动态载荷下股骨转子间区域皮质骨厚度对骨折类型影响的有限元分析
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摘要
目的髋部骨折的有限元研究多以股骨颈骨折为模型,而转子间骨折模型较少。文中旨在采用有限元分析方法,探讨股骨转子间皮质骨厚度对髋部近端骨折类型的影响。方法选取2017年10月广州中医药大学第一附属医院健康男性志愿者1例。初步建立三维模型,进行网格划分、定义材料属性及设置边界条件,构建厚皮质骨、中厚皮质骨、薄皮质骨模型。测量模型断裂时刻及该时刻的Von Mises应力云图、骨折线走行、最早失效单元的时间-压力曲线。结果薄皮质骨模型最易发生骨折,厚皮质骨模型最迟发生骨折。Von Mises应力云图显示,断裂发生起始时,各模型应力主要分布在股骨颈的后侧与转子间,并向下延伸至小转子后下方;随着转子间皮质厚度降低,股骨颈的最大应力范围逐渐缩小,并向股骨颈后下方及转子间转移;其中薄皮质骨模型的最大应力区域明显缩小,并主要分布于股骨颈基底部与转子间交界处;随着皮质骨变薄,小转子亦逐渐变成应力区。薄皮质骨模型在转子间及小转子周围均出现骨折线。最早失效单元的时间-压力曲线显示,薄皮质骨模型最早发生断裂,最大应力为51.6 Mpa;厚皮质骨模型最迟发生断裂,最大应力为96.4 Mpa;中厚皮质模型最大应力为89.7 Mpa。结论股骨转子间皮质骨厚度是影响髋部骨折类型的重要因素。
Objective The influence of intertrochanteric cortical thickness on hip fracture can be investigated by the finite element method( FEM),but few dynamic FEMs have been established to manifest the extension of the crack. This study aimed to investigate the influence of intertrochanteric cortical thickness on the proximal femoral fracture types by FEM. Methods We recruited a healthy male volunteer from the Department of Traumatic Orthopedics,the First Affiliated Hospital of Guangzhou University of Chinese Medicine in October 2017,established a 3-dimention model,and reconstructed thick,middle and thin intertrochanteric cortex proximal femur models by meshing,defining material properties and setting boundary conditions. We measured the crack moment and von Mises stress,distribution of the fracture line,and the time-stress curves of the earliest damage element. Results Fracture occurred the earliest in the thin-cortex femur model but the latest in the thick one. The von Mises stress contour plot showed that,when damage started,the stress was concentrated on the posterior femoral neck and intertrochanteric region,extending to the posterior inferior part of the lesser trochanter in all the three models and,with the decline of the intertrochanteric cortex thickness,the concentration of the von Mises stress gradually narrowed down and shifted to the intertrochanteric region. The narrowing of the von Mises stress was the most obvious in the thin-cortex model,mainly distributed on the junction of the basal femoral neck and the intertrochanteric region. With the thinning of the cortex,the lesser trochanter became the region of stress concentration. The time-stress curves showed that fracture occurred the earliest in the thin-cortex model,with the maximum stress of51.6 Mpa,but the latest in the thick-cortex model,with the maximum stress of 96.4 Mpa,and the maximum stress was 89.7 Mpa in the middle cortex model. Conclusion The thickness of the intertrochanteric cortex may be a determinant in the types of hip fracture.
Objective The influence of intertrochanteric cortical thickness on hip fracture can be investigated by the finite element method( FEM),but few dynamic FEMs have been established to manifest the extension of the crack. This study aimed to investigate the influence of intertrochanteric cortical thickness on the proximal femoral fracture types by FEM. Methods We recruited a healthy male volunteer from the Department of Traumatic Orthopedics,the First Affiliated Hospital of Guangzhou University of Chinese Medicine in October 2017,established a 3-dimention model,and reconstructed thick,middle and thin intertrochanteric cortex proximal femur models by meshing,defining material properties and setting boundary conditions. We measured the crack moment and von Mises stress,distribution of the fracture line,and the time-stress curves of the earliest damage element. Results Fracture occurred the earliest in the thin-cortex femur model but the latest in the thick one. The von Mises stress contour plot showed that,when damage started,the stress was concentrated on the posterior femoral neck and intertrochanteric region,extending to the posterior inferior part of the lesser trochanter in all the three models and,with the decline of the intertrochanteric cortex thickness,the concentration of the von Mises stress gradually narrowed down and shifted to the intertrochanteric region. The narrowing of the von Mises stress was the most obvious in the thin-cortex model,mainly distributed on the junction of the basal femoral neck and the intertrochanteric region. With the thinning of the cortex,the lesser trochanter became the region of stress concentration. The time-stress curves showed that fracture occurred the earliest in the thin-cortex model,with the maximum stress of51.6 Mpa,but the latest in the thick-cortex model,with the maximum stress of 96.4 Mpa,and the maximum stress was 89.7 Mpa in the middle cortex model. Conclusion The thickness of the intertrochanteric cortex may be a determinant in the types of hip fracture.
引文
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[12]Zhuang H,Li Y,Lin J,et al.Cortical thickness in the intertrochanteric region may be relevant to hip fracture type[J].BMCMusculoskel Dis,2017,18(1):305-309.
[13]Pellegrini A,Tacci F,Leigheb M,et al.Injuries of the trochanteric region:can analysis of radiographic indices help in prediction of recurrent osteoporotic hip fractures?[J]Acta Biomed,2017,88(4-S):43-49.
[14]Maeda Y,Sugano N,Saito M,et al.Comparison of Femoral Morphology and Bone Mineral Density between Femoral Neck Fractures and Trochanteric Fractures[J].Clin Orthop R,2011,469(3):884-889.
[15]王桂华,赵建宁.骨质量的影响因素及其检测方法[J].医学研究生学报,2011,24(10):95-98.
[16]孙喜凤,梁杰.老年性骨质疏松和瘦素的相关性研究进展[J].医学研究生学报,2014,27(6):669-672.
[17]Marco M,Giner E,Larraínzar-Garijo R,et al.Numerical Modelling of Femur Fracture and Experimental Validation Using Bone Simulant[J].Ann Biomed Eng,2017,45(10):2395-2408.
[18]李平.不同跌倒姿势与髋部应力变化关系的有限元分析[D].广州:广州中医药大学,2014.
[2]Bahaloo H,Enns-Bray WS,Fleps I,et al.On the Failure Initiation in the Proximal Human Femur Under Simulated Sideways Fall[J].Ann Biomed Eng,2018,46(2):270-283.
[3]Stone KL,Seeley DG,Lui LY,et al.BMD at multiple sites and risk of fracture of multiple types:long-term results from the Study of Osteoporotic Fractures[J].J Bone Miner Res,2003,18(11):1947-1954.
[4]Roberts BJ,Thrall E,Muller JA,et al.Comparison of hip fracture risk prediction by femoral a BMD to experimentally measured factor of risk[J].Bone,2010,46(3):742-746.
[5]Zhong RY,Wu XP,Liao EY,et al.Relationship between agerelated bone mass of the lumbar spine and skeletal size and their effects on the diagnosis of osteoporosis in women[J].Chin J Osteoporos,2012,18(2):99-105.
[6]Hayes WC,Piazza SJ,Zysset PK.Biomechanics of fracture risk prediction of the hip and spine by quantitative computed tomography[J].Radiol Clin N Am,1991,29(1):1-18.
[7]Morgan EF,Keaveny TM.Dependence of yield strain of human trabecular bone on anatomic site[J].J Biomech,2001,34(2001):569-577.
[8]Rieger R,Auregan JC,Hoc T.Micro-finite-element method to assess elastic properties of trabecular bone at micro-and macroscopic level[J].Morphologie,2018,102(336):12-20.
[9]Holzer G,von Skrbensky G,Holzer LA,et al.Hip fractures and the contribution of cortical versus trabecular bone to femoral neck strength[J].J Bone Miner Res,2009,24(3):468-474.
[10]Ward KA,Adams JE,Hangartner TN.Recommendations for thresholds for cortical bone geometry and density measurement by peripheral quantitative computed tomography[J].Calcif Tissue Int,2005,77(5):275-280.
[11]Zebaze RM,Ghasem-Zadeh A,Bohte A,et al.Intracortical remodelling and porosity in the distal radius and post-mortem femurs of women:a cross-sectional study[J].Lancet,2010,375(9727):1729-1736.
[12]Zhuang H,Li Y,Lin J,et al.Cortical thickness in the intertrochanteric region may be relevant to hip fracture type[J].BMCMusculoskel Dis,2017,18(1):305-309.
[13]Pellegrini A,Tacci F,Leigheb M,et al.Injuries of the trochanteric region:can analysis of radiographic indices help in prediction of recurrent osteoporotic hip fractures?[J]Acta Biomed,2017,88(4-S):43-49.
[14]Maeda Y,Sugano N,Saito M,et al.Comparison of Femoral Morphology and Bone Mineral Density between Femoral Neck Fractures and Trochanteric Fractures[J].Clin Orthop R,2011,469(3):884-889.
[15]王桂华,赵建宁.骨质量的影响因素及其检测方法[J].医学研究生学报,2011,24(10):95-98.
[16]孙喜凤,梁杰.老年性骨质疏松和瘦素的相关性研究进展[J].医学研究生学报,2014,27(6):669-672.
[17]Marco M,Giner E,Larraínzar-Garijo R,et al.Numerical Modelling of Femur Fracture and Experimental Validation Using Bone Simulant[J].Ann Biomed Eng,2017,45(10):2395-2408.
[18]李平.不同跌倒姿势与髋部应力变化关系的有限元分析[D].广州:广州中医药大学,2014.