Small Variations in the Over-sizing of Cementless Cups Significantly Affects Strength of Fixation

Long-term fixation of cementless acetabular cups critically depends on the initial stability of the shell/bone interface. While most surgeons try and achieve adequate stability by selecting a press-fit cup than the final reamer, the interference achieved varies with the accuracy of reaming and the true size of the implant. The purpose of this study was to examine the effect of variations in the dimensions of the cup and the reamed acetabulum on the mechanical fixation of hemispherical shells.