Effects of orthopedic implant and host bone properties on stress-shielding induced osteopenia

Abstract

Stress shielding is a term commonly used in literature to describe a bone density reducing phenomenon which occurs due to long-term exposure of bone tissue to sub-homeostatic levels of mechanical stimuli. A number of mechanobiological models ranging in complexity and purpose have been developed with the general overall intent of predicting bone remodeling behavior under a set of prescribed conditions. A previously developed heuristic model is expanded in the present work through model calibration with physiological data and the development of a reduced bone-implant-construct (BIC) mechanical model configurable for patient factors such as age, gender, and associated bone properties. The resulting model is subsequently validated and used to develop a comparative analysis on the longterm bone density loss with respect to the relative mechanical and geometric properties of the bone and implant device across both age and gender. Pending empirical validation, the results of the study may lend guidance to more optimal patient-specific implant selection and design with long term effects of implant properties on bone density as a primary consideration.