On the viscosity and pH of synovial fluid and the pH of blood.

During the last ten years there have been many studies of the physical and chemical properties of synovial fluid in relation to the production and prevention of joint lesions. These researches on the properties of normal human synovial fluid have nearly all been done on specimens obtained post morteFn, all other work on the normal having been done on fluid obtained from the joints of cattle. Furthermore, there appears to have been no investigation into the changes, if any, in normal human synovial fluid with age or with variations in pH, which by affecting the viscosity may have an important effect on the lubrication and nutrition of the joint surfaces. To elucidate these problems we studied: 1) the viscosity ofsynovial fluid from normal human kneejoints at different ages; 2) viscosity changes in traumatic and osteoarthritic knee joints; 3) the relationship between the pH of blood and synovial fluid in normal, injured and osteoarthritic knee joints; and 4) the pH of synovial fluid at different ages.