The Experimental Study For The Impactive Injury Of Acetabular Cartilage

PartⅠEstablishment of experimental animal model forthe impactive Injury of acetabular cartilageand study of Quantifying the impactive energyObjective To discusses the feasibility of establishing the animal model for the impactive injury of acetabular cartilage and quantify the energy. Methods Thirty New Zealand white rabbits were divided into high energy and low energy groups randomly, of which the two groups which were made through the homemade impactive equipment by impacting the right acetabular cartilage of rabbit at 35cm and 15cm with 0.400kg weight vertically and simulating the mechanism of impactive injury of human acetabular cartilage. The another group was control group. Each group was 10,in which the distinguish standard of high and low energy group was that the impactive energy was 25Mpa for cartilage .The observation of quantifying the energy and the analysis of statistics were made for two model groups. The observation of macrography and histology (stained by HE and safarnin O) were made for three groups, which were killed postinjuriously at 6 hour. The average age and weight of these rabbits was 0.5 years old and 2.5±0.5kg. Results The impactive average force was 203.910N and 105.919N for the high and low energy group respectively. There was no statistical significance(P>0.05) through comparing the two model groups and the former groups in which the impactive average force was measured 203.937N and 105.849N through 30 rabbits under the same circumstance respectively. There was no statistical significance(P>0.05)through comparing the pressure of two model groups (28.862Mpa and 14.992Mpa, respectively) and the former groups (28.866Mpa and 14.982Mpa, respectively).We found the increasing of the cranny of cartilage, the coarseness of chondral surface, the great severity of chondral injury, the increasing of the flat cells and the increasing of chondrocyte death in high energy group. The staining of safarnin O was made mild in high energy and in low energy group and normal in control group. Conclusions The model had good duplicability and stability through the method of establishing the animal model in which the simple operative method,small wound and convenient nurse was obtained so easilyis that the animal model was spread easily.The study of the change of short and long period was made to provide the experimental base and reason through the animal model.PartⅡThe study of MRI after the impactive Injury of acetabular cartilageObjective To discuss the excellent sequence of MRI for displaying and diagnosing the impactive injury of acetabular cartilage. Methods Twenty New Zealand white rabbits were made through the homemade impactive equipment by impacting the right acetabular cartilage of rabbit at 35cm with 0.400kg weight vertically and simulating the mechanism of impactive injury of human acetabular cartilage. The observation of quantifying the energy and the analysis of statistics were made for 20 rabbits. The observation and the evaluation of MRI with different sequence for the imaging of acetabular cartilage by three experienced doctors by which the MRI was read through double–blinded in radiative department at 6 hour before and after operation. The sensitivity and the especiality of chondral injury were evaluated through the diagnosis of different sequence according to the standard of Collins'pathological diagnosis. The results of SNR and CNR of different sequence were evaluated describly. The average age and weight of these rabbits was 0.5 years old and 2.5±0.5kg. Results The impactive average force was 203.944N for the experimental group. There was no statistical significance(P>0.05) through comparing the experimental group and the former group in which the impactive average force was measured 203.937N through 30 rabbits under the same circumstance. There was no statistical significance(P>0.05)through comparing the pressure of experimental group (28.867Mpa) and the former group (28.866Mpa).The arc strap was showed for cartilage in different MRI sequence. The low signal was showed for cartilage in T1WI and STIR/T/FSE/PSAT. The middling or low signal was showed for cartilage in T1/C/FSE/C+, in which the arthrography was showed high signal. The middling or high signal was showed for cartilage in T2WI. The hoariness signal was showed for cartilage in T2*/C/RF-FAST/VOL and T2*/T /FE/MTC/MAST.The excellent SNR was obtained in T2* / C/RF-FAST/VOL and T2*/T/FE/MTC/MAST in which the MRI was most clear. Among the result of SNR, T2*/C/RF-FAST/VOL and T2*/T/FE/MTC/MAST good, T1WI,T2WI and T1/C/FSE/C+ fair, STIR/T/FSE/PSAT bad. Among the result of CNR, comared cartilage with bone cortex, T2*/C/RF-FAST/VOL and T2*/T/FE/MTC/MAST excellent , T2WI fair, T1WI,STIR/T/FSE/PSAT and T1/C/ FSE /C+ bad; comared cartilage with bone marrow, T2*/C/RF-FAST/VOL and T2*/T/FE/MTC/MAST excel- lent, T1WI good,others fair; comared cartilage with fat, T1WI,T2*/C/RF-FAST /VOL,T2*/T/FE/MTC/MAST and T1/C/ FSE /C+ excellent, T2WI good, STIR /T/ FSE /PSAT fair and comared cartilage with muscle, T2*/C/RF-FAST/VOL and T2*/T/FE/ MTC/MAST good,others bad.To the sensitivity, T2*/ C/RF-FAST/VOL as the same as T2*/T/FE/ MTC/MAST probably>T1/C/ FSE /C+>T2WI>T1WI>STIR/T/FSE/PSAT and the especiality is as the same as the sensitivity probably according to the Collins'diagnostic standard. Conclusions FSE T1WI and T2WI were use as the routine sequence for diagnosing the chondral injury. T2*/C/RF-FAST/VOL and T2*/ T/FE /MTC/ MAST were used as the best sequence. T1/C/ FSE /C+ as arthrography was used as the examinatong of surface of articular cartilage and had particularity and potential clinical value in diagnosing the defects of the surface of cartilage.PartⅢThe study of macrography, histology, pathology and apoptosis After the impactive injury of acetabular cartilageObjective To discuss the change of short and long peoriod for the impactive injury of acetabular cartilage by using different energy,the pathological mechanism of chondral injury and the relation between chondrocyte apoptosis and cartilage degeneration. Methods fifty-four New Zealand white rabbits were divided into high energy and low energy groups randomly, of which the two groups which were made through the homemade impactive equipment by impacting the right acetabular cartilage of rabbit at 35cm and 15cm with 0.400kg weight vertically and simulating the mechanism of impactive injury of human acetabular cartilage. The another group was control group. Each group was 18.The observation of quantifying the energy and the analysis of statistics were made for two model groups. The observation of macrography, histology (stained by HE, safarnin O and toluidine blue), transmission electron microscope, scanning electron microscope and the method of TUNEL were made for the three groups which were killed postope- ratively at 6 hour,4 week and 24 week. The average age and weight of these rabbits was 0.5 years old and 2.5±0.5kg.The pathological sections were read by the double-blinded method for estimating the Mankin's score after the impactive injury of acetabular cartilage and observing the chondrocytes apoptosis. Results The impactive average force was 203.924N and 105.853N for the high and low energy group respectively. There was no statistical significance(P>0.05) through comparing the two model groups and the former groups in which the impactive average force was measured 203.937N and 105.849N through 30 rabbits under the same circumstance respectively. There was no statistical significance(P>0.05)through comparing the pressure of two model groups (28.864Mpa and 14.983Mpa, respectively) and the former groups (28.866 Mpa and 14.982Mpa, respectively).We found with time extending, the increasing of the cranny of cartilage, the coarseness of chondral surface, the great severity of chondral injury, the increasing of the flat cells and the increasing of chondrocyte death in high energy group. The staining of safarnin O and toluidine blue was weaker in high energy group with time extending, mild in low energy group and normal in control group. Among transmission electron microscope, there were decreasing of cellar organ, the increasing of chond- rocyte, the increasing of asymmetry of chromatin and the forming of more vacuole in high energy group. Among scanning electron microscope, the increasing of the cranny of cartilage, the nudity of more collagen fibre that arrange turbulently, even the exposure of subchondral bone in high energy group. The differences of operative results between the Mankin's score of high energy group and the one of control group at different times as well 6 hour, 4 week and 24 week were significant (P<0.05). The difference of operative results between the Mankin's score of low energy group and the one of control group at 6 hour was significant (P<0.05). But at 4 week and 24 week, there was no statistical significance(P>0.05)between the Mankin's score of low energy group and the one of control group. The differences of operative results between the rate of chondrocyte apoptosis of high energy group and the one of control group at different times as well 6 hour,4 week and 24 week were significant (P<0.05) through the method of TUNEL. The difference of operative results between the rate of chondrocyte apoptosis of low energy group and the one of control group at 6 hour was significant (P<0.05) through the method of TUNEL. But at 4 week and 24 week, there was no statistical significance(P>0.05)between the rate of chondrocyte apoptosis of low energy group and the one of control group through the method of TUNEL. The differences of operative results between the rate of chondrocyte apoptosis of high energy group and the one of low energy group at different times as well 6 hour,4 week and 24 week were significant (P<0.05)through the method of TUNEL. Conclusions We think there was different in the mechanism of the injury and the degen eration of cartilage between high energy group and low energy group. The mechanism of the injury and the degeneration in high energy group was caused by destroying the collagen fibre framework, but in low energy group by destroying chondrocyte .The severity of chondrocyte apoptosis was related with the severity of impactive energy and the injury of cartilage nearly. The chondrocyte apoptosis was the one of the early injury reaction of cartilage. The excessive chondrocyte apoptosis maybe caused the degeneration of cartilage.PartⅣThe comparative study between MRI and pathology after the Impactive injury of acetabular cartilage Objective To discuss the histological and pathological base of the change of MRI signal after the impactive injury of acetabular cartilage. Methods Thirty New Zealand white rabbits were made through the homemade impactive equipment by impacting the right acetabular cartilage of rabbit at 30cm with 0.400kg weight vertically and simulating the mechanism of impactive injury of human acetabular cartilage. The observation of quantifying the energy and the analysis of statistics were made for 30 rabbits. The observation of macrography and histology (stained by HE, safarnin O and toluidine blue) were made for the experimental group which were killed postinjuriously at 6 hour,4 week and 24 week. The result which was compared with the result of patholoty and the evaluation of MRI for the imaging of acetabular cartilage by three experienced doctors by which the MRI was read through double–blinded in radiative department at 6 hour,4 week and 24 week postinjuriously. The average age and weight of these rabbits was 0.5 years old and 2.5±0.5kg.The grade of MRI and pathology were according to Recht's and Collins'standard. Results The impactive average force was 262.735N for the experimental group. There was no statistical significance(P>0.05) through comparing the exp- erimental group and the former group in which the impactive average force was measured 262.748N through 30 rabbits under the same circumstance respectively. There was no statistical significance(P>0.05)through comparing the pressure of experimental group (27.323Mpa) and the former group (27.324Mpa). Through the comparative result between MRI and pathology, 3 cases were Recht 0,in which 2 cases Collins 1; 9 cases were RechtⅠ,in which 1 cases Collins 2; 8 cases were RechtⅡas the same as Collins'grade; 8 cases were RechtⅢas the same as Collins'grade; 2 cases were RechtⅣas the same as Collins'grade;the difference were significant (P<0.05) between the result of MRI and pathology. Conclusions The result of MRI and pathology showed positive correlation highly.When the degree of injury of cartilage was severe,the more consistency was obtained between the grade of MRI and pathology,whereas,the less consistency was obtained between them.When the pathological change was not enough to cause the change of signal,the sensitivity and veracity of MRI for diagnosing the injury of cartilage need further improve,whereas,the more consistency in sensitivity and veracity was obtained between MRI and pathology.The diagnosis of early injury of cartilage is feasible through the examination of MRI.PartⅤThe influence for impactive injury of high energy of acetabular Cartilage by injecting sodium hyaluronate to articular cavityObjective To discuss the influence of impactive injury of high energy of acetabular cartiage by injecting SH to articular cavity. Methods Twenty–four New Zealand white rabbits were divided into model group and control group randomly, of which the two groups which were made through the homemade impactive equipment by impacting the right acetabular cartilage of rabbit at 45cm with 0.400kg weight vertically and simulating the mechanism of impactive injury of human acetabular cartilage. Each group was 12.The model group was injected SH.The control group was injected NaCl solution. The observation of macrography, histology (stained by HE, safarnin O and toluidine blue), transmission electron microscope, scanning electron microscope and the method of TUNEL were made for the three groups that were killed postinjuriously at 4 day and 4 week. The observation of quantifying the energy and the analysis of statistics were made for two groups. The target ash value was measured through analyzing the imaging obtained by sections stained by safarnin O and the rate of chondrocyte apoptosis was observed through double-blinded method.The target ash value and the rate of chondrocyte apoptosis was analyzed by statistics.The average age and weight of these rabbits was 0.5 years old and 2.5±0.5kg. Results The impactive average force was 153.331N for the experimental group. There was no statistical significance(P>0.05) through comparing the experimental group and the former group in which the impactive average force was measured 153.327N through 30 rabbits under the same circumstance. There was no statistical significance(P>0.05)through comparing the pressure of experimental group (31.254Mpa) and the former group (31.253 Mpa). There was no statistical significance (P>0.05)between the impactive energy and the impactive pressure of the model group and the control group. We found with time extending, the increasing of the cranny of cartilage, the coarseness of chondral surface, the great severity of chondral injury, the increasing of the flat cells and the increasing of chondrocyte death in the model group. The staining of safarnin O and toluidine blue was made weaker in both groups at 4 day and 4 week postinjuriously. But in both groups, the staining of safarnin O of control group was made weaker than that of the model group. The target ash value of the model group was lower than the control group. The difference was significant (P<0.05) between both groups. Among transm- ission electron microscope, there were decreasing of cellar organ, the increasing of chondrocyte and the increasing of asymmetry of chromatin in the control group. Among scanning electron microscope, the increasing of the cranny of cartilage and the nudity of more collagen fibre that arrange turbulently in the control group were showed. The difference was significant (P<0.05) between the rate of chondrocyte apoptosis of the model group and the control group at 4 day and 4 week respectively. Conclusions SH may decrease the chondrocyte apoptosis. SH which can't prevent the degeneration of cartilage to heal the chondral injury can rehabilitate cartilage and stay the injury of high energy of cartilage. The severity of impactive energy had some influence on SH for the treatment of impactive injury of acetabular cartilage. The impactive injury of cartilage whether or not with the acetabular fracture should be treated by injecting SH to hip articular cavity under the circumstance of sterile operation immediately and once a week for four weeks. Though the method maybe did not heal the injury of cartilage, it can protect and rehabilitate cartilage after impactive injury for staying the degeneration of cartilage that could happen osteoarthritis.