生物型自锁式人工髋关节假体的改良设计

Modified design of biotype self-locking hip joint prosthesis

背景:人工髋关节假体需要满足与股骨髓腔良好的结构相容性和原骨组织的生物力学传递性。但是目前个体解剖特点的差异性和置换后局部区域的应力集中现象,直接影响术后股骨-假体柄之间的结合及力流传递、股骨重建,最终导致部分患者髋关节无菌性松动。目的:采用有限元方法分析改良生物型自锁式髋关节假体螺钉固定的生物力学特点,为其应用于髋关节置换提供参考数据。方法:实验设计分2组,分别为传统生物型髋关节假体及生物型自锁式髋关节假体。根据髋关节置换生物型自锁式假体有限元模型,建立28种螺钉固定方式。于Minics系统生成3D,优化假体,并进行假体设计,在Solidworks软件中与股骨重新定位及装配,完成后导入Ansys进行接触设置,Ansys分析假体-股骨-螺钉的应力及位移分布,并比较股骨及假体的应力峰值及位移峰值,分析假体置入后的生物力学稳定性。结果与结论:1通过Ansys有限元方法分析比较股骨、传统生物型髋关节假体及生物型自锁式髋关节假体的应力和位移分布,股骨最小应力峰值为15.698 MPa,假体最小应力峰值为45.491 MPa,螺钉最小应力峰值为8.359 MPa;股骨最小位移峰值为1.125 3 mm,假体最小位移峰值为1.039 6 mm,螺钉最小位移峰值为0.566 4 mm;2与股骨及传统生物型髋关节假体比较,28种自锁式髋关节假体中,E组承受的应力最小;A-F组位移变化最小;综合应力和位移的变化情况,A-F组是最佳组合,其中股骨-假体-螺钉最大应力分别为18.936,59.494,12.382 MPa;股骨-假体-螺钉最大位移分别为1.125 3,1.039 6,0.626 3 mm;3提示A-F组应力和位移参数是28种自锁式生物型髋关节假体螺钉固定中的最佳参数组合,是研发自锁式生物型髋关节假体的推荐指标。

BACKGROUND：Hip prosthesis needs to meet the good structural compatibility with femoral bone marrow cavity and the biomechanical properties of the original bone tissue.However,the difference of individual anatomical characteristics and the stress concentration in the local area after replacement directly affect postoperative combination of femoral prosthesis stem,force flow transfer and femoral reconstruction,and finally result in aseptic loosening of hip joint in some patients.OBJECTIVE：To analyze the biomechanical characteristics of modified biotype self-locking hip prosthesis by the method of finite element analysis,and to provide the reference for the application of self-locking hip prosthesis in hip replacement.METHODS：Experimental design contained traditional biotype hip joint prosthesis group and self-locking hip joint prosthesis group.In accordance with the finite element models of self-locking hip prosthesis,28 kinds of screw fixation were established.Three-dimensional models were generated in the Minics system.After the optimization of prosthesis,prosthesis was designed.In the Solidworks software,the femur was re-positioned and set for contacting set in Ansys to analyze the stress distribution and displacement distribution of the femoral-prosthesis-screw by Ansys.We compared the peak of stress and displacement of the femur and prosthesis,and analyzed the biomechanical stability of prosthesis.RESULTS AND CONCLUSION：（1） By using the Ansys finite element method,we analyzed the stress and displacement distribution of the femoral-prosthesis-screw.The minimum stress peak value of the femur was 15.698 MPa.The minimum stress peak value of prosthesis was 45.491 MPa.The minimum stress peak value of screw was 8.359 MPa.The minimum displacement peak value of femur was 1.125 3 mm.The minimum displacement peak value of prosthesis was 1.039 6 mm.The minimum displacement peak value of screw was 0.566 4 mm.（2） Compared with the traditional biotype hip joint prosthesis group,in 28 kinds of self-locking hip joint prostheses,the stress was minimum in the group E.The displacement was minimum in groups A-F.Regarding comprehensive stress and displacement,groups A-F were the best combination.The maximum stress of femoral-prosthesis-screw was 18.936,59.494 and 12.382 MPa.The maximum displacement of femoral-prosthesis-screw was 1.125 3,1.039 6 and 0.626 3 mm.（3） These findings indicated that the stress and displacement parameters of groups A-F was the best parameter combination in 28 kinds of self-locking hip joint prostheses,and it is the recommended index of researching and developing self-locking hip prosthesis.