Phf. Nicholson et Ml. Bouxsein, Quantitative ultrasound does not reflect mechanically induced damage in human cancellous bone, J BONE MIN, 15(12), 2000, pp. 2467-2472
This study investigated the ability of quantitative ultrasound (QUS) to det
ect reductions in the elastic modulus of cancellous bone caused by mechanic
al damage. Ultrasonic velocity and attenuation were measured using an in-ho
use parametric imaging system in 46 cancellous bone cores from the human ca
lcaneus, Each core was subjected to a mechanical testing regime to (a) dete
rmine the predamage elastic modulus, (b) induce damage by applying specifie
d strains in excess of the yield strain, and (c) measure the postdamage ela
stic modulus, The specimens were divided into four groups: a control group
subjected to a nominally nondestructive 0.7% maximum strain (epsilon (m)) a
nd three damage groups subjected to increasing strain levels (epsilon (m) =
1.5, 3.0, and 4.5%), QUS measurements before and after the mechanical test
ing showed no significant differences between the control group and damage
groups, despite highly significant (p < 0.001) reductions in the elastic mo
dulus of up to 72%, These results indicate that current QUS techniques do n
ot intrinsically reflect the elastic properties of cancellous bone. This is
consistent with ultrasonic properties being determined by other factors (a
pparent density and/or architecture), which normally are associated strongl
y with elastic properties, but only when bone is mechanically intact. Clini
cally, this implies that ultrasound cannot be expected to detect bone fragi
lity in the absence of major changes in bone density and/or trabecular arch
itecture.