| Chapter1 The biomechanical study of ACL bundles' functional classificationObjective:To investigate the biomechanical function and classification of the ACL bundles and provide biomechanical evidence for the later experiments and clinical therapy.Methods:6 fresh cadaveric knees from adult human beings were utilized in this investigation.We classified ACL into four bundles on the basis of ACL location in knee: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:1.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.2.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 biomechanicaI innuence of ACL rupture on the medial tibial plateauObjective:To investigate the biomechanical influences of partial and total ACL rupture on the medial tibial plateau and provide theoretic evidence for prevention and cure ostarthritis.Methods:10 fresh cadaveric knees from adult human beings were classified into four group on the basis of test sequence:ACL intact group,AMB broken group,PLB broken group and ACL total broken group.The knees were applied with 200N～800N axial loading force when they flexed 0°,30°,60°,90°.The strain on the medial tibial plateau was measured and analyzed by SPSS for windows 13.0,the statistic significance was set atα=0.05.Results:1.In ACL intact group:①In 0°position,the strain of anterior part and the middle part of tibial plateau were not significantly different(P＞0.05) and were larger than posterior part(P＜0.05).②In 30°positions,the largest strain was on the middle part of the medial 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).③In 60°position,anterior part showed to be tensile strain while middle part and posterior part compressive strain,the strain of anterior part and the middle part of tibial plateau were not significantly different(P＞0.05).④In 90°position,anterior part showed to be tensile strain while middle part and posterior part compressive strain,the strain of posterior part and the middle part of tibial plateau were not significantly different(P＞0.05).2.In AMB broken group:①In 0°position,The strain on the anterior part,middle part and posterior part were not significantly different from that in ACL intact group(P＞0.05).②In 30°positions,the strain on the anterior part and the middle part was not significantly different from that in ACL intact group(P＞0.05);Under 400N～800N loading,the stain on the posterior part was larger than that in ACL intact group,the difference was significant(P＜0.05).③In 60°position,anterior part showed to be tensile strain while middle part and posterior part compressive strain.Under 200N loading, the strain on the posterior part was not significantly different from ACL intact grou(P＞0.05).Under 400N～800N loading,the stain on anterior part,middle part and posterior part were larger than that on ACL intact group,the difference was significant(P＜0.05).④In 90°position,anterior part showed to be tensile strain while middle part and posterior part compressive strain.Under 200N loading,the strain on the anterior part,middle part and posterior part were not significantly different from ACL intact group(P＞0.05).Under 400N～800N loading,the stain on anterior part,middle part and posterior part were larger than that in ACL intact group,the difference was significant(P＜0.05).3.In PLB broken group:①In 0°position,Under 200N loading,the strain on the anterior part,middle part and posterior part were not significantly different from ACL intact group(P＞0.05).Under 400N～800N loading,the stain on anterior part,middle part and posterior part were larger than that on ACL intact group,the difference was significant(P＜0.05).②In 30°positions,expect the strain on the middle part was smaller than that in ACL intact group under 800N loading(the difference was significant(P＜0.05) ) the strain on the anterior,middle and posterior parts was not significantly different from that in ACL intact group(P＞0.05).③In 60°positions,The strain on the anterior,middle and posterior parts was not significantly different from that in ACL intact group (P＞0.05).④In 90°positions,expect the strain on the middle part was larger than that in ACL intact group under 600N,800N loading(the difference was significant(P＜0.05) ) the strain on the anterior,middle and posterior parts was not significantly different from that in ACL intact group(P＞0.05).4.In ACL total broken group:In all condition the strain on the anterior,middle and posterior parts was larger than that in ACL intact group,the difference was significant(P＜0.05)Conclusion:1.ACL total rupture may cause abnormal load on the medial tibial plateau in all the positions.2.AMB rupture may cause abnormal load on the all part of the tibial plateau in flexed positions(30°,60°,90°).3.PLB rupture may cause abnormal load on all parts of the medial tibial plateau in extended positions(0°). Chapter 3 The histological influence of ACL rupture on the medial tibial plateauObjective:Observe tissue construction changes and IL-1,MMP-13 express in the medial tibial plateau cartilage,to further explore the degeneration mechanism of the medial tibial plateau articula cartilage after ACL rupture.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 medial tibial plateau cartilage were observed 1,3,6,8 weeks later.Results:1.Gross observation:As the time lasted,the medial 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.3.IL-1βexpression:All the experimental groups had higher IL-1βexpression than that in control groups (P＜0.01).In experimental groups,IL-1βexpressed 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:1.ACL rupture may cause cartilage degeneration on the medial tibial plateau.2.The increased IL-1βand MMP-13 expression suggest that IL-1β,MMP-13 may participate in cartilage degeneration on the medial tibial plateau after ACL rupture.
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