Author:
Castoldi Natalia M.,Pickering Edmund,Sansalone Vittorio,Cooper David,Pivonka Peter
Abstract
AbstractThe mechanical quality of trabecular bone is influenced by its mineral content and spatial distribution, which is controlled by bone remodelling and mineralisation. Mineralisation kinetics occur in two phases: a fast primary mineralisation and a secondary mineralisation that can last from several months to years. Variations in bone turnover and mineralisation kinetics can be observed in the bone mineral density distribution (BMDD). Here, we propose a statistical spatio-temporal bone remodelling model to study the effects of bone turnover (associated with the activation frequency $$\mathrm {Ac.f}$$
Ac
.
f
) and mineralisation kinetics (associated with secondary mineralisation $$T_\textrm{sec}$$
T
sec
) on BMDD. In this model, individual basic multicellular units (BMUs) are activated discretely on trabecular surfaces that undergo typical bone remodelling periods. Our results highlight that trabecular BMDD is strongly regulated by $$\mathrm {Ac.f}$$
Ac
.
f
and $$T_\textrm{sec}$$
T
sec
in a coupled way. Ca wt% increases with lower $$\mathrm {Ac.f}$$
Ac
.
f
and short $$T_\textrm{sec}$$
T
sec
. For example, a $$\mathrm {Ac.f}=$$
Ac
.
f
=
4 BMU/year/mm$$^3$$
3
and $$T_\textrm{sec}$$
T
sec
= 8 years result in a mean Ca wt% of 25, which is in accordance with Ca wt% values reported in quantitative backscattered electron imaging (qBEI) experiments. However, for lower $$\mathrm {Ac.f}$$
Ac
.
f
and shorter $$T_\textrm{sec}$$
T
sec
(from 0.5 to 4 years) one obtains a high Ca wt% and a very narrow skew BMDD to the right. This close link between $$\mathrm {Ac.f}$$
Ac
.
f
and $$T_\textrm{sec}$$
T
sec
highlights the importance of considering both characteristics to draw meaningful conclusion about bone quality. Overall, this model represents a new approach to modelling healthy and diseased bone and can aid in developing deeper insights into disease states like osteoporosis.
Funder
New Frontiers in Research Fund Exploration
Australian Research Council
Queensland University of Technology
Publisher
Springer Science and Business Media LLC
Subject
Mechanical Engineering,Modeling and Simulation,Biotechnology