Reliability theory for load bearing biomedical implants

At present, load-bearing implants are designed on a deterministic basis int which the structural strength and applied loading are given fixed values, and global safety factors are applied to (i) cover any uncertainties in the se quantities, and (ii) to design against failure of the component. This ap proach will become increasingly inappropriate as younger and more active pa tient demands become more exacting and as devices become more complex. The present work describes a preliminary investigation in which a scientific an d probabilistic technique is applied to assess the structural integrity of the knee tibial tray. It is envisaged that by applying such a technique to other load bearing biomedical devices, reliability theory may aid in future lifing procedures and materials/design optimisation. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.