| Objectives : Intertrochanteric femoral fracture,which happened between the base of femoral neck and the lesser trochanter. Intertrochanteric femoral fracture is more common in the elder,female patients older male three times,as China entered the aging of the population and the population life extension, intertrochanteric femoral fracture showed a rising trend.Conservative treatment complications of intertrochanteric femoral fracture, operation is the first choice of treatment.The PFNA system is widely used in clinics for the treatment of intertrochanteric fractures with internal fixation devices, the unique spiral blade design can enhance the pressure effect on bone, increase the anchor force and strengthen the anti rotation.Although the design of PFNA system has many advantages, but there are still PFNA blades exit and cut out the cases of acetabulum caused by loose screw blade.This experiment is established by the finite element method of PFNA system for the treatment of intertrochanteric femoral fracture of three-dimensional finite element model, the simulation of postoperative functional exercise at different stages of the exercise was to load, calculation and analysis of biomechanical effects of different load loosening of PFNA blades, to provide biomechanical basis weight-bearing functional exercise guidance of patients, reduce the occurrence of complications.Methods:Using 64 slice CT get the healthe volunteer,image femur data.Importing the bone DICOM data into Mimics 10.01 software for editing and creating 3D model of intertrochanteric femoral fracture.According to the system parameters of the PFNA data in the modeling software pro/Engineer Wild Fire 4 to create 3D modeling.Importing the two models into Hyper Mesh11.0 and assembling as the operative standard.Then using finite element analysis software Ansys15.0 are analyzed,load 300 N, 600 N,1200N, 2400 N four load respectively, simulation of postoperative functional exercise at different stages of loading condition, comparison of various circumstances PFNA blade and the stress distribution and displacement distribution changes.According to the results of the stress nephogram and displacement nephogram in PFNA system model,the blade maximum stress value and the total displacement peak focused primarily on the spiral blade near the femoral head.With the increase of the load, the peak value of the stress and displacement peak showed a gradually increasing trend.When loading a load of 300N、600N、1200N、 2400 N,the stress are 48.06 Mpa, 96.12 Mpa, 144.18 Mpa,192.24 Mpa and the displacement peak are 1.7174 mm, 2.9828 mm, 3.5793 mm,4.1759 mm.Conclusion: 1.This study firstly by using spiral CT scan to acquire the image data of proximal femur, Through the Mimics10.1 and Hyper Mesh11.0 to establish the PFNA system three-dimensional finite element model of intertrochanteric femoral fractures.Its shape is consistent with the entity bones.The successful construction of the PFNA system in the treatment of intertrochanteric femoral fracture of femur in the three-dimensional finite element model, the whole model is divided into 862278 nodes,152082 units, the division of three dimensional finite element model of PFNA with143068 nodes, 31849 units.The modle can more accurately reflect the charcteristics of intertrochanteric femoral fracture anatomy and mechanical.The model can be used repeatedly and has laid a good foundation for further study PFNA systerm.2..Through the finite element analysis that increased weight can cause the PFNA blade loose.After the operation can not be too early to weight-bearing exercise. |
PDF Full Text Request