Effect of hip stem taper on cement stresses.

The aim of this study was to use finite element models to investigate the effect of the design of the taper of polished, collarless, total hip replacement femoral components on stresses in the cement mantle surrounding the component. A single-taper prosthesis, double-taper prosthesis, and triple-taper prosthesis were compared. Peak stresses and stress distributions in the cement mantle were found to be a function of taper design, although the differences between designs were minor. Using a probability of failure technique based on the initial cement stress distribution, a triple-taper prosthesis was predicted to cause less cement mantle damage (0.15% of the volume of the cement mantle failing after 20 million loading cycles) than a double-taper prosthesis (0.74%) or a single-taper prosthesis (1.50%). Further research is required to confirm this finding.