Experimental Study Of Two Different Surgical Methods In Treating Femoral Defects

ObjectiveTo investigate and evaluate the curative effect of two different surgical methods intreating femoral defects of New Zealand white rabbits, finding out the most optimalsurgical method to shorten the time of traction therapy, in order to provide a theoreticalbasis for rational choice of treatment of bone defects.Method41New Zealand white rabbits, weighing2.25～3.25kg,3～5month old, wereprovided by the Experimental Animal Center of the Jinan Military General Hospitalwithout limiting the female and male.5New Zealand white rabbits selected randomly,were made into the15mm defects model. X-ray was used to make sure that the15mmdefects were not healed by themselves after12months.1New Zealand white rabbit wasused for the pre-experiment of distraction osteogenesis, in order to find experience. Therest30New Zealand white rabbits were randomly divided into2groups: group A andgroup B. Defects from group A were treated by surgical method of primary bonelengthening, defects from group A were treated by surgical method of lengthening withlong osteotomy. The broken ends of the defects begun to extend after1week. Specimenfrom group A and group B were extended at the speed of1mm/d, for15days and thegeneral conditions were recorded. All the specimen were raised in the same conditionsand antibiotic was used continuously for5days and the cut were changed fresh in time.X-ray was taken for all the specimen from group A and group B at0day,15days,8weeks,12weeks after the defects were treated. And the condition of defect heal wasobserved. The histology condition was observed2weeks,6weeks,12weeks after thedefects were treated. At the12week, mechanical test was used to evaluate the heal ofdefects. All the data from group A and group was analysed.ResultThere is no significant deference between group A and Group B in fixation after15 days. There is significant deference between group A and Group B in the performance ofX-ray after8weeks and12weeks. The strength of group B was greater than the group A(p﹤0.05). The results of biomechanical test manifest the three point bending staticstiffness,the maximum load and reversing of the callus of group B were sronger than the group A(p﹤0.05). Histological examination results suggest that group B than groupAmature callus.Conclusion1. The femoral bone defects model of New Zealand white rabbit were establishedsuccessfully and the15mm defects can not heal by themselves.2. The surgical method of lengthening with long osteotomy is better than the surgicalmethod of primary bone lengthening in treating bone defects, though they are botheffective in treating bone defects.