| Objective:Masquelet technique,also known as the induced membrane technique,is currently an effective method for treating large bone defects in limbs.It is an urgent problem for this technology how to reduce the use of autogenous bone.In order understand how to reduce the amount of autogenous bone,an experiment was designed by using an animal experimental model.Autogenous bone together with calcium phosphate cement was used to fill the bone defect and the equivalent verification test was established.It is expected the feasibility of this surgical program can provide reference for the clinical application.Methods:44 healthy adult New Zealand white rabbits were selected and 8 rabbits were randomly selected according to the random number table method for pre-experiment and then euthanized.The radius was separated by interception of the both forelimb,and the middle part of the radius was intercepted at 1.5cm.The radial bone marrow cavity was approximately equivalent to a cylinder,and the bottom diameter was measured.The remaining 36 experimental rabbits were randomly divided into groups A,B,C and D(9 rabbits each group)according to the random number table method.In all groups,bone defects from the limbs of the rabbits were prepared with bilateral radial osteotomy at 1.5 cm.PMMA bone cement was implanted into the bone defect area and the surgical incision was sutured.Under the normal conditions,a completely induced membrane could be formed around the bone cement after 5 weeks of feeding.One rabbit randomly selected from each group was killed by air embolism.The induced membrane tissue was extracted and sectioned into a pathological section.PMMA bone cement was removed from the remained 32 rabbits,leaving the induced membrane intact.The bone defects were filled within the tubes of the intact induced membranes in four different ways for each of the four groups of the rabbits.Group A: autogenous bone was supplemented with calcium phosphate cement.Calcium phosphate bone cement was formed into a columnar structure,which is similar in size to the medullary cavity in the radius defect area.After the calcium phosphate cement was placed into the medullary cavity with similar size in the center of the defect,the autogenous ilium bone grains were placed into a ring around the cement column.Group B: The defects were solely filled with autologous ilium granules.Group C: Solely filled with calcium phosphate cement column alone.Group D: no padding.Group A is the experimental group,while B,C and D are the different groups.During the operation,the volume of autologous bone implanted in group B was measured and calculated,which represented the bone graft volume of conventional autologous bone transplantation,and the percentage of bone saving was estimated by combining the volume of columnar calcium phosphate bone cement,which represented bone saving.At the third and seventh weeks the filling transplantation of the induced membrane cavity,X-ray examination was performed on the surgical area to observe the bone healing in the bone defect area.The results were statistically analyzed by Lane-Sandhu X-ray score.32 rabbits were killed by air embolism after X-ray examination on the rabbits at the 7th week.Bilateral radius was taken for gross observation,and tissue from the bone defect area was extracted for histological observation.Results:1 In the preliminary experiment,the diameter of radius was measured and the model of calcium phosphate bone cement was selected:According to statistical analysis,the measured value of medullary cavity diameter in the middle segment of the radius was approximately normal distribution,with a mean value of 3.1mm,which was representative.According to the measurement results,3mm plastic flexible rubber tube was selected and sterilized to prepare for the preparation of columnar calcium phosphate bone cement.2 Histological observation of extracted membrane after the induced membrane formation: A large number of fibroblasts and new capillaries were observed under the microscope.The results were similar to the histological structure of the induced membrane observed by Zhao et al.and proved the success of modeling.3 Results of repeated measurement anova on X-ray evaluation of lane-sandhu in groups A,B,C and D at the third and seventh week after the induced membrane cavity filling transplantation:3.1 Overall comparison(two-factor analysis of repeated measures of variance): Comparison between four groups,comparison between two time points,and interaction between groups and time were all significant(P<0.05).It was suggested that the X-ray scores of Lane-Sandhu were different among groups A,B,C and D.The X-ray scores of Lane-Sandhu in the four groups had significant changes at two time intervals.The X-ray scores of Lane-Sandhu in the four groups had different trends with time,so further comparison was needed.3.2 Inter-group comparison(one-way ANOVA+multiple comparisons): At the third and seventh week after the filling transplantation of induced membrane cavity,there was no significant difference in Lane-Sandhu X-ray scores between groups A and B(P>0.05),while pairwise comparison between the other groups revealed significant difference in Lane-Sandhu X-ray scores(P<0.05).Combined with data analysis: the X-ray scores of Lane-Sandhu in group A and group B were similar and significantly higher than those in group C and D at the third and seventh week after the induced membrane cavity filling transplantation.At the third and seventh week after filling transplantation of the induced membrane cavity,the X-ray score of Lane-Sandhu in group C was higher than that in group D.Combined with experimental analysis: group A and group B had similar results in bone defect repair.The circular implantation of autogenous iliac bone grains around the calcium phosphate cement column can replace the operation of autogenous iliac bone grains implanted in the bone defect area alone,thus reducing the use of autogenous bone.3.3 Intra-group comparison(paired-samples T test):At the third and seventh weeks after the filling transplantation of the induced membrane cavity.The X-ray scores of Lane-Sandhu in group A,B and C were significantly different(P<0.05).The X-ray scores of lane-sandhu in group D showed no significant difference(P>0.05).Combined with data analysis,the X-ray scores of lane-sandhu in group A,B and C at 7 weeks after the second stage of induced membrane were all higher than those at 3 weeks after the second stage of induced membrane implantation.In group D,the X-ray scores of Lane-Sandhu at week 7 were similar to those at week 3 after induction of intramural implantation.Combined with experimental analysis: the bone defect repair effect of group D did not change significantly with time,so it could be used as a blank control group.4 Naked eyes and histological observation4.1 Naked eyes observation: At the seventh weeks after the induced membrane cavity filling transplantation.In group A,calcium phosphate cement column was located in the center of bone defect,surrounded by sclerotic bone and blurred fracture line.In group B,the bone defect was mostly surrounded by sclerotic bone.The fracture line was fuzzy,and the medullary cavity was formed.In group C,calcium phosphate cement column was located in the center of the bone defect,surrounded by fibrous connective tissue.There was a small amount of bone formation near the fracture ends on both sides,but no bone connection was formed.In group D,osteosclerosis was observed at the fracture end of bone defect,and no bone connection was observed4.2 Histological observation: At the seventh weeks after the filling transplantation of the induced membrane cavity.Under the microscope of group A,good plastic bone cortex was observed,and the calcium phosphate bone cement in the center of the medullary cavity disappeared,leaving a cavity.Under the microscope of group B,the plastic bone cortex and the normally developed medullary cavity were observed.Under the microscope of group C,the calcium phosphate bone cement in the center of the medullary cavity disappeared.Leaving a cavity,and a small amount of cortical bone around the cavity formed without plasticity.In group D,fibrous junction formation was seen under microscope.No bone cells were seen.5 Calculation of autologous bone mass saving: after statistical analysis,the volume of autologous bone implanted in group B was approximately normal distribution,and its mean value was representative.After calculation,the average volume of implanted autogenous bone in group B is 0.23cm3,and the volume of columnar calcium phosphate bone cement is about 0.11cm3.The bone saving is about 47.83%.Conclusion:The application of autologous bone plus calcium phosphate bone cement in Masquelet can achieve the same experimental effect as filling the bone defect with autologous bone.This experimental method can effectively reduce the use of autologous bone.Compared with conventional autogenous bone transplantation,autogenous bone was saved by about 47.83%.This experimental method can also provide a reference for clinical application of Masquelet technology in the treatment of large bone defects. |
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