Comparisons of fixation stiffness of some hip stems with specific geometries

Appropriate design of stem geometry for a hip joint prosthesis is important for secure initial .xation. In this report, we introduced .xation stiffness as a criterion for the evaluation of the initial .xation. Some contemporary stems with distinctive geometries were estimated using this criterion. Finite element (FE) models were constructed for the computer simulation. The displacement of stem and femur model was calculated. The ratio of displacement to the vertical load was de.ned as .xation stiffness. As the results, the z-axis .xation stiffness estimated on the Intra-Medullary Cruciate stem, the VerSys stem, and the Per.x SV stem were evaluated as 461 MN/mm, 264 MN/mm, and 313 MN/mm, respectively. The .xation stiffness in the z direction was superior for the IMC stem than other two stems.