不同面积的髋臼后壁骨折对髋臼应力分布影响的三维有限元分析

[目的]应用三维有限元方法探讨不同面积髋臼后壁骨折对髋臼受力分布的影响,为临床治疗方法的选择提供依据。[方法]构建髋臼的三维有限元数字模型,根据Letournel髋臼骨折分类标准制作髋臼后壁1/3、2/3、3/3髋臼缺失模型,选择适合于后壁骨折的双足直立位进行应力加载,利用Ansys软件分别记录髋臼后壁完整及1/3、2/3、3/3后壁骨折情况下的臼顶负重区、前壁及剩余后壁各方向分应力及合应力大小。[结果]髋臼后壁骨折使臼顶负重区应力依次增加20%、26%、33%(相对于髋臼正常状态),以垂直方向应力最为显著;前壁应力依次降低22%、30%、35%;剩余后壁应力依次增加39%、47%、54%。[结论]后壁骨折改变了髋臼各壁应力的大小与分布,当髋臼后壁骨折缺损达1/3时,髋关节的负重特征即已发生明显改变,需要切开复位内固定,修复关节面以维持稳定。     

不同内固定方式治疗髋臼顶压缩骨折后髋臼负重区接触特性的研究

目的建立髋臼顶压缩骨折模型,采用压敏片技术测量并探讨3种不同内固定方式固定后髋臼负重区接触特性。方法将16具新鲜成人半骨盆标本随机均分为4组,每组4具。D组为完整髋臼对照组;其余3组制备髋臼顶压缩骨折模型后,A组采用重建接骨板固定方法、B组采用顺行排钉螺钉固定方法、C组采用逆行排钉螺钉固定方法固定骨折。将压敏片贴于股骨头上,于倒置的单足站立位行轴向加载压缩试验,分别测量各组髋臼负重区的负重区面积、平均应力及峰值应力。结果载荷为500 N时,D组髋臼负重区面积显著高于其余各组,平均应力和峰值应力显著低于其余各组,差异均有统计学意义(P0.05)。B、C组髋臼负重区面积显著高于A组,平均应力及峰值应力显著低于A组,差异均有统计学意义(P0.05);B、C组间比较上述指标差异均无统计学意义(P0.05)。结论对于髋臼顶压缩骨折,即使行解剖复位并坚强内固定,髋臼负重区接触特性也不能恢复至正常水平;顺行及逆行排钉螺钉固定与重建接骨板固定相比,能够增加髋臼负重区面积,降低平均应力及峰值应力,可降低创伤性关节炎的发生率。     

髋臼发育不良的光弹性生物力学研究

目的 从生物力学角度探讨髋臼发育不良继发骨关节炎的发病机理,为髋臼旋转截骨术提供依据。方法 用环氧树脂制作骨盆、股骨模型,其中包括４个不同Ｓｈａｒｐ角、３个不同软骨厚度及３个颈干角模型,采用二维光弹性方法进行生物力学分析。结果 随着Ｓｈａｒｐ角的增大,髋关节的合力增大,生物应力向髋臼外侧缘移动;关节软骨缺损一半时,髋关节合力未见明显变化,当关节软骨不存在时,生物应力为正常时的２．５倍;随着颈干角的增大,生物应力集中的位置没有变化,但生物应力及合力随之增大。结论 髋臼发育不良因生物力学因素可继发骨关节炎,髋臼旋转截骨术是对其有效的治疗方法。     

个性化3D打印多孔钛合金加强块重建重度髋臼骨缺损的有限元分析

目的 建立个性化3D打印多孔钛合金加强块重建重度髋臼骨缺损有限元模型,分析个性化3D打印多孔钛合金加强块、螺钉以及骨的生物力学和临床应用安全性。方法 利用1例Paprosky ⅢA型髋臼骨缺损病人的骨盆CT数据建立完整的个性化3D打印多孔钛合金加强块重建重度髋臼骨缺损有限元模型,模拟1倍体重（单足站立）、4倍体重（步行）和6倍体重（慢跑）加载负荷下分析加强块、螺钉以及骨的应力分布。结果 个性化3D打印多孔钛合金加强块的最大应力分布为10.130 MPa（1倍体重）、40.706 MPa（4倍体重）和61.213 MPa（6倍体重）,固定加强块的螺钉最大应力分布为12.424 MPa（1倍体重）、50.250 MPa（4倍体重）和75.860 MPa（6倍体重）,骨面应力分布最大应力分布为10.439 MPa（1倍体重）、42.627 MPa（4倍体重）和64.554 MPa（6倍体重）。结论 有限元模拟术后即刻完全负重站立时所有部件的应力分布均小于其屈服强度,不会发生失效;但是于步行和慢跑加载负荷下,与加强块和螺钉接触骨面的部分区域松质骨会发生失效。因此从有限元分析角度考虑,病人术后即刻可以进行完全负重站立康复锻炼,但是不能进行完全负重的步行或慢跑康复运动。     

动力化前路方形区钛板螺钉系统固定伴有对侧骨盆前环不稳的髋臼双柱骨折的站位有限元分析

目的 利用有限元技术探讨当对侧骨盆前环不稳时,动力化前路方形区钛板螺钉系统(DAPSQ)内固定治疗髋臼双柱骨折的生物力学稳定性.方法 利用有限元分析技术建立正常人体全骨盆有限元模型并进行有限元验证,建立3种骨折内固定模型:A:DAPSQ固定右侧髋臼双柱骨折模型,左侧耻骨支完整;B:DAPSQ固定右侧髋臼双柱骨折模型,左侧耻骨上下支骨折但不予固定;C:DAPSQ固定右侧双柱骨折模型,左侧耻骨上下支骨折,但耻骨上支采用钛板固定.限制各模型的三维自由度,加载生理载荷后进行有限元计算,分析比较各内固定模型骨折端的位移及应力分布情况.结果 通过对A、B、C3组骨折模型的髋臼横向、纵向位移及应力云图分析与比较后发现,C组在骨盆环稳定时采用DAPSQ固定模型的横向及纵向位移小,符合复位标准,应力分布均匀,无明显高度集中现象.骨折线上的横向及纵向位移呈现B＞C＞A,站位下A、B、C纵向位移分别为(1.315 ±0.171)、(1.490 ±0.247)、(1.334 ±0.160) mm,站位横向位移分别为(1.185±0.700)、(1.337±0.080)、(1.198 ±0.103) mm.结论 在应用DAPSQ固定髋臼双柱骨折时,只有在确保对侧骨盆前环的稳定前提下,DAPSQ才能提供有效可靠的固定.     

重建髋臼前后柱完整性的生物力学研究

目的：运用平面有限元及光弹实验原理，研究髋臼负重区前后柱骨折后的应力分布，阐明髋关节骨性关节炎产生病理基础和力学机制。方法：建立骶髂关节和髋关节平面有限元模型，模拟单腿站立负重状态，分析髋臼负重区及近负重区在不同骨折类型和位移下的应力分布。结果：髋臼负重区的裂缝型和台阶型骨折局部应力增大；负重区内位移一致的台阶型较裂缝型骨折局部出现应力集中。近负重区较负重区内的骨折所产生的应力小。结论：髋臼负重区骨折应尽可能达到解剖复位，尤以台阶型为著。恢复髋臼前后柱的完整性，可减少负重区的应力集中，减小髋臼病损、延缓关节退变的发生。早期的髋臼重建对后期因髋关节骨性关节炎行人工髋关节置换术提供可靠骨性结构，使手术有更多的选择空间。     

成人髋臼发育不良Bernese经髋臼周围骨盆截骨术的两维有限元分析

目的：建立成人髋臼发育不良Bernese经髋臼周围骨盆截骨术后模型，并进行生物力学有限元分析。方法:制备尸体标本成人髋臼发育不良模型，并利用Ansys 6．0软件，对髋臼发育不良Bernese术后矫枉过正及合适矫正模型进行生物力学分析。结果：术后矫枉过正模型组外侧、前侧髋臼边缘出现应力增加趋势，作用于髋臼及股骨头的水平分力及剪应力是正常组的2—3倍。结论：探讨髋臼合适矫正的标准Bernese术后髋臼矫枉过正，将会导致髋臼进行性的向前侧、外侧突起畸形及股骨头颈髋臼盂唇撞击综合征。久之导致骨性关节炎。     

重建髋臼前后柱完整性的生物力学研究

目的 运用平面有限元及光弹实验原理,研究髋臼负重区前后柱骨折后的应力分布,阐明髋关节骨性关节炎产生病理基础和力学机制。方法 建立骶髂关节和髋关节平面有限元模型,模拟单腿站立负重状态,分析髋臼负重区及近负重区在不同骨折类型和位移下的应力分布。结果 髋臼负重区的裂缝型和台阶型骨折局部应力增大;负重区内位移一致的台阶型较裂缝型骨折局部出现应力集中。近负重区较负重区内的骨折所产生的应力小。结论 髋臼负重区骨折应尽可能达到解剖复位,尤以台阶型为著。恢复髋臼前后柱的完整性,可减少负重区的应力集中,减小髋臼病损、延缓关节退变的发生。早期的髋臼重建对后期因髋关节骨性关节炎行人工髋关节置换术提供可靠骨性结构,使手术有更多的选择空间。     

电阻片应变法在测量三翼臼固定后骨盆应力变化中的应用

目的应用电阻片应变法测量骨盆髋臼骨缺损模型三翼臼固定后髋臼上方的应力值。方法成年男性尸体骨盆标本4只，无髋关节骨质缺损或畸形。于臼顶处造成节段性骨缺损，缺损面积约为髋臼面积的20％。根据三翼臼扩展角度不同分为0、36、45和60°4个实验组，并设立无缺损、无翼假体骨盆为对照组。在4只骨盆标本上各布置7组电阻应变花，1、2和3号位置为骨盆外侧与臼杯3个翼对应的髋臼上方，4号位置为骨盆外侧髋臼与骶髂关节连线近端，5、6和7号位置于骨盆内侧髋臼与骶髂关节连线由外下向内上方均匀分布。模拟单腿站立时髋关节负重情况，进行150、300、450、600、750和900N分级加载，收集各组各级加载和卸载时应变片应变信息。结果测试点最大等效应力为6．93MPa，最小等效应力为1．08MPa。结论骨盆髋臼骨缺损三翼臼固定后，在宿主骨没有引发高应力区，为翼间移植骨的生长提供了力学环境下的数据。     

应用三维光弹法治疗髋臼发育不良的生物力学研究

髋关节是机体中最大的负重关节 ,其发病率与生物力学的变化密切相关。我们应用三维光弹法研究髋臼发育不良的力学变化对其治疗提供生物力学基础。一、材料与方法1.模型的制作 :利用成人女性含有Ｌ3 的骨盆及股骨头为阳模 ,制成ｓｈａｒｐ角 45度、5 0度、5 5度、6 0度的环氧树脂模型 ,用硫化硅橡胶模拟关节软骨。2 .模型载荷设计及应力冻结 :模型在冻结恒温箱内组装 ,采用下肢固定从椎骨向下加热 ,重量为 45Ｎ ,髂嵴前 1/ 4、2 / 4、3/ 4处与大粗隆间 ,小粗隆下 10ｃｍ与坐骨结节之间用金属丝连接 ,拉力为 5Ｎ ,模拟臀中肌肉及内收肌。用 2…     

Reconstruction of type II+III pelvic resection with a modular hemipelvic endoprosthesis: a finite element analysis study

Objective: To conduct a biomechanical study of the whole reconstructed pelvic ring using a modular hemipelvic endoprosthesis. Methods: A subject‐specific finite‐element (FE) model of the whole pelvic ring, including the pelvis, sacrum and main ligaments, was constructed. Type II+III pelvic resection was simulated on the FE model. Then a three‐dimensional model of a reconstructed pelvic ring with a modular hemipelvic endoprosthesis was developed, and FE analysis performed to compare the stresses along the bilateral arcuate lines of the reconstructed and normal pelvis in the bipedal standing position. Comparison between bilateral stress distributions along the sciatic notch was also performed. The characteristics of load transmission within the endoprosthesis were also studied. Results: No significant difference in the stresses along the bilateral arcuate lines was observed between the reconstructed and normal pelvis. The stress distribution on the prosthesis along the sciatic notch paths was significantly greater than that on the unaffected side in the same position. The peak stress of the implant on the S1 vertebral body was 182.9 MPa under a load of 600N. Study of load transfer on the implant showed that the posterior side of the column between the point of iliac fixation and the acetabulum was subject to the greatest stress. Conclusion: This FE study showed that a modular hemipelvic endoprosthesis can restore load transfer between the sacrum and acetabulum on simple standing. Future implant design should aim to decrease the stress concentration and make the biomechanical performance more balanced.     

A stress analysis of acetabular reconstruction in protrusio acetabuli

We are reporting the results of a finite-element analysis of acetabular reconstruction for total hip replacement in the presence of protrusio acetabuli. In a protruded acetabulum, cortical bone stresses on the medial part of the pelvic wall increase with medial placement of the acetabular component, while normal placement of the component (more lateral placement) reduces these stresses. Metal backing of a polyethylene acetabular component causes a reduction in the peak cement and trabecular-bone stresses. A metal protrusio ring about only the periphery of the acetabular component increases stress levels within the lateral part of the pelvic cortex and has little effect on stresses in the medial part of the pelvic wall. A complete metal protrusio cup increases stresses in the lateral part of the pelvic cortex while decreasing substantially the stresses in the medial part of the cortex and the trabecular bone. Prosthetic reinforcement of the medial part of the acetabular wall has little effect on stress patterns in the acetabular region. Clinical Relevance: The major long-term problem with cemented total hip prostheses is loosening. Loosening is probably related in part to the stress state in the cement and surrounding bone. The protruded acetabulum is particularly difficult to reconstruct in a manner that ensures longevity of the total hip replacement. In patients with protrusio acetabuli, the prosthetic acetabulum should be placed in a normal and not in a protruded position. A metal-backed acetabular component or a complete metal cup incorporated within the cement reduces stress levels within the medial aspect of the pelvic bone and thus may reduce the incidence of loosening.     

Morphological characteristics of the bony birth canal in patients with developmental dysplasia of the hip (DDH): investigation by three-dimensional CT

We investigated the three-dimensional morphological characteristics of the pelvis in adult female patients with developmental dysplasia of the hip (DDH), using computerized tomography (CT) images. Forty-two subjects with normal hips and 40 DDH patients were recruited for the study. In the DDH group, the average transverse diameter of the pelvic inlet was significantly less and the average transverse diameter of the pelvic outlet was significantly greater than the measurements in the normal group. Further, the bony birth canal in DDH patients exhibited a higher incidence of anthropoid-type geometry, as defined by a longer sagittal diameter relative to the transverse diameter of the pelvic inlet. These findings indicate a characteristic pelvic geometry and suggest different development of the pelvis in the transverse direction in DDH patients. In addition, the obstetric conjugate length/transverse diameter of the pelvic inlet ratio was correlated to the degree of severity of acetabular dysplasia. This finding suggests that DDH is a manifestation of a developmental characteristic of the pelvis. Received: May 8, 2000 / Accepted: January 9, 2001     

The Variation of the Pelvis in Unilateral Crowe Type IV Developmental Dysplasia of the Hip

ObjectiveTo investigate variation of the pelvis in unilateral Crowe type IV developmental dysplasia of the hip (DDH) and analyze the reliability of pelvic landmarks.MethodsWe retrospectively received preoperative anteroposterior pelvic radiographs for 89 adult patients with unilateral Crowe type IV DDH at our institution between September 2008 and May 2019. Forty‐eight patients without a false acetabulum was type IVA and 41 with a false acetabulum was type IVB. The heights of the ilium, acetabulum, and ischium areas in affected and unaffected sides were measured. The ratios of the three areas in entire pelvis are calculated. The discrepancies of bilateral iliac crest, inferior sacroiliac articulation, teardrop, and ischial tuberosity on the bisector of the pelvis were also measured.ResultsThe mean heights of the ilium, acetabulum, ischium areas in the affected side were 74.4, 88.6, and 37.0 mm, respectively, in type IVA group and 77.7, 83.5, and 37.8 mm, respectively, in type IVB group. The heights in the unaffected side were 82.1, 84.6, and 43.8 mm, respectively, in type IVA group and 84.6, 82.0, and 44.0 mm, respectively, in type IVB group. The ratios of the ilium, acetabulum, ischium areas in affected side of Crowe type IVA group were 0.37, 0.44, and 0.19, respectively, and the ratios in unaffected side were 0.39, 0.40, and 0.21, respectively. The ratios in affected side of Crowe type IVB group were 0.39, 0.42, and 0.19, respectively, and the ratios in unaffected side were 0.40, 0.39, and 0.21, respectively. The discrepancies of bilateral iliac crest, inferior sacroiliac articulation, teardrop, and ischial tuberosity on the line of the bisector of the pelvis in Crowe type IVA group were 5.6, 5.2, 2.0, and 7.1 mm, respectively. Those in Crowe type IVB group were 8.1, 3.5, 3.5, and 4.9 mm, respectively.ConclusionsPelvic asymmetry was a common occurrence in unilateral Crowe type IV DDH in adults. Furthermore, it should be reliable to use teardrop as pelvic landmark to balance leg length discrepancy in preoperative planning.     

Optimization of the position of the acetabulum in a ganz periacetabular osteotomy by finite element analysis

Periacetabular osteotomy (PAO) is a surgical procedure to correct acetabular orientation in developmental dysplasia of the hip (DDH). It changes the position of the acetabulum to increase femoral head coverage and distribute the contact pressure over the cartilage surface. The success of PAO depends significantly on the surgeon's experience. Using computed tomography data from patients with DDH, we developed a 3D finite element (FE) model to investigate the optimal position of the acetabulum following PAO. A virtual PAO was performed with the acetabulum rotated in increments from the original center edge (CE) angle. Contact area, contact pressure, and Von Mises stress in the femoral and pelvic cartilage were analyzed. Five dysplastic hips from four patients were modeled. Contact area, contact pressure, and Von Mises stress in the cartilage all varied according to the change of CE angle through virtual PAO. An optimal position could be achieved for the acetabulum that maximizes the contact area while minimizing the contact pressure and von Mises stress in the pelvic and femoral cartilage. The optimal position of the acetabulum was patient dependent and did not always correspond to what would be considered a “normal” CE angle. We demonstrated for the first time the interrelation of correction angle, contact area, and contact pressure between the pelvic and femoral cartilage in PAO surgery. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 472–479, 2013     

Computerized axial tomography of pelvic ring fractures

The radiographs of all patients admitted to the Naval Hospital, Oakland with the diagnosis of pelvic trauma from 1981 through 1985 were reviewed. Thirty-one patients sustained single or double vertical ring fractures. Fifteen of these patients underwent both plain radiography and Computerized Axial Tomographic (CAT) scans in the evaluation of their pelvic injuries. The CAT scans of these pelvic injuries aided in detecting occult sacroiliac disruptions, determining the extent of posterior ring comminution, evaluating possible extension of the pelvic fractures into the acetabulum, assessing pelvic ring stability, and demonstrating soft-tissue injuries within the pelvis. Six pelvic injuries were diagnosed as single vertical breaks in the pelvic ring and nine were diagnosed as double vertical breaks in the pelvic ring by plain radiographs. CAT scanning demonstrated occult posterior ring disruptions in four patients which led to the reclassification of their injuries to double vertical fractures. CAT scanning also demonstrated significant degrees of sacral comminution in five patients which altered surgical treatment plans in all five patients. Two fractures were classified as unstable based on marked sacral comminution demonstrated on CAT scan. Extension of the pelvic ring fractures into the acetabulum was suggested on plain radiographs in three patients and was excluded by review of the CAT scans in these patients. Significant intrapelvic hematomas were demonstrated in three patients and urine extravasation into the hip joint from a bladder laceration was seen in one patient with the CAT scan.(ABSTRACT TRUNCATED AT 250 WORDS)     

髋臼周围肿瘤切除腓骨重建骨盆环的应变研究

目的探讨髋臼周围肿瘤切除后腓骨重建骨盆环的应变。方法选择健康成人尸体骨盆标本6例，按照Ennecking对骨盆肿瘤Ⅱ型切除标准行髋臼周围切除，行腓骨重建骨盆环；双足站立位，在0～500N垂直分级载荷下，采用应变片及应变花对重建后骨盆关键部位的应变进行检测，并和正常骨盆各对应点的应变值进行对照。结果与正常组比较，重建骨盆各测点应变变化较大。在双足站立位，500N垂直载荷下，重建侧骨盆之骶块最大主应变明显小于完整骨盆（P〈0．05）；而健侧髋臼弓状线应变稍增大；双侧耻骨上支应变绝对值增大、由正常状态下的压应变变为拉应变。结论利用人体双足站立位髋臼周围肿瘤Ⅱ型切除腓骨重建骨盆环的生物力学模型进行检测；用腓骨重建的骨盆具有与正常骨盆相似的应变，但不能完全恢复骨盆正常的应力传导功能。     

Prenatal development of the human pelvis and acetabulum.

The prenatal development of the human pelvic bone and acetabulum has been studied by means of classical histology and microradiography. The embryonic phase leads to a fully developed hip within 8 weeks of gestation. The fetal period is a growth phase, including the following main features: endochondral ossification of the ilium from the ninth week, asymmetrical development of the iliac shaft from the fifteenth week, "chondroid-like" tissue formation above the acetabulum from the twenty-sixth week and haversian bone remodelling from the twenty-eighth week. The fetal development of the pelvis and acetabulum seems to be highly related to mechanical stimuli, the most important being the gluteal muscular activity and the simultaneous pressure of the femoral head.     

髋臼前倾和后倾的影像学及生物力学研究

目的探讨髋臼前、后倾的影像学特点和在前、后倾时髋臼缘的生物力学特点,为临床治疗提供相关的依据。方法应用成年防腐骨盆标本制作4例发生髋臼前倾及后倾的骨盆模型,拍模型的标准骨盆正位片,模型加载,分别对前倾组及后倾组进行生物力学测定和影像学观察。结果标准骨盆正位片上前倾时出现“人”字形,后倾时出现交叉征及后壁征。前倾组各点应变值正常时与前倾时经秩和检验,P〈0．05,差异有统计学意义;后倾组各点应变值正常时与前倾时经秩和检验P〈0．05,差异有统计学意义。结论本实验对髋臼前、后倾髋臼缘力学测定,可以推测髋臼前、后倾与许多髋关节退行性疾病有密切联系。通过影像学特点早期发现、早期治疗,并根据生物力学特点制定适当的方案,可提高临床治疗效果。     

The role of computerized tomographic scanning in the evaluation of major pelvic fractures

Twenty-five patients with double vertical fractures of the pelvic ring had evaluations by both plain radiography and computed-tomography scanning of the pelvis. In eight of the twenty-five patients, the interpretation that was made from the plain radiographs, based on the classification of Pennal et al., changed when additional anatomical information was provided by the computed-tomography scan. We recommend that computed tomography be used for: (1) double vertical fracture-dislocations of the pelvic ring in which plain radiographs are inadequate to judge pelvic stability, (2) fractures of the pelvic ring with extension into the acetabulum, and (3) major injuries to the hemipelvis that are to be treated by open reduction and internal fixation. However, due to the increased cost and radiation exposure, routine computed-tomography scanning is not justified for all injuries to the pelvic ring.