A new comprehensive approach for bone remodeling under medium and high mechanical load based on cellular activity

Abstract

Most of the last century, bone remodeling models have been proposed based on the observation that bone density is dependent on the intensity of the applied mechanical loads. Most of these cortical or trabecular bone remodeling models are related to the osteocyte mechanosensitivity, and they all have a direct correlation between the bone mineral density and the mechanical strain energy. However, experiments on human athletes show that high-intensity sport activity tends not to increase bone mineral density but rather has a negative impact. Therefore, it appears that the optimum bone mineral density would develop for "medium"-intensity activity (or medium mechanical loads) and not for the highest-intensity one.In this work, we propose a new continuum approach based on bone cell activity being either positive or negative as a function of the intensity of the applied mechanical load. At standard earth gravity without exercise, bone homeostasis is observed with cell activity being at equilibrium. When "medium loads" such as "low-intensity" or "optimized" sport activity are applied, cells are activated and an increase of bone density occurs. On the other hand, "high-intensity loads" such as over-training lead to bone density decrease or bone degradation. Our results are in agreement with the literature and enable us to foresee applications such as optimal sport training for best physical conditions.Communicated by Emilio Barchiesi. George and Allena share first-authorship. MSC2010: 65Z05, 92C05.

Finite memory model of bone healing in analysis of moving interface between mandible tissue and bone substitute material after tooth implant application

“…Detail considerations about the mathematical simulation of bone remodelling are given elsewhere [30], and an alternative version was given in [22,23,27], but a summary formulation is reported in the following.…”

Prediction of Cortical Bone Thickness Variations in the Tibial Diaphysis of Running Rats

“…The model proposed here is based on the work by George et al [46]. It is developed at a continuous scale to predict the equivalent bone density, either in the cortical or in the trabecular regions.…”

“…It could be possible to study/predict bone density variations (bone remodeling) as a function of time for different load conditions when providing an adequate coupling between the bone mechanical response and the cell reaction to drive the bone remodeling. In this work, we evaluate, from experimental data, a continuous theoretical numerical model based on George et al [46] to study bone density variations under medium or high mechanical loads and compare these numerical results with experimental ones obtained from running rats. We show that the bone density either increases or decreases, depending on the running exercise intensity and that cell activity is directly related to this evolution.…”

In-depth gaze at the astonishing mechanical behavior of bone: A review for designing bio-inspired hierarchical metamaterials

“…In fact, it depends on the concentrations of nutrients, hormones, and other factors that have a broad variability from person to person. Some authors introduced these effects with a more complex formulation of the stimulus (see, e.g., [51,52,176,177,178], as well as [179,180], to model the dynamics of the biochemical reactions involved).…”