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OBJECTIVE: Femoral head necrosis is a challenging condition in orthopaedics, and the occurrence of collapse is an important factor affecting the prognosis of femoral head necrosis. Sclerosis bands are known to influence the collapse of the femoral head, yet there is a lack of research on the biomechanical role of sclerosis bands in non-vascularized fibular grafting surgery. This study aims to evaluate the biomechanical impact of sclerosis bands in femoral head necrosis and their role in non-vascularized fibular grafting surgery (NVFG) using finite element analysis. METHODS: We constructed 11 finite element models based on CT scan data of a normal hip joint, simulating different sclerosis band thicknesses and defect scenarios. The models were analyzed for changes in femoral head displacement and von Mises stress. We constructed a hip joint model based on CT data from a normal hip joint, and after reconstruction, assembly, and optimization using 3-matic. We created five groups consisting of 11 finite element analysis models of the hip joint. Mesh partitioning and mechanical parameter settings were performed in ANSYS. The changes and differences in femoral head displacement and von Mises stress of these models were analyzed. RESULTS: Increasing sclerosis band thickness led to reduced peak displacement of the femoral head by 28.6%, 42.9%, and 47.6%, and increased surface von Mises stress by 28.3%, 13.8%, and 13.0%, respectively. Post-surgery, peak displacement decreased in all groups compared to pre-surgery levels. Increasing sclerosis band thickness post-surgery resulted in decreased maximum von Mises stress of the femoral head by 13.9%, 3.0%, and 8.1%. Defect volume in the defect groups correlated with increased peak displacement of the femoral head by 10.0%, 30.0%, and 100.0%, and increased surface maximum von Mises stress of the femoral head by 9.3%, 14.0%, and 15.1%. CONCLUSION: Sclerosis band formation exacerbates von Mises stress concentration on the femoral head surface. However, thicker sclerosis bands improve post-NVFG stability and mechanical performance. Larger anterior lateral sclerosis band defects significantly compromise postoperative stability, increasing the risk of collapse. Protecting the anterior lateral sclerosis band during NVFG surgery is crucial.
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BACKGROUND:The distribution of the necrotic area plays an important role in hip preservation treatment.At present,there are few studies on whether the difference in the three-dimensional spatial distribution of osteonecrosis of the femoral head affects the clinical outcome of fibular support. OBJECTIVE:To explore the relationship between the spatial distribution and clinical outcome at the sites of osteonecrosis of the femoral head and fibular support using CT three-dimensional reconstruction so as to provide a basis for optimizing the applicable conditions of fibular support and improving the hip preservation effect of fibular support. METHODS:Eighty patients with osteonecrosis of the femoral head who were treated with fibular support for hip preservation from January 2010 to January 2021 were selected as the study subjects according to the inclusion criteria.They were followed up for at least 2 years.According to the clinical outcome,the patients were divided into the successful hip preservation group(n=55)and the failure hip preservation group(n=25).3D reconstruction was performed according to the preoperative and postoperative CT images of the patients.According to the three-column theory,the femoral head was divided into outer nine areas,middle nine areas and inner nine areas(L1-9,C1-9,and M1-9)to explore the spatial distribution of necrotic area of the femoral head and fibular support area and its relationship with clinical outcome. RESULTS AND CONCLUSION:(1)Before operation,the necrotic area of the femoral head was mainly distributed in L1,L2,L4,L5,C1,C2,C4,and C5(the upper and middle part of the anterior part of the outer ninth area and the middle part of the middle ninth area).After operation,the fibular support area was mainly distributed in L5,L6,C5,and C6(the middle and lower part of the outer ninth area and the middle and lower part of the middle ninth area).(2)There were significant differences in the distribution of osteonecrosis of the femoral head between the successful hip preservation group and the failure hip preservation group in L8(the posterior middle part of the outer ninth area),C3(the anterior lower part of the middle ninth area),C6(the lower middle part of the middle part of the inner ninth area)and M2(the anterior middle part of the inner ninth area)(P<0.05).There was a significant difference in the distribution of fibular support in L5 and L6(middle and lower part of outer nine)(P<0.05).Among them,the L8 region could be used as an independent predictor of hip preservation failure in fibular support surgery.The area under the curve of the L8 single factor prediction model was 0.698[95%CI(0.575,0.822)];the sensitivity was 76%,and the specificity was 63.6%.(3)It turns out,when the necrotic area involves L8,C3,C6,and M2,especially L8,the failure of fibular support may increase,and when the fibular support involves L5 and L6,the effect of hip preservation is often not ideal.
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BACKGROUND:Bone has bioelectric effects.However,bone defects can lead to loss of endogenous bioelectricity in bone.The implantation of bone tissue engineering scaffolds with bioelectric effect into bone defects will replenish the missing electrical signals and accelerate the repair of bone defects. OBJECTIVE:To introduce the bioelectric effect of bone tissue and expound the repair effect of electrical stimulation on bone defects,summarize the research progress of bioelectric effect applied to bone tissue engineering,in order to provide new ideas for the research of bone tissue engineering. METHODS:Relevant articles were searched on CNKI,WanFang,PubMed,Web of Science and ScienceDirect databases,using"bioelectrical effect,bioelectrical materials,electrical stimulation,bone tissue engineering,bone scaffold,bone defect,bone repair,osteogenesis"as the English and Chinese search terms.Finally,87 articles were included for analysis. RESULTS AND CONCLUSION:(1)Bioelectrical effect combined with ex vivo electrical stimulation to design bone tissue engineering scaffolds is an ideal and feasible approach,and the main materials involved include metallic materials,graphene materials,natural bio-derived materials,and synthetic biomaterial.At present,the most widely used conductive material is graphene material,which benefits from its super conductivity,large specific surface area,good biocompatibility with cells and bones,and excellent mechanical properties.(2)Graphene materials are mainly introduced into the scaffold as modified materials to enhance the conductivity of the overall scaffold,while its large surface area and rich functional groups can promote the loading and release of bioactive substances.(3)However,there are still some major challenges to overcome for bioelectrically effective bone tissue engineering scaffolds:not only electrical conductivity but also the overall performance of the bracket needs to be considered;lack of uniform,standardized preparation of bioelectrically effective bone tissue engineering scaffolds;extracorporeal electrical stimulation intervention systems are not yet mature enough;lack of individualized guidance on stent selection to enable the selection and design of the most appropriate stent for patients with different pathologies.(4)When designing conductive scaffolds,researchers have to deeply consider the comprehensive effects of the scaffolds,such as biocompatibility,mechanical properties,and biodegradability.This combination of properties can be achieved by combining multiple materials.(5)Beyond that,clinical translation should be the ultimate consideration for conductive stent design.On the basis of evaluating the safe current threshold for electrical stimulation to act on the human body and facilitate the repair of bone defects,animal experiments as well as basic experiments are designed and then applied to the clinic to achieve the ultimate goal of applying bioelectrical effect bone tissue engineering scaffolds in the clinic.