| Objective: To study the effects of recombination bone xenograft pipe(medullary cavity with autogeneic cancellated bone) fixation with plate in repairing large segmental bone defects.Methods:Twenty four maturate goats were divided into two groups randomly , 12 animals respectively in experiment group and control group.The large segmental bone defects of animal models were made after anesthesia. Experimental group were planted xenogenic deproteinized pipe fill with autogeneic cancellated bone,then fixed with dynamic compression plate;Control group with xenogenic deproteinized pipe , but fixed with Locked Intramedullary.At 4,8,12 weeks postoperatively,all animals were made X-ray examation,and gray density w ere quant ified .Four goats of each group were killed,The maximum diameter of the callus were measured and observed,then the limbs were taken as specimens for biomechanical test and histopathological examination. biomechannics test was carried out axial compression,torsion testing and three piont bending testing in WDW-100.The score of X-ay examination were grades according to Samamtha standard,and the statistical analysis were carried out by SPSS 11.0 finally.Result: Loosening or breakage of plates or screws were found for one animal in the experiment group,while the internal fixations kept the right site in control group.At 12 weeks,bone callus was to surround xenogenic deproteinized pipe and host cortical bone,fracture area repaired completely in experiment group and control group.It could be seen that a little callus growth experiment group .The score of X-ray examination at all times were graded according to Samamtha standard,and the result showed that the quality and quantity of new bone formation were statistical different between experimental group and control group at 4 weeks (P<0.05), but this were not statistical different at 8, 12 weeks .The distinct difference were found in gray density at 8,12 weeks Betweeen experiment group and control group(P<0·01).The distinct difference were found in biomechanical test at 8 and 12 weeks (P<0·05),but control group was better at 4 weeks.Histological observation showed that,in transverse sections of xenografts significantl higher bone turn over occurred in the inner cortical area of the xenografts compared to the outer cortical and midcortical areas in experimental group.Conclusion: xenogenic deproteinized pipe fill with autogeneic cancellated bone associated with plate in repairing large segmental bone defects has enormous osteogenicity,can promote bone healing.It's a reliable treatment for reconstruction of large segmental bone defects.,Autogeneic cancellated bone accelerated the vascularization and creeping substitution of the massive cortial bone. |
