This study compared the effects of axial dynamization and staged destabilization on fracture healing. Bilateral midshafts of canine tibiae were osteotomized and fixed with an external fixator. The hind limbs were divided into two groups: the destabilized group in which the fixator's stiffness was progressively reduced over time and the axially dynamized group in which the fixator was axially dynamized. The healed tibiae were tested for 3-point bending in the anteroposterior plane. The biomechanical tests performed 2 months postoperatively revealed that the side with the destabilized fixator was more rigid than the side with the axially dynamized fixator, but the differences were insignificant (P=.20). This study showed staged destabilization of the fixator's stiffness was as effective on the enhancement of fracture healing as axial dynamization.