摘要
背景:目前研究股骨头有限元模型多采用单例或较少样本建模用于特定的生物力学研究,对于模型稳定性研究不多。目的:以正常股骨头和股骨头坏死建模进行多样本的模型对照,通过应力分布规律和力学参数的对比,分析模型的准确性和稳定性,为股骨头坏死塌陷防治提供力学基础。方法:选择20髋经1年非手术治疗稳定未塌陷的股骨头为实验组,20髋单侧股骨头坏死患者的健侧设为正常组。采集股骨头CT数据分别建立有限元模型,观察正常股骨头与股骨头坏死应力分布、股骨头负重区最大等效应力与最大总形变量,对比并统计分析。研究方案经中国中医科学院望京医院医学伦理委员会批准,患者签署知情同意书。结果与结论:①建立了正常股骨近端、无坏死股骨近端和坏死骨有限元模型,单元数和节点数分别为502 568±114 196、692 608±154 678,449 954±125 824、623 311±171 401,19 133±13 167、27 577±19131;②模拟单足站立位进行载荷设定的云图显示:当施以体质量2.5倍压强作用于股骨头负重区表面时,正常股骨头负重区表面应力均匀,应力延压力性骨小梁均匀分布在股骨头内,股骨距承受大部分应力;股骨头坏死负重区表面及坏死区出现应力集中区域,头内应力分散于股骨头颈交界,股骨颈内外侧应力相当,且股骨头坏死产生的形变多于正常股骨头;③股骨头坏死与正常股骨头的负重区最大总形变量分别为(4.14±1.31),(1.36±0.22)mm,最大等效应力分别为(1.94±0.77),(0.75±0.19)MPa,差异有统计学意义(P <0.05),且两组数据偏于集中,模型稳定性较好。通过多样本的正常股骨头与股骨头坏死比较,证明了基于CT灰度值直接赋值反映了股骨头坏死的实际力学特性,具有较好的准确性和稳定性。
BACKGROUND: Previous studies have reported that femoral head finite element models are mostly modeled with single or few samples for specific biomechanical research, but there is little research on model stability. OBJECTIVE: To compare the models of normal femoral head and osteonecrosis of the femoral head with multiple samples, and to analyze the accuracy and stability of the models through the comparison of stress distribution and mechanical parameters, so as to provide mechanical basis for prevention and treatment of collapse of osteonecrosis of the femoral head. METHODS: Totally 20 sides uncollapsed of osteonecrosis of the femoral head one year of non-surgical treatment were selected as the experimental group, and the healthy side of 20 patients with unilateral osteonecrosis of the femoral head were set as the normal group. The CT data of the femoral head were collected to establish the finite element model. The stress distribution of normal femoral head and osteonecrosis of the femoral head, the maximum equivalent stress and the maximum total deformation at the weight-bearing area of the femoral head were observed and compared. This study was approved by the Medical Ethics Committee of Wangjing Hospital of China Academy of Chinese Medical Sciences. Patients signed the informed consent. RESULTS AND CONCLUSION:(1) The finite element models of normal proximal femur, non-necrotic proximal femur and necrotic bone were established. The number of elements and nodes were 502 568±114 196, 692 608±154 678;449 954±125 824, 623 311±171 401;19 133±13 167, 27 577±19 131, respectively.(2) When the load was set by simulating one-foot standing position, the cloud image showed that when 2.5 times body weight applied to the weight-bearing area of the femoral head;the surface stress of the weight-bearing area of the normal femoral head was uniform. The stress was uniformly distributed in the femoral head along the stress trabeculae, and the calcar femorale bears the most. The stress concentration area appeared on the surface of the weight-bearing area and the necrotic area of osteonecrosis of the femoral head. The stress was scattered and distributed on the inner and outer sides of the femoral neck and the femoral head of osteonecrosis of the femoral head produced more deformation than the normal femoral head.(3) The maximum total deformation of the weight-bearing area of the osteonecrosis of the femoral head and the normal femoral head was(4.14±1.31) mm and(1.36±0.22) mm and the maximum equivalent stress was(1.94±0.77) MPa and(0.75±0.19) MPa, respectively, and with statistically significance(P < 0.05). Moreover, two groups of data tend to be concentrated and the models are stable. Through the comparison of multi-sample normal femoral head and osteonecrosis of the femoral head, the CT gray-assigned method reflects the actual mechanical properties of osteonecrosis of the femoral head, and has good accuracy and stability.
作者
薛志鹏
李泰贤
李?
何海军
黄泽青
孙继高
陈卫衡
Xue Zhipeng;Li Taixian;Li Yan;He Haijun;Huang Zeqing;Sun Jigao;Chen Weiheng(Wangjing Hospital ofChina Academy of Chinese Medical Sciences,Beijing 100102,China)
出处
《中国组织工程研究》
CAS
北大核心
2020年第3期395-400,共6页
Chinese Journal of Tissue Engineering Research
基金
国家自然科学基金(81373801),项目负责人:何海军
北京市自然科学基金(7182186),项目负责人:陈卫衡~~
关键词
CT灰度值赋值
股骨头坏死
有限元模型
单元数
节点数
应力分布
最大等效应力
最大总形变量
CT gray-assigned method
osteonecrosis of femoral head
finite element model
number of elements
number of nodes
stress distribution
maximum equivalent stress
maximum total deformation
