Our aim was to determine the relationship between age and the mechanical an
d physical properties of trabecular bone, to describe the patterns in which
the variations in these properties take place, and to investigate the infl
uence of the physical properties on the mechanical characteristics of trabe
cular bone during growth. We used 30 lambs in three age groups and 20 sheep
in two age groups. Cubes of subchondral bone were cut from the proximal ti
bia according to a standardised protocol, We performed non-destructive comp
ression tests of the specimens in three orthogonal directions and compressi
on tests to failure in the axial direction. The physical properties of the
specimens were also determined, The data were correlated with age and compa
red in skeletally immature and mature animals. Multiple regression analyses
were performed between the mechanical and the physical properties.
Age correlated positively with elastic modulus, bone strength, energy absor
ption to failure, elastic energy, mechanical anisotropy ratio, tissue densi
ty, apparent density, apparent ash density, and bone mineral content, and i
nversely with ultimate strain, viscoelastic energy absorption, relative ene
rgy loss, the collagen content of bone and the percentage porosity, The val
ues of all variables were significantly different in the skeletally mature
and immature groups. The apparent density of trabecular bone tissue tvas fo
und to be tbe major predictor of its compressive mechanical properties. Tog
ether with the content of bone muscle and bone collagen, the apparent densi
ty.