Test Methods for Accurate and Robust Material Property Measurements of Rodent Cortical Bone

Direct measurements of cortical bone material properties are difficult to achieve in rodent long bones due to the inherently small dimensions and difficulties in machining standard test specimen geometries [1]. Bone tissue properties in nearly all rodent studies are thus limited to estimates from flexural tests of long bone diaphyses. In addition to the inaccuracies imposed by the bending stress state itself, these material property estimates are further confounded by the non-uniform geometry of long bones along the diaphyseal length. The goal of this work was to develop a series of techniques to improve the accuracy and precision of material property measurements in rodent long bones, with explicit mathematical correction for geometrical complexity and multiple measurements from individual bones. In combination, these techniques provide a pragmatic serial test routine for collecting multiple direct measurements of cortical tissue elastic modulus and strength, with a potential for improving sensitivity and statistical power in skeletal studies using rodents.