Dynamic compressive behavior of human meniscus correlates with its extra-cellular matrix composition

The menisci of the knee play a significant role in the complex biomechanics of the joint and are critically important in maintaining articular cartilage health. While a general form-function relationship has been identified for the structural orientation of the extra-cellular matrix of the meniscus, the role of individual biochemical components has yet to be fully explored. To determine if correlations exist between the dynamic and static compressive modulus of human menisci and their major extra-cellular matrix constituents (collagen, glycosoaminoglycan and water content), 12 lateral and 11 medial menisci from 13 adult donors were examined. The results showed that in dynamic compression at high loading frequencies (0.1-1 Hz) the menisci behave as a rubber-like elastic material while at lower frequencies (0.01-0.03 Hz) significant viscous dissipation occurs. While regional variations in compressive moduli and extra-cellular matrix composition were observed, the magnitude of both dynamic and static compressive moduli were found to be insensitive to collagen content (p>0.4). However, this magnitude was found to significantly increase with increasing glycosaminoglycan content (p<0.001) and significantly decrease with increasing water content (p<0.001). The results of this study identify significant relationships between the viscoelastic behavior of the meniscus and its extra-cellular matrix composition.