The effects of dehydration on the surface morphology of articular cartilage

Environmental scanning electron microscopy (ESEM) was used to study the morphology of the articular surface and the effects of dehydration. Study of the physiological surface at high magnification has previously been limited by the preparation procedures required for both scanning and transmission electron microscopy (SEM and TEM). Using ESEM, which does not require such preparation, it was noted that the surface of fully hydrated articular cartilage was smooth at all magnifications and that surface features quickly formed upon dehydration. Subsequently it was found that dehydration damage resulting from exposure of the cartilage to air for periods of between 6 and 48 min was not reversible by immersion of the cartilage in a nutrient solution. The results imply that irreversible damage to the articular surface could result from even brief exposure to air, similar to that experienced during operative procedures. Such damage to the surface could initiate anomalous wear and lubrication processes in synovial joints, possibly leading to degenerative joint conditions.