The3-D Finite Element Analysis Of The Diaphyseal Modular Prosthesis Of Proximal Femur

Objective (1) though using three-dimensional modeling software to establish the normal adult femur model and the diaphyseal modular prosthesis model matching of the proximal femur;(2)to facilitate research and analysis, we set up the control group, the short nail group, the long nails group and the three nails group;(3) In the four groups of models, through3D finite element analysis method we cross-sectionally compare the different stress distributions of the overall, prosthesis, plate, screw; we longitudinal compare the different stress distributions of the overall, prosthesis, plate on the condition that the study fixed distant stem length in8cm and proximal prosthetic stem in1cm,2cm,3cm,4cm and5cm, respectively.Methods (1) Selecting1case (40-year-old,70kg) healthy men imaging data, we imported the CT scan databases of total femur into the Mimics10.0software for three-dimensional reconstruction and export the preliminary model in STL format file. We imported the preliminary model into Geomagic studio10.0for three-dimensional further the total femur reconstruction in iges format file. We imported the total femur model into the ANSYS12.0and established proximal femoral bone defect model and simplified prosthetic model in matching of proximal femoral bone defect model.(2) Loads were established and applied on proximal femur to the largest strength when an adult of70kilogram under normal walking for every models in four group. Through the analysis and calculation, we got stress distribution of the model overall, prosthesis, screw finally. We observed and recorded the Von Mises stress, Z axis stress and shear stress data.Results (1) the diaphyseal modular prosthesis of the proximal femur apply to the100mm range of the proximal femur;(2)through the finite element analysis, the result of the cross-sectionally comparison is no obvious effect in the implant or bone own stress and strain under changing the proximal stem length and fixed distant stem length in8cm;(3) In the four groups of models, we longitudinal compare the different stress distributions and found the overall stress decreases, the prosthesis stress increased slightly, the screw the stress increased obviously and bone own stress gradually reduce. The stability of the four groups as follows:the three nails group is superior to the long nails, the long nails group is superior to the short nail group, the short nail group is superior to the control group.Conclusion (1)the diaphyseal modular prosthesis of the proximal femur apply to the100mm range of the proximal femur. After the diaphyseal modular prosthesis of the proximal femur reconstruct the proximal femur bone defects, it conforms to the femur biomechanics characteristics and restore the femoral integrity and stress conduction;(2)through the finite element analysis, the result of the cross-sectionally comparison is no obvious effect in the implant or bone own stress and strain under changing the proximal stem length and fixed distant stem length in8cm, the stress mainly concentrated in the inside and outside of the proximal distant stem, In the allowed extent of the remnants of the medullary cavity length, endoprosthesis with longer shaft should be utilized to improve the stability;(3) In the four groups of models, we longitudinal compare the different stress distributions and found the overall stress decreases, the prosthesis stress increased slightly, the screw the stress increased obviously and bone own stress gradually reduce. The stability of the four groups as follows:the three nails group is superior to the long nails, the long nails group is superior to the short nail group, the short nail group is superior to the control group. Therefore, the stable reconstruction of the proximal bone should be established by the neck long nails.