| Chapter1 The biomechanical study of ACL bundles' functional classificationObjective:To investigate the biomechanical function of the ACL bundles and their internal correlation and provide biomechanical evidence for the later experiments and clinical therapy.Methods:6 fresh cadaveric knees from adult human beings were used. Selected the bilateral anterior part of the ACL tibial insertion and the bilateral posterior part of the ACL femoral insertion as the measure parts correspond to:anteromedial area fiber bundle(anteromedial bundle),anterolateral area fiber bundle(anterolateral bundle),posteromedial area bundle(posteromedial bundle)and posterolateral area bundle(posterolateral bundle).The strain on the ACL bundles was measured when the knees were applied with 800N axial loading force in 0°,30°,60°,90°positions.The bundles were functional classified by cluster analysis.Results:1.In 0°position,the strain on the posterolateral and anterolateral bundles was significantly larger than the posteromedial and anteromedial bundles(P＜0.05),There were no significant diference between the posterolateral and anterolateral bundles(P＞0.05)and so did the posteromedial and anteromedial bundles(P＞0.05);In 30°and 90°position,the strain on the posteromedial and anteromedial bundles was significantly larger than the posterolateral and anterolateral bundles(P＜0.05),There were no significant difference between the posteromedial and anteromedial bundles(P＞0.05)and so did the posterolateral and anterolateral bundles(P＞0.05);In 60°position, the strain on the posteromedial bundle was the largest,and then the anteromedial,posterolateral,anterolateral bundle,the differences among bundles were all significant(P＜0.05).2.The strain on the posteromedial and anteromedial bundles was increased by degrees when the knee flexed 0°,30°,60°,90°,and all the difference were significant(P＜0.01);There were no significant changes of the strain on the anterolateral bundle among different angles(P＞0.05).The strain on the posterolateral bundle in 60°position was larger than 0°,30°,90°positions,the differences were significant(P＜0.05); The strain in 30°position was significantly smaller than 0°and 90°positions (P＜0.05),but the difference of strain between 0°and 90°positions was not significant(P＞0.05).3.Cluster analysis classfied the anteromedial bundle and the posteromedial bundle as one class and the anterolateral and posterolateral bundles as the other class.Conclusion:Compared with the posteromedial area and anteromedial area fiber bundles,the strain on the posterolateral area and anterolateral area fiber bundles was significantly larger in 0°position and smaller in 30°,60°,90°positions,means the posterolateral area and anterolateral area fiber bundles mainly maintain stability of the knee in extended positions,the posteromedial area and anteromedial area fiber bundles mainly maintain stability of the knee in flexed positions.Combined with the cluster analysis results,ACL may be classified into the anteromedial functional fiber bundle and the posterolateral functional fiber bundle.Chapter 2 The biomechanical influence of ACL rupture on the lateral tibial plateauObjective:To investigate the biomechanical influences of partial and total ACL rupture on the lateral tibial plateau and provide theoretic evidence for early ACL repair.Methods:6 fresh cadaveric knees from adult human beings were divided into ACL intact group(6 samples),AMB broken group(3 samples),PLB broken group(3 samples)and ACL total broken group(6 samples).The knees were applied with 200N-800N axial loading force when they flexed 0°,30°,60°,90°.The strain on the lateral tibial plateau was measured and analysed.Results:1.In ACL intact group:①In 0°position,the largest strain was on the middle part of the lateral tibial plateau,then the anterior part and the smallest on the posterior part,and the differences among the parts were all significant(P＜0.01).②In 30°,60°,90°positions,the largest strain was on the middle part of the lateral tibial plateau,then the posterior part and the smallest on the anterior part,and the differences among the parts were all significant(P＜0.05).2.In AMB broken group:①In 0°position,the stain on the anterior part was smaller than that in ACL intact group,the difference was significant(P＜0.05);The strain on the posterior part and the middle part was not significantly different from that in ACL intact group(P＞0.05).②In 30°,60°,90°positions,the strain on the anterior part and the middle part was not significantly different from that in ACL intact group(P＞0.05);the stain on the posterior part was smaller than that in ACL intact group,the difference was significant(P＜0.05).③In 90°position,the strain on the posterior part was not significantly different from that on the middle part(P＞0.05)and in the others positions the compares among the parts were similar to that in ACL intact group.3.In PLB broken group:①In 0°position,the stain on the anterior part was smaller than that in ACL intact group,the difference was significant(P＜0.01);The strain on the middle part and the posterior part was significantly larger that in ACL intact group(P＜0.01).②In 30°,60°,90°positions,the strain on the anterior,middle and posterior parts was not significantly different from that in ACL intact group(P＞0.05).③The compares among the parts in all the positions were similar to that in ACL intact group.4.In ACL total broken group:①In 0°position,the stain on the anterior part was significantly smaller than that in ACL intact group(P＜0.01); The strain on the middle part and the posterior part was significantly larger that in ACL intact group(P＜0.01).②In 30°position,the stain on the anterior part was not significantly different from that in ACL intact group(P＞0.05); The strain on the middle part and the posterior part was significantly larger that in ACL intact group(P＜0.05).③In 60°and 90°positions,the strain on the anterior part and the middle part was not significantly different from that in ACL intact group(P＞0.05);The strain on the posterior part was significantly larger that in ACL intact group(P＜0.05).④In 90°position, the strain on the posterior part was not significantly different from that on the middle part(P＞0.05)and in the others positions the compares among the parts were similar to that in ACL intact group.Conclusion:1.AMB rupture may cause abnormal load on the posterior part of the lateral tibial plateau in flexed positions.2.PLB rupture may cause abnormal load on all parts of the lateral tibial plateau in extended positions.3. ACL total rupture may cause abnormal load on the lateral tibial plateau in all the positions.4.The abnormal load changes may have relations to the tibia antelocation. Chapter 3 The histological influence of ACL rupture on the lateral tibial plateauObjective:Observe tissue construction changes and IL-1,MMP-13 express in the lateral tibial plateau cartilage,to further explore the influence of ACL rupture on the lateral tibiaI plateau,and provide clinical diagnosis and therapy conferences for ACL injure.Methods:48 male New Zealand rabbits were randomly divided into four groups,and all were under one side posterior leg ACL cut and the opposite side as the control.HE staining and immunohistochemical methods were used. Tissue construction and IL-1β,MMP-13 expression changes of the lateral tibial plateau cartilage were observed 1,3,6,8 weeks later.Results:1.Gross observation:As the time lasted,the lateral tibial plateau cartilage had the color changed,the gloss decreased,the surface abrased and even had ulcer on the cartilage.2.Routine HE staining:There are abnormal cartilage surface and cell disposition after 3 weeks.The Mankin scores in experimental groups increased as the time lasted,the differences among the groups were all significant(P＜0.01);there was no significant difference between 1-week group and control group(P＞0.05),the Mankin scores in the other experimental groups were significantly higher than that in control group (P＜0.01).3.IL-1βexpression:All the experimental groups had higher IL-1βexpression than that in control groups(P＜0.01).In experimental groups,IL-1β expressed significantly lower in 1-week group than that in 3,6,8-week groups (p＜0.05);In 6-week group,IL-1βexpressed higher than that in 3-week group and 8-week group(P＜0.01).IL-1βexpressed higher in 8-week group than that in 3-week group(P＜0.01).There were no signifigant differences among the control groups(P＞0.05).4.MMP-13 expression:All the experimental groups had higher IL-1βexpression than that in control groups(P＜0.01).In experimental groups,MMP-13 expressed significantly lower in 1-week group than that in 3,6,8-week groups(p＜0.01);In 6-week group,MMP-13 expressed higher than that in 3-week group and 8-week group(P＜0.01).There was no significant difference between 3-week group and 8-week group (P＞0.05).There were no signifigant differences among the control groups(P＞0.05).Conclusion:ACL rupture may cause cartilage degeneration on the lateral tibial plateau.The increased IL-1βand MMP-13 expression suggest that IL-1β,MMP-13 may participate in cartilage degeneration on the lateral tibial plateau after ACL rupture.
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