The effects of hip prosthesis stem cross-sectional profile on the stresses induced in bone cement.

Abstract

Bone cement has often been regarded as a weak link in a joint replacement structure. In spite of this, there has been little work published concerning experimental analysis of stresses in the cement. The purpose of the experiments described in this paper was to study the effects of some hip prosthesis stem designs on stresses in bone cement. The opportunity was also taken to examine some hypothetical designs. Photoelastic results show that some current designs of prosthesis stems cause less stress concentrations in cement than former designs. Stem designs which appeared good from photoelastic considerations also performed well in mechanical tests involving the impression of stem profiles in bone cement. A modification to current prosthesis stems is proposed which improves the ability of the cement to resist deformation.