Department of Infrastructure Engineering, The University of Melbourne, Parkville, Victoria, Australia.
Centre for Limb Lengthening & Reconstruction, Epworth Hospital Richmond, Richmond, Victoria, Australia.
Int J Numer Method Biomed Eng. 2021 Jul;37(7):e3466. doi: 10.1002/cnm.3466. Epub 2021 Apr 26.
Bone fracture treatments using Ilizarov circular fixator (ICF) involve dealing with uncertainties about a range of critical factors that control the mechanical microenvironment of the fracture site such as ICF configuration, fracture gap size, physiological loading etc. To date, the effects of the uncertainties about these critical factors on the mechanical microenvironment of the fracture site have not been fully understood. The purpose of this study is to tackle this challenge by using computational modelling in conjunction with engineering reliability analysis. Particularly, the effects of uncertainties in fracture gap size (GS), level of weight-bearing (P), ICF wire pretension (T) and wire diameter (WD) on the fracture site mechanical microenvironment at the beginning of the reparative phase of healing was investigated in this study. The results show that the mechanical microenvironment of fracture site stabilised with ICF is very sensitive to the uncertainties in P and GS. For example, an increase in the coefficient of variation of P (COV ) from 0.1 to 0.9 (i.e., an increase in the uncertainty in P) could reduce the probability of achieving a favourable mechanical microenvironment within the fracture site (i.e., Probability of Success, PoS) by more than 50%, while an increase in the coefficient of variation of GS (COV ) from 0.1 to 0.9 could decrease PoS by around 30%. In contrast, an increase in the uncertainties in T and WD (COV increase from 0.1 to 0.9) has little influence on the fracture site mechanical microenvironment (PoS changes <5%).
骨骨折治疗使用伊利扎罗夫环形固定器（ICF）涉及处理的不确定性，范围广泛的关键因素，控制骨折部位的力学微环境，如 ICF 配置，骨折间隙大小，生理负荷等。迄今为止，这些关键因素的不确定性对骨折部位力学微环境的影响尚未得到充分理解。本研究的目的是通过计算建模与工程可靠性分析相结合来解决这一挑战。特别是，在修复愈合的修复阶段开始时，研究了骨折间隙大小（GS）、承重水平（P）、ICF 线预张力（T）和线径（WD）不确定性对骨折部位力学微环境的影响。结果表明，ICF 稳定骨折部位的力学微环境对 P 和 GS 的不确定性非常敏感。例如，P 的变异系数（COV）从 0.1 增加到 0.9（即 P 的不确定性增加）可使骨折部位获得有利力学微环境的概率（即成功概率，PoS）降低 50%以上，而 GS 的变异系数（COV）从 0.1 增加到 0.9 可使 PoS 降低约 30%。相比之下，T 和 WD 不确定性的增加（COV 从 0.1 增加到 0.9）对骨折部位力学微环境的影响很小（PoS 变化<5%）。
