發(fā)布時間：2018-04-09 09:07

  本文選題：股骨頸骨折　切入點：有限元分析　出處：《河北醫(yī)科大學(xué)》2017年碩士論文

【摘要】：目的:1建立股骨近端的有限元模型。2利用三維繪圖軟件分別繪制3種不同Pauwels分型的股骨頸骨折模型及4種不同類型的股骨頸內(nèi)固定模型:分別為“正三角形”排列的三枚空心拉力螺釘模型;“倒三角形”排列的三枚空心拉力螺釘模型;“矩形”排列的四枚空心拉力螺釘模型;“菱形”排列的四枚空心拉力螺釘模型。3利用Ansys軟件,比較分析4種不同空心拉力螺釘內(nèi)固定方式對3種不同Pauwels分型的股骨頸骨折斷端及內(nèi)固定物的應(yīng)力分布、位移大小。綜合評價每種空心拉力螺釘內(nèi)固定的固定特點。通過比較分析不同內(nèi)固定方式生物力學(xué)的穩(wěn)定性,為臨床的應(yīng)用提供理論依據(jù)及指導(dǎo)性建議。方法:1不同Pauwels分型的股骨頸骨折的有限元模型的構(gòu)建:通過X線檢查排除髖部的骨折、腫瘤及畸形等骨質(zhì)破壞的存在。采用Somatom Sensatim 64排螺旋CT掃描正常人股骨近端,自股骨頭上方至小轉(zhuǎn)子下方,掃描方法為電壓:120k V,電流200m A,掃描層厚1mm,層間距1mm,將圖像存儲為DICOM格式,共獲得250個DICOM圖像數(shù)據(jù),并導(dǎo)入個人計算機(jī)的Mimics 14.0軟件中,確定閾值后,構(gòu)建出正常骨頭的三維模型。將以上模型以STL格式導(dǎo)入到自動化逆向工程軟件Geomagic Studio 12.0中,對模型進(jìn)行光順、平滑、裁剪、偏移、布爾減運算等處理,分別得到更為精細(xì)的模型文件,從而能夠得到更為精細(xì)、精確的股骨頸模型文件,結(jié)果以Iges格式輸出保存。將Geomagic Studio中生成的Iges格式文件導(dǎo)入Solid Works軟件中,進(jìn)行實體重構(gòu),切割骨折線,分別為30°,50°,及70°。從而生成實體模型。2內(nèi)固定模型的構(gòu)建:在Solid Works軟件中構(gòu)建4種不同空心拉力螺釘排列方式的內(nèi)固定模型,分別為:a:“正三角”形排列的三枚空心拉力螺釘模型;b:“倒三角”形排列的三枚空心拉力螺釘模型;c:矩形排列的四枚空心拉力螺釘模型;d:菱形排列的四枚空心拉力螺釘模型。其中,空心拉力螺釘全長100mm,直徑6.5mm,螺紋、中空部分忽略不計。所構(gòu)建的空心拉力螺釘與股骨相互定位,完成空心釘植入,并應(yīng)用布爾運算刪除空心拉力螺釘處骨骼。生成節(jié)點和單元后導(dǎo)入有限元分析軟件Ansys(ANSYS公司,美國)進(jìn)行處理分析。3骨折內(nèi)固定有限元模型的材料賦值、邊界條件及加載:將以上模型導(dǎo)入模擬軟件Ansys Workbench中,繼而導(dǎo)入Mimics軟件中根據(jù)灰度賦予不同的材料屬性,并重新導(dǎo)入Ansys中施加邊界條件和約束,模擬骨頭受力情況,忽略關(guān)節(jié)之間的摩擦力,忽略關(guān)節(jié)軟骨,簡化處理肌肉及肌腱的應(yīng)力作用。并假設(shè)骨折面完全斷裂并處于完全接觸狀態(tài),骨折斷端接觸面的摩擦力為0.2,將股骨近端有限元模型的小轉(zhuǎn)子下緣全部節(jié)點的自由度約束為0作為邊界條件;遠(yuǎn)端在x、y、z軸上的位移為0。采用目前常用的簡化模型,僅考慮髖臼窩作用于股骨頭上的力及大轉(zhuǎn)子鄰近的外展肌力(臀中肌與梨狀肌)及股外側(cè)肌作為有限元分析的外載荷,給予軸向600N應(yīng)力,沿軸向向下,平均作用于髖臼和股骨頭的接觸面,從而模擬受力,進(jìn)行運算。4評價指標(biāo),通過3種指標(biāo)對4種內(nèi)固定模型(a~d)的力學(xué)性能進(jìn)行綜合分析:㈠內(nèi)固定物的應(yīng)力分布及應(yīng)力峰值;㈡股骨頭及內(nèi)固定的位移和峰值;㈢頭側(cè)骨折斷端的應(yīng)力分布及應(yīng)力峰值。結(jié)果:通過獲得正常人股骨近端的CT掃描數(shù)據(jù),利用Mimics、Geomagic Studio等軟件,建立股骨頸骨折的有限元模型,這種方法可行性高,且建模速度快,對人體損傷極小。有限元方法是生物力學(xué)研究的一種理論方法。通過賦予其各種組織、結(jié)構(gòu)的材料屬性,能夠模擬出不同結(jié)構(gòu)的幾何模型,并且能很好的反映其生物力學(xué)特性。所以,可以成為標(biāo)本生物力學(xué)研究很好的補充。對于不同Pauwels分型,最優(yōu)的置釘方式是菱形排列的四枚空心拉力螺釘。對于Pauwels I型股骨頸骨折,4種模型的應(yīng)力峰值分別為:a:46.382MPa;b:32.159MPa;c:43.985 MPa:d:24.342 MPa。頭側(cè)股骨頸骨折斷端應(yīng)力峰值分別為:a:5.840 MPa;b:7.440 MPa:c:3.731 MPa:d:6.311 MPa。股骨頭處位移峰值為:a:0.610mm;b:0.608mm;c:0.598mm:d:0.595mm;對于Pauwels II型股骨頸骨折,4種模型的應(yīng)力峰值分別為:a:46.763 MPa;b:39.979 MPa;c:49.619 MPa:d:25.692 MPa。頭側(cè)股骨頸骨折斷端應(yīng)力峰值分別為:a:4.971 MPa;b:7.332 MPa:c:3.161 MPa:d:5.734 MPa。股骨頭處位移峰值為:a:0.634mm;b:0.635mm;c:0.622 mm:d:0.631mm;對于Pauwels III型股骨頸骨折,4種模型的應(yīng)力峰值分別為:a:51.432 MPa;b:39.477 MPa;c:51.515 MPa:d:26.949 MPa。頭側(cè)股骨頸骨折斷端應(yīng)力峰值分別為:a:6.163 MPa;b:10.070 MPa:c:5.257 MPa:d:9.552 MPa。股骨頭處位移峰值為:a:0.662mm;b:0.654mm;c:0.644 mm:d:0.644mm。結(jié)論:通過有限元分析得出:對于不同Pauwels分型的股骨頸骨折,矩形、菱形四枚拉力螺釘固定的骨折在壓力作用下產(chǎn)生的移位小于正、倒三角拉力螺釘固定的骨折,可有效穩(wěn)定骨折斷端;相比于正、倒三角及矩形四枚拉力螺釘,菱形四枚拉力螺釘結(jié)構(gòu)具有更大的應(yīng)力分散作用。既能夠達(dá)到較為穩(wěn)定的生物力學(xué)穩(wěn)定性,又能夠有效防止股骨頸短縮。
[Abstract]:Objective: to establish 1 finite element model of proximal femur.2 using three-dimensional drawing software were drawn 3 different types of Pauwels femoral neck fracture model and 4 kinds of different types of femoral neck fracture model: as the "triangle" with the three cannulated screw model; inverted triangular arrangement of three hollow screw model; "rectangular" with the four cannulated screw model; "diamond" arrangement of four cannulated screws fixation model using.3 Ansys software, a comparative analysis of the broken ends and internal stress distribution, the displacement of 4 different cannulated screws internal fixation methods of the 3 different Pauwels types of femur fracture of the neck. A comprehensive evaluation of characteristics of fixed fixed each hollow screw. Through comparative analysis of different internal fixation biomechanical stability, provide a theoretical basis and guidance for clinical application On the construction of finite element model. Methods: 1 different Pauwels types of femoral neck fracture: through X-ray examination to exclude hip fractures, tumors and malformations of bone destruction. Using Somatom Sensatim with 64 slice spiral CT scan of normal proximal femoral head, from above to below the small rotor, scanning method voltage: 120K V 200m, current A, slice thickness 1mm, spacing 1mm, images will be stored as DICOM format, received a total of 250 DICOM image data, and import of personal computer software Mimics 14, to determine the threshold, to construct three dimensional model of normal bone. The above model in STL format into automatic reverse engineering software Geomagic Studio 12, smoothing, smoothing, clipping, offset on the model, Boolean subtraction processing, respectively, to obtain more precise model files, which can be more precise, accurate femoral neck model file, The results in Iges format output. The Iges format file into Solid Works software to generate Geomagic Studio in solid reconstruction, cutting the fracture line was 30 degrees, 50 degrees, and 70 degrees. To build a solid model is generated by.2 internal fixation model: construction arrangement of 4 kinds of hollow screw internal fixed model in Solid Works software respectively: a: triangle shaped arrangement of three cannulated screws fixation model; b: inverted triangle shaped arrangement of three cannulated screw model; c: rectangular array of four cannulated screws fixation model; d: diamond arranged four cannulated screws fixation model. The hollow screw, length 100mm, diameter 6.5mm, thread, the hollow part is negligible. The hollow screw and femur constructed by mutual positioning, complete hollow screw implantation, and the application of Boolean operation to remove bones. Hollow tension screw generation The nodes and elements into finite element analysis software Ansys (ANSYS company, USA) for analysis and processing of.3 internal fixation of fracture finite element model of the material assignment, boundary conditions and loading: the above model into the simulation software Ansys Workbench, and then import the Mimics software based on the gray with different material properties, and re applied into Ansys the boundary conditions and constraints, simulated bone stress, neglecting friction between joints, ignoring the articular cartilage, simplify the stress treatment of muscle and tendon. It is assumed that the fracture surface and complete rupture of the state of complete contact state, fracture broken end friction contact surface is 0.2 degrees of freedom constraint small rotor proximal femur finite element the lower edge of the model of all nodes is 0 as the boundary condition; the distal in X, y, Z axis displacement for 0. of the current commonly used simplified model, considering only the acetabular fossa on the femoral Abductor nearby and the forces on the rotor (piriformis muscle and gluteus medius) and vastus lateralis muscle as the load of finite element analysis, given the 600N axial stress along the axial direction, the contact effect on the average acetabular and femoral head surface to simulate the stress, calculate.4 evaluation index. Of the 4 kinds of internal fixation model by 3 indexes (a~d) to make a comprehensive analysis of the mechanical properties: the internal fixation of the stress distribution and the peak value of two; internal fixation of femoral head and the displacement and the peak; three head side of the fracture stress distribution and the peak value of the broken end. Results: by CT scan data the normal person, the proximal femur using Mimics Geomagic Studio software, establish the finite element model of femoral neck fracture, this method is highly feasible, and fast modeling speed, minimal damage to human bodies. The finite element method is a theoretical method of biomechanical research. By giving the various groups Fabric, material property, can simulate the geometric models of different structures, and can reflect the biomechanical characteristics very well. So, can complement the biomechanical well studied. For different Pauwels types, the way is the optimal arrangement of the diamond nail four cannulated screws fixation for femoral I Pauwels. Fracture of the neck, the peak stress of 4 models respectively: a:46.382MPa; b:32.159MPa; the broken end of the peak stress were c:43.985 MPa:d:24.342 MPa., head of a femoral neck fracture: a:5.840 MPa; b:7.440 MPa:c:3.731 MPa:d:6.311 MPa. femoral head displacement peak: a:0.610mm; b:0.608mm; c:0.598mm:d:0.595mm; for Pauwels type II femoral neck fracture, stress peak the 4 models were: a:46.763 MPa; b:39.979 MPa; the broken end of the peak stress were c:49.619 MPa:d:25.692 MPa., head of a femoral neck fracture: a: 4.971 MPa; b:7.332 MPa:c:3.16 1 MPa:d:5.734 MPa. femoral head displacement peak: a:0.634mm; b:0.635mm; c:0.622 mm:d:0.631mm; Pauwels III for femoral neck fracture, the stress peak of 4 models respectively: a:51.432 MPa; b:39.477 MPa; the broken end of the peak stress were c:51.515 MPa:d:26.949 MPa., head of a femoral neck fracture: a:6.163 MPa; b:10.070 MPa:c:5.257 MPa:d:9.552 MPa. the femoral head displacement peak: a:0.662mm; b:0.654mm; c:0.644 mm:d:0.644mm. conclusion: the finite element analysis for different Pauwels types of femoral neck fracture, rectangle, diamond four lag screws fracture produced under pressure is lower than the normal displacement, inverted triangle screw fixation of fractures can effectively stabilize fracture compared with the end; Yu Zheng, inverted triangle and rectangle four screw, four screw diamond structure has bigger stress dispersion effect. Both can achieve a relatively stable The stability of the biomechanics can also effectively prevent the short necking of the neck of the femur.

【學(xué)位授予單位】：河北醫(yī)科大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：R687.3

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