The effect of porosity of articular cartilage on the lubrication of a normal human hip joint.

The effect of porosity of articular cartilage on the lubrication of a normal human hip joint has been studied. The poroelasticity equation of articular cartilage and the modified Reynolds equation for the synovial fluid lubricant have been successfully solved under squeeze-film motion and for the conditions experienced in a normal human hip joint. It has been shown that porosity of the articular cartilage depletes the lubricant film thickness, rather than increasing it, particularly when the lubricant film thickness becomes small. Furthermore, it has been shown that articular cartilage can be treated as a single-phase incompressible elastic material in the lubrication modelling under physiological walking conditions.