Experimental Study On Repairing Large Bone Defects With NCS/PRP-gel Based On Masquelet Technique

Background:Bone defect refers to the destruction of bone morphology and structural integrity.Bone defect is a difficult disease that orthopedics doctors often encounter in clinical work.In the 1980 s,Schmitz first proposed the concept of critical bone defect: the length of the bone defect of the long bone skeleton was 1.5 times the diameter of the skeletal cadre,which was the critical bone defect.If the length of the bone defect exceeds the critical bone defect standard,we will call it a large bone defect.Large bone defects could not be repaired by natural healing.The repair of large bone defects is a long-term problem for orthopedic clinicians.The causes of large bone defects include trauma,infections,post-tumor resection,and congenital diseases.At present,the methods for repairing large bone defects mainly include vascularized autogenous bone graft,allogeneic bone graft,Illzarov bone transplantation,and tissue engineering bone repaired technique.However,these technologies are limited in clinical application due to their own clinical defects.In 1986,Masquelet(France)proposed the concept of "inducing membrane" and began to study the application of inducing membrane-related technologies in clinical practice.In 2000,literature reported that the application of "inducing membrane" technology in the treatment of 35 cases of long tubular bone defects.The average bone defect length was 4 ~ 25 cm.An average of 4 months passed after inducing membrane formation and bone grafting.Medical imaging examination showed that the bone defect area healed well and the formation of the bone healing was basically complete.Thereafter,people called this technique "Masquelet Technique".Masquelet technique does not need to use microsurgical techniques in operation,no need to use external fixation brackets,its postoperative patient care is simple and sufficient length of large bone defects can be repaired.Against the background of the rapid development of biomaterials and bone tissue engineering repaired technology,Masquelet technique is increasingly popularized in large bone defects,and its related research is also gradually deepened.Objective:The Masquelet technique is widely used and the operation is gradually mature.At the same time,the technique still has certain technical defects.For example,secondary surgery is required to increase physical trauma and psychological damage to the patient,and the source of autogenous bone is limited.This experiment is based on Masquelet technique to implant nCS / PRP-gel into bone defect area instead of Masquelet technique second-stage autogenous iliac cancellous bone graft.We compare the results of n CS / PRP-gel implantation and autogenous iliac bone graft.Finally,we can conclude whether the above two osteogenic results are the same.We hope that the nCS / PRP-gel can be used to replace the autogenous iliac cancellous bone graft of traditional Masquelet technique to repair large bone defects.Methods:This research plan was divided into groups according to the observation time after the second-stage operation of Masquelet technique(the second-stage operation was scheduled 6 weeks after the first-stage operation of Masquelet technique),and the group was 3W,4W,6W,8W.The experimental design used 20 3-month-old New Zealand rabbits.The number of rabbits used in each group was 5 and the 5 rabbits in each group were divided into 3 experimental groups and 2 control groups.However,due to the limitations of the experimental site and environment during the experiment,only 17 rabbits were left.Therefore,the remaining 17 3-month-old New Zealand rabbits were taken as the research object.They were divided into the above 4 groups(regardless of male or female)according to the randomized principle.Bone defects were created in the first stage of surgery(the average diameter range of skeletal cadre was 0.6-0.8 cm and the length of bone defect was 1.5 cm)and bone cement placeholders were placed.The second-stage operation was carried out 6 weeks after the first-stage operation.After the second-stage operation,it was divided into four groups: 3W,4W,6W and 8W.The 3W group included 2 rabbits(1 experimental group,1 control group).The 4W group included 9 rabbits(3 experimental groups,6 control groups).The 6W group included 4 rabbits(2 experimental groups,2 control groups).The 8W group included 2 rabbits(1 experimental group,1 control group).The experimental group of New Zealand rabbits used Masquelet technique to remove the bone cement placeholder in the auto-inducing membrane cavity and implanted nCS / PRP-gel to repair the bone defect area.The control group of New Zealand rabbits used Masquelet technique to remove the bone cement placeholder in the auto-inducing membrane cavity in the second phase,and took the cancellous bone from the ipsilateral iliac bone to repair the bone defect area.3,4,6,and 8 weeks after the second-stage operation,X-rays were taken,appearance measurement was taken,and materials were taken.The bone was stained with H & E.Immunochemistry was used to detect BMP-2,VEGF,and TGF-β1.The expression of Runx-2,VEGF and TGF-β1 was detected by the RT-PCR.We compared the statistical difference of the above indexes between the experimental group and the control group,and then found out whether the difference in osteogenesis results between the experimental group and the control group is significant.Results:By comparing the experimental group and the control group of rabbits with osteoblastic results at 3,4,6,and 8 weeks after the second-stage of Masquelet technique,bone appearance photos and X-ray photos were taken.There was no obvious difference in morphology.The statistical analysis of spatial bone pixel by X-ray showed no difference between the experimental group and the control group(P> 0.05).There was no obvious histological difference between the experimental group and the control group in H & E staining.Both the experimental group and the control group were immunohistochemically tested for BMP-2,VEGF,and TGF-β1.The results showed that the expression of BMP-2,VEGF,TGF-β1 in the experimental group was higher than that in the control group.The difference between the experimental group and the control group showed that it increased first and then decreased with time.The overall change trend of the experimental group and the control group at 3W,4W,6W,and 8W was the same.We could think that the experimental group and the control group are basically the same in the osteogenesis results,but the mechanism of the experimental group and the control group to form bone was different.Runx-2,VEGF and TGF-β1 were detected by RT-PCR in the experimental group and the control group.The results showed that the Runx-2,VEGF,TGF-β1 gene expression in the experimental group were higher than the control group at 3W,4W,and 6W.The difference between the experimental group and the control group showed that it increased first and then decrease with time.The overall change trend of the experimental group and the control group at 3W,4W and 6W was the same.We could think that the experimental group and the control group were basically the same in the osteogenesis result,but the mechanism of the experimental group and the control group to form bone was different.Conclusion:The osteogenic results of implanting nCS / PRP-gel based on Masquelet technique to repair large bone defects are basically the same as autogenous iliac cancellous bone graft.We could consider using the implantation of nCS / PRP-gel based on Masquelet technique to replace the autogenous iliac cancellous bone to repair large bone defects.However,the bone formation mechanism of implanting nCS / PRP-gel based on Masquelet technique to repair large bone defects was different from autogenous iliac cancellous bone graft.