The Role of Synovial Fluid in Joint Lubrication

This paper reviews some of the recent trends in lubrication of natural and artificial joints focusing the functions of synovial fluid. While elasto-hydrodynamic lubrication is the major mechanism in human joints, they operate with adaptive multimode lubrication. Though the effect of cartilage porosity is small in fluid film lubrication condition, fluid may be pressed out from the cartilage to the gap in mixed lubrication region and it lubricates cartilage effectively. Cushion form joint proved to result better lubrication condition. However, it needs the assistance of supplemental lubrications at startup.