t Studies suggest that fluid motion in the extracellular
space may be involved in the cellular mechanosensitivity
at play in the bone tissue adaptation process. Previously,
the authors developed a mesoscale predictive structural
model of the femur using truss elements to represent trabecular
bone, relying on a phenomenological strain-based
bone adaptation algorithm. In order to introduce a response
to bending and shear, the authors considered the use of beam
elements, requiring a new formulation of the bone adaptation
drivers. The primary goal of the study presented here
was to isolate phenomenological drivers based on the results
of a mechanistic approach to be used with a beam element
representation of trabecular bone in mesoscale structural
modelling. A single-beam model and a microscale poroelastic
model of a single trabecula were developed. A mechanistic
iterative adaptation algorithm was implemented based on
fluid motion velocity through the bone matrix pores to predict
the remodelled geometries of the poroelastic trabecula
under 42 different loading scenarios. Regression analyses
were used to correlate the changes in poroelastic trabecula
thickness and orientation to the initial strain outputs
of the beam model. Linear (R2 > 0.998) and third-order
polynomial (R2 > 0.98) relationships were found between
change in cross section and axial strain at the central axis,
and between beam reorientation and ratio of bending strain
to axial strain, respectively. Implementing these relationships into the phenomenological predictive algorithm for the
mesoscale structural femur has the potential to produce a
model combining biofidelic structure and mechanical behaviour
with computational efficiency.