Dynamics of articular joints visualised by MRI: Joint flexion, cartilage-compression and solute-perfusion

Abstract

Since articular cartilage is avascular, the continued viability of the chondrocytes, and hence of the cartilage structure, depends on the mass transport of nutrients from the synovial fluid into the cartilage and of proteoglycan from the chondrocytes. Although those processes have been studied for isolated specimens (Maroudas 1970, Urban 1992, Burstein et al. 1993), in an intact joint the effects of joint flexion and extension, and of the associated waves of cartilage compression, can be expected to enhance what would otherwise be a passive, diffusive process. In anticipation of making such studies we demonstrate here in-vivo the visualisation by Magnetic Resonance Imaging (MRI) of joint flexion/extension and of cartilage compression, and ex-vivo the perfusive diffusion of organic molecules through an intact articular joint.