Association of Interlocking-Nail and Bone Plate (Plate-Nail) as a New Method of Fixation for Long Bones Fractures in Dogs
L.A.L. Muzzi; R.A. Muzzi; A.T. Giannico; L.R. Mesquita
Support by FAPEMIG (Process # EDT-56/07).
To properly bone repair of the fragmented diaphysis fractures it is necessary that the method of fixation eliminate the various forces acting on the site of the injury, supporting for a long period the loads imposed on the fractured bone. The objective of the plate-nail method was associated in a single system the characteristics of interlocking-nail and bone plate in relation to the neutralization of the forces of compression, rotation, shear and bending. It was formulated that the new method provides superior stability and rigidity of the system setting, allowing better repair of bone. The first patient was a bitch of the Fila Brasileiro breed that had a fragmented fracture in the humeral diaphysis. The plate-nail system was properly implemented, allowing rigid fixation of the fracture. Assessments were made at 30, 60, 90, 180 and 270 days postoperatively. It was observed radiographically at 30 days the formation of bone callus and the presence of the line of fracture. The animal was moderately lame, with partial support of the affected limb. At 60 days, there was remodelling of bone callus, and to 90 days, there were no lines of fracture. At 180 days, there was normal weight-bearing in affected limb and adequate bone consolidation, observed also at 270 days after surgery. The new plate-nail method was used in other four animals: two mixed breed dogs and a German Shepherd that presented with fractures in the middle third of the tibial diaphysis and one mixed breed dog with spiral fracture in the humeral diaphysis. In all the cases, there was good reduction of bone fractures with appropriate axial alignment. The radiographic evaluation showed mild and gradual formation of bone callus in the first 60 days with bone remodelling and absence of the line of fracture at 90 days. At 180 days postoperatively, there was normal weight-bearing and the bone healing was in the remodelling process. The plate-nail system of fixation promoted adequate stability of the fracture and supported the loads imposed on the bone axis without promoting the fatigue of the implant, showing an excellent perspective on bone fixation and repair of complex fractures of long bones in dogs.