The Development And Biomechanical Study Of NiTi Shape Memory Alloy Amplectant Femur Prothesis Of Stemless Hip Prosthesis

Objective:According to the measured results of the superior extremity of Femoral bone and the characteristics of Nitinol,consider the biomechanical ascendancy of stemless hipprosthesis,a special internal fixator—NiTi Shape Memory Alloy amplectant femur prothesis of Stemless Hip Prosthesis(NTAF-SHP) was designedMethod:We got anatomy parameters of superior extremity of Femoral bone of 24 adult with vernier caliper.According to the measured data and the anatomy characteristic of Femoral bone,NTAF-SHP was designed:24 Femoral bone were divided into four groups,three groups were implanted with NTAF-SHP (experimental group),stem hipprosthesis(the first control group),stemless hip prosthesis(the second control group) respectively.The last one was the normal group.Firstly,Detect the fixed stability with DaojingAG-1 electron almighty material test system:four groups were axial loaded 100N-1000N,according measuring the bias to observe the stability of intern fixed.Secondly,Pasting strain gages to superior extremity of Femoral bone to do strain test.Observe the distribution of stress on superior extremity of Femoral bone.Result and conclusion:(1)compressed experiment result shows:Under the role of 800Nf,the bias of normal group is 0.48±0.02mm,the first control group is 0.75±0.01mm,the second control group is 0.88±0.11mm;the experimental group is 0.66±0.02mm,The displacement of normal group is smaller than the other 3 groups obviously,the statistics analysis shows notable discrepancy(p＜0.01);the displacement of the experimental group is smaller than the other 2 groups,the statistics analysis exist discrepancy(＜0.05).(2) surveying and analyzing the stress of femora after installed the 3 different types hip prosthesesevery group test result shows:the stress of 6,7,8,9 measure point is big,that means calcar femoral and compression bone trabecula are the major weight-bearing structure.When implanting three different prosthesis respectively,the stress level on the upper femora shows to drop.But the stress of medical cortex of bone of the experimental group is bigger than the first control group and the second control group.The static strength of NiTi shape memory alloy amplectant femur prothesis of stemless hip prosthesis agrees with the biomechanics rule and its static equilibrium and stabilization is very well.