title: Indentation properties and glycosaminoglycan content of human menisci in the deep zone.
abstract: Menisci are two crescent shaped fibrocartilaginous structures that provide fundamental load distribution and support within the knee joint. Their unique shape transmits axial stresses (i.e. "body force") into hoop or radial stresses. The menisci are primarily an inhomogeneous aggregate of glycosaminoglycans (GAGs) supporting bulk compression and type I collagen fibrils sustaining tension. It has been shown that the superficial meniscal layers are functionally homogeneous throughout the three distinct regions (anterior, central and posterior) using a 300 μm diameter spherical indenter tip, but the deep zone of the meniscus has yet to be mechanically characterized at this scale. Furthermore, the distribution and content of GAG throughout the human meniscal cross-section have not been examined. This study investigated the mechanical properties, via indentation, of the human deep zone meniscus among three regions of the lateral and medial menisci. The distribution of GAGs through the cross-section was also documented. Results for the deep zone of the meniscus showed the medial posterior region to have a significantly greater instantaneous elastic modulus than the central region. No significant differences in the equilibrium modulus were seen when comparing regions or the hemijoint. Histological results revealed that GAGs are not present until at least ~600 μm from the meniscal surface. Understanding the role and distribution of GAG within the human meniscus in conjunction with the material properties of the meniscus will aid in the design of tissue engineered meniscal replacements.
authors: Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, USA.
authors: John T
authors: JT
authors: Moyer
authors: Ryan
authors: R
authors: Priest
authors: Troy
authors: T
authors: Bouman
authors: Adam C
authors: AC
authors: Abraham
authors: Tammy L Haut
authors: TL
authors: Donahue
mesh_terms: D000368:Aged; D006025:Glycosaminoglycans / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008422:Materials Testing; D008592:Menisci, Tibial / Q000378:metabolism*; D008875:Middle Aged
chemical_list: D006025:Glycosaminoglycans