In young pigs walking normally, we recorded the principal compressive
strains (epsilon 2) as revealed by strain gauges attached to the shaft of
the radius. We found no correlation between the mean principal compressive
strain and either age or weight in normal animals over the three-month time
span of the experiment. Directly after unilateral removal of the ulnar
diaphysis, the principal compressive strain on the radial shaft increased
by two to two and one-half times its normal value. The increased level of
strain in the radius caused by ulnar ostectomy resulted in a rapid and
substantial remodeling response in the radius, but three months after ulnar
ostectomy, the area of bone enclosed by the periosteal perimeter of the
overstrained radius approached the value for the radius and ulna together
in the contralateral limb, as did the cross-sectional area of the bone
tissue in the mid-shaft of that radius. Three months after unilateral
ostectomy, the principal compressive strain was not significantly different
in the left and right radii and approached normal values.