Sixteen dogs and 14 anatomic tibiae were studied to determine the effect of a pressurized brace on a canine tibial fracture model. Bilateral tibial fractures were treated with an external fixator for 48 days. At 48 days, the pressurized brace was applied to one tibia, and a conventional cast was applied to the opposite tibia. The dogs were allowed unrestricted weight bearing until 88 days. Postmortem biomechanical studies indicated that tibiae were stronger on the side treated by the pressurized brace. This was reflected in torque values, energy, and degrees of rotation. The histomorphometry of the periosteal bone of the fracture sites disclosed a more dense periosteal callus on the side treated with a pressurized brace. In vitro mechanical studies in cadaveric tibias at 30 degrees rotation indicated that the pressurized brace provided significantly more stability.