Jianfeng Li1, Xia Zhao1, Xiaojie Hu1, Chunjing Tao2, Run Ji2. 1. 1 College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China. 2. 2 National Research Center for Rehabilitation Technical Aids, Beijing, China.
Abstract
INTRODUCTION: The unilateral external fixator has become a quick and easy application for fracture stabilization of the extremities; the main value for evaluation of mechanical stability of the external fixator is stiffness. The stiffness property of the external fixator affects the local biomechanical environment of fractured bone. METHODS: In this study, a theoretical model with changing Young's modulus of the callus is established by using the Castigliano's theory, investigating compression stiffness, torsional stiffness and bending stiffness of the fixator-bone system during the healing process. The effects of pin deviation angle on three stiffness methods are also investigated. In addition, finite element simulation is discussed regarding the stress distribution between the fixator and bone. RESULTS: The results reveal the three stiffness evaluation methods are similar for the fixator-bone system. Finite element simulation shows that with increased healing time, the transmission of the load between the fixator and bone are different. In addition, the finite element analyses verify the conclusions obtained from the theoretical model. CONCLUSIONS: This work helps orthopedic doctors to monitor the progression of fracture healing and determine the appropriate time for removal of a fixation device and provide important theoretical methodology.
INTRODUCTION: The unilateral external fixator has become a quick and easy application for fracture stabilization of the extremities; the main value for evaluation of mechanical stability of the external fixator is stiffness. The stiffness property of the external fixator affects the local biomechanical environment of fractured bone. METHODS: In this study, a theoretical model with changing Young's modulus of the callus is established by using the Castigliano's theory, investigating compression stiffness, torsional stiffness and bending stiffness of the fixator-bone system during the healing process. The effects of pin deviation angle on three stiffness methods are also investigated. In addition, finite element simulation is discussed regarding the stress distribution between the fixator and bone. RESULTS: The results reveal the three stiffness evaluation methods are similar for the fixator-bone system. Finite element simulation shows that with increased healing time, the transmission of the load between the fixator and bone are different. In addition, the finite element analyses verify the conclusions obtained from the theoretical model. CONCLUSIONS: This work helps orthopedic doctors to monitor the progression of fracture healing and determine the appropriate time for removal of a fixation device and provide important theoretical methodology.
Authors: P L N Fernando; Aravinda Abeygunawardane; Pci Wijesinghe; Parakrama Dharmaratne; Pujitha Silva Journal: Med Eng Phys Date: 2021-11-04 Impact factor: 2.242
Authors: Jakob G Wolynski; Milan M Ilić; Kevin M Labus; Branislav M Notaroš; Christian M Puttlitz; Kirk C McGilvray Journal: Ann Transl Med Date: 2022-05