Callus response to micromovement during elongation in the rabbit.

The purpose of this investigation was to determine whether induced micromovement during the elongation period could improve the consolidation of diaphyseal elongation obtained by callus distraction. Two series of paired rabbit hindlimbs were studied. The surgical procedure and the waiting period were identical. During elongation, one hindlimb was stimulated, and the other was the control. The consolidation period was 2 days. Reproducible tibial osteotomy and lengthening of the two tibiae was confirmed radiographically. The mineralized callus was quantified by dual-beam x-ray absorptiometry. The callus diameters were measured. Bones were axially compressed to failure. Callus volume, mineral quantity, mineral density, and resistance to failure were not different on the stimulated side compared with the unstimulated side, so micromovement applied during elongation had no effect on bone consolidation. For all tibiae, resistance to failure of the callus was significantly correlated to callus volume, to callus mineral content, and to callus mineral density.