CHARACTERIZATION OF LOCAL ANISOTROPIC ELASTIC PROPERTIES OF FEMORAL AND TIBIAL DIAPHYSIS USING ACOUSTIC TRANSMISSION MEASUREMENTS AND ACOUSTIC MICROSCOPY.

Using two different acoustic techniques, the present work had three major purposes: (i) to investigate inhomogeneity patterns in anisotropic elastic constants of both human tibia and femur using a standard transmission method, (ii) to investigate the entire cross section of the same cortical bones using a low-frequency acoustic microscope and (iii) to correlate the acoustic impedance values obtained with this microscope with the c33 (longitudinal direction) found in transmission. 80 femoral and 120 tibial specimens prepared from 20 pairs of femur and tibia obtained at autopsy were investigated. The longitudinal elastic stiffness was significantly higher in the tibia when compared to the femur while all other elastic constants were identical. The elastic stiffness patterns were completely different for the two bones and in good agreement with the average acoustic impedance found with the acoustic microscope in the same anatomical locations.