Static and modal analysis of different internal fixation methods for treating femoral neck fractures with bone defects
Objective To explore the static characteristics of different internal fixation methods for the treatment of femoral neck bone defect fractures and the effects of natural and constrained modes on internal fixation.Methods Firstly,based on CT images,a femoral neck fracture model and a femoral neck bone defect fracture model were established with two different internal fixation devices,the femoral neck internal fixation system (FNS) and the inverted triangular cannulated screw (CS) .Then,the stress,displacement distribution and peak values of different fracture internal fixation models,as well as the displacement peak values,frequencies,and natural and constrained mode shapes under a triple body load were simulated.Results Under the two types of internal fixation methods,the peak stresses of internal fixation for femoral neck bone defect fractures (337.69 MPa,618.58 MPa) were significantly higher than those of femoral neck fracture models (149.38 MPa,300.57 MPa).The peak stresses (107.75 MPa,93.78 MPa) and displacements of the femoral head (5.244 mm,4.415 mm) were also higher than those of femoral neck fracture models[(95.73 MPa,85.64 MPa),(4.367 mm,3.478mm)].In the case of the same fracture type,FNS internal fixation model had lower displacement peak and more uniform stress distribution compared to the CS internal fixation model.The modal analysis results showed that vibration had a certain impact on the stability of internal fixation,and the frequency range of the constrained mode was smaller than the natural mode.The displacement peak of FNS in the natural mode decreased by 6.99％ compared with that of CS,and the displacement peak in the constrained mode decreased by 14.02％.Conclusions Bone defects can seriously damage the mechanical environment of internal fixation.Whether it is a common fracture model or a bone defect fracture model,FNS fixation has better static and dynamic characteristics than CS fixation.In clinical treatment,the influence of the inherent and constrained frequencies of the femur and internal fixation devices should be considered to avoid issues such as internal fixation failure caused by resonance.
femoral neck fracturebone defectfinite element analysismodal analysisinternal fixation
万方数据
维普
