Comparative Study of Biological Material Mechanical Characteristics for Medial and Lateral Human Meniscus

Objective:To conduct the multiple-section and multiple-slice biological material mechanical experimental study on the medial and lateral meniscus of human knee,compare the difference in the mechanical characteristics,and analyze the injury mechanism in order to provide experimental references for treatment,repair or artificial material replacement after injury occurrence.Method:Take twelve medial and lateral meniscuses,six each from the right no-lesion knees of adult males of ages between 20 to 45 years old.Divide meniscuses into the anterior horn,the body,and the posterior horn.Frozenly sectioning the anterior horn and the posterior horn along the horizontal plane and the frontal plane,and sectioning the body along the horizontal plane and the sagittal plane to make standard testing specimen.Use the biological materials mechanical characteristics testing system,located at the Mechanical Experimental Center of Shanghai University,to conduct the one-dimensional tensile and stress relaxation experiments.The experimental data are statistically processed and the medial and lateral meniscuses are compared for 1) the horizontal plane and the coronal plane of the anterior horn;2) the horizontal plane and the coronal plane of the posterior horn;3) the sigittal plane and the horizontal plane of the body.Results:1) The instantaneous elastic response of the anterior horn and the posterior horn of the inside meniscus is significantly greater than that of the outside meniscus(P≤0.05),and the instantaneous elastic response of the body of the outside meniscus is significantly greater than that of the inside meniscus(P≤0.05);2)There is no significant difference in the stress relaxation rate for each section of the inside and outside meniscus(P>0.05);3) Four items of tensile capacity are significantly high(P≤0.05).Conclusion:1)The instantaneous elastic responding index of the anterior horn and the posterior horn of the medial meniscus is significantly larger than that of the lateral meniscus,while index of the medial body is significantly smaller than that of the lateral.(P≤0.05);2) The ability to adjust load capacity is substantially the same for each section of the medial and lateral meniscuses.If the joint range of motion is moderate and preparations are fully made,it should be able to avoid the damage caused by the uneven load;3)The anti-tensile ability of the lateral meniscus is weaker than that of the medial meniscus,which might be one of the reasons for common urgent and chronic injury from the perspective of bio-mechanics of materials.