BACKGROUND:The induced membrane technique(Masquelet technique)is a novel two-stage surgical approach for the reconstruction of large bone defects,gaining increasing popularity in clinical applications.However,the precise mechanism underlying its bone defect repair is still not fully understood.OBJECTIVE:To review the background,repair mechanism and advantages of the induced membrane technique,the characteristics of the induced membrane,membrane-bone graft communication,selection of animal models,types and morphology of bone cement,the effects of loaded antibiotics on the induced membrane,choice of fixation methods,and bone tissue engineering materials to provide new insights for the future treatment of critical-sized bone defects and the improvement of the induced membrane technique.METHODS:A literature search was conducted in PubMed,Web of Science,and CNKI databases,covering publications from 1986 to 2024.A total of 890 references were retrieved.Manual screening and analysis were performed based on inclusion criteria related to the fundamental research of induced membrane technique,excluding those with poor relevance to the topic and duplicates.The included literature comprised original experimental studies,reviews,meta-analyses and other relevant publications.Finally,72 articles were included for summary and analysis.RESULTS AND CONCLUSION:(1)The mechanism underlying the bone defect repair using this technique remains unclear,but both the membrane and bone grafting are indispensable.(2)The induced membrane is a distinctively layered tissue rich in various bone-forming related cells,growth factors,and blood vessels,with its vascularization and secretion of growth factors dynamically changing overtime.(3)In terms of animal model selection,sheep are more similar to humans in anatomical structure,weight-bearing patterns,and bone remodeling.However,rats are more suitable considering their lower feeding costs,easier handling,and shorter modeling period.(4)Polymethyl methacrylate is not the only material that can be used to induce a biomembrane,and there may be more suitable materials capable of inducing higher-quality biomembranes.The recommended dose of antibiotics(primarily vancomycin)is 1-4 g per 40 g polymethyl methacrylate.(5)For animal fixation,especially in rats,the use of steel plates is more widespread,providing a more reliable and reproducible fixation method.(6)In the future,there is potential for new materials to replace autogenous bone and enhance the bone repair capabilities of the Masquelet technique.

BACKGROUND:The induced membrane technique(Masquelet technique)is a novel two-stage surgical approach for the reconstruction of large bone defects,gaining increasing popularity in clinical applications.However,the precise mechanism underlying its bone defect repair is still not fully understood.OBJECTIVE:To review the background,repair mechanism and advantages of the induced membrane technique,the characteristics of the induced membrane,membrane-bone graft communication,selection of animal models,types and morphology of bone cement,the effects of loaded antibiotics on the induced membrane,choice of fixation methods,and bone tissue engineering materials to provide new insights for the future treatment of critical-sized bone defects and the improvement of the induced membrane technique.METHODS:A literature search was conducted in PubMed,Web of Science,and CNKI databases,covering publications from 1986 to 2024.A total of 890 references were retrieved.Manual screening and analysis were performed based on inclusion criteria related to the fundamental research of induced membrane technique,excluding those with poor relevance to the topic and duplicates.The included literature comprised original experimental studies,reviews,meta-analyses and other relevant publications.Finally,72 articles were included for summary and analysis.RESULTS AND CONCLUSION:(1)The mechanism underlying the bone defect repair using this technique remains unclear,but both the membrane and bone grafting are indispensable.(2)The induced membrane is a distinctively layered tissue rich in various bone-forming related cells,growth factors,and blood vessels,with its vascularization and secretion of growth factors dynamically changing overtime.(3)In terms of animal model selection,sheep are more similar to humans in anatomical structure,weight-bearing patterns,and bone remodeling.However,rats are more suitable considering their lower feeding costs,easier handling,and shorter modeling period.(4)Polymethyl methacrylate is not the only material that can be used to induce a biomembrane,and there may be more suitable materials capable of inducing higher-quality biomembranes.The recommended dose of antibiotics(primarily vancomycin)is 1-4 g per 40 g polymethyl methacrylate.(5)For animal fixation,especially in rats,the use of steel plates is more widespread,providing a more reliable and reproducible fixation method.(6)In the future,there is potential for new materials to replace autogenous bone and enhance the bone repair capabilities of the Masquelet technique.

BACKGROUND:Intramedullary nail has achieved a good clinical result in the treatment of femoral shaft fractures,but some patients still have aseptic nonunion due to mechanical instability.The femur is the longest and largest bone in the human body,but there are few studies on whether the fracture of the femur has different biomechanical results in different areas and the influence of different inserting methods on the stability of fracture fragments in different areas. OBJECTIVE:To analyze the biomechanical characteristics of anterograde and retrograde intramedullary nails in the treatment of different areas of femoral shaft fractures,and to evaluate the best way of insertion to reduce the incidence of nonunion. METHODS:CT data of a healthy volunteer were selected to import into the software of Mimics 19.0 and Geomagic studio 2017 to extract and optimize the three-dimensional model of the right femur.The anterograde and retrograde intramedullary nail models were built with Solidworks 2017 software and assembled with femoral shaft fracture models at different fracture areas according to standard surgical techniques.The models were imported into Abaqus 2017 software in STEP format to set material attribute parameters,boundary conditions,load and submit calculation,and the results were viewed in the visualization module.Among them,the antegrade and retrograde intramedullary nails of the upper femoral shaft fracture were A1 and A2 models,B1 and B2 models in the middle segment,and C1 and C2 models in the lower segment. RESULTS AND CONCLUSION:(1)In models A1,B1 and C2,the overall stress distribution of the femur was more uniform,and the placement,the displacement and angle of the fracture site,and inversion angle of the proximal femoral bone fragment were smaller.(2)For the upper and middle femoral shaft fractures,the anterograde intramedullary nail has a better biomechanical effect.For lower femoral shaft fractures,a retrograde intramedullary nail is preferable.

OBJECTIVE： To investigate the effects and its mechanism of calcium phosphate bone cement （CPC） loading total flavonoids of Davallia mariesii on osteogenic differentiation of induced membrane in rats. METHODS： Drug-loading CPC and drug-loading polymethyl methacrylate （PMMA） cement were prepared with the contents of Qianggu capsules （total flavonoids of D. mariesii as active ingredient） using CPC and PMMA cement as carrier. Totally 64 male SD rats were randomly divided into drug-loading CPC group， drug-loading PMMA cement group， no-drug CPC group， no-drug PMMA cement group， with 16 rats in each group. The femur of rats was separated and osteotomized to prepare bone defect model， and then the corresponding bone cement was implanted. Four weeks after modeling， the induced membranes of rats were cut and protected. Bone cement was taken out and autogenous cancellous bone was implanted. At the 4th week after modeling， X-ray photographs were taken on the hind limb bones of rats. At the 4th week after modeling and 6th week after bone grafting， induced membranes and new bone were taken from the bone defect area of rats respectively. HE staining was used to observe the morphology of induced membrane， and the width of bone rabecular and the number of osteoblasts of new bone tissue were measured. Immunohistochemistry was used to detect the protein expression of BMP-2 and VEGF in induced membrane. Western blotting assay was used to detect the protein expression of Smad1， Smad4 and Smad7 in new bone. RESULTS： Compared with other 3 groups， the degradation of bone cement in drug-loading CPC group was more obvious in the bone defect areas， which showed that the formation of induced membrane was observed and the bone defect areas were smaller； capillary endothelial cells were abundant and orderly arranged in the induced membranes， and the width of bone trabeculae and the number of osteoblasts in the new bone tissue increased significantly （P＜0.05）； the protein expression of BMP-2 and VEGF in the induced membrane， the protein expression of Smad1， Smad4 and Smad7 in new bone were increased significantly （P＜0.05）. CONCLUSIONS： CPC loading total flavonoids of D. mariesii promotes the formation of induced membrane osteoblast in bone defect model rats， which may be associated with regulating osteoblast differentiation by activating BMP-2/Smad pathway； at the same time， it can promote bone healing by promoting the differentiation of vascular endothelial cells， accelerating the formation of capillary network and increasing the expression of vascular endothelial cells.