The Experiment Of The Chitosan Membrane For Prevention Of Postoperative Adhesions Of The Knee Joint

Objective: The postoperative adhesions following the surgical operation of knee joint are very thorny complications met usually in clinical works.They lead to decrease range of motion(ROM)of the knee.The surface of operative wound is protected against adhesions by using a biological membrane.Chitosan membrane with the good degradation and biocompatibility and hemostasis is applied to the operation of the knee.The objective of this animal experiment is to observe the effects of using a chitosan membrane in a knee operation in an articular adhesion model in rabbits for prevention postoperative adhesions.Methods: Thirty-two health mature male Newzealand white rabbits were randomly divided into two groups,the chitosan membrane group(experiment) and the control.All animals underwent a synovium excision of the right knee joint under strict sterile conditions.A chitosan membrane was putted in the suprapatellar pouch area and fixated with around soft tissue in the experiment group,whereas no film in the control.Following theoperation,the knee joint was immobilized in the fully flexed position with a plaster cast for 4 weeks while the ankle was maintained in the fully dorsiflexed position.Six rabbits in each group were killed and the casts were removed after 4 weeks for macroscopic findings.The joint was opened and adhesions in the suprapatellar pouch area were observed and semiquantitatively evaluated on a severity score of 0-4 .0:no adhesions; l:filmly, weak adhesions;2:mild adhesions; 3: moderately dense adhesions;4:dense, fibrousadhesions.Immediately after the above evaluation,the righ knee joints were excisied with the surrounding soft tissue.The sample section were made after decalcification in hydrochloride-methylic aid mixed solution and stained by VG's collagenous fiber special method and viewed under light microscope.The rabbits remaining in each group were used for the biomechanical evaluations.while the rabbits were deeply anesthetized ,the right thigh was firmly fixed on the table and the lower leg was hooked by a looped steel wire which was attached to the other end by a 550g weight as a horizontal tenssion. Fully extension of knee was 0 .These rabbits were killde for biochemical analysis.The knee was opened and approximately 40mg wet weight of the adhesion tissue was obtained from the suprapatellar capsula area.the samples were lyophilized and store at -20 for analysis.Based on the method of Woessner,total collagen was determined on the basis of hydroxyproline content. According to the Chan andCole's method,collagen types ratio in adhesion tissue was determined by analysis of the data expressed as a percentage of type- III collagen to the total of types I and III Collagen.All data were done statistical analyses with SPSS(8.0) statistical software package.The grades are represented as the mean+SD,other results as the mean + SE.A11 data were analyzed by t test and P<0.05 was set as significant.Results: One rabbit in experiment group died and two rabbits had pressure ulcer from the casts(one in the control,the other in experiment ).These three animals were excluded from the evaluations,and remaining 29 were studied.Six rabbits in each group for macroscopically finding,dense fibrous adhesions were observed in the control group.whereas little adhesinos in experiment group.The scores for adhesion in former was grades 3.0 + 0.6 and in later was 1.8+0.4.The former was significantly higher than the later group(P<0.05).Histological findings showed that dense fibrous tissue in the control group and loose fibrous tissue in another group.Otherwise,there was a mild unspecific in- flammatory response with middle amounts of plasmacyte and lymphocyte infliltration. Biomechanical date for 8 rabbits in experiment group and 9 in the control revealed that the contracture angle in former was 8.1+2.6 and in later 73.6+4.5 .The former group was significantly smaller than the later (P<0.01).Through biochemical analyses,the adhesions in experiment group contained 51.6+8.3 u g of total colla...