Induced Membrane Technique Combined EBM And 3D Printed Scaffolds To Repair Bone Defects

Background and Objective:The treatment of long bone defect remains a greatchallenge in the field of orthopedics.Induced membrane technique(IMT)has been applied widely in treating large bone defect.However,large amounts of autologousbone were needed.The aim of this study was to investigate the effect of IMT combiningenhancedbonemarrow(eBM)with3Dprinted Polylactide-Hydroxyapatite(PLA-HA)scaffolds on repairing long bone defect in rabbit model.Infection of bone is one of the prime reasons for long bone defect.It is reported that surgical mask may be a contamination source in the surgical procedure.In this study,we also investigated the leading causes for surgical mask contamination.Methods:In vitro,multilineage differentiation assays were performed toevaluate the differentiation potential of the bone marrow mesenchymal stem cells(BMSCs)isolated from eBM.Surface morphology of 3D printed PLA-HA scaffolds were analyzed by Micro-CT and SEM.BMSCs were seeded on the surface of 3D printed PLA-HA scaffolds to investigate the biocompatiblity of 3D printed PLA-HAscaffolds.In vivo,thirty-six rabbits were randomly divided into four equal groups:IM/ICBG group,PLA-HA group,IM/PLA-HA group,IM/PLA-HA/eBM group.HEstainingandimmumohistochemical staining were used to investigate the characteristics of IM.After 8,12,16weeks,X-ray plain radiography,Micro-computed tomography(Micro-CT),histological analysis were performed.The surfaces of the surgical mask were cut,on an average,into three parts,and an impression was made on the sterile agar plate on a clean bench and incubated for 48 hours in an aerobic humid atmosphere at 37~°C,and then CFUs were counted.Results:In vitro,eBM-BMSCs grow rapidly and possess potential of trilineagedifferentiation.3D printed PLA-HA scaffolds have a unique space structurepossessing great biocompatibility.In vivo,IM has substantial blood vessels and also secretes numerous growth factors by HE staining and immumohistochemical staining.After 8,12,16weeks,X-ray plain radiography,Micro-CT,histological analysis demonstrated that IM in conjunction with PLA-HA and eBM can completely repair large bone defect in rabbit model.With wearing time extension,an increasing trend can be seen in the CFUs from the surface of surgical mask.Conclusions:IM possesses a great biological property;eBM-BMSCs have anexcellent potential of trilineage differentiation;3D printed PLA-HA scaffolds possessing an excellent biocompatiblity provided a scaffold for eBM;IM in conjunction with 3D printed PLA-HA scaffold and eBM successfully repaired long bone defect,which may be a promising way to treat long bone defect;In the procedures of orthopedic surgery,we should take measures to decrease thecontamination of surgical mask to reduce the rate of infected bone defect.