不同长度及材质锁骨钩钢板内固定治疗肩锁关节脱位三维有限元分析

目的 对肩锁关节脱位采用不同长度及材质的锁骨钩钢板进行内固定时的应力分布进行有限元分析。方法 选取锁骨钩钢板内固定肩锁关节脱位患者CT数据,数据导入Mimics 21.0软件进行锁骨钩钢板内固定肩锁关节脱位建模,通过Ansys Workbench 17.0对模型进行有限元分析。A组为6孔不锈钢锁骨钩钢板内固定模型,B组为6孔钛合金锁骨钩钢板内固定模型,C组为8孔不锈钢锁骨钩钢板内固定模型,D组为8孔钛合金锁骨钩钢板内固定模型。设定边界及载荷条件,模拟肩锁关节正常活动情况下（用手拿起杯子模拟进食动作）锁骨与钢板应力分布。结果 Von Mises应力云图显示,锁骨应力主要分布于锁骨中外1/3处,钢板应力主要分布于锁骨钩钢板的弯曲部分。钛合金锁骨钩钢板内固定后在相同位置上锁骨的应力要高于不锈钢锁骨钩钢板内固定。6孔钢板内固定后锁骨中外1/3处产生更大的应力。不锈钢锁骨钩钢板内固定后钢板上应力大于钛合金锁骨钩钢板内固定时产生的应力。6孔钢板内固定后锁骨钩与钢板连接处受到的应力更大。与钛合金锁骨钩钢板相比,肩峰对不锈钢锁骨钩钢板产生的压力更大。与8孔钢板相比,肩峰对6孔钢板产生的压力更大。结论 ...     

股骨远端骨折三种内固定方法生物力学比较研究与临床应用

目的：对股骨远端骨折三种内固定方法定量生物力学评价,为临床选择有效的内固定方法提供理论依据。方法：取12具新鲜尸体股骨标本,制成股骨髁间骨折（AO分类的C1型）,采用股骨髁上交锁髓内钉,L形髁钢板,加压钢板三种内固定方法,进行实验应力分析,比较不同内固定方法的优劣,并以有限元理论分析进一步论证它的结果。结果：发现在受同等载荷条件下,髁上交锁髓内钉固定最佳,而采用加压钢板固定的股骨髁强刚度较差（P＜0．05）,临床手术47例,按Kolmert功能评定标准,优良率分别为：股骨髁上交锁髓内钉94．1％,L形髁钢板82．4％,加压钢板76．9％。结论：采和股骨髁上交锁骨内钉固定方法优于其它内固定方法,值得临床推广应用。     

加压内固定取板术后骨结构的分析

本文报告自1992年开始用X射线源的双能骨密度仪测定10例加压内固定、骨折Ⅰ期愈合患者骨密度的变化,对加压钢板取出后骨结构的变化及应力遮挡效应作用进行分析、前臂骨折中,钢板固定超过18个月的患者,其钢板下骨密度与对照侧无明显差异。说明无明显骨萎缩发生。固定少于18个月的1例患者(13个月),其钢板下骨密度明显低于对照侧。结果表明,固定18个月后,钢板下的血循环已恢复正常。固定13个月的患者,其钢板下血循环尚未完全恢复,引起骨密度下降。说明加压内固定应在术后1.5—2年取板。     

锁骨骨折手术治疗临床观察

目的分析、观察两种手术方法治疗不稳定锁骨骨折临床效果。方法对76例不稳定锁骨骨折分别实施克氏针或钢板内固定治疗。结果随访5～18个月，平均10个月。所有患者术中均无意外发生，无1例伤口感染及骨折不愈合。愈后优良率克氏针组85．3％；钢板组88．5％。结论克氏针或钢板内固定治疗不稳定锁骨骨折安全、有效，粉碎骨折首选采用钢板内固定。     

胫骨平台后外侧骨折带状钢板固定的有限元分析

[目的]研究胫骨平台后外侧骨折不同内固定模型在轴向载荷作用下骨块位移、钢板应力的分布规律,探讨符合力学原理的最佳内固定。[方法]应用有限元相关软件建立胫骨平台后外侧骨折有限元模型,包括Ⅰ、Ⅱ和Ⅲ度骨折,并分别用三种钢板固定方式,包括外侧解剖钢板、带状钢板和后侧支撑钢板。设定边界及载荷条件,模拟体重60 kg的慢跑步(1 200 N)情况下胫骨平台后外侧骨折三种固定方式下胫骨平台位移、应力分布及钢板螺钉承受应力情况。[结果]在有限元软件中构建了胫骨平台后外侧骨折钢板固定三维有限元模型;三种固定模型在轴向载荷为1 200 N时,带状钢板与外侧解剖型钢板及后方重建支撑钢板的轴向位移接近;随着载荷增大,三种固定方式下胫骨与螺钉所承受的应力值也随之增大,但各组总体位移与最大应力值均比较接近。[结论]利用有限元相关软件建立的胫骨平台后外侧骨折有限元模型及钢板内固定有限元模型能有效模拟骨折真实情况。使用带状钢板固定后外侧胫骨平台骨折能达到外侧解剖型钢板后方重建钢板固定的生物力学效果。     

髋动力螺钉与锁定钢板治疗不同年龄组股骨粗隆间骨折疗效比较

目的比较动力髋螺钉（DHS）和股骨近端解剖锁定钢板治疗不同年龄组股骨粗隆间骨折的临床效果。方法对2006年3月至2011年3月采用动力髋螺钉（DHS）54例和股骨近端解剖锁定钢板内固定42例股骨粗隆间骨折进行回顾性分析,两种内固定方法患者以65岁为标准分成两组,比较其疗效差异。结果患者平均随访15．5个月（11～26个月）,65岁以下DHS内固定组愈合率90．47％,锁定钢板内固定组愈合率94．44％,两组间无统计学意义（P〉0．05）;65岁以上DHS内固定组愈合率69．70％,锁定钢板内固定组愈合率91．67％,两组间有统计学意义（P〈0．05）。按髋关节功能MerleDaubigne标准评价,65岁以下DHS内固定组优良率62．96％,锁定钢板内固定组为80．95％,两组间有统计学意义（P〈0．05）。结论无明显骨质疏松的粗隆间骨折,DHS和股骨近端解剖锁定接骨板均是内固定的理想选择。高龄患者伴有明显骨质疏松粗隆问骨折,股骨近端解剖锁定接骨板疗效明显优于DHS,可以减少术后并发症的发生。     

斜T形钢板与外固定架均结合克氏针内固定治疗桡骨远端C型骨折的疗效对比

目的比较斜T形钢板与外固定架均结合克氏针内固定治疗桡骨远端C型骨折的疗效对比分析。方法回顾性分析自2006—01—2013-06分别采用斜T形钢板内固定与外固定架结合克氏针内固定治疗桡骨远端C型骨折44例。结果所有患者获得12～18个月（平均16．5个月）的随访。术后12个月采用腕关节功能Gartland—Werley评分对术后疗效进行评估：内外固定组优良率分别为81．0％（17,21）、82．6％（19／23）,并发症发生率分别为9．52％（2／21）、13．04％（3／23）。2组比较差异无统计学意义（P〉0．05）。术后6个月内固定组掌倾角、尺偏角明显优于外固定组,差异有统计学意义（P〈0．05）。结论2种固定方式治疗桡骨远端C型骨折均可达到较为满意的临床效果,斜T形钢板内固定术后短期内影像学结果稍好,对于远期疗效而言,选用外固定架结合克氏针内固定有创伤小、恢复快、成本低、操作方便等特点。     

低应力钢板与降解垫圈减少因应力遮挡引发骨质疏松的实验研究

为减少内固定钢板应力遮挡效应，我们设计了一种减应力桥形钢板和可降解垫圈，将两者结合使用，进行了实验动物的比较观察，结果报道如下。一、材料与方法１．实验用减应力桥型钢板的设计与生物力学测定　桥形钢板长４２ｍｍ，宽５．５ｍｍ，中央部隆起２ｍｍ，长１４ｍｍ；普通直形钢板长４２ｍｍ，宽５．５ｍｍ；减应力钢板主要改进在钢板的中部。２．可吸收降解垫圈的设计　垫圈材料为Ｌ左旋聚乳酸。垫圈外径３．５ｍｍ，内径２．５ｍｍ，厚１．１ｍｍ。３．家兔骨折模型的制备与大体观察指标　新西兰兔３０只，体重２．５～３．０ｋｇ…     

Pilon骨折的手术治疗体会

目的探讨Pilon骨折手术治疗采用内固定方法的选择。方法回顾性分析本院自2006年1月至2009年6月间采用胫骨远端外侧异型钢板或AO三叶草钢板手术内固定治疗Ⅱ型、Ⅲ型Pilon骨折46例,其中Ⅱ型34例、Ⅲ型12例。结果经6个月～3年的术后随访,临床疗效优良率达89．1％,其中胫骨远端外侧异型钢板手术固定者达90．6％,AO三叶革钢板固定达85．7％。结论针对Ⅱ型、Ⅲ型Pilon骨折的骨折块状况,应结合软组织的损伤程度,合理选用内固定方法,可达到骨折的稳妥固定,具有早期关节活动,利于骨折愈合的优点。     

股骨近端内侧支撑固定的有限元分析

目的通过有限元分析股骨转子间骨折六部分分型各型骨折经股骨近端内侧钢板固定后的稳定性,探讨股骨近端内侧钢板对股骨近端内侧壁的支撑作用。方法运用有限元法建立股骨转子间骨折六部分分型各型骨折以股骨近端防旋髓内钉(PFNA)、内侧钢板(双皮质)、PFNA+内侧钢板(单皮质)固定后的模型。按参考文献提供参数,对模型的边界条件及材料属性进行设定,按体重70 kg的成人正常行走时髋部受力峰值进行加载。按上述条件得到21组内固定模型的应力与形变位移图,分析各组模型重要部位的应力峰值及各骨折块的位移数据。结果PFNA固定各型骨折时,股骨各重要位置承受应力变化及骨折块位移幅度均较小,大转子部位的骨折块位移增加幅度稍大;内侧钢板固定时,随着骨折块的增加,尤其是外侧骨折块的增多,股骨重要位置处及内固定自身所承受的应力均明显的增加,骨折块位移大幅增加,但内侧骨折块位移幅度始终较小;PFNA+内侧钢板固定时,股骨各重要位置承受应力变化及骨折块位移幅度是3种内固定方式中最小的。结论股骨近端内侧钢板能有效减小股骨近端应力的集中程度,对股骨近端内侧壁起到较好的支撑作用;对于不稳定型骨折应用PFNA辅助内侧钢板固定时较单独应用PFNA能有效降低股骨所受应力,各骨折块位移均未见明显增加,且内固定本身应力未见明显异常,能起到坚强固定的作用。     

颈椎前路融合手术中钢板摆放角度对颈椎稳定性影响的有限元分析

目的:利用有限元分析的方法,比较颈前路融合手术中钢板偏离颈椎长轴与钢板标准摆放的生物力学性能。方法:选取一名健康女性志愿者并进行CT扫描(C1-T1),应用Mimics 19.0,Geomagic Studio 2015,Solidworks 2018,Ansys Workbench 17.2等软件建立下颈椎(C3-C7)模型进而验证模型的可靠性,随后置入不同角度、不同长度的颈前路钢板,从而建立颈前路椎间盘切除减压融合术(anterior cervical discectomy fusion,ACDF)模型,在C3上施加73.6 N轴向压力及1 NM的纯力矩,使模型产生屈曲、后仰、侧弯及旋转活动,观察模型应力云图,记录器械最大应力值及椎间活动度并进行分析比较。结果:建立下颈椎(C3-C7)有限元模型,与已发表的关于颈椎活动度的文献相对比,验证了模型的有效性。钢板摆放偏移轴线对内固定器械的应力分布、最大应力值及椎间活动度影响较小;单节段钢板相比于双节段钢板对钢板偏移的力学影响更小。结论:在颈椎前路钢板与颈椎长轴存在角度时对颈椎的力学稳定性影响不大。在临床手术钢板倾斜小于20°时,无须重新调整钢板位置。     

脊髓损伤后神经轴突导向分子Semaphorin 3A表达的研究

目的:研究后脊髓损伤大鼠Semaphorin 3A表达的变化,探索脊髓损伤后轴突再生受到抑制的可能机制。方法:40只雌性健康SD大鼠,8周龄,体质量(210.00±9.88)g,随机分为对照组(A组,20只)和模型组(B组,20只)。A组仅切开T10全椎板及T9、T11部分椎板,对脊髓未作其他处理;B组切开T10全椎板及T9、T11部分椎板采用脊髓横切法制作脊髓损伤的动物模型。两组分别在术后3、7、14、28、42 d(每组每个时间点4只)进行灌注、获取脊髓组织,然后进行HE染色,同时按照SP试剂盒的操作步骤进行Semaphorin 3A的表达。结果:单纯脊髓横切损伤后,损伤局部发生出血坏死,局部水肿,神经变性、坏死以及囊腔形成,胶质细胞增生胶质瘢痕形成。对照组Semaphorin 3A只在灰质区有低水平表达。模型组术后3 d脊髓损伤损伤区Semaphorin 3A无表达,14 d时脊髓损伤损伤区Semaphorin 3A的表达显著增加,处在较高的水平,28 d时Semaphorin 3A的表达呈中等水平,42 d时Semaphorin 3A阳性表达恢复到正常水平。结论:脊髓损伤后Semaphorin 3A表达升高,可能是抑制轴突再生的机制之一。     

Biomechanical comparison of four different posterior malleolus fixation techniques: A finite element analysis

PurposeThe objective of this study was to compare the biomechanical behavior of four fixation methods for posterior malleolar fracture (PMF) by finite element analysis (FEM).MethodsFour internal fixation techniques used for fixation of PMF were assessed by FEM - a computational study: posterior one-third tubular 3.5 mm buttress plate (PP) with one screw (PP 1 screw), PP with two screws (PP 2 screws), two cannulated 3.5 mm lag screws in the antero-posterior (AP) direction (AP lag screws), and two postero-anterior (PA) cannulated 3.5 mm lag screws (PA lag screws). PMF with 30% and 50% fragment sizes were simulated through computational processing reconstructed from computed tomography (CT). The simulated loads of 700 N and 1500 N were applied to the proximal tibial end. The FEM evaluated the total and localized displacements of the PMF. For the analysis of stresses, the variables maximum principal (traction) and minimum principal (compression) were used. For the metallic implants, the equivalent von Mises stress (VMS) was used.ResultsPA lag screw showed the lowest values for total and localized displacement, minimum and maximum total stress, and VMS in both physiological conditions and sizes of posterior malleolus involvement. The localized displacement was statistically lower for lag screws compared to PP techniques at 700 N (p < 0.05) and 1200 N (p < 0.05). The maximum total stress was statistically lower for PA lag screws compared to PP 1 fixation with 700 N (p = 0.03) and 1200 N (p = 0.039).ConclusionPA lag screws yield better results in terms of total and localized displacement, minimum and maximum total stress, and VMS in both physiological conditions and sizes of posterior malleolus involvement. These results demonstrate that PA lag screws are biomechanically the most efficient technique for the fixation of PMF.     

Cervical ossification of the posterior longitudinal ligament: factors affecting the effect of posterior decompression

Objective: Decompression procedures for cervical myelopathy of ossification of the posterior longitudinal ligament (OPLL) are anterior decompression with fusion, laminoplasty, and posterior decompression with fusion. Preoperative and postoperative stress analyses were performed for compression from hill-shaped cervical OPLL using 3-dimensional finite element method (FEM) spinal cord models.

Methods: Three FEM models of vertebral arch, OPLL, and spinal cord were used to develop preoperative compression models of the spinal cord to which 10%, 20%, and 30% compression was applied; a posterior compression with fusion model of the posteriorly shifted vertebral arch; an advanced kyphosis model following posterior decompression with the spinal cord stretched in the kyphotic direction; and a combined model of advanced kyphosis following posterior decompression and intervertebral mobility. The combined model had discontinuity in the middle of OPLL, assuming the presence of residual intervertebral mobility at the level of maximum cord compression, and the spinal cord was mobile according to flexion of vertebral bodies by 5°, 10°, and 15°.

Results: In the preoperative compression model, intraspinal stress increased as compression increased. In the posterior decompression with fusion model, intraspinal stress decreased, but partially persisted under 30% compression. In the advanced kyphosis model, intraspinal stress increased again. As anterior compression was higher, the stress increased more. In the advanced kyphosis +?intervertebral mobility model, intraspinal stress increased more than in the only advanced kyphosis model following decompression. Intraspinal stress increased more as intervertebral mobility increased.

Conclusion: In high residual compression or instability after posterior decompression, anterior decompression with fusion or posterior decompression with instrumented fusion should be considered.     

Notch sensitivity jeopardizes titanium locking plate fatigue strength

IntroductionNotch sensitivity may compromise titanium-alloy plate fatigue strength. However, no studies providing head-to-head comparisons of stainless-steel or titanium-alloy locking plates exist.Materials and methodsCustom-designed identically structured locking plates were made from stainless steel (F138 and F1314) or titanium alloy. Three screw-hole designs were compared: threaded screw-holes with angle edges (type I); threaded screw-holes with chamfered edges (type II); and non-threaded screw-holes with chamfered edges (type III). The plates’ bending stiffness, bending strength, and fatigue life, were investigated. The stress concentration at the screw threads was assessed using finite element analyses (FEA).ResultsThe titanium plates had higher bending strength than the F1314 and F138 plates (2.95:1.56:1) in static loading tests. For all metals, the type-III plate fatigue life was highest, followed by type-II and type-I. The type-III titanium plates had longer fatigue lives than their F138 counterparts, but the type-I and type-II titanium plates had significantly shorter fatigue lives. All F1314 plate types had longer fatigue lives than the type-III titanium plates. The FEA showed minimal stress difference (0.4%) between types II and III, but the stress for types II and III was lower (11.9% and 12.4%) than that for type I.ConclusionsThe screw threads did not cause stress concentration in the locking plates in FEA, but may have jeopardized the fatigue strength, especially in the notch-sensitive titanium plates. Improvement to the locking plate design is necessary.     

3D打印多孔钛钢板一体化植入体修复髋臼后壁粉碎性骨折合并骨缺损的初步研究

目的 :探讨应用计算机辅助设计(computer aided design,CAD)结合3D打印技术对髋臼后壁粉碎性骨折合并骨软骨缺损进行修复重建的可行性,评估多孔钛合金支架钢板一体化植入体复合氮化钛生物陶瓷涂层的生物力学性能。方法:基于连续断层CT图像,利用CAD软件来构建具有特定三维内部结构的多孔钛钢板一体化植入体数字模型,以Ti6Al4V粉末为原材料打印出实体并于其关节面复合氮化钛涂层,观察植入体与髋臼匹配和贴附情况;利用Ansys软件进行有限元建模,分析正常组、传统组及植入体组髋臼在相同载荷状态下的应力分布、应力传导及形变位移等情况,验证植入体的生物力学性能。结果:植入体的多孔钛合金支架与髋臼匹配程度良好,钢板形态基本与骨表面贴附,根据Matta复位标准评定为优。有限元分析结果显示:植入体重建后髋臼在Von Mises应力峰值13.38 MPa接近正常组13.11 MPa,小于传统组15.66 MPa;植入体重建后的髋臼在应力分布和传导与正常组基本一致,稍优于传统组;植入体的最大相对位移为0.166 mm,处于可以接受的范围。结论:3D技术制备的多孔钛合金支架钢板一体化植入体复合氮化钛涂层具备优良的匹配度和生物力学性能;解剖重建使后壁头臼应力分布及传导恢复比较理想,接近正常的髋关节,其为临床治疗髋臼后壁粉碎性骨折合并严重骨缺损的病例提供新选择。     

单钉-沟槽柱翼钢板加WDFC治疗腰椎滑脱症的生物力学实验

目的：采用力学实验的方法,检验单钉-沟槽柱翼钢板加WDFC（Wendeng fusion cage）对腰椎滑脱复位固定后腰骶部的稳定程度。方法：取死后1～2h内生前健康成人尸体,男9具,女3具,随机分2组,各取腰骶段（L3-S3）湿骨,制作腰椎滑脱疾病模型;采用单钉-沟槽柱翼钢板加WDFC分别制成单节段和跨节段固定试件,贴应变片。采用电测法,对每个试件分别测试2次应变值。实验获得的数据运用GRAFTOOL软件进行处理。结果：单节段与跨节段非破坏性压缩实验中相关系数、相关曲线无明显斜率变化。在单节段弯扭组合试验中试件各点应力均大致呈线性增长。在跨节段弯扭实验中,出现两侧对应点不对称斜率,失去稳定状态。结论：通过实验证明单钉-沟槽柱翼钢板加WDFC治疗腰椎滑脱复位固定后有着良好的稳定性,在各种加载过程当中,应力与应变在大于人体行走负荷状态下均呈线性分布。同时,通过弯扭实验也证明单节段固定抗扭转性较跨节段固定有更好稳定性。     

骨质疏松性肱骨近端骨折PMMA骨水泥强化螺钉钢板固定的有限元分析

目的：借助有限元分析的方法探讨肱骨近端聚甲基丙烯酸甲酯（polymethyl methacrylate,PMMA）骨水泥强化螺钉钢板固定对骨质疏松性肱骨近端骨折内固定稳定性的影响。方法：制作肱骨近端2部分骨折伴干骺端骨缺损的不稳定肱骨近端骨折数字化模型,分别建立肱骨近端骨水泥强化螺钉钢板固定及普通螺钉钢板固定的有限元模型,分析螺钉周围松质骨应力、整体刚度、钢板最大应力及螺钉最大应力。结果：肱骨近端骨水泥强化螺钉钢板固定的头端6枚螺钉周围松质骨最大应力分别为：1号钉1.07 MPa,2号钉0.43 MPa,3号钉1.16 MPa,4号钉0.34 MPa,5号钉1.99 MPa,6号钉1.57 MPa,普通螺钉钢板固定为：1号钉2.68 MPa,2号钉0.67 MPa,3号钉4.37 MPa,4号钉0.75 MPa,5号钉3.30 MPa、6号钉2.47 MPa。两组模型的整体刚度分别为：骨水泥结构448 N/mm、普通结构434 N/mm。钢板的最大应力均出现在结合孔：骨水泥结构701 MPa、普通结构420 MPa。螺钉的最大应力均出现在4号钉的尾端：骨水泥结构284 MPa、普通结构...     

Stress analysis of the cervical spinal cord: Impact of the morphology of spinal cord segments on stress

Objective: Although there are several classifications for cervical myelopathy, these do not take differences between spinal cord segments into account. Moreover, there has been no report of stress analyses for individual segments to date.

Methods: By using the finite element method, we constructed 3-dimensional spinal cord models comprised of gray matter, white matter, and pia mater of the second to eighth cervical vertebrae (C2–C8). We placed compression components (disc and yellow ligament) at the front and back of these models, and applied compression to the posterior section covering 10%, 20%, 30%, or 40% of the anteroposterior diameter of each cervical spinal cord segment.

Results: Our results revealed that, under compression applied to an area covering 10%, 20%, or 30% of the anteroposterior diameter of the cervical spinal cord segment, sites of increased stress varied depending on the morphology of each cervical spinal cord segment. Under 40% compression, stress was increased in the gray matter, lateral funiculus, and posterior funiculus of all spinal cord segments, and stress differences between the segments were smaller.

Conclusion: These results indicate that, under moderate compression, sites of increased stress vary depending on the morphology of each spinal cord segment or the shape of compression components, and also that the variability of symptoms may depend on the direction of compression. However, under severe compression, the differences among the cervical spinal segments are smaller, which may facilitate diagnosis.     

骶髂关节解剖型棒-板内固定系统的生物力学评价

目的：探讨采用新型骶髂关节解剖型棒-板内固定系统（SABP）治疗骨盆骶髂关节骨折脱位的生物力学性能。方法：采集新鲜的冷冻尸体骨盆标本20具,造成骨盆骨折模型,采用实验应力分析方法,对SABP内固定和骶骨螺钉结合Galveston技术内固定、骶骨棒固定、重建钢板固定、骶髂关节螺钉等5种固定作对照比较,分别测定它们的刚度和强度,用以评价骨盆的稳定性。结果：采用新型骶髂关节解剖型棒-板内固定系统治疗骨盆骶髂关节骨折脱位,较骶骨螺钉结合Galveston技术内固定、骶髂关节螺钉、重建钢板固定、骶骨棒固定其骨盆的刚度分别高10%、11%、16%、21%,强度分别高12%、14%、21%、31%;应变分别小13%、14%、22%、25%,位移分别小10%、12%、16%、20%,差异有统计学意义（P〈0.05）,并且超过正常人骨盆标本,但差异无统计学意义（P〉0.05）。结论：采用新型SABP内固定装置治疗骨盆骨折,其强度、刚度最佳,优于其他内固定方法,是一种理想的新型内固定器械。