| Objective1 The biomechanical mechanism of Jianpi huogu recipe was discussed based on the finite element model with convenient,accurate and high repeatability simulation results,which could be widely available.2 The risk factors of femoral head collapse were analyzed based on the clinical data of different outcomes of femoral head necrosis,and the collapse was predicted by loading asynchronous frequency simulation,which provided scientific basis for clinical treatment and rehabilitation.Method1 Biomechanical mechanism of Jianpi huogu recipe in treatment of early and middle stage non-traumatic osteonecrosis of the femoral head.20 cases of stable osteonecrosis of the femoral head after 1 year treatment were set as experimental group,20 cases of unilateral osteonecrosis of the femoral head of the contralateral set as normal group.Two groups of patients were treated with Jianpi huogu Recipe for two courses of treatment,while receiving arterial perfusion of chinese herbal drugs treatment for 1 time,act on crutch during the treatment.Method for establish three-dimensional finite element model:①Three-dimensional models of proximal femur and necrotic bone were reconstructed with DICOM 3.0 images of hip CT guided by Mimics image processing software.② Use Geomagic to lubricate that surface of the three-dimensional model,and deleting the overlap part of the intersection of the three-dimensional model of the proximal femur and the necrotic bone through boolean operation to obtain the three-dimensional model of the proximal femur without necrosis and the three-dimensional model of the necrotic(Normal femoral head only do surface lubrication).③ Mesh generation using ANSYS mechanical APDL,Export nodes,elements and prep7 files.④The materials of different models were material assignment by mimics.A finite model was created by work bench 14.0 to determine the constraints and loading conditions,and simulate the loading walking gait(Equivalent to 2.5times the loading weight),Stress conduction,maximum equivalent stress and maximum total deformation in the femoral head surface,proximal femur and inside the proximal femur during simulated walking of normal femoral head and osteonecrosis of the femoral head,Maximum equivalent stress and maximum total deformation of necrotic bone and weight-bearing area before and after treatment of femoral head necrosis were analyzed.2 Establishment of prediction method of collapse and different gait simulation of Jianpi huogu recipe for early and middle stage non-traumatic osteonecrosis of the femoral head20 cases of stable osteonecrosis of the femoral head after 1 year treatment were set as experimental group,20 cases of unilateral osteonecrosis of the femoral head of the contralateral set as normal group,20 cases of collapsed femoral head were set as collapsed group.The treatment method was the same as above.Method for establish three-dimensional finite element model was the same as above.Simulated loading walking jogging,running gait(Equivalent to 2.5,5,8 times the loading weight).Gender,age,side,BMI,ARCO stage and necrosis location were observed in stable group and collapse group as Risk factors of collapse.Gait analysis was used to observe the maximum equivalent stress and maximum total deformation of femoral head in normal group,stable group and collapse group before treatment-Maximum equivalent stress and maximum total deformation of femoral head weight bearing area in different gait before treatment in normal group,stable group and collapse group.Maximum equivalent stress and maximum total shape variables in different gait weight bearing areas of femoral head in normal group.Maximum equivalent stress and maximum total shape variables of femoral head weight-bearing area and necrosis area in different gait before and after treatment in stabilization group.Maximum equivalent stress and maximum total deformation of weight bearing and necrosis area of femoral head in different gait before and after treatment in collapse group.Result1 Biomechanical mechanism of Jianpi huogu recipe in treatment of early and middle stage non-traumatic osteonecrosis of the femoral head.1.1 Mechanical conduction mechanism analysis resultsThe maximum equivalent stress and the maximum total deformation in the loading area of the experimental group were greater than those in the normal group,and the difference was statistically significant(p<0.05).The results of walking finite element analysis in the normal group showed that the stress on the femoral head surface was uniform and no stress concentration was found when the pressure equivalent to 2.5 times the weight of the femoral head was applied to the load-bearing area of the femoral head.It can be seen from the femoral head cross-sectional view that the internal pressure stress of the femoral head and the compressive bone trabecula are uniformly distributed in the femoral head and the proximal inner edge of the femur Bear most of the compressive stress,at the same time,the maximum equivalent stress also happens in the femoral distance.The outer edge of femoral neck bears only a small amount of stress.the minimum equivalent stress appears at the apex of the greater trochanter.the minimum equivalent stress appears at the apex of the greater trochanter.The results of walking finite element analysis of femoral head necrosis show that the pressure equivalent to 2.5 times the weight of the femoral head acts on the surface of the femoral head in the weight-bearing area of the femoral head and there are multiple stress concentration areas on the surface of the femoral head.lt can be seen from the profile that the stress surface is scattered in the stress concentration area,and the stress distribution on the stress surface is very uneven.At the same time,the internal pressure stress of femoral head was dispersed at the junction of femoral head and femoral neck.compared with the phenomenon of overlap of normal femoral head compressive stress and compressive bone trabecula,the external pressure stress of femoral neck in experimental group was increased obviously,the internal pressure stress of proximal femur was equal to the external pressure stress,and the maximum equivalent stress of proximal femur was at distal femur.1.2 Biomechanical mechanism of Jianpi huofu recipe in treatment of non-traumatic osteonecrosis of the femoral headAfter 3 months and 1 year treatment,the total deformation of the weight-bearing area were decreased compared with before treatment(p<0.05).The maximum equivalent stress in the weight-bearing area of Jianpi huogu recipe was decreased 3 months after and 1 year after treatment compared with that before treatment.there was no significant difference between the maximum equivalent stress in the weight-bearing area 3 months after treatment and before treatment(p>0.05).After 3 months and 1 year treatment,the total deformation of necrotic area of Jianpi huogu recipe decreased compared with that before treatment(p<0.05).The maximum equivalent stress in the weight-bearing area of Jianpi huogu recipe was increased 3 months and 1 year after treatment compared with that before treatment.there was no significant difference between the maximum equivalent stress in the weight-bearing area 1 year after treatment and before treatment(p>0.05).There was significant difference in the maximum equivalent stress between 3 months after treatment and before treatment(p<0.05).Before treatment,the internal pressure stress of femoral head was dispersed at the junction of femoral head and femoral neck,and the external.stress of femoral neck was increased significantly compared with that of normal femoral head.the internal and external pressure stress of femoral head was equal.It can be seen from the femoral head profile that the internal pressure stress of the femoral head gradually concentrates at the femoral calcar 3 months after treatment and 1 year after treatment.the stress at the junction of the femoral head and neck is more uniform than that before treatment,and the stress on the lateral side of the femoral neck is less than that before treatment.It can be seen from the whole figure that the proximal femoral inner edge bears most of the stress,and the stress on the outer edge is obviously less than that before treatment.the stress concentration phenomenon is obviously improved compared with that before treatment,and the compressive stress is gradually transferred to the distal end along the femoral calcar.2 Establishment of prediction method of collapse and different gait simulation of Jianpi huogu recipe for early and middle stage non-traumatic osteonecrosis of the femoral head2.1 risk factors of femoral head collapseThere were more females in stable group than in collapsed group(p<0.05).The stability group Ⅱa was more than the collapse group,Ⅱc was less than the collapse group,the difference was statistically significant(p<0.05).The inside of necrosis was more in the stable group than in the collapsed group,while the lateral necrosis was less in the latter group(p<0.05).The weight of collapse group was heavier than that of stable group(p<0.05).There was no significant difference in other baseline data(p>0.05).2.2 different gait simulation analysis2.2.1 comparison of the maximum equivalent stress and the maximum total deformation in the walking load-bearing area before treatment in normal,stable and collapsed groups.The maximum equivalent stress and the maximum total deformation of normal group,stable group and collapse group were significantly different(p<0.05),and the order of normal group,stable group and collapse group increased in turn.2.2.2 maximum total deformation of different gait weight-bearing areas in normal,stable and collapsed groups before treatmentThe comparison of the maximal total deformation of different gait weight-bearing areas between normal group,stable group and collapse group before treatment showed that the maximal total deformation of weight-bearing areas increased in the order of walking,jogging and running,and the difference was statistically significant(P<0.05).Before treatment,the maximal total deformation of walking,jogging and running weight-bearing area increased in the order of normal group,stable group and collapse group(p<0.05).2.2.3 maximum equivalent stress of different gait load-bearing areas before treatment in normal,stable and collapsed groupsThe maximum equivalent stress of different gait weight-bearing area in normal group,stable group and collapse group before treatment showed that the maximum equivalent stress of weight-bearing area increased in the order of walking,jogging and running,and the difference was statistically significant(p<0.05).Before treatment,the maximum equivalent stress of walking,jogging and running weight-bearing area was increased in the order of normal group,stable group and collapse group,the difference was statistically significant(p<0.05).2.2.4 comparison of different gait in normal groupThe maximum equivalent stress and the maximum total deformation of the weight-bearing area in the normal group increased in the order of walking,jogging and running,and the difference was statistically significant(p<0.01).2.2.5 maximum total deformation and maximum equivalent stress in different gait weight-bearing areas before and after treatment in the stabilization groupThe maximum equivalent stress of load-bearing area and the maximum total deformation of load-bearing area in the stable group increased in the order of walking,jogging and running,and the difference was statistically significant(p<0.01).2.2.6 maximum total deformation and maximum equivalent stress of walking necrosis area before and after treatment in stable groupThe maximum equivalent stress in the necrotic area and the maximum total variable in the weight-bearing area in the stable group increased in the order of walking,jogging and running,and the difference was statistically significant(p<0.01).2.2.7 maximum total deformation and maximum equivalent stress of different gait load-bearing areas in collapse group before and after treatmentThe maximum equivalent stress and the maximum total deformation of the load-bearing area in collapse group increased in the order of walking,jogging and running,and the difference was statistically significant(p<0.01).2.2.8 maximum total deformation and maximum equivalent stress of walking necrosis area in collapse group before and after treatment2.3 ROC analysis of the maximum equivalent stress and the maximum total variable in the weight-bearing area before treatment in the stable and collapsed groups2.3.1 ROC analysisThe AUC corresponding to the maximum equivalent stress was 0.842 and 95%Cl was(0.693,0.938);The AUC corresponding to the maximum total variable was 0.752 and 95%CI was(0.591,0.875).There was a significant correlation between the maximum equivalent stress and the maximum total deformation with femoral head collapse(p = 0.000 and 0.001,respectively).2.3.2 Youden’ s index analysisWhen the maximum equivalent stress was 2.702MPa,the specificity and sensitivity of the predicted femoral head collapse were 85.0%and 75.0%.respectively,the specificity and sensitivity for predicting femoral head collapse were 70.0%and 75.0%,when the maximum total deformation was 4.761mm.Conclusion1 Biomechanical mechanism of Jianpi huogu recipe in treatment of early and middle stage non-traumatic osteonecrosis of the femoral head.1.1 normal femoral head weight bearing area of femoral head surface stress distribution is uniform,the femoral head internal compressive stress along the compressive bone trabecula bone conduction to the femoral calcar,the maximum equivalent stress is located in the femoral calcar.osteonecrosis of the femoral head due to necrosis of the bone can not effectively support the load-bearing area,the load-bearing area stress distribution is not uniform,stress concentration phenomenon is obvious,the load-bearing area compressive stress can not be smoothly conducted to the femoral calcar,but lateral conduction stress makes the femoral neck lateral compressive stress increases,compressive stress from the femoral shaft medial and lateral conduction to the distal femoral section stress peak.1.2 The Jianpi huogu recipe can improve blood circulation of the osteonecrosis of the femoral head,promote the generation of new bone,strengthen the strength and rigidity of the osteonecrosis of the femoral head,enable the necrotic bone to effectively support the load-bearing area of the femoral head,reduce the stress concentration phenomenon of the load-bearing area of the femoral head,and relieve the continuous high stress state of normal bone tissue in the necrotic bone area to achieve the therapeutic effect.2 Establishment of prediction method of collapse and different gait simulation of Jianpi huogu recipe for early and middle stage non-traumatic osteonecrosis of the femoral head.2.1 The study found that the risk factors of femoral head collapse were male,overweight,large osteonecrosis area,lateral necrosis.2.2 The results showed that there were differences in the initial biomechanical properties between the stable group and the collapsed group,the stress concentration phenomenon and the degree of stress conduction barrier in the collapsed group were more serious than those in the stable group.2.3 The results of finite edement simulation of different gait show that the maximum equivalent stress and the maximum total deformation of the load-bearing area increase with the acceleration of step frequency.It is suggested that the risk of collapse increases with the acceleration of gait frequency.2.4 The maximum equivalent stress and maximum total deformation in the weight-bearing area of femoral head is closely related to collapse of femoral head.when the maximum equivalent stress and the maximum total deformation in the weight-bearing area exceeds threshold,the collapse of femoral head should be highly vigilant. |
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