In Vitro Biomechanical Study of Proximal Femoral Nail Anti-rotation Fixation for Femoral Intertrochanteric Fracture with Femoral Neck Base Defect
Objective To evaluate the biomechanics of proximal femoral nail anti-rotation(PFNA)internal fixation in the treatment of intertrochanteric fracture of femur(IFF)with defects in different parts of the femoral neck base.Methods From May to July 2024,12 IFF models with bone defects in different parts of the femoral neck base were prepared.Experimental grouping scheme:Group A had no defect at the base of femoral neck;Group B had anteromedial defect at the base of femoral neck;Group C had medial defect at the base of femoral neck;Group D had posterior medial defect at the base of femoral neck,with 3 models in each group.All models were fixed by PFNA in standard way after successful preparation.Mechanical test scheme:Apply appropriate force to simulate the standing posture of normal people on the universal test machine for axial compression,record the axial displacement and axial stiffness of the femoral head under different loads,and the failure load of the fixed model.And the load-displacement curves of the 4 groups of models were plotted.Results Comparison of the axial stiffness among the models revealed that group A exhibited the highest axial compression stiffness at(48.05±0.83)N/m,with a statistically significant difference when compared to the other three groups(P＜0.05).Conversely,group B demonstrated the lowest axial compression stiffness at(35.67±1.03)N/m,which was also statistically significantly different from the remaining groups(P＜0.05).In terms of model failure load,group A recorded the highest failure load of(720.67±12.51)N,showing a statistically significant difference relative to all other groups(P＜0.05),while group B had the lowest failure load at(535.00±12.50)N,which was similarly statistically significant in comparison to the other three groups(P＜0.05).Regarding axial displacement under varying loads:for loads below 500 N,group B(the anteromedial defect group)exhibited significantly greater axial displacement than all other groups,with this difference being statistically significant as well(P＜0.05).At a load threshold of 600 N or more,an axial displacement exceeding 15 mm in group B was indicative of internal fixation failure;conversely,all measurements within the other three groups remained within effective ranges for internal fixation.Conclusion The bone defect in the neck of femur has an effect on the in vitro mechanical strength of IFF fixed internally by PFNA.The anterior medial defect of femoral neck base has the greatest influence on mechanical strength.Reconstruction and fixation of the bone defect area should be emphasized in the clinical treatment of IFF associated with the defect of the femoral neck base,especially the anterior medial bone defect.
Intertrochanteric fracture of femurFemoral neck base defectProximal femoral nail anti-rotationBiomechanics
万方数据
维普
