Study On The Infection Of Different Treatment Methods Of Open Fracture With Free Contaminated Bone Mass By Animal Experiment

Objective:To investigate the relationship between the soaking time of free bone block and postoperative infection in open fracture.Method::1、The adult male of 49 rats are randomly divided into 7groups,each group of 7（A-G）,each group in the left medial tibial do a 1.5cm long incision,exposing a tibia length of about 0.5cm of unicortical defect,removal of free bone,aseptic suture wound and then sterile dressing,Group A bone after placing 10 sterile back in situ,group B bone pollution after 10 hours without any treatment back in situ,group C bone pollution 10 hours when given normal saline,hydrogen peroxide,iodine washing back in situ,group D bone pollution 10 hourswhen given normal saline,hydrogen peroxide,iodophor rinse after Iodophor to soak for 10 minutesback in situ,group E bone pollution 10 hourswhen given normal saline,hydrogen peroxide,iodophor rinse,iodophor soaked after 20 minutes back in situ,group F bone pollution10 hours when given saline,hydrogen peroxide,iodophor rinse after iodophor soaked 30 minutes back in situ,group G bone pollution 10 hours when given saline,hydrogen peroxide,iodophor rinse,iodophor soaked after 40 minutes back in situ.To observe the wound of rat after operation if there is redness oozi.At the same time,the blood routine,ESR and C reactive protein are detected on the seventh day,after the rats killed,the bone samples are examined by bacteriology and pathology.2、Take a rat,scraping the double limbs hair,placed in sterile stage,iodophor disinfection of skin,free of lower limbs tibia and femur andthe cortical bone was divided into groups,which arerandomly divided into 7groups,each group of seven pieces.Thegroup A placed 22 degrees under aseptic conditions 10H reserve bacterial colony counts.The B group is placed in 22 10H under the condition of contamination of the contaminated samples,and then the alternate bacterial colonies are selected.In group C,the bone block is placed under the condition of 22 degrees after the contamination of 10H,and then the bacterial colony is counted;In group D,the bone block is placed under the condition of 22 10H under the condition of contamination of the contaminated specimen,and then treated with the above method,and then soaked in iodine for about 10 minutes.In group E,the bone block is placed under the condition of 22 10H under the condition of contamination of the contaminated specimen.After the debridement and flushing method,the residual bacteria colony is counted after soaking for 20 minutes;In group F,the bone block is placed under the condition of 22 10H under the condition of contamination of the contaminated specimen.After the debridement and flushing method was treated,the bacterial colonies are counted after soaking for about 30 minutes;In group G,the bone block is placed under the condition of22 10H under the condition of contamination of the contaminated specimen,and then the bacterial colony is counted by using the method of debridement and flushing and soaking with iodine for about 40 minutes.3、Statistical methods and software SPSS20.0 statistical software for statistical description and inference,qualitative data representation using frequency and percentage,quantitative data using the mean and standard deviation;components of qualitative dataare compared by chi square test（Fisher’or s exact test）,quantitative data are compared with single factor analysis of variance（in accordance with normal distribution）or rank sum test（does not conform to the normal distribution）,LSD（least significance of difference,the least significant difference method）for comparison between the22 groups,a=0.05 level test,when P<0.05 think the difference is statistically significant.Results:The seventh day after operation,the wound of rats showed no obvious swelling and no obvious local infiltration fluid,increased body temperature,no obvious difference;C reactive protein,leukocyte count,erythrocyte sedimentation rate,neutral ratio:single factor analysis of variance is used to compare the differences in groups of C reactive protein and white blood cell number,the neutral ratio,blood sedimentation,analysis results show no statistically significant difference between groups C C-reactive protein,leukocyte count,neutral ratio,ESR,F _{C reactive protein}=0.117,P=0.994;F_{the number of white blood cell}=1.01,P=0.432;F_{neutral ratio}=0.185 P=0.979,F_（ESR）=0.408,P=0.870.Bacterial colonies:rank test for differences comparison of bacterial colonies,the results show that:B group,E group,C group,=D group,F group,=G group,A group,X²=42.348,P<0.001,the difference was statistically significant in A group,B group,vs,Z=-3.606,P<0.001;group B vs C group.Z=-3.347,P=0.001;group C vs group D,Z=-0.129,P=0.897;group D vs group E,Z=-0.579,P=0.562;group E vs group F,Z=-3.141,P=0.002;group F vs group G,Z=-0.394,P=0.693.Postoperative infection rate:the chi square test or Fisher s test are used to compare the differences of bacterial culture results of the analysis showed that:B group>C group=D group=E group>F group=G group>A group,?²=31.764,P<0.001,vs in A group,B group,?²=10.286group,P<0.001;B vs C group?²=4.978,P=0.026;group C vs group D,?²=0.292,P=0.589;group D vs E group,?²=0.350,P=0.554;group E vs group F,?²=4.571,P=0.033;group F vs G group,?²<0.001,P=1.000.Conclusion:for open fracture free bone,with saline,hydrogen peroxide,iodophor after conventional treatment,again be soaked with Iodophor,differences in rates of infection,number of colony immersion time on the surface and after the recommended immersion time is more than 30min,It is hoped to provide some reference value for clinicians to deal with open free bone mass.