Dynamic Contact And Wear Prediction Of Metal-on-Metal Hip Joint Replacements Under Transient Walking Condition

A general model of computational wear prediction of hard-on-hard hip joint replacements under the dynamic loading and time-dependent motion was developed and subsequently ap-plied to carry out the wear prediction of the typical spherical and non-spherical metal-on-metal hip joint replacements under the three-dimensional physiological loading and motion experi-enced during walking condition. Finite element model for spherical contact mechanics was developed in order to simulate the contact pressure of hip joint replacements in the computa-tional wear prediction model. Fixed-tracked method was employed to make the data commu-nication of geometrical changes caused by wear during the simulation. It was found that the spherical bearing geometry of artificial hip joints became the non-spherical one due to the wear with time, at the same time, the corresponding contact area was increased, the distribu-tions of the contact pressure tended to be flatten, and the maximum contact pressure decreased. The non-spherical metal-on-metal hip joint can effectively increase the contact area, reducing the contact pressure, compared to spherical hip joints; significantly reduce the maximum wear depth. The computational wear prediction of hip joint replacements under the complex and the dynamic loading and motion condition and with the wear of both bearing surfaces can well be carried out numerically by the developed model, which is helpful to understand wear mecha-nism of hip joint replacements.