The influence of surface topography on wear debris generation at the cement/bone interface under cyclic loading

The long-term success of a total joint replacement can be undermined by loosening of the implant, generation of wear debris or a combination of both factors. In the present study the influence of the surface morphologies of the bone and cement mantle on loosening of cemented total joint replacements (THJRs) and development of wear debris were studied. Model cemented THJR specimens were prepared in which the femoral canal was textured using specific cutting tools. The specimens were subjected to cyclic loads inducing pure shear fatigue of the cement/bone interface. Changes in both the femoral canal and cement mantle resulting from fatigue were quantified in terms of the surface topography and the volume of wear debris. Loosening occurred with cyclic loading due to degradation of the cement and bone and resulted in the development of cement and bone particles. There was no correlation between the fatigue strength of the interfaces and the volume of wear debris. In general, the change in surface topography of the cement mantle with fatigue decreased with increasing volume of cement interdigitation. Femoral canal surfaces with symmetric profile height distribution (i.e., Gaussian surfaces) resulted in the lowest volume of generated debris.