Study On The Biomechanics Of The Treatment Of Avascular Necrosis Of The Femoral Head By Implanting Different Materials In Honeycomb Core Decompression Surgery

Objective: The purpose of this study is to analyze the biomechanics of femoral head after hydroxyapatite artificial bone,cortical bone,cancellous bone and titanium alloy screw in honeycomb core decompression surgery(HCD)respectively.To further observe and compare the stress changes of the femoral head after implantation of four kinds of materials in HCD,so as to provide the basis for choosing the appropriate materials for the treatment of avascular necrosis of femoral head(ANFH).Methods: In this study,one ANFH patient in our hospital was selected to study Arco stage I with the method of finite element analysis.The data of the upper femur of the affected side was acquired by CT scanning,and then it was imported into the disc in Dicom format for storage.The model was established by the software of Mimics 15.0,the load was set,the material value was assigned according to the material formula and gray value in the software,and the mesh was divided and optimized by the software of Hypermesh 13.0.Finally,the model was imported into the software of ANSYS 19.2 for finite element analysis to calculate the internal stress of the femoral head.The mean value of 30 nodes was calculated.SPSS 22.0software was used to analyze the data.All parameters were expressed as mean ± standard deviation.Single factor analysis of variance was used for statistical comparison.Results: 1.The results showed that there was no significant difference between the 3-hole and5-hole groups(P > 0.05)by comparing the stress changes of ANFH model,3-hole,5-hole and7-hole HCD models,and there was significant difference between the other two groups(P < 0.05).2.By comparing the stress changes of the femoral head model implanted with the same material in HCD with different hole numbers,it was found that the stress values of the group implanted with hydroxyapatite artificial bone,cortical bone,cancellous bone and titanium alloy screw were statistically significant(P < 0.05).However,there was no significant difference in stress value between the three hole group and the five hole group(P > 0.05).3.By comparing the stress changes of femoral head models implanted with different materials in the same number of holes HCD,(1)we found that in the 3-hole HCD group,The stress values of the non implanted group was compared with the group with cortical bone;titanium alloy screw group was compared with hydroxyapatite artificial bone group and cortical bone groupwere significantly different(P < 0.05),There was no significant difference in stress between the other groups(P > 0.05).(2)In the 5-hole HCD group,The stress values of the non implanted group was compared with the hydroxyapatite artificial bone group and the cortical bone group;cancellous bone group was compared with hydroxyapatite artificial bone group and cortical bone group;titanium alloy screw group was compared with hydroxyapatite artificial bone group and cortical bone group were significantly different(P <0.05).There was no significant difference in stress between the other groups(P > 0.05).(3)In the7-hole HCD group,The stress values of the non implanted group was compared with the hydroxyapatite artificial bone group and the cortical bone group;cancellous bone group was compared with hydroxyapatite artificial bone group and cortical bone group;titanium alloy screw group was compared with hydroxyapatite artificial bone group were significantly different(P <0.05).There was no significant difference in stress between the other groups(P > 0.05).Conclusion: 1.It is found that HCD can effectively change the stress distribution of the femoral head.After HCD,the internal stress value of the femoral head increases compared with that before operation.The more the number of HCD holes,the greater the internal stress value of the femoral head,which indicates that HCD can reduce the mechanical properties of the femoral head,and it needs to be supplemented with effective implants.2.Hydroxyapatite artificial bone,cortical bone,cancellous bone and titanium alloy screw can effectively improve the biomechanical properties of the femoral head after HCD,increase the supporting force in the femoral head,reduce the stress concentration,and effectively prevent the collapse of the femoral head.3.By comparing the 5 mm pressure reducing aperture of 3,5 and 7 holes HCD on the stress changes of femoral head,5 holes is the best.4.Considering the influence of four kinds of materials implanted in HCD on the collapse,fracture and stress change of femoral head,it is a better choice to implant hydroxyapatite artificial bone in HCD.