Assessment of trabecular bone tissue elasticity with resonant ultrasound spectroscopy

International audienceThe material properties of the trabeculae (tissue-level properties), together with the trabecular architecture and the bone volume fraction determine the apparent millimetre-scale bone mechanical properties. We present a novel method to measure trabecular tissue elastic modulus E t using resonant ultrasound spec-troscopy (RUS). The first mechanical resonance frequency f e of a freestanding cuboid specimen is measured and used to back-calculate E t. The steps of the back-calculation are (1) the apparent stiffness tensors C(˜ E t) is computed using micro-finite elements for a set of trial values of tissue Young's modulus˜Emodulus˜ modulus˜E t based on the computed tomography image of the specimen; (2) the modeled free-vibration resonance frequencies f m (˜ E t) of the specimen is calculated with the Rayleigh-Ritz method using C(˜ E t); (3) finally, E t is obtained by interpolation using f e and f m (˜ E t). Four bovine bone specimens were tested (nominal size 5×6×6 mm 3). Average (standard deviation) of E t was 13.12 (1.06) GPa. The measurement of a single resonance frequency enabled an estimation of tissue elasticity in line with available data. RUS is a non destructive technique relatively easy to implement compared to traditional mechanical testing. The novel method could contribute to a better documentation of bone tissue elasticity which is an important parameter of micro-finite element analyses for the * Corresponding author clinical assessment of bone strength