侧向冲击载荷作用下髋护具对股骨-骨盆复合体生物力学响应的影响

目的利用三维有限元法研究髋部护具对人体股骨-骨盆复合体在侧向冲击载荷作用下生物力学响应的影响。方法基于中国力学虚拟人模型库建立股骨-骨盆-软组织复合体的三维有限元模型,包括皮质骨、松质骨和软组织,并在此基础上建立髋部护具和股骨-骨盆-软组织复合体系统的三维有限元模型;同时,在两个模型中构建刚体平面仿真地面。约束地面刚体,对两个模型均施加侧向2 m/s的速度载荷,整个仿真分析时间设定为20 ms。通过三维有限元分析计算获得两模型受侧向冲击载荷过程中应力、应变变化特性,对比分析髋部护具对股骨-骨盆复合体生物力学响应的影响。结果髋部护具使股骨-骨盆复合体在侧向冲击载荷作用下的应力峰值出现时间提前4 ms以上,且应力应变水平出现大幅度降低;皮质骨上的应力峰值降低67.88%以上,松质骨上的峰值应力下降69.34%以上,松质骨上的压缩主应变峰值降低可达63%。结论在侧向冲击载荷作用下,髋部护具对股骨-骨盆复合体具有良好的保护作用,能够有效预防骨折的发生或降低骨折风险。     

侧向冲击载荷作用下股骨-骨盆复合体的生物力学响应

目的利用三维有限元分析方法研究股骨-骨盆复合体在人体侧向摔倒时冲击载荷作用下的生物力学行为特性。方法基于中国力学虚拟人模型库建立股骨-骨盆-软组织复合体的三维有限元模型,包括皮质骨、松质骨和软组织;同时,构建一个刚体平面仿真地面。约束地面刚体,对整个股骨-骨盆-软组织复合体模型施加侧向2 m/s的速度载荷,整个仿真分析时间设定为20 ms。通过三维有限元分析计算获得股骨-骨盆侧摔冲击过程中应力应变变化特性。结果在13 ms时,股骨大转子处软组织与地面的接触力达到最大值7 656 N,对应的骨盆软组织上的最大等效应力值为2.64 MPa。冲击过程中,耻骨联合处骨皮质上等效应力出现极大值,为142.64 MPa,接近其屈服强度;股骨颈和大转子处应力水平较高,股骨颈处皮质骨上的最大等效应力值为76.49 MPa;股骨颈处松质骨上的最大等效应力值为8.44 MPa,最大压缩应变值为0.94%;股骨大转子处松质骨上的最大等效应力值为8.50 MPa,最大压缩应变值为0.93%。结论人体股骨-骨盆复合体在侧摔减速冲击载荷作用下股骨颈、大转子及耻骨联合处易出现骨折。     

个性化全骨盆三维有限元建模及骶髂关节骨折脱位模拟

目的建立高度仿真的个性化的完整骨盆三维有限元模型,并在此基础上进行骶髂关节骨折脱位的模拟。方法从CT精确重建独立的左、右髋骨和骶骨实体模型,根据髋骨和骶骨的外形特征,利用专门的流线型生物力学有限元网格划分器生成规则的体网格模型,并进一步建立骶髂关节的终板、软骨、关节接触面,和骨盆上的主要韧带组织及耻骨间盘。在建立的完整模型上去掉一侧的骶髂关节韧带群进行骨折脱位模拟,并与正常的情况进行对比。结果建立了高精度的个性化全骨盆的三维有限元模型,包括左右髋骨和骶骨的皮质骨、松质骨,骶髂关节的终板、软骨和带摩擦的关节接触面,韧带包括骶髂骨间韧带、骶髂前韧带、骶髂后韧带、骶棘韧带、骶结节韧带、耻骨上韧带和耻骨弓状韧带,以及耻骨间盘。正常模型的加载模拟和骶髂关节骨折脱位模拟的预测结果均与文献试验生物力学结果相符合。结论利用专门的生物力学有限元建模工具能建立更复杂更精确的三维有限元模型,成为全骨盆生物力学分析研究的平台和基础。     

汽车后碰撞时人体头颈部的动力学响应及损伤分析

目的建立基于人体解剖学结构的精细化头颈部有限元模型,研究不同后碰撞速度下颈部损伤。方法该模型以人体头颈部CT扫描图像为基础,利用Mimics进行三维骨重建,通过Hyper Mesh完善颈部三维实体韧带、小关节等组织,并进行网格划分。生成的模型包括头部、8节椎骨(C1～T1)、6个椎间盘(包括纤维环、髓核和上下软骨终板)、小关节(包括软骨和关节囊韧带)、韧带、肌肉等结构,最后在有限元后处理软件中完成模型验证与后碰撞计算。结果分别对模型进行轴向冲击、前后屈伸和侧屈模拟并与实验数据对比,验证模型的有效性,并进行速度为20、40、60、80 km/h后碰撞计算。在20 km/h速度下,颈部无损伤出现,在40、60、80 km/h速度下,最早出现损伤的都是韧带。随着速度增加,颈部各组织受力不断增大。速度为80 km/h时,颈椎的密质骨、松质骨和纤维环最大应力分别为226. 4、11. 5、162. 8 MPa,当韧带应变达到极限时,开始出现撕裂。结论所建头颈部有限元模型具有较高的生物仿真度和有效性,可用于交通事故中颈部损伤分析的研究,在一定程度上有助于颈椎损伤的诊断、治疗和预防。     

韧带和跖腱膜在足部有限元分析中的力学作用

目前通过建立足部三维有限元系统模型进行足部生物力学仿真已经逐渐被应用,而在大多数足部三维有限元模型的静态分析中,韧带和跖腱膜等软组织是通过直接连接骨骼上相应的附着点形成的索单元来模拟,而关节软骨把相邻的骨骼直接固连在一起.这种用关节软骨固连的方式代替真实的骨骼间的滑动摩擦,增强了骨骼间的结构强度,可能会造成原本由韧带等起到维持骨骼间相互作用却完全由关节软骨代替,即在有限元模型中,可能韧带等组织对仿真不起力学作用.本文的研究目的是在双足站立、静态载荷,关节采用固连方式时,分析足部三维有限元模型中有无韧带和跖腱膜对足部各种组织应力分布以及组织结构形态变化等的影响.     

建立人体头颈动力学有限元模型和验证

目的建立符合解剖结构的头颈三维动力学有限元模型,研究冲击力作用下头颈部动力学响应。方法采用中国成年男性志愿者颈部CT扫描图像,获取颈椎三维点云数据,通过有限元前处理软件ICEM-CFD和Hyper Mesh建立颈部有限元模型。模型包括椎骨、椎间盘、小关节、韧带和软骨等组织,结合已建立并验证的头部有限元模型,装配成具有详细解剖结构的人体头颈部有限元模型。结果模型参考公开发表的头颈部轴向冲击实验数据进行验证,其颈部变形、头部加速度、接触力曲线以及损伤部位与实验数据吻合较好。结论动力学三维有限元模型可用于汽车安全、运动学损伤等领域人体头颈部的动态响应和损伤机制研究。     

骨盆垂直不稳定性骨折的生物力学研究

目的　利用人体骨盆标本制作骶髂关节骨折脱位模型,研究垂直不稳定性骨盆骨折中骶髂复合体生物力学损伤特点。 方法　成年男性冰冻骨盆标本6具,固定于MTS生物材料试验机上以2 m/s速度进行动态撞击,记录骶髂关节出现完全骨折脱位所需的最大撞击力及响应时间,用步态分析仪的动作捕捉系统测量骶髂复合体中韧带完全破坏时骶髂关节空间三维位移,解剖学方法观察骶髂复合体损伤特点。 结果　成功制备出骶髂关节骨折、脱位损伤模型,单侧骶髂复合体完全损伤所需的撞击力峰值平均值（4.05±0.42）kN,标本响应时间平均值为（22.99±1.89）ms,骶髂关节最大垂直位移平均为（8.15±1.34）　mm;骶髂复合体损伤以经骶髂关节骨折并脱位为多,髂腰韧带均表现为连同第四、五腰椎横突骨折,骶髂腹侧韧带相对薄弱易于髂骨止点处撕裂,骶髂后短韧带易发生髂骨侧的撕脱骨折,骶棘韧带骶结节韧带及盆底肌肉损伤不明显。 结论 骨盆垂直不稳定性骨折中骶髂复合体损伤具有一定的规律和特点,当骶髂关节垂直位移超过0.9 cm时提示后方骶髂复合体的韧带结构已全部破坏,骨盆环处于绝对不稳状态。     

跳伞着陆过程中膝关节损伤的有限元研究

目的利用膝关节有限元模型和模拟跳伞着陆实验数据,对半蹲式跳伞着陆过程进行数值模拟,并分析膝关节损伤的机理。方法对16名健康志愿者进行半蹲式模拟跳伞实验,跳落高度分别为0.32m,0.52m和0.72m。基于核磁共振成像建立人体膝关节的三维有限元模型,采用实验测得的膝关节运动学和地面反力数据对跳伞着陆过程进行数值模拟。结果关节内组织的应力水平随着跳落高度的增加而增加,外侧半月板和关节软骨承受了较大的载荷,前交叉韧带和内侧副韧带在屈膝角度达到最大时产生明显的应力集中。结论跳伞着陆的高速冲击是造成关节损伤的直接原因,外侧关节软骨和半月板更易受到损伤,前交叉韧带和内侧副韧带较易在屈膝幅度最大时发生撕裂。     

单腿站立姿态下Ⅰ+Ⅱ+Ⅲ型标准半骨盆假体生物力学研究

目的针对半骨盆假体发展中的标准化问题,建立Ⅰ+Ⅱ+Ⅲ型标准半骨盆假体模型,对受损骨盆进行骨盆环重建,并进行生物力学研究,以评价其力学响应特点。方法使用有限元方法模拟人体骨盆在单腿站立时的受力情况。所使用的骨盆模型包含相关关节软骨和韧带,以模拟真实体内环境。结果在单腿站立姿态载荷作用下,重建骨盆中应力分布与健康骨盆相似,应力均从S1面经由骶髂关节向下传递;骨与假体应力峰值低于材料的屈服极限。结论Ⅰ+Ⅱ+Ⅲ型标准半骨盆假体能够可靠地恢复受损骨盆的功能,研究结果为该种假体在使用中的力学可靠性提供初步的理论依据。     

骶髂螺钉内固定治疗骶髂关节复合体损伤的研究现状

骶髂关节复合体（Sacroiliac comp lex）是位于骨盆环后部的骨-韧带复合结构。包括骶髂关节（Sacroiliac joint,SIJ）,SIJ周围韧带、骶棘韧带、骶结节韧带及骨盆底的肌肉和筋膜。SIJ是躯干与下肢负荷传递的枢纽,占整个骨盆功能的60%。SIJ损伤的治疗效果对骨盆功能的恢复有决定意义。高能损伤的骨盆骨折多合并SIJ骨折脱位，破坏骶髂复合体的完整性。另外，许多下腰痛由单侧或双侧SIJ综合征引起，亦称为SIJ功能紊乱；妊娠后妇女因SIJ半脱位或全脱位，易患妊娠相关性骨盆痛。本文就骶髂螺钉内固定治疗骶髂关节复合体损伤的研究现状综述如下。     

骶髂关节韧带应用解剖学意义

背景：骨盆后部结构中,骶髂后韧带复合体、骶结节韧带和骶棘韧带的完整,对骨盆稳定性有重要作用。 目的：观察骶髂关节周围韧带解剖结构,了解各韧带对关节稳定性的作用。 方法：对20具防腐成年尸体骨盆标本,共40侧依次采用前后方入路,对骶棘韧带,骶结节韧带,耻骨联合及骶髂关节诸韧带结构进行解剖学观察。 结果与结论：骶髂关节周围韧带可分为3组：骶髂前韧带、骶髂骨间韧带和骶髂后韧带。耻骨上下韧带及耻骨前后韧带。骶棘韧带和骶结节韧带。此3组韧带主要有两个功能：连接脊柱和骨盆环;维持骨盆环的稳定。     

Effects of Cutting the Sacrospinous and Sacrotuberous Ligaments

The sacrospinous (SS) and sacrotuberous (ST) ligaments form a complex at the posterior pelvis, with an assumed role as functional stabilizers. Experimental and clinical research has yielded controversial results regarding their function, both proving and disproving their role as pelvic stabilizers. These findings have implications for strategies for treating pelvic injury and pain syndromes. The aim of the present simulation study was to assess the influence of altered ligament function on pelvis motion. A finite elements computer model was used. The two‐leg stance was simulated, with the load of body weight applied via the fifth lumbar vertebra and both femora, allowing for nutation of the sacroiliac joint. The in‐silico kinematics were validated with in‐vitro experiments using the same scenario of load application following SS and ST transection in six human cadavers. Modeling of partial or complete ligament failure caused significant increases in pelvis motion. This effect was most pronounced if the SS and ST were affected with 164% and 182%, followed by the sacroiliac and iliolumbar ligaments with 123% and 147%, and the pubic ligaments with 113% and 119%, for partial and complete disruption, respectively. Simultaneous ligament transection multiplied the effects on pelvis motion by up to 490%. Unilateral ligament injury altered the motion at the pelvis contralaterally. The experiments presented here provide strong evidence for the stabilizing role of the SS and ST. A fortiori, the instability resulting from partial or complete SS and ST injury merits consideration in treatment strategies involving these ligaments as important stabilizers. Clin. Anat. 32:231–237, 2019. © 2018 Wiley Periodicals, Inc.     

骶髂融合治疗下腰痛的生物力学效应

目的基于有限元方法,建立骶髂关节融合和接触的模型,比较两模型的生物力学差异,探究骶髂融合治疗下腰痛的生物力学机理。方法构建包含骨盆环、骶骨、部分股骨、关节软骨和关节连接的骨盆有限元模型两例,分别设定骶髂关节连接为接触和融合,探究在500 N载荷下,两例模型中骨盆环特别是骶髂关节处力学传导的差异。结果在融合条件下骶髂软骨承受的应力及位移明显低于接触条件,在双侧骶髂软骨处尤为明显,其中左骶骨关节处,位移由0.83 mm减低为0.23 mm,减低幅度达约261%,等效应力由6.6 MPa减低至5.0 MPa,减低约32%。但融合条件下,骨盆环应力的传递相对更集中。结论骶髂融合可能提供较好的疼痛治疗效果,但同时必须谨慎评估伴发骨盆损伤和股骨头损伤的危险性。     

3-D finite element analysis of the influence of synovial condition in sacroiliac joint on the load transmission in human pelvic system

The anterior part of the sacroiliac joint (SIJ) is a synovial joint, with little gliding and rotary movement between the contact surfaces of SIJ during locomotion. Due to its complex structure, especially when considering the surrounding ligaments, it is difficult to construct an accurate three-dimensional (3-D) finite element model for the human pelvis. Most of the pelvic models in the previous studies were simplified with either SIJ fusing together or without the sacral bone. However, the influence of those simplifications on the load transmission in human pelvis has not been studied, so the reliability of those studies remains unclear. In this study, two 3-D pelvic models were constructed: an SIJ fusing model and an SIJ contacting model. In the SIJ fusing model, the SIJ interfaces were fused together. In the SIJ contacting model, the SIJ interfaces were just in contact with each other without fusion. Compared with the SIJ contacting model, the SIJ fusing model have smaller movements in the SIJ. The stress distribution area in the SIJ fusing model on sacroiliac cartilages was also different. Those differences contributed to the decline of tensile force in the SIJ surrounding ligaments and the re-distribution of stress in the pelvic bones. In addition, the SIJ fusing model was far less sensitive to the increase in modulus of the sacroiliac cartilages, and decrease in stiffness of the ligaments surrounding the SIJ. The presence of synovia in the SIJ had greater influence on the load transmission in the human pelvic system. Therefore, the effect of the presence of synovia should not be neglected when the biomechanical behavior of human pelvis is being studied, especially for those studies related to clinical applications.     

骨盆骨折血管损伤的解剖学基础

目的：探讨骨盆骨折血管损伤的机制。方法：20具新鲜成年国人骨盆标本，采用前后双侧入路解剖，观察髂内外血管的走行特点、分型与骨盆韧带、骶丛神经的关系，观察血管在骨盆壁上的投影位置，测量每一根血管到骨壁的垂直距离，观察各动脉间的侧支吻合情况。结果：骨盆动脉血管根据口径可分为3类：(1)小口径动脉，直径小于3．0mm。(2)中等口径动脉，直径3．0～5．0mm。(3)大口径动脉，直径大于5．0mm。据血管距骨壁的距离可分为靠近骨壁的血管(平均距离小于10．0mm)及远离骨壁的血管(平均距离大于10．0mm)。阴部内动脉与骨壁关系不明显。骨盆动脉分支间有广泛的吻合支。结论：骨盆动脉解剖学特点决定了在骨盆骨折中损伤的机率，骨盆动脉有广泛吻合支是骨盆动脉出血止血困难的原因。     

A three-dimensional finite element analysis of the human hip

Abstract

A three-dimensional hip model was created from the MRI scans of one human subject based on constructing the entire pelvis and femur. The ball and socket joint was modelled between the hip’s acetabulum and the femoral head to analyse the multiaxial loads applied in the hip joint. The three key ligaments that reinforce the external surface of the hip to help to stabilise the joint were also modelled which are the iliofemoral, the pubofemoral and ischiofemoral ligaments. Each of these ligaments wraps around the joint connection to form a seal over the synovial membrane, a line of attachment around the head of the femur. This model was tested for different loading and boundary conditions to analyse their sensitivities on the cortical and cancellous tissues of the human hip bones. The outcomes of a one-legged stance finite element analysis revealed that the maximum of 0.056?mm displacement occurred. The stress distribution varied across the model which the majority occurring in the cortical femur and dissipating through the cartilage. The maximum stress value occurring in the joint was 110.1?MPa, which appeared at the free end of the proximal femur. This developed finite element model was validated against the literature data to be used as an asset for further research in investigating new methods of total hip arthroplasty, to minimise the recurrence of dislocations and discomfort in the hip joint, as well as increasing the range of movement available to a patient after surgery.     

Three-Dimensional Finite Element Models of the Human Pubic Symphysis with Viscohyperelastic Soft Tissues

Three-dimensional finite element (FE) models of human pubic symphyses were constructed from computed tomography image data of one male and one female cadaver pelvis. The pubic bones, interpubic fibrocartilaginous disc and four pubic ligaments were segmented semi-automatically and meshed with hexahedral elements using automatic mesh generation schemes. A two-term viscoelastic Prony series, determined by curve fitting results of compressive creep experiments, was used to model the rate-dependent effects of the interpubic disc and the pubic ligaments. Three-parameter Mooney-Rivlin material coefficients were calculated for the discs using a heuristic FE approach based on average experimental joint compression data. Similarly, a transversely isotropic hyperelastic material model was applied to the ligaments to capture average tensile responses. Linear elastic isotropic properties were assigned to bone. The applicability of the resulting models was tested in bending simulations in four directions and in tensile tests of varying load rates. The model-predicted results correlated reasonably with the joint bending stiffnesses and rate-dependent tensile responses measured in experiments, supporting the validity of the estimated material coefficients and overall modeling approach. This study represents an important and necessary step in the eventual development of biofidelic pelvis models to investigate symphysis response under high-energy impact conditions, such as motor vehicle collisions.     

Anatomical consequences of “open-book” pelvic ring disruption. A cadaver experimental study

“Open-book” pelvic fractures associate a diastasis and/or a fracture of the pubic rami with a posterior pelvic disruption of the sacro-iliac joint. These uni or bilateral lesions are potentially lethal mainly due to associated injuries and massive pelvic hemorrhage. The most frequently injured arteries are parietal branch of the commune, internal or external arteries because of their proximity to the bone, the sacro-iliac joint and the inferior ligaments of the pelvis. The pelvic bone dislocation and the increase of pelvic volume facilitate blood effusion. The aim of this study was to determine, on a cadaver fracture model, the direct anatomical consequences of “open-book” pelvic fracture on the ilio-lumbar pedicle and the pelvic cavity volume. Materials and methods: Bilateral open-book pelvic ring injuries were created in ten non-embalmed cadaver specimens by directly disrupting the pubic symphysis, the right and the left sacro-iliac joints. Pelvic volume was determined after total pelvic exenteration. Consequences of this fracture on vascular parietal network, nervous pelvic trunk and pelvic cavity volume were studied. Results: The mean volume of the pelvic cavity after complete visceral exenteration was 872.5 cm³ (extremes 580–756 cm³). The average increase of pelvic volume was 20.8% after 5 cm of pubic diastasis. In all cases, because of a transversal disposition of the ilio-lumbar pedicle with regard to the sacro-iliac joint, reproduction of the open-book fracture caused a venous dilaceration of the ilio-lumbar vein in 12 cases after 5 cm of pubic diastasis (12/20=60%). No arterial dilaceration was observed on the ilio-lumbar artery, but this artery was put in tension. Conclusion: Open-book fractures create an increase of pelvic volume that facilitates blood diffusion from parietal pelvic vascular network. Ilio-lumbar pedicle seems to be very vulnerable in this type of fracture because of its relations to the sacro-iliac joint and its transversal disposition with regard to this joint.