Feasibility Study Of Allograft Bone Pipe Fill With Autologous Bone On The Repair Of Large Segmental Bone Defects

Objective:To discuss the feasibility and effect of allograft bone pipe fill with autologous bone in repairing large segmental bone defects with allogeneic cortical bone plates associated with steel plate,with the purpose of providing new idea and experimental testimony to follow-up experiment and clinical application.Methods:Twenty seven goats were randonly allocated to 3 groups:experimental group, control group,blank control group.Then the large segmental bone defects of animal models were made after anesthesia.Experimental group were planted allograft bone-pipe fill with autologous bone and fixed with allogeneic cortical bone plates associated with plate;Control group with the same implant as experimental group but fixed with plate;Blank control group grafted with allograft bone-pipe and fixed with plate.The goats were breed and observed freely,treated with antibiotics regularly.At 4,8,12 weeks,the goats were examed by X-ray postoperatively;3 goats of each group were killed and investigations of the bone defects healing were made by means of gross observnation,bone density measurement by DEXA,biomechannics exam by carrying out axial compression,torsion testing in Biomix MTX858.The score of X-ray examination were grades according to Lane standard,and the statistical analysis were carried out by SPSS13.0 finally.Results:All wounds of animal cured primarily.Study of X-ray had shown:at 4 weeks,obvious bony callus image and fuzzy fracture lines appeared in experimental group,while the bony callus was more less,fractures lines were clear in control group,and little callus,cortical fragment still existing in blank control group and some scews were pulled out.At 8 weeks, bony callus increased obveriously and bony union were obveriously in experimental group,bony callus increased in control group too,but density was imhomogenous; High-desity image of cortical bone-pipe fragment still existed,more less bony callus and fuzzy fracture lines appeared in blank control group.At 12 weeks newborn cortex bone structure appeared and linked with host cortical bone,the medullary cavity appeared again,fracture area repaired completely.Much bone callus were oberved in control group,but no cortex bone stucture;It could be seen that a little callus growth in blank control group,border were more blurred,more less bony callus and one broken screw happened.The score of X-ray examination at all times were graded according to Lane standard,and the result showed that the quality and quantity of new bone formation were statistical different bewteen the experiment,the control group and blank control group(P＜0.05).Bone mineral denist examination:In the experimental group,bone mineral denisty of defects was much higher than that in the blank control group at 12 weeks.The stiffness of bone defects healing was detected by biomechanics:Among experimental group,control group and blank control group,distinct difference(P＜0.05)were found at immediately 4,8and 12weeks,and it were showed:experimental group＞control group＞blank control group.Conclusion:Allograft bone-pipe fill with autologous bone in repairing large segmental bone defects with allogeneic cortical bone plates associated with steel plate has enormous osteogenicity,can improve bone healing and prevent from delaying healing and nonunion effectively.It's easily operated and can be finished within one time,could be used for repairing large segmental bone defect.