Effect Of Posterior Cruciate Ligament Rupture On The Biomechanics Of Lateral Collateral Ligament

Objective To investigate the effect of the PCL rupture on the biomechanics of the biomechanics of lateral collateral ligament.Method The specimens in this experiment are 6 normal fresh knee joints of adult male.At first,all the 6 specimens,whose lateral collateral ligament straining were measured at different angles(0°,30°,60°and 90°) under different loads(200N,400N,600N and 800N),were regarded as the group with intact PCL.Then,3 specimens were randomly treated as the group with the anterolateral bundle of PCL ruptured.The other 3 knees were treated as the group whose posteromedial bundle of PCL ruptured. Measuring the straining of lateral collateral ligament of the two groups as step one.At last,cutting off the PCL completely in all 6 specimens as the group with the PCL completely ruptured and doing the measurement at the four angles under the four loads similarly.According to the hooke's law, take the result under unit 200N of test to carry on the statistical analysis.Results 1.Straining point of the intact PCL group:,the strains in all parts of the LCL is compressive at the 0°,30°,60°position.The differences of the strain between 0°and 30°,60°are of significance(p＜0.05),while difference of the strain between 30°and 60°are of no significance(p＞0.05). The strains in all parts of the LCL is tensile at the 90°position.2. Straining point of the ALB ruptured group:the strains in all parts of the LCL is compressive at the 0°and 30°position,difference of them are of of significance(p＜0.05).The strains in all parts of the LCL is tensile at the 60°and 90°position,difference are of of no significance(p＞0.05).3. Straining point of the PMB ruptured group:the strains in all parts of the LCL is compressive at the 0°,30°,60°position.The differences of the strain between 0°and 30°,60°are of significance(p＜0.05),while difference of the strain between 30°and 60°are of no significance(p＞0.05).The strains in all parts of the LCL is tensile at the 90°position.4.Straining point of the complete ruptured group:the strains in all parts of the LCL is compressive at the 0°,30°position.The strains in all parts of the LCL is tensile at the 60°,90°position,the strain at 90°are bigger than that at 60°(p＞0.05).5.Straining point of all groups at 0°:the strains in all parts of all groups are compressive.The strains in Femoral Footprints and fibula attachment of the LCL in all groups are of no significant difference(p＞0.05).The strains in caudomedial part of the LCL in the intact PCL group and the PMB ruptured group are bigger than in the ALB ruptured group and the complete ruptured group.6.Straining point of all groups at 30°:the strains in all parts of all groups are compressive.The strains in fibula attachment of the LCL in the intact PCL group are bigger than in the intact PCL group and the complete ruptured group(p＜0.05).7. Straining point of all groups at 60°:the strains of the intact PCL group and the PMB ruptured group are compressive.The strains of the the ALB ruptured group and the complete ruptured group are tensile.The difference between the intact PCL group and the PMB ruptured group and the ALB ruptured group and the complete ruptured group are of of significance (p＜0.05).While the difference between the ALB ruptured group and the complete ruptured group are of of no significance(p＞0.05).8.Straining point of all groups at 90°:The strains in all parts of the LCL of all groups are tensile.The strains in the ALB ruptured group and the complete ruptured group are bigger than in the intact PCL group and the PMB ruptured group(p＜0.05).while the difference between the ALB ruptured group and the complete ruptured group are of of no significance (p＞0.05).The same to the intact PCL group and the PMB ruptured group.Conclusions 1.The effect of the PCL rupture on the biomechanics of lateral collateral ligament(LCL) is inconspicuous when knee flexion angle is at 0°and 30°.2.The effect of the PMB rupture on the biomechanics of LCL is inconspicuous when knee flexion angle is at 60°and 90°.3.The effect of the PCL or ALB rupture on the biomechanics of LCL is noticeable when knee flexion angle is at 60°and 90°.