Finite Element Analysis Of Biomechanics After Fixation Of Femoral Intertrochanteric Fracture In Different Ways

Part 1Study on the Stability of Internal Fixation after PFNA Fixation and DHS Fixation with Different Types of Six-part Intertrochanteric FracturesObjective:Based on the six part fracture classification of intertrochanteric fractures,the biomechanical characteristics of extramedullary fixation(DHS)and intramedullary fixation(PFNA)were explored and compared with the previous comparisons of the advantages and disadvantages between the two Femoral intertrochanteric fractures of six-part fractures of the scientific and clinical value.Methods:1.According to the data of normal adult CT images,three-dimensional finite element model of proximal femur was established by Mimics,Geomagic Studio and Pro /E software,and osteotomy was performed according to the six part fractures classification of femoral intertrochanteric fractures.2.Use solidworks software to establish three-dimensional finite element models of extramedullary fixation(DHS)and intramedullary fixation(PFNA).3.The two-part and four-part fracture models were selected.After setting the parameters such as material properties and boundary conditions,the finite element model was obtained by orthodontic fixation with internal fixation(DHS)and intramedullary fixation(PFNA),and simulate the stress of the hip joint in the right leg standing in normal 70 KG normal adults.Von Mises stress distribution of DHS and PFNA and Von Mises stress distribution of femur under different internal fixation were studied,a nalyze the stability of the internal fixation model.Results:In the two-part fracture model,the stress distribution of extramedullary fixation(DHS)and intramedullary fixation(PFNA)occurred at the junction of the internal fixation devices,and no significant abnormality in the stress value was observed.In the four-part femur fracture model,the extramedullary fixation(DHS)fracture model,the femur side stress concentrated in the femur lesser trochanter,the internal fixation side stress concentrated in the tension nail and the sleeve junction;Intramedullary nailing(PFNA)fracture model,stress on the femur was concentrated in the internal fixation of distal femur medial cortex,and stress on the internal fixation side was concentrated in the interface between the intramedullary nail and head nail.Conclusion:The biomechanical distribution of extramedullary fixation(DHS)and intramedullary fixation(PFNA)in fixation of intertrochanteric two-part fractures was not significantly abnormal;in the case of a fixed four-part intertrochanteric fracture,the extramedullary fixation(DHS)fracture model The stress was abnormally concentrated and did not conform to the strong internal fixation stress distribution.However,there was no obvious abnormality in the biomechanical distribution in the intramedullary fixation(PFNA)model.Part 2Study on the Stability of Internal Fixation of PCCP Fixed and New Lateral Wall Reconstruction Plate after Six-part Fracture of Intertrochanteric FracturesObjective: Based on the finite element model of six part fracture classification of intertrochanteric fractures and the concept of femoral lateral wall,a new type of femoral lateral wall reconstruction plate was designed to provide a new,minimally invasive,scientific and effective lateral wall reconstruction Internal fixation equipment.In order to effectively prevent the failure of internal fixation to provide the best solution to the occurrence of complications.Methods: Design a new type of femoral lateral wall reconstruction plate,with the first part of the experimental method,select the three-part fracture(lateral wall rupture type)and six fractures were treated with PCCP and a new type of femoral external wall reconstruction plate simulating internal fixation,to study the Von Mises stress distribution of PCCP and the new type of femoral lateral wall reconstruction plate and Von Mises stress distribution under different internal fixation,and then analyze the stability of the internal fixation model.Results: PCCP fixed three-part fracture(lateral wall rupture)and six-part fracture internal fixation model,the femoral stress is relatively concentrated in the femoral small trochanter,internal fixation stress is mainly concentrated in the two PCCP pins In the middle part of the plate and the upper segment of the plate,the new type of femoral lateral wall reconstruction plate fixed three-part fracture(lateral wall rupture)and six-part fracture internal fixation model,the femoral stress concentrated in the small trochanter and the greater trochanter,internal fixation stress concentrated in the middle of the plate and the claw structure department.Conclusion: Through the biomechanical stress analysis between the two,compared with PCCP,the new type of femoral lateral wall reconstruction plate fixation of femoral intertrochanteric fractures has a poorer stabilizing effect on the lateral wall of intertrochanteric fractures.However,considering that the lateral reconstruction plate is only designed to assist in stabilizing the lateral wall of the intramedullary nail,Internal fixation system,to prevent nail breakage nail still has significant value.