Swing Phase Lubrication Analysis of a Novel Artificial Hip Joint

This paper investigates swing-phase cavitation formation and collapse in a novel artificial hip joint using a well-established transient mass-conserving finite element cavitation algorithm. Elastic elements and ellipsoidal cup surface geometry are incorporated into the new design to promote and enhance ‘squeeze-film’ action over ‘wedge-film’ action employed in conventional artificial hip joints. During the swing phase of the gait cycle, the lubricant film undergoes cavitation from normal separation of ball and cup surfaces. Reformation of a complete lubricant film is predicted over a wide range of sub-ambient cavitation threshold pressures, ball velocities, ellipticity specifications, and ball initial positions that are likely to be encountered in practice.