Mechanical stability of intertrochanteric fracture of femur with different internal fixation systems

Chen Xi; Tang Tao; Chen Tongbing; Li Qing; Zhang Wen

doi:10.12307/2025.105

Abstract：BACKGROUND:Intertrochanteric fracture of femur has various fracture types and fixation methods,and the mechanical stability of each fixation system is quite different.It is of scientific clinical significance to use finite element analysis method to carry out biomechanical research on various fixation systems. OBJECTIVE:To compare and analyze the mechanical stability of various internal fixations applied to femoral intertrochanteric fracture A031-A2.1 by finite element method. METHODS:Based on the validated finite element model of femur(Intact),the model was cut and made into A031-A2.1 intertrochanteric fracture of femur.Different internal fixation systems were implanted by simulating clinical operation methods,and fixation models of proximal femoral nail antirotation,dynamic hip screw,percutaneous compression plate and proximal femoral locking plate were established respectively.All nodes under the distal femur of the four groups of models were constrained,and compression loads of 700,1 400 and 2 100 N were applied to the femoral head.Von Mises stress distribution and compression stiffness of each group of models were observed through calculation and analysis,and mechanical stability of each group was compared. RESULTS AND CONCLUSION:(1)Through calculation and analysis,after calculating the compression stiffness by comparing the deformation of each model,the compression stiffness of each model under various loads showed the trend:physiological group>proximal femoral nail antirotation group>proximal femoral locking plate group>percutaneous compression plate group>dynamic hip screw group.The compressive stiffness of the complete physiological group model was significantly higher than that of all surgical group models.(2)The stress index was observed.Due to the stress shielding effect,the stress peak value of each fixed group was higher than that of physiological group,and the maximum peak value was concentrated on each internal fixation.Proximal femoral nail antirotation group had the smallest stress peak,while dynamic hip screw group had the highest stress.The stress distribution trend showed physiological group<proximal femoral nail antirotation group<percutaneous compression plate group<proximal femoral locking plate group<dynamic hip screw group.(3)The stress distribution in the bone model showed different results depending on the implantation location of internal fixation.(4)It is concluded that for intertrochanteric fracture of femur,all kinds of internal fixation can effectively fix it.Combined with the results of finite element analysis,proximal femoral nail antirotation group is a better internal fixation choice,showing the characteristics of small deformation,low stress peak,and uniform stress distribution.The mechanical effect of percutaneous compression plate group and proximal femoral locking plate group is excellent,and the fixation effect is close to proximal femoral nail antirotation fixation.The fixation effect of dynamic hip screw is not good,and the mechanical stability of this group is poor compared with other internal fixation.