| Posterior cruciate ligament(PCL) is one of the major stability of the knee. its main function is to control the shift and rotation of tibial. Posterior cruciate ligament injury is more common surgical diseases, often the result of greater violence. Secondary to cartilage degeneration and even osteoarthritis have been reported after the current instability in the knee after cruciate ligament injury, but it is little known whether deficiency of PCL effects on the the lateral femoral condyle In this study, Chapter one:strainings changes in different sites of lateral condyles of femur caused by PCL deficiency or rupture are observed through biomechanical approach to investigate biomechanical effect of deficiency or rupture of PCL on lateral condyles of femur. Chapter two: histological changes of lateral condyles of femur and change of bone density in Lateral femoral condyle subchondral bone are observed for investigating the degradation of Lateral femoral condyle cartilage caused by PCL rupture. Chapter three:expression of MMP7& collagen II in lateral condyles of femur are observed for investigating roles of MMP7& collagen II in the degradation of lateral femoral condyle cartilage So as to provide theoretical evidence whether deficiency of PCL effects on the lateral femoral condyle cartilage. This study have very important meanings for the protection of lateral meniscus and the avoidance of osteoarthritis after PCL injury. Chapter?The Effect of PCL Rupture on the Biomechanics of Lateral femoral condyleOBJECTIVE To investigate biomechanical effect of rupture of PCL on lateral femoral condyleMETHOD Strainings of lateral femoral condyle anterior part, middle part and posterior part in all fresh normal adult knee joint specimens including 12 specimens of intact PCL,6 of antelateral bundle(ALB) rupture,6 of postmedial bundle(PMB) rupture and 12 of complete rupture PCL are tested when the knee joints are loaded 200N,400N,600N and 800N at 0°,30°,60°and 90°of flexion.RESULT 1.?The straining of lateral femoral condyle middle part is negative values (pressing strainings) anterior part and posterior part are positive values (tensile strainings) at 0°of flexion.?The straining of lateral femoral condyle anterior part,middle part and posterior part shows no significant difference among all the groups under the loads of 200N at 0°of flexion,P>0.05;?The straining of lateral femoral condyle anterior part,middle part and posterior part shows no significant difference between PMB rupture group and PCL complete rupture group, between complete PCL group and ALB rupture group under the load of 400N and 600N at 0°of flexion,P>0.05; the correlation of the absolute value of straining in ALB rupture group and PCL complete rupture group are less than which in PMB rupture group and complete PCL group of lateral femoral condyle anterior part,middle part and posterior part,P<0.05??significant difference is showed among all the groups under the loads of 800N at 0°of flexion,P<0.05, under the same load and angle of flexion, the correlation of the absolute value of straining in every group of lateral femoral condyle anterior part,middle part and posterior part increases in this way of PCL complete rupture group> PMB rupture group>ALB rupture group> complete PCL group.2.?The straining of lateral femoral condyle anterior part and posterior part in complete PCL group,PMB rupture group, ALB rupture group and PCL complete rupture group are pressing strainings at 30°of flexion. There are no significant different in complete PCL group and PMB rupture group P>0.05, There are no significant different in PCL complete rupture group and ALB rupture group P>0.05.The correlation of the absolute value of straining in ALB rupture group and PCL complete rupture group are more than which in PMB rupture group and complete PCL group of lateral femoral condyle anterior part and posterior part,P<0.05.The straining of lateral femoral condyle middle part in complete PCL group and PMB rupture group are pressing strainings, there are no significant different between groups and in ALB rupture group and PCL complete rupture group are pressing straining,there are no significant different between groups at 30°of flexion.?The straining of lateral femoral condyle anterior part,middle part and posterior part shows no significant difference between ALB rupture group and PCL complete rupture group, between complete PCL group and PMB rupture group under the loads of 200N,400N,600N at 30°of flexion,P> 0.05. The straining of lateral femoral condyle anterior part is pressing straining and the straining shows significant difference in all groups under the load of 800N at 30°of flexion,P<0.05. The correlation of the absolute value of caudomedial part straining in every group increases in this way of PCL complete rupture group> ALB rupture group> complete PCL group> PMB rupture group. The straining of lateral femoral condyle middle part is pressing straining and the straining shows significant difference in ALB rupture group and PCL complete rupture group under the load of 800N at 30°of flexion, P<0.05. The correlation of the absolute value of middle part shows in complete PCL group are less than which in PMB rupture group P<0.05. The straining of lateral femoral condyle posterior part is pressing straining and the straining shows significant difference in all groups under the load of 800N at 30°of flexion,P<0.05. The correlation of the absolute value of caudomedial part straining in every group increases in this way of PCL complete rupture group> ALB rupture group>PMB rupture group> complete PCL group.3.?The straining of lateral femoral condyle anterior part,middle part and posterior part are pressing straining there are no significant difference in complete PCL group and PMB rupture group P>0.05. there are no significant difference in ALB rupture group and PCL complete rupture group P>0.05. The absolute value of lateral femoral condyle anterior part,middle part and posterior part in ALB rupture group and PCL complete rupture group are more than which in complete PCL group and PMB rupture group under the loads of 200N,400N,600N at 60°of flexion. P<0.05.?The straining of lateral femoral condyle anterior part,middle part and posterior part are pressing straining and shows significant difference in all groups under the load of 800N at 60°of flexion,P<0.05. The correlation of the absolute value of anterior part straining in every group increases in this way of ALB rupture group> PCL complete rupture group> PMB rupture group> complete PCL group. The correlation of the absolute value of middle part and posterior part straining in every group increases in this way of PCL complete rupture group> ALB rupture group> PMB rupture group> complete PCL group.4. The straining of lateral femoral condyle anterior part,middle part and posterior part are pulling strainings in all groups at 90°of flexion,and the straining of lateral femoral condyle anterior part shows significant difference in all groups under different load at 90°of flexion,P< 0.05.The correlation of the absolute value of medial meniscus caudomedial part straining in every group increases in this way of complete PCL group>PMB rupture group>PCL complete rupture group> ALB rupture group. The straining of lateral femoral condyle middle part and posterior part shows significant difference in all groups under different load at 90°of flexion,P<0.05.The correlation of the absolute value of medial meniscus caudomedial part straining in every group increases in this way of complete PCL group< PMB rupture group< ALB rupture group<PCL complete rupture group.CONCLUSION 1.Under the load of 200N PCL complete rupture, PMB rupture at 0°of flexion cause no effect on the straining in all regions of lateral femoral condyle.2.Under the load of 400N,600N and 800N, PCL complete rupture and PMB rupture at 0°of flexion is likely to cause abnormal straining in all regions of lateral femoral condyle.3. Under the load of 200N,400N and 600N, ALB rupture at 0°of flexion and PMB rupture at 30°,60°of flexion cause no effect on the straining in all regions of lateral femoral condyle.4. Under the load of 800N, ALB rupture at 0°of flexion and PMB rupture at 30°, and 60°of flexion cause apparently effect on the straining in all regions of lateral femoral condyle.5. Abnormal straining in all regions of lateral femoral condyle can be caused by ALB rupture at 30°,60°,90°of flexion and PMB rupture at 90°of flexion under different load.6. Abnormal straining in all regions of lateral femoral condyle can be caused by PCL rupture at 30°,60°,90°of flexion under different load. Chapter?The Research of Histology and bone density about Degeneration of lateral femoral condyle after Rupture of PCLOBJECTIVE To study bone density and histological effects on lateral femoral condyle in the secondary injury of the lateral femoral condyle after rupture of PCLMETHOD Lateral femoral condyle of 48 rabbits matched mode pairs both in experiment side which PCL were transacted and control side, at the 4th,8th,16th and 24th week, execute 12 rabbits randomly, then to observe lateral femoral condyle in general and through HE staining and BMD testingRESULT 1. The observation in general view showed that with times lateral femoral condyle of experiment group gradually wore, presenting greyish yellow color cartilage surface not smooth, there is wear and tear and even ulcers.2. Along with the increase of the time the observation of histology shows fibering of lateral femoral condyle, meanwhile, there are abnormal cell disposition and increasingly clustered cell. Histological evaluation of the degeneration in cartilage of femoral condyle in both groups:The scores at the 4th,8th,16th and 24th week were higher in the experimental group than those in the control group, showing significant difference, P <0.05; the scores of experimental group at the 24th week group> 16th week group> 8th week group> 4th week group,showing significant difference, P<0.05.3. femoral condyle bone mineral density decreased but there was no significant differences about bone mineral density testing of femoral condylar subchondral between the experimental group and contrast group at the 4th week.the femoral condyle bone mineral density are higher and there are significant differences about bone mineral density testing of femoral condylar subchondral compared with contrast group and the previous (4th Week,8th Week,16th Week)at the 24th week.CONCLUSION 1. Rupture of PCL could cause the degeneration of lateral femoral condyle with times.2. femoral condyle bone mineral density reduction in early PCL fracture, but there are no statistical significant difference. The femoral condyle bone mineral density increased and femoral condyle subchondral bone degeneration occur in late period Chapter?The expression of collagen?and MMP7 in lateral femoral condyle cartilageOBJECTIVE To explore the effect of PCL rupture on the expression of type II collagen, MMP7 in lateral femoral condyle cartilageMETHOD Lateral femoral condyle of 48 rabbits matched mode pairs both in experiment side which PCL were transacted and control side, at the 4th,8th,16th and 24th week, execute 12 rabbits randomly, then to observe lateral femoral condyle in immunohistochemisty staining, detect the expression of MMP7, and type?collagenRESULT 1. At the 4th,8th,16th and 24th week, expression of MMP7 is higher in experimental group than that in control group, showing significant difference, P<0.05.2. In experimental group, expression of MMP7 is higher at the 8th than that at 4th week, showing significant difference, P<0.05, expression of MMP7 is higher at the 16th and 24th week than that at 4th and 8th week, showing significant difference, P<0.05, and there is no significant difference between the 16th and 24th week,P>0.05.3. In experimental group, expression of collagen His higher at the 4th and 8th week than that in control group,at 24th week, expression of collagen?in experimental group is less than that in control group, showing significant difference, P<0.05, There are no significant difference between experimental group and control group with the expression of collagen?at the 16th week, P>0.05. 4. In experimental group, expression of collagen?is higher at the 8th week than that at 4th,16th and 24th week, showing significant difference, P<0.05; expression of collagen?is higher at the 16th week than that at 24th week, expression of collagen?is higher at the 4th week than that at 16th week and 24th week, showing significant difference, P<0.05.CONCLUSION 1. MMP7 displays rising firstly then expressing consistently after the rupture of PCL; collagen?displays high expression firstly then low expression in advanced stage after the rupture of PCL.2. collagen?and MMP7 can be observed as an index for the injury of lateral femoral condyle cartilage after the rupture of PCL. The high expression of MMP7, collagen?hints that the physio-pathological mechanism triggered by MMP7, collagen?is maybe one cause of the degeneration of lateral femoral condyle cartilage after the rupture of PCL. |
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