多孔钽块置入治疗股骨头缺血性坏死的生物力学及三维有限元分析

Biomechanical study and three-dimension finite element analysis on the treatment of the iscbemic necrosis of the femoral head using pieces of tantalum in adult

[目的]对比研究三种治疗成人股骨头缺血性坏死的生物力学方法;探讨髓芯减压对股骨头机械支撑力的影响及钽块置入治疗股骨头缺血性坏死的独特优势。[方法]选择健康成人右侧股骨为研究对象,经层厚2.0 mm的螺旋CT扫描得各断面图像,输入计算机识别和提取股骨轮廓并行三维重建。按生理状态下股骨力载荷的三维空间分布,施加髋关节接触力1 620 N,外展肌合力1 061 N,髂胫束力1 720 N。对股骨头三维有限元模型进行计算,求出股骨头受力模型在不同坏死角度,不同减压位置股骨头负重区表面的塌陷值。[结果]股骨头髓芯减压后的塌陷值明显增大,以负重区最为明显(P>0.05),且随着坏死角度的增大股骨头的塌陷值也随着增大。[结论]髓芯减压虽能清除死骨,但减压本身则进一步降低了股骨头的力学性能,单纯的植骨并不能增加股骨头的机械支撑力;髓芯减压基础上以多孔钽金属块为股骨头及软骨下骨板提供安全而有效的力学支撑,能有效防止塌陷,并为骨组织的修复提供条件。

[ Objective ] To study the biomechanics for the treatment of vascular necrosis of the femoral head by three differ- eat methods and explore core decompression of mechanical pulp femoral head support to influence and pieces of tantalum im- plant treatment of avascular necrosis of the unique advantage. [ Method ] The right femur of healthy adults was choosen as the research object, and CT scanning was conducted by 2 mm interval to get the images of cross sections. The images were then in- putted into computer to get contour of femur and rebuild 3D model. The hip joint reaction force of I 620 N,the abductor muscle force of 1061N, the vastus lateralis muscle force of 1 720 N were applied according to the three-dimensional space distribution of femur force under physiological state. For the avascular necrosis in different bearing model angle, different reduced pressure zone of the femoral head position were loaded the surface subsidence value. [ Result ] The core of the femoral head after decompres- sion pulp collapse increased in value, loading the area most obviously （ P 〉 0.05 ）, and with the increase of the femoral head necrosis angle value increased with the collapse. [ Conclusion ] Pulp core decompression can remove dead bone, but reduce pres- sure itself,further reduce the mechanical properties of the femoral head, simple cancellous bone grafts and cant increase the femoral head mechanical support. Pulp core based on the reduced pressure in porous metal tantalum piece for the femoral head bone and cartilage board to provide security and effective mechanical support, can effectively prevent the collapse, and provide the conditions for bone tissue repair.