Biomechanical Study And Finite Element Analysis Of Osteoporotic Femur Neck Injected Bone Cement

Object: Osteoporosis is a systemic bone metabolic disease,which causes vertebral fracture,femoral neck fracture is a common c linical pathological fracture,is the main threat to death in elderly patients.Percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP)were used to treat osteoporotic vertebral compression fractures(OVCF).The aim of this study is to detect the biomechanical effects and finite element analysis of bone cement on osteoporotic femoral neck,and to provide new choices and ideas for clinical prevention and treatment of osteoporotic femoral neck fracture.Method:(1)Biomechanical experiment: 21 healthy white rabbits were randomly divided into 3 groups: experimental group,control group and sham operation group.The bone mineral density of femoral neck was randomly divided into three groups: experimental group,control group and sham operation group.The rats in the experimental group and the control group were given castration + hormone injection for osteoporosis.After the model was successfully made,the bone of the experimental group was injected with bone cement.The control group was not inject ed with cement.The sham operation group was only working with the experimental group,Group the same way of operation without any other treatment.Six weeks later,complete CT scans were performed on the femur of all experimental animals.All test animals were sacrificed.After removal of the femoral specimens required for the experiment,the tendons and soft tissue attached to the bone surface were removed and stored at low temperature until biomechanical measurements were made.After spontaneous thawing at room temperature,the samples required for biomechanical measurements were taken and made,and the compression test was carried out on a biomechanical machine according to the previous experimental design.The data were recorded and the fracture position was observed.(2)Finite element analysis: The experimental specimen scanning data is stored in DICOM(Digital Imaging and Communications in Medicine)format,and the scanning data of DICOM format is imported into Mimics Research 17.0(Materialise's interactive medical image control system).In Mimics,Threshold and the three-dimensional reconstruction,into the 9-Matic after the grid optimization and meshing,the body mesh model to Mimics material assignment,and then the completion of the assignment of the volume grid model into the ABAQ US 6.14 Solve the analysis,then define the load and boundary constraints,and finally submit the analysis process.Result:(1)biomechanical experimental results: compression test results show that the experimental group compared with the control group,the elastic modulus,the breakdown point load,the breakdown point stress,the maximum load,the maximum stress and so on,the difference was statistically significant,P <0.05,but compared with sham operation group,the difference was not statistically significant,P> 0.05.(2)Finite element analysis: Three-dimensional finite element model of femoral neck was established by Mimics and ABAQUS.The finite element mesh was obtained.The number of experimental units was 256559,the number of nodes was 329102,the number of control units was 222705,the number of nodes 277455,the number of sham operation group was 222053 and the number of nodes was 318231.The results of ABAQUS analysis showed that the stiffness of the experimental group was the highest under the same loading condition,and the control group was the worst in the sham operation group.Conclusion: Injection of bone cement can increase the biomechanical strength of osteoporotic femoral neck and provide a new stra tegy for the clinical prevention and treatment of osteoporotic femoral neck fracture.