.Electrical stimulation can resist disuse to some extent by affecting the expression of osteoblasts and osteoclasts.Finally,in this paper,CT data and Boolean operation were used to construct the proximal femoral model after hip arthroplasty,and the material parameters close to the real situation were given to the bone model and implant,the bone remodeling process under three representative working conditions was simulated.Density loss due to stress shielding after hip arthroplasty and the effect of electric field on its resistance were discussed.The results show that electrical stimulation placed in the neck of the femur can effectively slow down this tendency.The model proposed in this paper can not only analyze the dynamic evolution process of bone remodeling under disuse,but also can be used for postoperative density prediction and evaluation of hip replacement,which provides some help and reference for describing physiological phenomena through mathematical methods in clinical practice.