经皮逆行拉力螺钉固定髋臼后柱骨折的临床解剖和三维有限元对比研究
发布时间：2018-08-18 14:35
【摘要】：研究背景：髋臼骨折(Acetabular Fractures)作为骨盆骨折的一种特殊类型,由于其波及髋关节面,属于关节内骨折。受伤机制多为直接暴力引起,临床上最常见致伤原因为压砸伤、高处坠落和交通事故。根据2014年的一项中美髋臼骨折流行病学对比调查研究显示,随着工业、建筑业规模的不断扩大,机动车数量的迅速增加,2005-2012年间,该类骨折的发生呈逐年增长趋势,其中青壮年男性是主要受伤人群。随着世界人口老龄化的加剧,患者的年龄有逐渐增加的趋势。髋臼周围解剖结构复杂,位置深在,手术难度较大,骨折术后易发生异位骨化、创伤性关节炎等并发症,一直以来是创伤骨科领域研究的重点和难点。在过去的半个世纪,随着手术技巧和人们对该类骨折认识的不断提高,针对髋臼骨折,目前临床上主张手术治疗,尤其对于累及髋臼负重区、移位明显和关节内存在游离骨折块的骨折类型,切开复位内固定已经成为该类骨折首选治疗方案。但是,传统的切开复位内固定手术具有失血量大,周围神经血管损伤,切口感染等手术并发症的风险。对于无移位或移位不明显的髋臼骨折类型,近年来有学者提出在术中透视辅助下,采用经皮拉力螺钉固定骨折的方法。该方法不仅具有显露范围小,失血量少,异位骨化发生率低等优点,更能够实现患肢早期功能锻炼,减少卧床时间,有利于获得满意的患肢功能恢复。因此,成为骨盆髋臼骨折微创治疗的重要研究方向。髋臼后柱作为髋臼的主要构成部分,骨折时常常累及该部位,目前的研究已经证明了采用经皮逆行拉力螺钉固定髋臼后柱骨折的可行性。国内外学者开展了大量的相关研究,主要包括后柱钉道的解剖学测量和置钉方法学的研究。目前,在进行经皮逆行拉力螺钉固定髋臼后柱骨折操作时,普遍选择坐骨结节作为进针点,但是由于坐骨结节区域为粗糙弧形骨面,缺乏定位标志,选择理想进针点存在困难。且髋臼后柱周围组织结构复杂,骨性通道狭长,骨质菲薄,置钉不慎则存在螺钉穿出骨板或误入关节的风险,造成医源性神经血管损伤或创伤性关节炎的发生,成为了限制该技术临床应用的主要原因。针对这一临床难点,有学者提出了经坐骨小切迹置入拉力螺钉的方法,认为该方法较传统方式具有定位更准确,力学稳定性更佳的优势,但是由于实验人群和实验方法的不同,相关报道所测量的钉道参数差异较大,且相关的内固定物生物力学稳定性对比实验也未见报道。随着计算机技术的不断发展,运用三维软件可以实现对骨盆的三维重建,精确测量相关解剖参数,并通过有限元分割、材料赋值,建立相应的骨折内固定模型,模拟生理状态,施加应力,实现对骨折内固定物生物力学稳定性的评价,具有可重复性高,节约成本和真实可靠的特点。本研究通过以志愿者骨盆CT原始断层扫描数据为材料,选择两种临床有代表性的置钉方案,在测量其钉道解剖数据的同时,对其生物力学稳定性进行分析比较,以期为临床应用提供参考。目的：1、利用CT影像数据建立骨盆三维模型,模拟两种不同方法置入后柱虚拟圆柱体,测量髋臼后柱骨性通道的相关解剖参数,对比两者之间存在的差异,为生物力学分析提供解剖学依据。2、在了解骨盆解剖的基础上,利用有限元专业分析软件,建立骨盆的三维有限元模型,并对该模型的可靠性进行分析与验证,探讨其作为生物力学研究方法的效果。3、在骨盆有限元模型的基础上,建立起两种不同的逆行拉力螺钉固定髋臼后柱骨折的模型,模拟生理状态对其进行相关生物力学分析,评价两种固定方式的生物力学特点,为临床应用提供参考。方法：1、随机收集2012年9月-2014年9月在我院行完整盆部CT断层扫描的成年志愿者的骨盆数据32例,男17例,女15例,排除骨质病变和解剖异常,扫描层厚0.5mm,将图像以DICOM格式输出,导入Mimics 14.1软件,重建骨盆三维模型,利用软件自带的功能,模拟置入髋臼后柱逆行拉力螺钉,测量并获得髋臼后柱骨性通道的相关解剖学参数。2、骨盆三维有限元模型的建立与验证：选择1例健康成年男性志愿者进行CT断层扫描并收集其原始数据,将数据进行等容切割,切割厚度0.5mm,以DICOM格式导出,导入Mimics 14.1三维软件,获得骨盆三维重建模型,然后应用Freefrom、Geomegic Studio等软件进行模型表面光滑和网格化处理等步骤,添加韧带等骨盆附属结构,建立骨盆实体三维有限元模型,施加垂直应力,观察骨盆的应力和位移云图,验证其有效性。3、逆行拉力螺钉固定髋臼后柱骨折有限元模型的建立与生物力学分析：参考相关文献,应用软件,模拟后柱骨折线对骨盆有限元模型进行截骨,并分别进行两种不同方式的后柱逆行拉力螺钉固定,建立起两种不同的骨折固定模型,模拟站立位和坐位,对模型进行应力加载,分别施加大小500N的垂直应力,分析两种不同的模型表现出的生物力学特性,评价指标为骨盆和内固定物的应力和位移分布云图,关节面骨折线上的位移。4、统计学分析：所得数据使用SPSS19.0软件进行统计学处理,比较不同性别以及不同内固定方案之间存在差异,方法使用独立样本t检验和配对样本t检验,α取值0.05,P0.05,数值结果采用“均数±标准差”(x±s)表示。结果：1、基于CT原始断层扫描数据建立的骨盆三维模型真实的还原了骨盆复杂的解剖形态,利用Mimics软件可以对模型进行空间角度、距离的测量。获得的测量内容包括：经坐骨结节置入的逆行拉力螺钉钉道男性与冠状面的呈角为(11.69±4.79)°,与矢状面成角为(10.34±3.60)°；女性与冠状面成角为(8.36±3.24)°,与矢状面成角为(12.56±3.48)°。冠状面(P=0.0040.05)与矢状面(P=0.0270.05)成角在性别间存在明显差异。经坐骨小切迹置入拉力螺钉男性与冠状面成角为(39.73±5.69)°,与矢状面成角为(18.46±5.72)°；女性与冠状面成角为(40.49±5.06)°,与矢状面成角为(16.11±6.62)°。冠状面(P=0.5770.05)与矢状面(P=0.1320.05)成角在性别间无明显差异。髋臼后柱拉力螺钉最大直径为,男性(9.32±1.84)mm,女性(8.51±1.59)mm,男女之间数据存在明显差异(P=0.0230.05),骨性通道平均长度为坐骨结节组男性(141.16±10.23)mm,女性(125.72±6.43)mm,坐骨小切迹组男性(115.03±11.19)mm,女性(91.38±9.96)mm,组间与性别之间数据存在明显差异(P=0.0010.05)。2、所建立的骨盆三维有限元模型,完成后的模型自动网格划分,节点490227个,网格295806个。模型最大应力值为32.45Mpa,位于坐骨大切迹周围,最大位移值为0.34mm,位于骶髂关节处,骨盆模型应力分布均匀对称,与实际情况相符,可以满足生物力学分析需求。3、将拉力螺钉固定髋臼后柱骨折模型分为四组：坐骨结节站立位组,坐骨结节坐位组,坐骨小切迹站立位组,坐骨小切迹坐位组。施加应力,分别得到骨折块和内固定拉力螺钉的应力分布云图和骨折位移云图。站立位时拉力螺钉的最大应力位于螺钉中部靠近骨折线附近的位置,坐骨结节组为6.52Mpa,坐骨小切迹组为6.75Mpa。坐位时应力主要集中于螺钉下部,坐骨结节组为14.01Mpa,坐骨小切迹组为36.05Mpa。关节面骨折线节点位移均数为坐骨小切迹站立位组(4.23±1.27)μm。坐骨结节站立位组(4.05±1.31)μm,坐骨小切迹坐位组(6.45±0.44)μm,坐骨结节坐位组(7.27±0.48)μm,其中坐位时的位移均数在两种内固定物之间存在统计学差异(P=0.0030.05)。结论：1、本研究应用Mimics三维软件和骨盆CT断层扫描数据,对骨盆进行建模并进行三维测量,所得模型仿真度高,相关测量数据精确可靠。利用该模型建立的有限元模型真实的反映了骨盆生物力学特性,可以用于相关生物力学分析研究。2、对比两种不同的后柱逆行拉力螺钉固定方法,得出采用经坐骨小切迹置钉的方法其骨折端应力与位移较采用经坐骨结节置钉方法小,提示经坐骨小切迹置钉具有一定的生物力学优势,但具体到临床应用尚需结合患者的具体情况决定。3、本实验的不足之处在于,受限于实验条件,测量数据样本数量较少。运用有限元法将模型不同骨质均设置为均匀同质的生物材料,但骨盆骨性结构复杂,其松质骨与皮质骨密度分布不均,故实验结果与实际情况必然存在一定差异,且由于髋臼后柱骨折线走行复杂,该骨折模型无法满足所有髋臼后柱骨折内固定物的生物力学分析需要。
[Abstract]:BACKGROUND: Acetabular Fractures, as a special type of pelvic fractures, are intra-articular fractures because of their impact on the hip joint surface. Most of the injuries are caused by direct violence. The most common causes of injuries in clinic are crush, fall and traffic accidents. According to an epidemiology of acetabular fractures in China and the United States in 2014 The comparative study shows that with the continuous expansion of industry and construction industry and the rapid increase of the number of motor vehicles, the incidence of such fractures increased year by year from 2005 to 2012, in which young and middle-aged men were the main injured population. In the past half century, with the continuous improvement of surgical techniques and people's understanding of this kind of fracture, the acetabular fracture has been advocated clinically. Open reduction and internal fixation has become the preferred treatment for acetabular fractures, especially those involving the acetabular load-bearing area, with obvious displacement and free fracture fragments in the joint. In recent years, some scholars have proposed to fix acetabular fractures with percutaneous lag screw assisted by intraoperative fluoroscopy. This method not only has the advantages of small exposure range, less blood loss, and low incidence of heterotopic ossification, but also can achieve early functional exercise of affected limbs, reduce bedridden time and is beneficial. The posterior column of the acetabulum, as the main component of the acetabulum, often involves this part of the acetabulum. The present study has proved the feasibility of using percutaneous retrograde lag screw to fix the posterior column of the acetabulum fracture. A large number of related studies, including anatomical measurements of the posterior column canal and methodological studies of screw placement. At present, the ischial tubercle is generally selected as the insertion point in the percutaneous retrograde lag screw fixation of acetabular posterior column fractures. However, because the area of the ischial tubercle is rough and curved, there is no localization mark, the ideal insertion point is chosen. Acetabular posterior column around the complex structure, narrow bone passage, thin bone, improper screw placement, there is a risk of screw penetration or incorrect into the joint, resulting in iatrogenic neurovascular injury or traumatic arthritis, has become the main reason for limiting the clinical application of this technique. A new method of inserting lag screw through ischial small notch was proposed. The method has the advantages of more accurate positioning and better mechanical stability than the traditional method. However, due to the difference between the experimental group and the experimental method, the parameters of the screw path measured by the relevant reports are quite different, and the biomechanical stability of the related internal fixator is compared with the experiment. With the continuous development of computer technology, three-dimensional reconstruction of the pelvis can be achieved by using three-dimensional software, accurate measurement of relevant anatomical parameters, and through finite element segmentation, material assignment, the establishment of the corresponding fracture internal fixation model, simulation of physiological state, stress, the realization of fracture internal fixation biomechanical stability evaluation. Price, repeatability, cost savings and reliability are the characteristics of this study. In order to provide a reference for clinical application, two representative screw placement schemes were selected based on volunteer pelvic CT data. Objective: 1. To establish a three-dimensional model of the pelvis using CT image data, simulate two different methods of implanting the posterior column virtual cylinder, measure the anatomical parameters of the posterior column of acetabulum, compare the differences between the two methods, and provide anatomical basis for biomechanical analysis. 2. On the basis of understanding the pelvic anatomy, use finite element professional points. Three-dimensional finite element model of the pelvis is established, and the reliability of the model is analyzed and validated. The effect of the model as a biomechanical research method is discussed. 3 Based on the finite element model of the pelvis, two different models of retrograde lag screw fixation of acetabular posterior column fracture are established, which simulate the physiological state of the pelvis. Methods: 1. 32 adult volunteers, 17 males and 15 females, who underwent complete pelvic CT scan in our hospital from September 2012 to September 2014, were randomly collected for pelvic data. Bone lesions and anatomical abnormalities were excluded. The scan thickness was 0.5mm. The images were taken as DICO images. M-format output, import Mimics 14.1 software, reconstruct the three-dimensional model of the pelvis, use the functions of the software, simulate the retrograde lag screw placement of the acetabular posterior column, measure and obtain the relevant anatomical parameters of the acetabular posterior column osseous channel. 2. Establishment and verification of the three-dimensional finite element model of the pelvis: A healthy adult male volunteer was selected for CT sectioning. Scanning and collecting the original data, isovolumetric cutting, cutting thickness of 0.5mm, deriving in DICOM format, importing Mimics 14.1 three-dimensional software to obtain the pelvic three-dimensional reconstruction model, then using Freefrom, Geomegic Studio and other software to smooth and mesh the surface of the model, adding ligaments and other pelvic appendages to build bones. Pelvic solid three-dimensional finite element model, applied vertical stress, pelvic stress and displacement nephogram observation, verify its effectiveness. 3, retrograde tension screw fixation acetabular posterior column fracture finite element model and biomechanical analysis: reference to relevant literature, application software, simulation of posterior column fracture line of pelvic finite element model osteotomy, and respectively Two different models of fracture fixation were established by using two different methods of retrograde lag screw fixation of posterior column. The model was loaded with stress in standing and sitting position. The vertical stress of 500 N was applied to the model. The biomechanical characteristics of the two models were analyzed. The evaluation indexes were pelvic and internal fixator stress and internal fixator stress. Distribution nephogram of displacement, displacement on fracture line of articular surface. 4. Statistical analysis: The data were processed by SPSS19.0 software, and the differences between different genders and different internal fixation schemes were compared. Methods The independent sample t test and paired sample t test were used. The values of alpha were 0.05, P 0.05. The numerical results were analyzed by means of "mean + standard deviation". Results: 1. The complex anatomy of the pelvis was restored based on the original CT scan data, and the spatial angle and distance of the pelvis were measured by Mimics software. The angle between the coronal plane and the sagittal plane was (11.69 [4.79] [10.34] [3.60]] and between the coronal plane and the sagittal plane was (8.36 [3.24] [12.56] and (12.56 [3.48]]]] respectively. The angle between the coronal plane (P = 0.0040.05) and the sagittal plane (P = 0.0270.05) was significantly different between the sexes. The angle between the posterior column of acetabulum and the sagittal plane was (18.46 [5.72]], the angle between the females and the coronal plane was (40.49 [5.06]], and the angle between the coronal plane (P = 0.5770.05) and the sagittal plane (P = 0.1320.05). There was no significant difference between the sexes. There was significant difference in the data between groups (P = 0.0230.05). The average length of bone passage was 141.16 (+ 10.23) mm in male, 125.72 (+ 6.43) mm in female, 115.03 (+ 11.19) mm in male and 91.38 (+ 9.96) mm in female. There was significant difference in the data between groups and between sexes (P = 0.0010.05). The three-dimensional finite element model of pelvis established. The model has 490227 nodes and 295806 grids. The maximum stress value of the model is 32.45 Mpa, and the maximum displacement value is 0.34 mm. It is located at the sacroiliac joint. The stress distribution of the pelvic model is uniform and symmetrical. It can meet the needs of biomechanical analysis. The posterior column fracture model was divided into four groups: ischial tubercle standing position group, ischial tubercle sitting position group, ischial small notch standing position group and ischial small notch sitting position group. In sitting position, the stress was mainly concentrated in the lower part of the screw, 14.01 Mpa in the sciatic tubercle group and 36.05 Mpa in the small sciatic notch group. The mean displacement in sitting position was significantly different between the two internal fixations (P = 0.0030.05). Conclusion: 1. In this study, the pelvis was modeled and measured by Mimics 3D software and CT scan data. The finite element model established by this model can reflect the biomechanical characteristics of the pelvis, and can be used for the biomechanical analysis. 2. Comparing the two different methods of retrograde lag screw fixation, the stress at the fracture end and the stress at the fracture end of the pelvis can be obtained by the method of small notch screw placement through the ischium. The displacement is smaller than that of trans-ischial tubercle nailing, suggesting that trans-ischial small notch nailing has certain biomechanical advantages, but its clinical application still needs to be decided according to the specific conditions of patients. 3. The deficiency of this experiment is that limited by experimental conditions, the number of measured data samples is less. Finite element method is used to model different bone. All of them are homogeneous biomaterials, but the pelvic bone structure is complex, and the distribution of cancellous bone and cortical bone mineral density is uneven. Therefore, there must be some differences between the experimental results and the actual situation.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3
本文编号：2189775
[Abstract]:BACKGROUND: Acetabular Fractures, as a special type of pelvic fractures, are intra-articular fractures because of their impact on the hip joint surface. Most of the injuries are caused by direct violence. The most common causes of injuries in clinic are crush, fall and traffic accidents. According to an epidemiology of acetabular fractures in China and the United States in 2014 The comparative study shows that with the continuous expansion of industry and construction industry and the rapid increase of the number of motor vehicles, the incidence of such fractures increased year by year from 2005 to 2012, in which young and middle-aged men were the main injured population. In the past half century, with the continuous improvement of surgical techniques and people's understanding of this kind of fracture, the acetabular fracture has been advocated clinically. Open reduction and internal fixation has become the preferred treatment for acetabular fractures, especially those involving the acetabular load-bearing area, with obvious displacement and free fracture fragments in the joint. In recent years, some scholars have proposed to fix acetabular fractures with percutaneous lag screw assisted by intraoperative fluoroscopy. This method not only has the advantages of small exposure range, less blood loss, and low incidence of heterotopic ossification, but also can achieve early functional exercise of affected limbs, reduce bedridden time and is beneficial. The posterior column of the acetabulum, as the main component of the acetabulum, often involves this part of the acetabulum. The present study has proved the feasibility of using percutaneous retrograde lag screw to fix the posterior column of the acetabulum fracture. A large number of related studies, including anatomical measurements of the posterior column canal and methodological studies of screw placement. At present, the ischial tubercle is generally selected as the insertion point in the percutaneous retrograde lag screw fixation of acetabular posterior column fractures. However, because the area of the ischial tubercle is rough and curved, there is no localization mark, the ideal insertion point is chosen. Acetabular posterior column around the complex structure, narrow bone passage, thin bone, improper screw placement, there is a risk of screw penetration or incorrect into the joint, resulting in iatrogenic neurovascular injury or traumatic arthritis, has become the main reason for limiting the clinical application of this technique. A new method of inserting lag screw through ischial small notch was proposed. The method has the advantages of more accurate positioning and better mechanical stability than the traditional method. However, due to the difference between the experimental group and the experimental method, the parameters of the screw path measured by the relevant reports are quite different, and the biomechanical stability of the related internal fixator is compared with the experiment. With the continuous development of computer technology, three-dimensional reconstruction of the pelvis can be achieved by using three-dimensional software, accurate measurement of relevant anatomical parameters, and through finite element segmentation, material assignment, the establishment of the corresponding fracture internal fixation model, simulation of physiological state, stress, the realization of fracture internal fixation biomechanical stability evaluation. Price, repeatability, cost savings and reliability are the characteristics of this study. In order to provide a reference for clinical application, two representative screw placement schemes were selected based on volunteer pelvic CT data. Objective: 1. To establish a three-dimensional model of the pelvis using CT image data, simulate two different methods of implanting the posterior column virtual cylinder, measure the anatomical parameters of the posterior column of acetabulum, compare the differences between the two methods, and provide anatomical basis for biomechanical analysis. 2. On the basis of understanding the pelvic anatomy, use finite element professional points. Three-dimensional finite element model of the pelvis is established, and the reliability of the model is analyzed and validated. The effect of the model as a biomechanical research method is discussed. 3 Based on the finite element model of the pelvis, two different models of retrograde lag screw fixation of acetabular posterior column fracture are established, which simulate the physiological state of the pelvis. Methods: 1. 32 adult volunteers, 17 males and 15 females, who underwent complete pelvic CT scan in our hospital from September 2012 to September 2014, were randomly collected for pelvic data. Bone lesions and anatomical abnormalities were excluded. The scan thickness was 0.5mm. The images were taken as DICO images. M-format output, import Mimics 14.1 software, reconstruct the three-dimensional model of the pelvis, use the functions of the software, simulate the retrograde lag screw placement of the acetabular posterior column, measure and obtain the relevant anatomical parameters of the acetabular posterior column osseous channel. 2. Establishment and verification of the three-dimensional finite element model of the pelvis: A healthy adult male volunteer was selected for CT sectioning. Scanning and collecting the original data, isovolumetric cutting, cutting thickness of 0.5mm, deriving in DICOM format, importing Mimics 14.1 three-dimensional software to obtain the pelvic three-dimensional reconstruction model, then using Freefrom, Geomegic Studio and other software to smooth and mesh the surface of the model, adding ligaments and other pelvic appendages to build bones. Pelvic solid three-dimensional finite element model, applied vertical stress, pelvic stress and displacement nephogram observation, verify its effectiveness. 3, retrograde tension screw fixation acetabular posterior column fracture finite element model and biomechanical analysis: reference to relevant literature, application software, simulation of posterior column fracture line of pelvic finite element model osteotomy, and respectively Two different models of fracture fixation were established by using two different methods of retrograde lag screw fixation of posterior column. The model was loaded with stress in standing and sitting position. The vertical stress of 500 N was applied to the model. The biomechanical characteristics of the two models were analyzed. The evaluation indexes were pelvic and internal fixator stress and internal fixator stress. Distribution nephogram of displacement, displacement on fracture line of articular surface. 4. Statistical analysis: The data were processed by SPSS19.0 software, and the differences between different genders and different internal fixation schemes were compared. Methods The independent sample t test and paired sample t test were used. The values of alpha were 0.05, P 0.05. The numerical results were analyzed by means of "mean + standard deviation". Results: 1. The complex anatomy of the pelvis was restored based on the original CT scan data, and the spatial angle and distance of the pelvis were measured by Mimics software. The angle between the coronal plane and the sagittal plane was (11.69 [4.79] [10.34] [3.60]] and between the coronal plane and the sagittal plane was (8.36 [3.24] [12.56] and (12.56 [3.48]]]] respectively. The angle between the coronal plane (P = 0.0040.05) and the sagittal plane (P = 0.0270.05) was significantly different between the sexes. The angle between the posterior column of acetabulum and the sagittal plane was (18.46 [5.72]], the angle between the females and the coronal plane was (40.49 [5.06]], and the angle between the coronal plane (P = 0.5770.05) and the sagittal plane (P = 0.1320.05). There was no significant difference between the sexes. There was significant difference in the data between groups (P = 0.0230.05). The average length of bone passage was 141.16 (+ 10.23) mm in male, 125.72 (+ 6.43) mm in female, 115.03 (+ 11.19) mm in male and 91.38 (+ 9.96) mm in female. There was significant difference in the data between groups and between sexes (P = 0.0010.05). The three-dimensional finite element model of pelvis established. The model has 490227 nodes and 295806 grids. The maximum stress value of the model is 32.45 Mpa, and the maximum displacement value is 0.34 mm. It is located at the sacroiliac joint. The stress distribution of the pelvic model is uniform and symmetrical. It can meet the needs of biomechanical analysis. The posterior column fracture model was divided into four groups: ischial tubercle standing position group, ischial tubercle sitting position group, ischial small notch standing position group and ischial small notch sitting position group. In sitting position, the stress was mainly concentrated in the lower part of the screw, 14.01 Mpa in the sciatic tubercle group and 36.05 Mpa in the small sciatic notch group. The mean displacement in sitting position was significantly different between the two internal fixations (P = 0.0030.05). Conclusion: 1. In this study, the pelvis was modeled and measured by Mimics 3D software and CT scan data. The finite element model established by this model can reflect the biomechanical characteristics of the pelvis, and can be used for the biomechanical analysis. 2. Comparing the two different methods of retrograde lag screw fixation, the stress at the fracture end and the stress at the fracture end of the pelvis can be obtained by the method of small notch screw placement through the ischium. The displacement is smaller than that of trans-ischial tubercle nailing, suggesting that trans-ischial small notch nailing has certain biomechanical advantages, but its clinical application still needs to be decided according to the specific conditions of patients. 3. The deficiency of this experiment is that limited by experimental conditions, the number of measured data samples is less. Finite element method is used to model different bone. All of them are homogeneous biomaterials, but the pelvic bone structure is complex, and the distribution of cancellous bone and cortical bone mineral density is uneven. Therefore, there must be some differences between the experimental results and the actual situation.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3
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