Micromechanical properties of the healthy canine medial meniscus

Aims: Knowledge of the micromechanical characteristics of the menisci is required to better understand their role within the stifle joint, improve early diagnosis of meniscal lesions, and develop new treatment and/or replacement strategies. The aim of the study was to determine the mechanical properties of the healthy medial canine meniscus and to evaluate the effect of regional (caudal, central, and cranial) and circumference (axial and abaxial) locations on these properties.Methods: To study the micromechanical properties of the medial menisci in healthy (Beagle) dogs, the influence of regional (caudal, central, and cranial) and circumference (axial and abaxial) locations were evaluated. Nanoindentation-relaxation tests were performed to characterize the local stiffness and the viscoelastic prop-erties at each region and specific circumference. Linear interpolation onto the indentation points was performed to establish a map of the micromechanical property heterogeneities.Results: The results indicate that the cranial region was significantly stiffer and less viscous than the central and caudal regions. Within the central region the inner part (axial) was significantly stiffer than the periphery (abaxial). Within the caudal region the inner part was significantly less viscous than the periphery.Conclusion: Significant regional and radial variations were observed for both the stiffness and the viscoelastic properties. Moreover, a viscous behavior of the entire medial meniscus was observed (elastic fraction <0.5). These results deter the use of average elastic modulus to study the regional mechanical properties of healthy meniscus.