The importance of physicochemical swelling in cartilage illustrated with a model hydrogel system.

The physicochemically derived swelling stress in articular cartilage plays a crucial role in determining the pattern of stress sharing between the exudable fluid and the 'solid' components comprising its matrix. This pattern of stress sharing in turn influences the manner in which cartilage consolidates or deforms in compression via the outflow of fluid. Synthetic hydrogels exposed to a variety of cationic blocking solutions provide simplified model systems for exploring quantitatively the influence of the intrinsic swelling parameter on consolidation behaviour, thus yielding further insights into the fundamental parameters controlling the biomechanical properties of complex tissues such as articular cartilage.