The permeability of bovine articular cartilage was measured in an
apparatus designed to permit this measurement while the fluid pressure
gradient across the cartilage and the axial compressive strain applied to
the cartilage were varied independently. For all of the pressure gradients
tested the permeability of the cartilage decreased as the compressive
strain increased. From previous work, it was postulated that joint
lubrication is accomplished first by fluid exudation into the joint space.
both at the leading edge of the moving contact area and between portions of
the opposing cartilaginous surfaces, and second by imbibition of the
expelled fluid back into the cartilage toward the trailing edge of the
contact area caused by the "elastic" recovery of the tissue. The present
work extends this model to include the condition that the permeability of
cartilage is dependent on the extent to which it is deformed.