Tensile stress-strain characteristics of the human meniscal material.

The nonlinear stress-strain characteristics of the human menisci were determined by uniaxial elongation tests performed on circumferential and radial specimens prepared from different regions, layers, and locations. The properties of the collagen fibers and the matrix were calculated using the test results along with the values of the volume fractions of the meniscal components. Regression analysis showed that only three parameters, the elastic modulus, the maximum strain, and the strain intersect, are sufficient to define the nonlinear stress-strain relation up to failure. For radial specimens, the layer had a significant effect (p < 0.01) on the elastic modulus and the maximum strain, but had no effect on the strain intersect and the maximum stress. For the same specimens, the region had a significant effect (p < 0.01) only on the strain intersect and the maximum stress. For circumferential specimens, analysis indicated no significant effect of either the region, the layer, or the location of the specimens on the material parameters defining the stress-strain relation.