有限元分析先天性髋关节半脱位及髋臼发育不良的应力变化

Stress change of congenital subluxation of hip and dysplasia of acetabular by finite element analysis

目的 建立构成及形态接近实际的髋关节模型对髋关节进行有限元分析。从力学角度对关节发育、关节稳定性 ,骨关节炎等方面进行初步探讨。方法 收集 7～ 14岁正常儿童 9例及先天性髋关节半脱位及髋臼发育不良病例 16例 (男 8例 ,女 17例 )的X线片 ,建立二维有限元网格 ,分析各组的生物力学特点。结果 髋臼合力各组平均值为 :正常组 2 10 .1N/cm2 ;髋关节半脱位组745 .4N/cm2 ;髋臼发育不良组 5 39.6N/cm2 。股骨头合力各组平均值为 :正常组 2 18.6N/cm2 ;髋关节半脱位组 6 36 .5N/cm2 ;髋臼发育不良组 332 .4N/cm2 。各组受力差异具有统计学意义。正常组受力集中于髋臼顶 ,其他两组受力集中于髋臼边缘。结论 髋关节结构的改变使关节受力明显增加 ,关节发育异常 ,稳定性丧失 ,最终演变为骨关节炎。

Objective To make a primary mechanic research of the development, articular stability and osteoarthritis on hip models by finite element. Methods A two dimension finite element web of the roentgenographs of 9 normal children and 16 cases of subluxation of congenital hip and dysplasia of acetabulum (8 boys, 17 girls) were set up to analyze the biomechanical character through computer calculation. Results The average acetabular stress was 210.1 ?N/cm 2 in normal group, 745.4 ?N/cm 2 in subluxation group and 539.6 ?N/cm 2 in acetabular dysplasia group. The average stress on femoral head was 218.6 ?N/cm 2 in normal group, 636.5 ?N/cm 2 in subluxation group and 332.4 ?N/cm 2 in acetabular dysplasia group. The results had apparent statistic difference. The stress was focused on acetabular roof in normal group and on acetabular margin in the others. Conclusion The osteoarthritis is resulted from changing in structure which leads to stress increasing, instability and abnormal development of the hip in children.