Ultrafiltration of Synovial Fluid by Cartilage

The ultrafiltration process of synovial fluid across the articular surface is one of the important mechanisms relating to the physiology of synovial joint mechanics. A model for studying such a process is given in this paper. An impermeable upper boundary is given a downward uniform speed so that it forces a macromolecular solution to flow through a bottom filter. The forced convection process sets up a concentration gradient in the solution whereas the diffusion process acts against the concentration gradient. This interaction results in the dependence of the instantaneous concentration distribution on Peclet number. The histories of the formation of gel during the ultrafiltration process are also calculated for various prescribed values of critical concentrations. The results are examined with regard to their implications on the mechanics of synovial joints and on other biomechanical applications.