Mechanical validation of whole bone composite tibia models

Composite synthetic models of the human tibia have recently become commerci ally available as substitutes for cadaveric specimens. Their use is justifi ed by the advantages they offer as a substitute for real tibias. The presen t investigation concentrated on an extensive experimental validation of the mechanical behaviour of the whole bone composite model, compared to human specimens For different loading conditions. The stiffness of the tibias was measured with a torsional load applied along the long axis, and with a ben ding load applied both in the latero-medial and in the antero-posterior dir ection. The bending stiffness of the composite tibias matched well with tha t of the cadaveric specimens. This was not true for the torsional stiffness . In fact, the composite tibias were much stiffer than the cadaveric specim ens, possibly due to the structure of the reinforcement material. The inter -specimen variability for the composite tibias was much lower than that for the cadaveric specimens. Thus. it seems that the composite tibias are suit able to replace cadaveric specimens for certain types of test; whereas they might be unsuitable for others, depending on the loading regimen. (C) 2000 Elsevier Science Ltd. All rights reserved.