Articular Cartilage and Meniscal Fibrocartilage Mechanics: Evidence for Differences in Ultrastructure and Function of Proteoglycans

The organization and function of proteoglycans have been extensively studied in articular cartilage. Proteoglycans are widely dispersed throughout articular cartilage [1] and resist compressive as well as shear loads through high hydrostatic pressures, low fluid permeability and stiffening of the collagen network [2]. Few studies have investigated the organization and function of proteoglycans in meniscal fibrocartilage. Previous studies have shown PG degradation leads to decreased meniscal fibrocartilage mechanics [3,4]. In contrast to articular cartilage, meniscal fibrocartilage PGs are concentrated around circumferential collagen fibers [2]. To better understand the role of proteoglycans in meniscal fibrocartilage, the proteoglycan interactions within the tissue can be manipulated without extracellular matrix degradation. The goal of this study was to compare the effects of osmotic swelling stress on articular cartilage and meniscal fibrocartilage mechanics by varying osmotic strength and tissue compressive offset.