DT-MRI Based Numerical Simulation of Collagen Fiber Deformation in Human Articular Cartilage

Within the articular cartilage (composed of fluid, electrolytes, chondrocytes, collagen fibers, proteoglycans and other glycoproteins) fibers of predominantly Type II collagen provide tensile strength and stiffness to the solid phase, a proteoglycan gel. Collagen fibers exhibit a high level of structural organization usually consisting of three sub-tissue zones: (i) a superficial tangent zone with fibers which are tangential to the articular surface, (ii) a middle zone with fibers isotropically oriented, (iii) a deep zone with fibers oriented perpendicular to the subchondral bone [1]. Given the importance of this collagen fiber fabric in the mechanical properties of articular cartilage, many destructive and nondestructive experimental methods have been pursued to characterize fiber orientation and density.