Study On The Risk Factors And Biomechanical Mechanism Of Hip Fracture Caused By Falls In The Aged

ObjectiveThrough the collection of clinical medical records,specimen biomechanical experiments combined with finite element analysis,the risk factors of hip fracture in the elderly were identified,and biomechanical analysis was carried out on the proximal femoral end of the elderly by simulating standing and falling,so as to clarity the biomechanical mechanism of hip fracture caused by torsion and impact violence.Method1.419 clinical records were collected,and the possible risk factors of hip fracture in senile patients were retrospectively analyzed based on the basic data,combined with basic diseases and fall posture.2.Six gross samples were selected to simulate the impact of the patients on the ground before(3 cases)and after falling(3 cases).The Bose machine was used to apply loads,and the failure load,failure state,point principal strain and deformation were recorded respectively.3.CT data of 3 elderly patients with hip fracture were selected to segment the healthy femur proximal end to establish a finite element model,simulate standing and falling,adjust the coordinate system and set the boundary conditions,calculate the total deformation,equivalent stress and maximum principal stress,and obtain the nephograph.Result1.Among the 419 cases,152 were males and 267 were females.The mean age was 78.97 years.246 cases of femoral neck fracture and 173 cases of intertrochanteric fracture were found.With the increase of age,intertrochanteric fracture of femur showed an increasing trend,while neck fracture of femur showed a decreasing trend,and this trend was significantly correlated(R=0.822,P=0.045).In terms of gender,paired T-test(P=0.442>0.05)showed no significant difference.There were 329 cases with underlying diseases,mainly hypertension,diabetes,stroke or dementia and so on.With the increase of age,the proportion with no underlying diseases gradually decreased,while the proportion with multiple underlying diseases gradually increased,and there was no statistical difference between groups.Fall posture:1 19 patients were included.In the torsion group,intertrochanteric fracture occurred in 34(77.3%)and neck fracture occurred in 10(22.7%).In the non-torsion group,intertrochanteric fracture occurred in 7 cases(9.3%)and femoral neck fracture occurred in 68 cases(90.7%),with statistically significant difference in paired sample correlation coefficients(P<0.001).2.The supporting phase of the gross specimen experiment:failure load(5966.67±1436.43N),the strain in the intertrochanteric zone increased with the increase of the load,and there was a statistical difference.Fall phase:failure load(3081.33±331.43N),the strain of neck region of femur increased with the increase of load,there was a statistical difference;The load-deformation curve,whether the supporting phase or the falling phase,increases with the increase of the load,and rises slowly until the ultimate fracture occurs after the yield point.3.The maximum principal stress nephogram of finite element analysis showed that the maximum value appeared in the lower part of the greater trochanter of the supporting phase,and the principal stress value was greater than the upper part of the neck of the femur.The maximum stress of fall phase mainly occurred in the upper region of femoral neck,and the principal stress increased with the increase of adduction Angle.Maximum principal strain:All of them mainly occurred in the greater trochanter of femur and increased with the increase of load.However,in the fall phase,with the increase of adduction Angle,the principal strain in the greater trochanter decreased with statistical difference.The equivalent stress distribution nephogram:the equal support force mainly concentrated in the inner neck of femur and the lesser trochanter.The fall phase mainly concentrated in the neck of femur.With the increase of the adduction Angle,the femoral neck area gradually decreased,while the femoral shaft area under the greater trochanter gradually increased.ConclusionWith the increase of age,the proportion of intertrochanteric fracture of femur increased gradually,while the proportion of femoral neck fracture decreased gradually.The proportion with no underlying diseases gradually decreased,while the proportion with multiple underlying diseases gradually increased.Prior to instability,intertrochanteric fractures of the femur are likely to occur if the body is torsional,and neck fractures of the femur are likely to occur if the body is not torsional.In the bracing phase,the deformation and strain were mainly concentrated in the intertrochanteric region near fracture failure.In the fall phase,it is mainly concentrated in the femoral neck area.The maximum deformation of propping phase and falling phase occurs in the great trochanter region,and the maximum deformation of falling phase decreases with the increase of the adduction Angle.The equal-effect force of support is mainly distributed in the inner compressive strain region,and the equal-effect force of fall is mainly distributed in the tensile strain region,which also provides mechanical support for reducing the occurrence of such adverse events.