Three-dimensional Finite Element Analysis Of Structural Bone Grafts In Segmental Bone Defects In The Acetabular Weight-bearing Area During Total Hip Arthroplasty

Objective: 1.To establish a three-dimensional finite element model of segmental bone defect in the acetabular weight-bearing area.2.Finite element analysis of structural bone graft reconstruction with different internal fixation methods for different degrees of segmental bone defects in the acetabular load-bearing area,and research of three different internal fixation methods for total hip replacement with structural bone grafts The influence of postoperative acetabular mechanical stability provides theoretical support for clinicians to make surgical decisions and provides new ideas for the individualized reconstruction of joint surgery.Methods: 1.According to the inclusion and exclusion criteria,volunteers were selected to obtain normal hip CT data,and the CT data were imported into computer software for processing to establish the pelvis and hip joint MASK.Geomagic stdio was used for smoothing.The model was imported into NX assembly and imported into ANSYS workbench 18.0 for evaluation.A finite element model of acetabular weight-bearing segmental bone defect was established.Then according to the common situation of clinical acetabular weight-bearing area defect cases,the acetabular defect is standardized to different degrees,the defect area is divided into three equal parts,and the acetabular edge weight-bearing area is divided to obtain three different levels of hips.A finite element model of the molar load-bearing area defect;2.Reconstructed acetabulum using double screw fixation,single steel plate compression fixation and nail plate combination fixation on three models,and then perform total hip replacement to obtain the postoperative model,and import the postoperative model.ANSYS workbench 18.0 was used to conduct a biomechanical finite element analysis to investigate the initial stability differences of the cups in different situations.Results: 1.The finite element models of segmental bone defects in the acetabular weight-bearing area were established by applying related computer software technology,which can be used for further research.2.The initial stability of the acetabular cup was reconstructed by finite element analysis of the structural bone graft.The analysis results showed that the average deformation value of the bone graft block,the micro-movement value of the bone graft block,and the acetabulum under the three degrees of defect in the simple screw group.The mean lateral stress values were significantly different from those of the single steel plate group and the nail plate combination fixation group(P <0.01),while the single steel plate group and the nail plate combination fixation group had differences in the average deformation value of the bone graft at the time of total defects(P <0.05).),There was no significant difference in the average deformation value between the 2/3 defect and the 1/3 defect(P> 0.05).The single plate group and the nail plate combination fixation group were the micro-movement values of the bone graft on the three types of defects,and the acetabular side.There was no significant difference in the average stress values(P> 0.05).Conclusions: 1.Based on CT data and finite element analysis through relevant computer software,a finite element analysis model of acetabular weight-bearing segmental bone defects with different degrees of defects was accurately established.2.In the acetabular reconstruction with structural bone grafting of segmental bone defects in the acetabular weight-bearing area,the initial stability of the acetabular cup provided by the double screw fixation method is the worst.There is not much difference in the initial stability of the cup,but the nail-plate combination fixation method can provide better initial stability in the case of total defect of the acetabular weight-bearing segmental bone defect.