COLLAGEN FIBRE ARCHITECTURE AND PROTEOGLYCAN DISTRIBUTION IN FEMALE KNEE MENISCI ACROSS REPRODUCTIVE AND POST-REPRODUCTIVE AGE GROUPS

Abstract

The structural integrity of the knee meniscus depends on the precise spatial organisation of its extracellular matrix, composed primarily of type I collagen arranged in circumferential, radial, and surface-oriented fibre bundles, interpenetrated by a proteoglycan-rich ground substance whose hydrophilic properties confer the viscoelastic behaviour essential for meniscal load-transmission and shock-absorption functions (Fox et al., 2015; Makris et al., 2011). Proteoglycans — predominantly aggrecan, biglycan, and decorin — interact electrostatically with water molecules to generate the swelling pressure that resists compressive loading, while collagen fibres bear the circumferential tensile (hoop) stresses generated during axial loading of the knee (Berthiaume et al., 2005; Messner & Gao, 1998).