Li Jianfeng, Zhao Xia, Hu XiaoJie, Tao Chunjing, Ji Run
Beijing University of Technology, Beijing, China.
National Research Center for Rehabilitation Technical Aids, Beijing, China.
Biomed Mater Eng. 2018;29(4):473-483. doi: 10.3233/BME-181003.
Unilateral external fixators are widely used in orthopedics to stabilize fractured bones and in the treatment of limb deformities. The main value for evaluation of mechanical stability of the external fixator is fixator stiffness. The fixator stiffness is an important factor as it will influence the biomechanical environment to which fixator and regenerating tissues are exposed.
The main objective of this work was to monitor the transmission of stress and the change of displacement generated in fixator-bone system under three loading conditions during healing process.
In this study, a finite element model with changing Young's modulus of the callus is established, finite element analysis was used to investigating stress and deformation of fixator-bone system caused by axial load, torsional load and bending load during three healing stages.
The results reveal that at different healing stages, stress distribution between the fixator and fractured bone is different, the position of displacement is mainly concentrated in the fracture site and proximal bone and with the increase of healing time, the deformation decreased.
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 useful information.
单侧外固定器在骨科中广泛用于固定骨折的骨骼以及治疗肢体畸形。评估外固定器机械稳定性的主要指标是固定器刚度。固定器刚度是一个重要因素，因为它会影响固定器和再生组织所处的生物力学环境。
本研究的主要目的是监测愈合过程中三种加载条件下外固定器-骨骼系统中应力的传递以及位移的变化。
在本研究中，建立了一个骨痂杨氏模量不断变化的有限元模型，采用有限元分析方法研究三个愈合阶段轴向载荷、扭转载荷和弯曲载荷引起的外固定器-骨骼系统的应力和变形。
结果表明，在不同愈合阶段，固定器与骨折骨之间的应力分布不同，位移位置主要集中在骨折部位和近端骨骼，并且随着愈合时间的增加，变形减小。
本研究有助于骨科医生监测骨折愈合进程，确定拆除固定装置的合适时间，并提供有用信息。
