Objectives. Small animal models of fracture repair primarily investigate
indirect fracture healing via external callus formation. We present
the first described rat model of direct fracture healing. Methods. A rat tibial osteotomy was created and fixed with compression
plating similar to that used in patients. The procedure was evaluated
in 15 cadaver rats and then in vivo in ten Sprague-Dawley
rats. Controls had osteotomies stabilised with a uniaxial external
fixator that used the same surgical approach and relied on the same
number and diameter of screw holes in bone. Results. Fracture healing occurred without evidence of external callus
on plain radiographs. At six weeks after fracture fixation, the
mean