The role of corticotomy and osteotomy in the treatment of bone defects using the Ilizarov technique.

Posttraumatic bone defects are usually bridged using autogenous or exogenous cancellous bone grafts. These grafts consolidate to form a solid bone structure that is mechanically stiffer than natural bone. Likewise, the procedure of corticotomy and distraction is appropriate for treatment of bone defects. In our experiment, a 2-cm bone defect was created in 25 sheep tibiae. We performed corticotomy or osteotomy of the intact bone, thus creating a bone segment that was drawn across the defect using a specially designed traction device. The limb was stabilized using an external fixator. Four groups were formed for comparison: corticotomy and osteotomy with distraction at a rate of 1 mm/day; corticotomy and osteotomy with immediate transportation of the segment to the docking site. The animals were killed after 4, 8, 12, 16 and 52 weeks. Evaluation of the results was based on standard radiographs. In the two groups involving gradual transportation, spontaneous bone regeneration occurred in all cases whereby after corticotomy the new bone was tubular (around the medulla). Following osteotomy, bone regeneration occurred initially on the dorsal and lateral sides of the tibia leaving a defect on the ventral and medial sides. This defect subsequently closed. At the end of segment transportation, healing was observed at the docking site. In Groups 3 and 4, the bone did not regenerate at all. Therefore, this procedure, immediate transportation, was not investigated further because no clinical success could be expected from its application.