Comparative Study Of Repairation For Massive Defect Of Femur Of Goats With Three Different Kinds Of Allograft Tubiform Bone Composite Material

Objective:To design an ideal artifical bone material for rapid repair of traumatic segmental defect of long bone of goat by comparing three different kinds of allograft tubiform bone composite material.This study belongs to the research on feasibility of repairation for massive defect of femur of goats with allograft tubiform bone combined with autogeneic cancellated.For the purpose of seeking for best combination with allograft tubiform bone.Methods:28 goats(total 56 tibia),12-month-old,no limit on male or female,15～18kg.24 goats of them were were divided into three groups-experimental group A:allograft tubiform bone with autoallergic cancellated bone stuffed in.B:allograft tubiform bone with decalcified bone matrix combine with red blood marrow(DBM\RBM) stuffed in;C:allograft tubiform bone with recomstituted bone xenograft(RBX) stuffed in;and other 4 goats were assigned to control group:allograft tubiform bone with nothing stuffed in.Then animal models of tubbiness bone defect in middle of shaft of femur were made,and grafting and internal fixation were carryed out under general anesthesia monitor according to the arranging groups above.The goats were breed and observed freely,treated with antibiotics and examed by X-ray postoperatively.2 goats of each experimental group and 1 goat of control group was killed,followed up with investigations of the fractures healing at 4,8,12,16weeks,the specimen of femur should be in experience of gross morphology,X-ray examination,biomechanics test by carrying out axial compression,torsion testing,three point bending test in Biomix MTX858,and histopathology observation.The score of X-ray examination and histology observations were graded according to Samantha standard.The statistical analysis were carried out by SPSS13.0 finally.Results:All wounds of operative animal cured primarily.At 4 weeks,study of X-ray showed:sclerotin absorption happened in control group,and there could be find "cab" callus in two ends of host bone.On the contrary,the highest bone density could be seen in experiment group A,while lower in experimental group B.Biomechanics test displayed:The highest stiffness was detected in experiment group A,and there had no significant deviation between A and C(P＞0.05) according to statistical analysis.Adversely,the control group got the lowest scores in all biomechanics tests(p＜0.05).Histological observation:More cartilaginous callus and "absorption lacuna" appeared in tubal wall of experiment group A and C compared to experiment group B,at the meantime,bone absorption could be seen in control group;At 8 weeks,X-ray image showed:"clearance" between host bone and tubiform bone was not enlarged in control group,and "cab"callus was still exist.Experiment group B kept the Integrity outline of tubiform bone,while the juncture between host bone and transplant becomed vague,by comparison,the experiment group A and C provided an higher well-distributed density contrast to other groups.On the other hand,the result of biomechanic tests showed the lowest stiffness in control group compared to experiment groups.Oberzevation of Histological showed:More cartilaginous "islands" appeared in lumina of experiment group A and C,and many of "island" began to calcify,while less happened in group B;At 12 weeks,The phenomenon "fusion"was seen in the group A and C while group C got closer scores of X-ray grades to group A(P＞0.05),by contrast,partly "fusion" appeared in the group B.At the meanwhile,the structure of tubiform bone was distorted in control group followed up with plates distortion and screws loosening.The scores of biomechanics tests were still lowest in control group compared to other three groups(P＜0.05).Statistic ananlysis on the scores of histological obervezation showed a significant diffrerence between three experiment group and control group(P＜0.05),the cortex of tubiform bone of group A and C started to mould,and the size of "absorption lacuna" growed down;At 16 weeks,and the ends of tubiform bone were partly covered with fibrous tissue and structure of tubiform bone was destroyed,and the lowest score it got on X-ray examination,biomechanics exam and histopathology observation by compared with other groups.Experiment group C was still got similar score to group A on all types of tests(P＞0.05),and there was no significant difference between A and C according to statistics result,but both of them(A,C) got higher scores than group B and control group(P＜0.05),finally the order of three kinds of tests showed:experiment groupA＞experiment groupC＞experiment groupB＞control group)Conclusions:1."allograft tubiform bone+autoallergic cancellated bone" posses the superiority of osteoacusis and bone induction,it also can provide hight level of strength,also it can shorten the time of bone deficit repairing;2."allograft tubiform bone + RBX" has similar ability of repairing in bone deficit and it could be the best substitution for "allograft tubiform bone+autoallergic cancellated bone" while the autogenous bone is insufficient 3.The ability of bone repairing and formation of "allograft tubiform bone+DBM\RBM" is inferior to "allograft tubiform bone with autoallergic cancellated bone stuffed in" and "allograft tubiform bone with RBX stuffed in",it may relate to the pore rate and degradation veloc;4.Purely allograft tubiform bone can not provide sufficient ability of osteoacusis and bone induction, also it can not supply long term stable and supporting for bone repairting.