Effects Of 3D Printed Porous Scaffold On Bone Integration Ability Of Titanium Alloy Implants

BACKGROUND:Since the first case of artificial joint prosthesis implantation,the stability of the prosthesis implant has been widely concerned.But the stability of the prosthetic implant has not yet reached a satisfactory level.For example,in the total knee replacement surgery,the host bone-prosthesis implant contact surface instability can produce mechanical damage,aseptic loosening,instability,prosthesis fractures and many other issues,eventually causing the prosthesis to fall off or ectopic.It makes the patient had to extend the length of hospital stay,suffering from physical and mental damage at the same time also bear the additional economic burden.Therefore,it is important to improve the stability of the prosthetic implants in the host bones.With the progress of the study,it has been found that to achieve good stability of the implant,there is a need for a combination of a biological form between the host bone and the prosthetic implant.For good bony binding,the implant needs to be "porous".The concept of "Bone combination" & "porosity",opened a new field of prosthetic implant design,people began to design a variety of 3D print porous scaffolds to study the combination of prosthesis implant and host bone situation.In today's clinical application of orthopedic implants,the most common material is Ti6Al4 V,its biocompatibility,low elastic modulus,corrosion resistance and other advantages are of concern,making it the most widely used medical titanium alloy material.Therefore,this study uses Ti6Al4 V as a material,from the biological properties of bone and bone combination requirements,relying on 3D print porous scaffolds,to study the effect of porous structure on bone integration ability of prosthesis implants.OBJECTIVE:In this study,we investigated the effect of porous structure on osteoblast differentiation and the ability of bone implantation to evaluate the effect of porous structure on the osseointegration of prosthesis implants.METHODS:In this experiment,we will detect 300 um and 500 um two different aperture of the 3D printing titanium alloy porous scaffolds.In the in vitro experimental part,we conducted a flow cytometry test,cell proliferation assay,cell morphology and adhesion experiments,alkaline phosphatase quantitative experiments;in the in vivo experimental part,we selected male rabbits as experimental animals,the scaffold is surgically implanted in rabbit femoral condyle,sacrificed 4 weeks after feeding,bone ingrowth analyzed by Micro-CT and the histological staining.RESULTS:Two different aperture of the 3D printing titanium alloy porous scaffolds were not cytotoxic.In the in vitro experimental part,there was no significant difference in BMSCs proliferation between the two groups;in the in vivo experimental part,there are more new bone formation around the 300 um pore scaffolds,and the bone grows deeper into the aperture.CONCLUSION:The porous structure of the scaffold is critical to the bone integration and the hole diameter has an effect on the ability of bone's integrate to the scaffold.A suitable scaffold structure can promote bone tissue growth,so that the prosthesis implant in the host bone can be more stable.In the in vitro experimental part,300 um pore scaffolds did not significantly stimulate the proliferation of BMSCs,but can improve the ability of scaffolds to promote osteogenic differentiation;in the in vivo experimental part,compared to 500 um pore scaffolds,300 um pore scaffolds formed more bone tissue around the hole and inside.