Quantifying Mechanical Properties in a Murine Fracture Healing System Using an Inverse Geometric Nonlinear Elasticity Modeling Framework

Understanding bone remodeling and mechanical property characteristics is important for assessing treatments to accelerate healing or in developing diagnostics to evaluate successful return to function. The murine system whereby mid-diaphaseal tibia fractures are imparted on the subject and fracture healing is assessed at different time points and under different therapeutic conditions is a particularly useful model to study. In this work, a novel inverse geometric nonlinear elasticity modeling framework is proposed that can reconstruct multiple mechanical properties from uniaxial testing data. This is investigated within the context of a murine cohort (n=3) that are 14 days post fracture. This work is the first to report mechanical properties of a callus using an inverse problem methodology whereby 2758.4 +/- 682.5 kPa, 0.467 +/- 0.009 were found to be the Young's modulus and Poisson's ratio, respectively. In addition better consistency of the reconstructed metrics over more traditional metrics is demonstrated.