THE INFLUENCE OF THE STEM-CEMENT INTERFACE IN TOTAL HIP-REPLACEMENT -A COMPARISON OF EXPERIMENTAL AND FINITE-ELEMENT APPROACHES

Experimental and finite element investigations were carried out on axi symmetric models of the femoral component of a total hip replacement. In one instance, the interface between the stem and the surrounding bo ne cement was assumed to be rigidly bonded; in a second, it was allowe d to slip. For the latter case, a friction coefficient of 0.2 was dete rmined experimentally. The predictions of the finite element models de monstrated excellent agreement with the results from the experimental tests at all sites where comparisons were made, thus validating these models. The effect of stem-cement slip was shown to reduce the maximum shear stress in the cement mantle by approximately 30 per cent.