Thickness effects on maximum von-Mises stress of a cement mantle in total hip replacement - a finite element study.

Aim: the present study seeks to increase the life term of fully cemented total hip replacements by minimizing the stress values within the cement mantle. Methods: three-dimensional (3d) finite element analyses have been carried out to investigate the effects of varying cement thickness on the von-Mises stress of a cement mantle. the magnitude and location of maximum von-Mises stress within the cement mantle have been studied for both straight and tapered prosthetic stems. Results: For prosthetic stems having lower radii sizes, the maximum stress zone is found in the upper region of the cement mantle whilst for stems with higher radii sizes the maximum stress zone is found in the lower region of the cement mantle. For the same cement thickness, straight stems are found to produce lower maximum stress values in the cement when com- pared to tapered stems. Finally, for the straight models with the same cement thickness, maximum stress values are found to decrease with increasing stem radius. Conclusions: It can be concluded that the maximum stress values in the cement mantle decrease with decreasing cement thickness. (Journal of Applied Biomaterials & Biomechanics 2009; 7: 111-5)