Tibial lengthening in rabbits by callus distraction: A comparison of two techniques (Part 1)

In this study, 20 young adult New-Zelland albino rabbits were used. Daily optimum distraction amounts were studied The right tibia of each rabbit was osteotomized subperiosteally at the tibia-fibular junction level and external circular fixator (Ilizarov type) applied. Rabbits were divided into three groups. The first group was distracted 0.5 mm and the second 10 mm per day Distraction was applied once a day. begining in the 12th postoperative day and continued for three weeks Atter a period of distraction, fragments were stabilize for two weeks in a neutral position The third group was the control group and nothing was done postoperatively The study was stopped at the 47th postoperative day During the study period; Clinical, radiological (x-ray and CT), scintigraphical (dynamic and static) and histopathological evaluations were performed. There were no clinical complications. In the distraction zone of the first group. premature new bone formation developed at the third distractional week and tended to ossify. Maximum 14 percent tibiallengthening was achieved in this group. In the second group maximum 24 percent Iengthening was achieved and radiologic and histologic evaluations revealed that the distraction zone had epiphysis like characteristics. In both groups 99m Tc-MDP scintigraphy has shown increased biood pool image and osteoblastic activity in the distraction zone. There was no significant difference between the experimental and control groups scintigraphycally (p>0.05, NS). We conclude that a distractional rate of 1 mm per day achieves better results.