ADAPTIVE BONE REMODELING AROUND BONDED NONCEMENTED TOTAL HIP-ARTHROPLASTY - A COMPARISON BETWEEN ANIMAL-EXPERIMENTS AND COMPUTER-SIMULATION

Severe loss of bone related to stress-shielding is one problem threate ning the long-term integrity of noncemented total hip arthroplasty. It is widely accepted that this phenomenon is caused by adaptive bone re modeling according to Wolff s law. Recently, quantitative bone-remodel ing theories have been proposed, suitable for use in computer-simulati on models in combination with finite-element codes, which can be appli ed to simulate the long-term effect of the remodeling process. In the present paper, the results of such a computer simulation are compared with those in an animal experiment. A three-dimensional finite-element model was constructed from an animal experimental configuration conce rning the implantation of a fully coated femoral hip prosthesis in dog s. The simulation results of the adaptive bone-remodeling process (geo metric adaptations at the periosteal surface and density adaptations w ithin the cancellous bone) were compared with cross-sectional measurem ents of the canine femurs after 2 years of follow-up. The detailed com parison showed that long-term changes in the morphology of bone around femoral components of total hip replacements can be fully explained w ith the present quantitative adaptive bone-remodeling theory.