FEA Comparison Of Mechanical Characteristics Between A2FN And PFNA-Ⅱ(long) For Subtrochanteric Fractures Of The Aged

Objectives：The biomeehanical stability of A2FN and PFNA-Ⅱ(long) forsubtrochanteric fractures of the aged were explored by the Three-Dimensional FiniteElement Analysis. The comparation of A2FN and PFNA-Ⅱ(long) gives sometheoretical mechanics proofs in clinical selection of implants for such fractures.Methods：By CT axial scanning normal old female’s femur to capture relatedmaterials to establish three-dimensional finite element model, by using MxliteviewVertion1.18、Mimics10.0、GeoMagic Studio9.0、HyperMesh、Ansys11.0to establishthree-dimensional finite element model of unilateral subtrochanteric fracture(left,similarly hereinafter), and according to the data of A2FN and PFNA-Ⅱ(long) toestablish three-dimensional finite element model, to import the unilateralsubtrochanteric fracture model, to set boundary conditions and load conditions, andto do some biomechanics of three-dimensional finite element analyze and to get thedistributing map of femur、implants、fracture cross-section’s stress and stress values,and to get the distributing map of proximal femur’s displacement and displacementvalues, and to get the gaps of different direction fracture cross-section, in this way tocompare the stability between the two different fixing methods.Results：The3-D FEA models of the femoral subtrochanteric fracture of the aged、the A2FN and the PFNA-Ⅱ(long) were built up. The outcome demonstrates thatunder the physiological load conditions of the gait of statically standing and the peakforces associated with the stance phase of gait the stress of A2FN(experimentalgroup)system’s implant was significantly lower than the PFNA-Ⅱ(long)(controlgroup) system; but the stress of the experimental group’s femur and fracture cross-section was significantly higher than the control group; Both the experimentalgroup’s displacement values of proximal femur and the experimental group’s gaps ofdifferent direction fracture cross-section were slightly lower than the control group,but there is no significant differences between the two groups in the gaps of differentdirection fracture cross-section.Conclusions：The3-D FEA models of the femoral subtrochanteric fracture of theaged、 the A2FN and the PFNA-Ⅱ(long) were built up. According the analyzing thethree-dimensional finite element of biomechanics of the A2FN and the PFNA-Ⅱ(long)for transverse femoral subtrochanteric fractures(32-A3.1,AO classification), thecomparison shows that the stability of A2FN is slightly better than thePFNA-Ⅱ(long).