坐股韌帶重建穩(wěn)定機(jī)制三維有限元分析及其生物力學(xué)意義_圖文

1、Y1055123分類號(hào):R77單位代碼:10343學(xué) 號(hào):20041135固濕州睹訾院 碩士學(xué)位論文論文題目:坐股翅董重建穩(wěn)定扭劍三維直阻五盆揖叢 甚生物力堂意望研究生姓名:李永獎(jiǎng)學(xué)科專業(yè):外科學(xué)(骨科類 型:科學(xué)型指導(dǎo)教師:張力成教授楊國(guó)敬教授湯呈宣副教授 二零零七年五月商品優(yōu)勢(shì)淘寶的商品數(shù)目在近幾年內(nèi)有了明顯的增加, 從汽車、 電腦到服飾、 家居用品,分類齊全,更是設(shè)置網(wǎng)絡(luò)游戲裝備交易區(qū),網(wǎng)游迷們值得來(lái) 看一看。 作為拍賣網(wǎng)站,淘寶突出的優(yōu)點(diǎn)是,如果商品的剩余時(shí)間在 1小時(shí) 以內(nèi),時(shí)間的顯示是動(dòng)態(tài)的,并且準(zhǔn)確顯示到了秒。服務(wù)優(yōu)勢(shì) 比普通店鋪更有吸引力的是他的服務(wù),他不光是大賣家 和大品牌的

2、集合,同時(shí)也提供比普通店鋪更加周到的服務(wù):1、 七天無(wú)理由退換貨 淘寶商城賣家接受買家七天內(nèi)無(wú)理由退 換貨,無(wú)需擔(dān)心買到的不合適,或者買到的東西和實(shí)際相差太大。 2、 2、正品保障 淘寶商城賣家所賣物品都是正品行貨,接受買 家的監(jiān)督和淘寶的監(jiān)督。坐股韌帶重建穩(wěn)定機(jī)制三維有限元分析及其生物力學(xué)意義 中文摘要一、研究目的附著于髖關(guān)節(jié)骨結(jié)構(gòu)的關(guān)節(jié)囊韌帶有助于限制股骨頭相對(duì)于髖臼的位移, 而可允許復(fù)雜的旋轉(zhuǎn)和平面運(yùn)動(dòng)組合,盡管這個(gè)重要的功能,髖關(guān)節(jié)囊韌帶經(jīng)常 在用來(lái)治療骨性關(guān)節(jié)炎的全髖關(guān)節(jié)置換術(shù)(T臥以及用來(lái)治療關(guān)節(jié)囊內(nèi)移位骨 折的半髖關(guān)節(jié)置換術(shù)中被部分或全部切除。本研究通過(guò)計(jì)算機(jī)三維有限元分析從 仿

3、真學(xué)角度模擬TI-IA術(shù)后髖關(guān)節(jié)脫位來(lái)驗(yàn)證和考察THA術(shù)后假體脫位的生物力學(xué) 機(jī)制以及髖關(guān)節(jié)囊韌帶重建對(duì)THA術(shù)后髖關(guān)節(jié)穩(wěn)定的作用及其生物力學(xué)機(jī)理。主 要包括:l、髖關(guān)節(jié)三維有限元模型的構(gòu)建及三維有限元分析,探討髖關(guān)節(jié)生物力學(xué)特性 并為構(gòu)建髖關(guān)節(jié)周圍韌帶提供定量的空間基礎(chǔ)以及模擬TIIA提供基礎(chǔ)模型。 2、人工髖關(guān)節(jié)假體三維有限元模型的構(gòu)建及三維有限元分析,并模擬THA與髖 關(guān)節(jié)進(jìn)行裝配,進(jìn)一步探討其生物力學(xué)意義。3、坐股韌帶重建三維有限元模型的構(gòu)建及三維有限元分析,探討其相關(guān)的生物 力學(xué)意義,驗(yàn)證該模型的可行性及可靠性。4、包括坐股韌帶重建的T眥術(shù)后假體脫位過(guò)程三維有限元分析,并與僅有金屬

4、模型進(jìn)行比較探討關(guān)節(jié)囊韌帶重建對(duì)髖關(guān)節(jié)的穩(wěn)定機(jī)制。二、材料和方法1、髖關(guān)節(jié)三維有限元模型構(gòu)建及有限元分析。模型構(gòu)建分3個(gè)步驟完成:獲取 cT圖象:對(duì)一具濕髖關(guān)節(jié)(女,49歲進(jìn)行cT斷層成像,每imm層厚掃面一次, 所得圖象直接存入cT機(jī),刻錄光盤,獲取表示髖關(guān)節(jié)每層橫截面的圖象。處理 凹圖象:將髖關(guān)節(jié)cT掃面圖象以DICOM格式存入計(jì)算機(jī),按照掃面的順序逐張?zhí)?理每一張cT圖象,去除圖象中骨骼周圍的軟組織,得到處理后的髖關(guān)節(jié)每一斷層 cT圖象。重建cT圖象:選取圖象左邊標(biāo)尺的上端點(diǎn)為第一基準(zhǔn)點(diǎn),下端點(diǎn)為第 二基準(zhǔn)點(diǎn),使每一層的兩基準(zhǔn)點(diǎn)嚴(yán)格保持一致;以髖關(guān)節(jié)的近端為z軸正方向, 遠(yuǎn)端為負(fù)方向;計(jì)

5、算圖象中各像素點(diǎn)間的灰度值“梯度”確定圖象的輪廓,對(duì)每層圖象進(jìn)行處理,提取髖臼及股骨近端外表面和內(nèi)表面的一系列關(guān)鍵點(diǎn),連接輪 廓點(diǎn)得到表示髖關(guān)節(jié)形狀的內(nèi)、外輪廓線,導(dǎo)入三維有限元模型構(gòu)建軟件中進(jìn)行 重建。單元屬性設(shè)定應(yīng)變率為0.Ol,泊松比為0.3。三維有限元分析采用有限元 分析軟件SolidWorks2006進(jìn)行,網(wǎng)格劃分采用三維十結(jié)點(diǎn)四面體實(shí)體單元。 2、人工髖關(guān)節(jié)假體三維有限元模型的構(gòu)建及有限元分析利用有限元分析軟件 SolidWorks 2006SP0.0進(jìn)行,建模之前根據(jù)假體的工程圖特征先將全髖假體拆 分成4部分,即鈦金屬骸臼杯、聚乙烯內(nèi)襯、股骨頭、股骨柄。分別分析各個(gè)部 分的結(jié)構(gòu)特

6、征,將外形結(jié)構(gòu)輸入到有限元軟件中,生成體積,構(gòu)建出零件的三維 實(shí)體模型。將所構(gòu)建的零件按假體的整體特征進(jìn)行裝配,獲取一組非商業(yè)性質(zhì)的 人工全髖假體三維有限元模型。將所構(gòu)建模型輸入COSMOSWorks2006軟件進(jìn)行網(wǎng) 格劃分,采用完全程序自動(dòng)劃分方法。模擬人體坐位腿交叉動(dòng)作過(guò)程,分析假體 脫位過(guò)程的角活動(dòng)度和相應(yīng)的假體應(yīng)力場(chǎng)分布情況。3、坐股韌帶重建三維有限元模型的構(gòu)建:選擇多重獨(dú)立連接界面來(lái)構(gòu)建髖關(guān)節(jié) 囊韌帶。坐股韌帶被定位在適當(dāng)?shù)慕馄手亟ㄖ裹c(diǎn)處,骨結(jié)構(gòu)的詳細(xì)解剖特性均來(lái) 自于上述的cT數(shù)據(jù)及由其構(gòu)建的髖關(guān)節(jié)骨解剖結(jié)構(gòu)有限元模型,劃分的有限元 網(wǎng)格為建立關(guān)節(jié)囊韌帶附著區(qū)域提供定量的空間基礎(chǔ)

7、。在計(jì)算模型中,關(guān)節(jié)囊韌 帶的準(zhǔn)確定位是借助于共同的參考點(diǎn)而完成的。開(kāi)始的幾何材料測(cè)量來(lái)自于 Hewitt的實(shí)驗(yàn)工作,關(guān)節(jié)囊韌帶以實(shí)驗(yàn)依據(jù)的材科特性進(jìn)行六面體連接單元網(wǎng) 格劃分。對(duì)于不同高彈性材料模型,在關(guān)節(jié)囊韌帶擬合實(shí)驗(yàn)應(yīng)力一應(yīng)變曲線方面, 選擇高彈性模型操作。4、髖關(guān)節(jié)囊韌帶重建生物力學(xué)有限元分析。在以上幾步實(shí)驗(yàn)的基礎(chǔ)上,將模型 導(dǎo)入有限元分析軟件ABAQUS6.6及COSMOS Works2006模擬坐位腿交叉動(dòng)作載荷, 計(jì)算通過(guò)輸入一系列增加的股骨假體屈曲內(nèi)收角位移來(lái)運(yùn)行,屈曲和內(nèi)收比為2 :1。同時(shí),髖臼承受由髖部肌肉收縮力經(jīng)股骨頭傳導(dǎo)的應(yīng)力沖擊,942N關(guān)節(jié)接 觸合力通過(guò)位于股骨頭

8、中心的Bezier面實(shí)體參考結(jié)點(diǎn)進(jìn)行加載,載荷的方向模 擬步態(tài)周期髖關(guān)節(jié)峰載荷,于額狀面內(nèi)與垂直軸位22.5。的后中方向。以屈曲:內(nèi)收2:1的比率,模型連續(xù)操作直到有限元計(jì)算當(dāng)接觸合力離開(kāi)指定的杯載荷 負(fù)重面產(chǎn)生數(shù)值不穩(wěn)定而終止,即當(dāng)髖臼合阻力矢量活動(dòng)方向從負(fù)重面移向內(nèi)襯 唇斜面的時(shí)刻,預(yù)示著脫位。在這個(gè)時(shí)點(diǎn)上,計(jì)算變成數(shù)字不穩(wěn)定,這個(gè)狀態(tài)可2溫州醫(yī)學(xué)院碩士學(xué)位論文能意味著生理的頭開(kāi)始無(wú)限制的自由向外滑出凹面。計(jì)算獲取假體脫位過(guò)程的角 活動(dòng)度和相應(yīng)的阻力矩值以及假體界面產(chǎn)生的vorl Mises應(yīng)力值分布情況,并對(duì) 結(jié)果進(jìn)行歸納分析。三、結(jié)果經(jīng)建模后得到了在體髖關(guān)節(jié)三維有限元模型、右側(cè)髖關(guān)節(jié)三

9、維有限元模型、 人工髖關(guān)節(jié)假體三維有限元模型:在髖關(guān)節(jié)三維有限元模型模擬THA、關(guān)節(jié)囊韌 帶(坐股韌帶重建三維模擬的基礎(chǔ)上進(jìn)行計(jì)算,得出人體坐位腿交叉動(dòng)作載荷 下,假體脫位動(dòng)態(tài)過(guò)程中各個(gè)工況下Von Mises應(yīng)力結(jié)果:僅金屬模型情況下 股骨屈曲90。時(shí)關(guān)節(jié)面最大主應(yīng)力值為5.045Mpa,屈曲92.5。時(shí)最大主應(yīng)力 值為5.540Mpa,屈曲95。時(shí)為6.280Wpa,屈曲97.5。時(shí)為6.362Mpa,屈曲 100。時(shí)為7.480Mpa:而增加坐股韌帶重建的THA脫位模型分別為4.676Mpa, 5.579Mpa,6.986Mpa,7.293Mpa, 18.819Mpa。動(dòng)態(tài)過(guò)程中杯中心的

10、股骨阻力 矩值在僅金屬模型股骨屈曲90。為0.2N.m,屈曲92.5。時(shí)為O.5N.m,屈曲95。 時(shí)為0.7N.m,屈曲97.5。時(shí)為0.6N.in,屈曲100。時(shí)為0.7N.m,屈曲102.5。 時(shí)為0.75N.m,屈曲105。時(shí)為7.75N.m,屈曲107.5。時(shí)為11.25N.m,屈曲110。 時(shí)為11.5N.m,屈曲112.5。時(shí)為lO.5N。m,屆曲115。時(shí)為9.3N.m,屈曲117.5。 時(shí)為8.1N.m,屈曲120。時(shí)為5.2N.m,屈曲122.5。時(shí)為3.8N.m,屈曲125。時(shí) 為0.6N.m,而增加坐股韌帶重建的全髖脫位模型分別為7.5N.m,7.2N.in,7.6N.

11、m, 7.9N.m,7.8N.m,8.3N.m。13.8N.m。16.7N.m,18.1N.m,16.2N.m,14.8N.m, 13.8N.m,12.3N.m,10.7N.nl,7.4N.m。僅金屬模型的典型阻力距輪廓包括三個(gè) 明確的階段,起始非O的基線力矩,代表超高分子聚乙烯內(nèi)襯與股骨頭之間 軸承磨察(摩擦率=0.038:從起初(阻力距輪廓小的部分到最終完全的碰 撞連接開(kāi)始(阻力矩輪廓線性增加部分;開(kāi)始于近峰阻力矩的半脫位階段而 表現(xiàn)為股骨阻力矩值的下坡,直到計(jì)算不穩(wěn)定的開(kāi)始(相應(yīng)指生理脫位。相反, 在增加坐股韌帶的模型中,角運(yùn)動(dòng)輸入能夠提供更大的阻力,因?yàn)殛P(guān)節(jié)囊累積的 拉緊使得整個(gè)坐位腿

12、交叉脫位過(guò)程中的阻抗明顯增加。增加坐股韌帶重建的模型 和僅有金屬的模型相比降低了撞擊點(diǎn)和脫位點(diǎn)峰應(yīng)力各為17%、31%,峰阻力 矩增加了57%,并提供了2.29倍的穩(wěn)定性(曲線下的面積。在整個(gè)實(shí)驗(yàn)中的各 個(gè)工況中均能夠清楚地顯示整個(gè)整體的應(yīng)力結(jié)果、應(yīng)交結(jié)果、位移結(jié)果及變形結(jié)溫州醫(yī)學(xué)院碩士學(xué)位論文果。比如僅有金屬模型股骨屈曲97.5。時(shí)最小應(yīng)力值出現(xiàn)于4633號(hào)節(jié)點(diǎn),位置 處于3.79582哪,-12.2788嘲,-23.1805舢,力值為15878.4N/m2,最大應(yīng) 力值出現(xiàn)于13515號(hào)節(jié)點(diǎn),位置處于一26.0584唧,18.1485珊,98.9955咖, 力值為6.36214e+006N

13、/m2。應(yīng)變結(jié)果:最小應(yīng)變處于5905號(hào)節(jié)點(diǎn),位置處于 一3.55608咖,-9.17404咖,-8.6409唧,應(yīng)變值為:6.5561e-007;最大應(yīng)變 處于2560號(hào)節(jié)點(diǎn),位置處于0.816801咖,14.6763咖,-1.60733舢,應(yīng)變值 為0.00146277。位移結(jié)果:最小位移處于6984號(hào)節(jié)點(diǎn),最大位移處于6224號(hào) 節(jié)點(diǎn),位移分布范圍:0mO.000876198m。變形結(jié)果:比例因子為15.947, 能夠清楚地顯示整個(gè)整體的變形結(jié)果。四、結(jié)論l、本實(shí)驗(yàn)構(gòu)建的三維有限元模型為系統(tǒng)地研究THA術(shù)后假體脫位生物力學(xué)機(jī)制 開(kāi)辟了新的途徑;重建髖關(guān)節(jié)囊韌帶后將提供更大的靜力支持,因此

14、也需要更大 的扭轉(zhuǎn)力矩才能使假體發(fā)生撞擊和脫位;坐股韌帶作為髖關(guān)節(jié)后方關(guān)節(jié)囊一個(gè)確 切的解剖結(jié)構(gòu),對(duì)后方穩(wěn)定裝置的力學(xué)完整性起到重要的作用,髖關(guān)節(jié)成型術(shù)中 應(yīng)該重建髖關(guān)節(jié)囊韌帶。分析結(jié)果圖可以看出,髖關(guān)節(jié)囊韌帶重建既有助于穩(wěn)定 髖關(guān)節(jié),其降低撞擊點(diǎn)和脫位點(diǎn)的最大主應(yīng)力值,從另一側(cè)面可能證實(shí)該技術(shù)可 降低由于撞擊處應(yīng)力過(guò)大所致的磨損介導(dǎo)的假體松動(dòng)率。2、本實(shí)驗(yàn)結(jié)論為臨床重建關(guān)節(jié)囊技術(shù)推廣應(yīng)用提供理論依據(jù)。關(guān)鍵詞全髖關(guān)節(jié)置換術(shù);假體脫位;坐股韌帶;生物力學(xué);三維有限元分析Three.Dimensional Finite Element Analysis of Stable Mechanism Fo

15、r lschiofemoral Ligament Reconstruction and It's Biomechanical SignificanceABSTRACTObjective:The hip capsule functions in conjunction們m the bony components of the hip to constrain translation between the head of the femur and the acetabulum,while allowing complex combinations of ratation and pla

16、nar movements.Dsepite this important biomechanical function,the hip capsule often is excised partially or completely during THA for treatment of arthritis and in hemiarthroplasty for displaced intracapsular hip fi'actures.The purpose of this study is to explain the biomechanical mechanism of tot

17、al hip dislocation and the related biomechanical significance of capsule ligament reconstruction with threedimensional(3Dfinite element analysis from emulation aspect and investigate the role of the hip capsule ligament in stable mechan/sm ofhipjoint.Including:1.To construct the 3-D finite element h

18、ip joint model and analysis with 3-D finite element method,and to investigate its biomechanical significance,furthermore,the consruction of hip joint's 3-D finite element model(FEMprovides basic data for research on mechanical behavior ofhipjoint and THA,and the model￥111"fae酆3,which were z

19、oned with a three-dimensional.allquadrilateral rigid body finite element mesh, provide a quantitative spatial basis for establishing capsule attachment sites.2.To consI朝lct and validate the 3-D FEM of total hip dislocation and to investigate the related biomechanical significance.3.To construct and

20、validate the 3-D FEM of ischiofemoral ligament reconstruction and investigate the related biomechanical significance.4.To implement capsular ischiofemoral ligament in a totalhip dislocation FEM.andthis soft-tissue-augmented FEM Was used to investigate the biomechanical characteristics oftotal hip di

21、slocation,and explore or show that capsule enhancementmakes a substantial contribution in stability,compared to an otherwise identical hardw粼niy model.MateriaIs and Methods:L Construction of3-D finite element ofhipjoint and analysis with 3-D fiIli鈀element. Stepl.We obtained the CT inlages from a fem

22、ale adlIlt volunteer(49-year-oldwho received a computer tomography(CT,and lmm be協(xié),am two CT slices.All the images werc saved in CT machine and then made into compact disc(CD'from which we attained every cross-section of the hip joint.Step2.We processed the CT images with them in DICOM format and

23、 clean the parenchyrna around thehip joint in scanning sequence.So we got every processed CT picture.Step3.CT images were reconstructed as follows:we chosed the upper and nether endpoint in left ruler as the first and second datum mark respectively,which kept in accordance strictly in every slice.In

24、 the middle hipjoint section,we set the midpoint oftwo pixels that possessed the maximal distance as the origin of the 3-D reference flame,and the proximal hip joint as the positive direction of Z axis and the distal one as negative.The gray gradients between pixels were calculated to confirm the pr

25、ofile ofthe image.Then we processed the image、itIl selecting a series of key points in outer and inner surfaces.and obtained the inner and outer figure linespresenting the shapeof hip joint when connecting the points.Finally we reconstruct them using 3-D finite element soft.We set stress rate as O.0

26、l in element property and the poisson's rate Was assumed to be 0.3.step4.Analysis were carried out using the finite elementanalysis softSolidWorks2006,with threedimensional 10一node tetrahedral entity mesh generation method.2.Construction of3-D finite element total hip prosthesis model and analys

27、is with 3-D finite element.T0tal hip hardware prosthesis FEM consisted of four component parts: a titanium metal backing,an ultra-high molecular weight polyethylene(UHMWPE acetabular component,and a CoCr alloy femoral component(including head and neck.The geometry adopted Was that ofa common and unc

28、ommercial metal-backed THA prosthesis,with the models of four parts were constmctured separately and assembled by means of SolidWorks2006soRware, calculated by溫州醫(yī)學(xué)院碩士學(xué)位論文 COSMOSWorks2006software,selecting automatic dividatur by program completely, divided into 17195nodes,11062units,analysis of the c

29、ompression distribution and amount oftotal hip component when simulated seated leg-crossing manurer.3.n蛇inclusion ofhip capsule representation was the option for multiple independent contact interfaces,and the ischiofemoral ligament sectors were incorporated into the whole-joint FEM at anatomically

30、appropriate insertion points,using rigid body renitions of the femur and henri-pelvis.n地detailed anatomic features of these bony structulfeS were extracted CT data,using edgedetection methods operating on l-mm Serial Sections.Triangulated surfaces were fitted to the resulting pDint cloud data for th

31、e femur and hemi-pelvis.These surfaces,which were zoned with a 3-D, all-quadrilateral rigid body finite element mesh using SolidWorks2006mesh generator,provide a quantitative spatial basis for establishing capsular ligament attachment sites.Accurate registration of the origin and the insertion secto

32、r of ischiofemoral ligament in this computational model was achieved using common reference points and the geometric and mechanical properties obtained from Hewitt's experimental worL Theischiofemoral ligament Was meshed entirely with hexahedral continuum elements having experimental-based mater

33、ial characteristics. Of the various hyperelastic material models examined,the Yeoh hyperelasic model Was Selected,in terms of fitting of experimental stressstrain curves for the ligament Sectors.4.Based on the above experiment,nOW that capsular ligament inclusion in the total hip dislocation model h

34、as been achieved,and calculated by ABAQUS6.6and COSMOSWorks2006finite element soRwat,and the finite element analysis Was a nonlinear,large displacement,multiple load step solution.An erectly-seated maneuver Was exmnded kinematically from the seated position(90。of femoral flexion,6。of adduction,and 0

35、。ofendorotation,by incrementally rotating the femur in a ratio of 2 :l:0of flexion:adduction:endorotation.This temporal kinematic data,when input to a 47-muscle optimization model,yielded output to a posteromedially directed joint load of 1.5times body weight(942Nin the pelvic reference frame during

36、 seated leg-crossing.These specific hip joint contact force components were applied to the溫州醫(yī)學(xué)院碩:學(xué)位論文acetabular component model through an analytically rigid body reference node at the femoral head center.The load orientation WaS representative of peak gait cycle hip loading and had a fixed pelvic o

37、rientation of22.5。from the vertical in the frontal plane.1rI倫modeled maneuver WaS continued until the finite element computation aborted,due to numerical imbalance as the resultant contact force escaped the intended cup be撕ng surface,indicative of a dislocation.The primary outcome measure utilized i

38、n the present study WaS the resultant resisting moment developed about the cup center,prior to the oecBrrence of dislocation.The finite element analysis reported full field stress,strain,and displacement data,foreach time point in the leg-crossing maneuver.All forces acting through the femoral head,

39、or at the site of impingement,were transferred through thecontinuum ofthe acetabular component to the rigidly supported nodes on the bone side surface ofthe acetabular shell.Therefore, forces and moments about the cup center could be readily determined from the cup backing nod body reference node,wh

40、ich was placed at the cup center,and compared these results between soft-tissue-augmented model and an otherwise identical hardware-only model.Results:After construction,we have got models like the hip joint 3-D FEM in vivo,hip joint 3-D FEM,total hip prosthesis 3-D FEM;and we got the Von Mises stre

41、ss calculating from simulations of total hip dislocation and ischiofemoral ligament reconstructed in THA when simulated seated leg-crossing manuver:the strongest stress value of hardwareonly models were 5.045Mpa in 900femoral flexion,5.540Mpa in 92.50 femoral flexion,6.280Mpa in 950femoral flexion,6

42、.362Mpa in 97.50femoral flexion, 7.480Mpa in 100。 femoral flexion; and the value of capsular-ligament-angmented FEMs Wel-e 4.676Mpa,5.579Mpa,6.986Mpa,7.293 Mpa,18.819Mparespectively.ne resultant resisting moment developed about the cup center ofhardware-only models wel"e 0.2N.m in 90。femoral fl

43、exion,0.5N.m in 92.50femoral flexion,0.7N.m in 950femoral flexion,0.6N.m in 97.50femoral flexion,0.7N.m in 100。femoral flexion,O.75N.m in 102.50femoral flexion,7.75 N.m in 105。femoral flexion.11.25N.m in 107.5。femoral flexion,11.5N.m in 110。溫州醫(yī)學(xué)院碩士學(xué)位論文femoral flexion,10.5N.m in 112.5。femoral flexion

44、,9.3N.m in 115。femoral flexion, 8.1N.m in 117.5。femoral flexion,5.2N.m in 1200femoral flexion,3.8N.m in 122.5。femoral flexion,0.6N.m in 125。femoral flexion;and ischiofemoml ligament augmented models were 7.5N.m,7.2N.m,7.6N.m,7.9N.m,7.8N.m,8.3N.m,13.8 N.m,16.7N.nl18.1N.IIl16.2N.In,14.8N.m,13.8N.m,12.

45、3N.m,10.7N.m,7.4 N.m.respectively.Typical resisting moment profiles for hardw刪nly models consisted of three distinct phases:an initial non-zel"O baseline moment due to bearing friction between the UHMWPE liner and the femoral head(friction coefficient=O.038;the onset(toe region of the resisting

46、 moment profileand eventual full engagement of impingement contact(1inearly increasing portion of the resistingmoment profile;anda subhixation phase which initiates near the peal, resisting moment and is signalled by downslope of the femoral resisting moment value,untilonset ofcomputational instabil

47、ity(corresponding to physical dislocation. In the capsule-ligament-enhanced model,by contrast,the angular motion input Was met with substantial resistance due to progressive tautening of the capsular ligament even from the initiation of flexion.This tautening resistance resulted in a dramatic increa

48、se in the resisting moment developed throughout the seated leg-crossing maneuver.Once impingement occurred,there、棚an additional,more precipitous spike of resisting moment,roughly comparable to that seen for impingement onset in the hardware-oniy model.Since this taughtened tissue lies appreciably ec

49、centric to the neck-liner impingement fulcrum,it works efficiently“in parallel'with the implant itself to resist the tendency for dislocation,reducing the peal(polythylene stresses at the impingement site and at the head egress site by typically 17%and 31% respectively,and increasing the pcal【re

50、sisting moment by typically 57%,relative to the hardware-oniy case.The energy required to dislocate is measured as the area under the curve from impingement to dislocation,using the trapezoidal rule.These preliminary results show that capsule-ligament representation provides approximately a 2.29-fol

51、d increase in construct stability,compared to all otherwise identical hardware-only eonstnlct.111e stress、strain、displacement and transfiguration revealed the whole result in the dislocation sequence clearly.For example,the least stress value溫州醫(yī)學(xué)院顧t學(xué)位論文ofhardware-onlymodel when 97.5。femoral flexion

52、presented in node 4633,locating in 3.79582mm,12.2788mm,-23.1805mm.and the value was 15878.4N/m2;the strongest one presented in node 13515,locating in-26.0584ram,18.1485ram, 98.9955mm,and the value Was 6.36214e+006N/mA2.The result of strain was that the least WaS presenwxl in node 5905,locating in-3.

53、55608mm,-9.17404nnn,8.“09 ram,and the value WaS 6.5561e007;the strongest one presented in node 2560, locating in O.816801啪114.6763ram,-1.60733mm,and the value Was O.00146277. Displacement:the smallest one was in the node 6984,and the biggest ong was in 6224, displacement range:0mO.000876198m.The tra

54、nsfiguration revealed the whole result clearly with factor ofproportion Was set tO be 15.947.ConehisioIII!"-1.(DFinite element analysis of total hip dislocation has opened new avenues for understanding the biomechanical factors underlying this alltoo-common major complication ofTHA.the present

55、study provides the precise total hip dislocation 3-D FEM for research on the related mechanical behavior.The capsular ligament reconstruction lends more suppon to the hip flexion and adduction,and significantly higher torque Was needed to impinge or dislocate the hip.The isehiofemoral ligament,a dis

56、crete strtlcture within the posterior capsule of the hip joint,may be the most important contributor to the mechanical integrity of the posterior stable structure. The joint capsule ligament must be reco刪in hip arthroplasty.We caIl see from the results that the capsule-ligament-enhanced model reduce

57、d the peak polyethlene stresses at the impingement site and at the head egress site may prove that the capsular repair could reduce the rate ofwear-related aseptic loosening.2.This experiemtal conclusion is valuable to be extended in clinical application.【Key words】Total Hip Arthroplasty;Dislocation

58、;Ischiofemoral Ligament; Biomechanics;Three-Dimensional Finite Element Analysis溫州醫(yī)學(xué)院碩士學(xué)位論文坐股韌帶重建穩(wěn)定機(jī)制三維有限元分析及其生物力學(xué)意義 前 言隨著全髖關(guān)節(jié)置換術(shù)(T眥技術(shù)的日趨成熟,術(shù)后假體脫位發(fā)生率已大大 減少,但仍是僅次于磨損介導(dǎo)的無(wú)菌性松動(dòng)的常見(jiàn)并發(fā)癥之一m,其發(fā)生率在初 次置換病例組達(dá)2%11%。Phillips“1回顧性研究分析隨訪的13000例THA后發(fā) 現(xiàn)假體脫位率為3.996,Yon Knoch01在一個(gè)大于5年的臨床隨訪研究中發(fā)現(xiàn),初 次THA術(shù)后假體脫位率高達(dá)30%。而在全髖關(guān)節(jié)

59、翻修的病例組術(shù)后假體脫位率 將翻2倍咖。再脫位的病例中有1/3需要行翻修手術(shù),其中僅有60%獲得穩(wěn)定“ 耐。不管是初次還是再次脫位,每次都會(huì)給患者留下嚴(yán)重的后果,加上發(fā)病率較 高,將給社會(huì)造成巨大的經(jīng)濟(jì)負(fù)擔(dān)。T1A術(shù)后脫位大部分發(fā)生于術(shù)后45周,屬早期脫位,約占7096,其中以后 脫位多見(jiàn),且多見(jiàn)于后方入路帆”。Dorr等。1報(bào)道在術(shù)后1個(gè)月內(nèi)發(fā)生脫位占21%, 3個(gè)月內(nèi)發(fā)生脫位的占54%,2年以后發(fā)生脫位的占15%;引起THA術(shù)后假體脫位 的因素很多,主要包括手術(shù)入路、軟組織損傷的修復(fù)重建程度、假體的設(shè)計(jì)與安 放、患者的依從性、既往髖部手術(shù)史等幾個(gè)方面。Mohler等啪認(rèn)為7096脫位發(fā)生 于術(shù)后45周內(nèi),并認(rèn)為主要原因是假