Análise biomecânica ex vivo de dois métodos de osteossíntese de pelve em cães

Abstract

Approximately 25% of all fractures in dogs involve the pelvis, of which 18-46% are iliac fractures. Conservative treatment can be performed in simple cases where minimum displacement occurs fractured fragments. However when there is severe displacement of the fragments, pelvic canal narrowing and involvement of weight bearing, surgical fixation is indicated. A variety of techniques have been described for the iliac fracture fixation. The highest percentage of successful cases can be attributed to the use of plates. Other methods used include pins, cerclage wire and compression screw. This study evaluated biomechanically the use of cortical allografts preserved in honey for the stabilization of transverse osteotomy of the ilium in dogs, as well as the use of hemicerclage wire isolated this cases, and compared the of two methods against the forces of bending. Were prepared cortical bone implants removed from humerus of dogs that eventually died for reasons not related to this research. The implants were preserved in honey for a period between 30 and 128 days. Were tested bilaterally thirteen canines pelves which held the body transverse osteotomy of the ilium. One hemipelvis of each dog was stabilized with a bone graft fixed by two hemicerclage wire and the contralateral hemipelvis with hemicerclage wire alone. To test the strength of flexion was used a manual compression machine where hemipelvis each was mounted on a wooden support. It was established that the time to stop the application of bending force would be when the fissure of the fracture suffer traction until half the width of the ilium (TMLI) or to failure. The strength of flexion needed to TMLI was significantly higher (P = 0.03) for hemipelves stabilized with bone implants (mean ± SD: 16.54 ± 5.29 kg) than for hemipelves stabilized with hemicerclage wire used alone (mean ± SD: 12.54 ± 4.01 kg). The force applied to fail was also statistically higher (P = 0.002) for hemipelves stabilized with bone implants (mean ± SD: 20.16 ± 7.3 kg) than in stabilized with hemicerclage wire used alone (mean ± SD: 12.54 ± 4.01 kg). The results showed that the use of cortical bone implants is a viable alternative for fixing the iliac osteotomy and is more resistant to strength of flexion in relation to the use of hemicerclage wire used in isolation.