STRESS SHIELDING AFTER TOTAL KNEE REPLACEMENT MAY CAUSE BONE RESORPTION IN THE DISTAL FEMURG. H. van Lenthe, MSc1; M. C. de Waal Malefijt, MD, PhD1; and R. Huiskes, PhD, Professor, Biomechanics Section11 Institute of Orthopaedics, University of Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Correspondence should be sent to Professor R. Huiskes. Inadequate bone stock is often found in revision surgery of femoral components of total knee replacements. Our aim was to test the hypothesis that these remodelling patterns can be explained by stress shielding, and that prosthetic bonding characteristics affect maintenance of bone mass. We made a three-dimensional finite-element model of an average male femur with a cemented femoral knee component. This model was integrated with iterative remodelling procedures. Two extreme prosthetic bonding conditions were analysed and gradual changes in bone density were calculated. The long-term bone loss under the femoral knee component resembled clinical findings which confirms the hypothesis that stress shielding can cause distal femoral bone loss. Our study predicts, contrary to clinical findings, that an equilibrium situation is not reached after two years, but that bone resorption may continue. This hidden bone loss may be so drastic that large reconstructions are needed at the time of revision. This article has been cited by other articles:
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