Theoretical studies of elastohydrodynamic lubrication of artificial hip joints

Theoretical studies of fluid-film lubrication in artificial hip joints are reviewed. The importance of developing effective numerical tools to solve realistic and complex lubrication problems in artificial hip joints has been emphasized. The elastic deformation of the bearing surfaces has been shown to play a dominant role in promoting elastohydrodynamic lubrication in various forms of artificial hip joints using different bearing surfaces. Both the bearing geometry and the structural supports can have a significant effect on the predicted lubricant film thickness. The importance of elastic deformation is further enhanced synergistically with the transient variation in load and speed to ensure a maximum effectiveness of the transient elastohydrodynamic lubrication mechanism in artificial hip joints. The recent application of the fast Fourier transform technique, in conjunction with the finite-element method to calculate the elastic deformation, not only enables more complex structural supports to the acetabular cup to be considered, but also offers the potential of analysing both transient and mixed lubrication problems in artificial hip joints.