An experimental study was carried out to verify the development and performance of a flexible external fixator on the bone healing process of the tibia of sheep submitted to a transverse diaphyseal osteotomy. It was used twenty Santa Inês sheep with average weigh of 37kg divided in groups, according to the period of postoperative observation of 30, 45, 60 and 90 days. At the end, the animals were sacrificed and the tibiae were removed for study of transverse callus volumetric by computed tomography and destructive mechanical testing. The results had shown that the formation of voluminous callus occurred, thus characterizing the occurrence of displacement of axial load to the focus of the osteotomy, promoted by the used external fixator used. The mechanical testing showed that the comparisons between the respective intact and operated groups were significantly different (P<0.05) except for the group with 90 days, which demonstrated equivalent stiffness when compared to normal bone. In none of the animals there was development of pseudarthrosis or non-union of the bone. Given the results, it was conclude that the use of the flexible fixator covered in this research for treatment of long bones fractures in medium animals was easy to apply, reproducible and recommended.
sheep; flexible external fixation; bone healing; callus formation
