On the basis of data obtained from in-vitro friction tests using both cartilage and widely differing artificial surfaces, a general model for boundary lubrication of joint cartilage by synovial fluid is presented. It postulates that one portion of the synovial lubricating glycoprotein (LGP) is adsorbed to the surface. Reduction in surface shear is accomplished by formation of hydration shells about the polar portions of the adsorbed LGP creating a thin layer of viscous structured water at the surface. Mutual electrostatic repulsion between charged polysaccharide moieties aids in separation of the adsorbed surface layers. The hydration shell also serves as a check valve to control the movement of water out of and into the cartilage matrix during motion.
The boundary lubricating ability of eleven synovial fluids was measured in a miniaturized latex-glass test system. The specimens were obtained at necropsy from knees in which the degree of degenerative joint disease varied from none to very severe. The lubricating ability of boundary lubricating ability under physiological conditions despite the fact that the test surfaces were not cartilaginous and the loading was relatively low (up to 47 pounds per square inch).the fluid was independent of the viscosity over a wide range of shear rates. It was not diminished even in advanced lesions. In two additional fluids, the mucin clot was poor; the lubricating ability of one of these was compromised. Thus, although degenerative joint disease, during its quiescent stages, is not associated with defective synovial lubrication, the possibility that transient defects might lead to cartilage wear during life has not been excluded. The measurements are believed to be valid indicators of Portions of this study were taken from a dissertation submitted by Warren H. Davis, Jr., in partial fulfillment of the requirements for the degree of Doctor of Philosophy from the State University of New York at Stony Brook.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.