Epoxy putty external skeletal fixation in a tibiotarsal fracture of a wild choroy parakeet (Enicognathus leptorhynchus)

J I Arias,C Beato,A Espinoza

doi:10.1590/1678-4162-7474

Abstract

Tibiotarsal fractures are common in birds because in most birds this is the longest, most exposed bone in the leg. Transverse fractures are most common and rotational and shear forces must be stabilized in order to achieve good bone regeneration. A 230g male Slender-billed Parakeet or Choroy parakeet (Enicognathus leptorhynchus), with more than five years of age, was received with non-weight bearing lameness with 24 hours duration. X-rays were taken, and these revealed a closed, complete, non-comminuted transverse fracture of the distal diaphysis of the left tibiotarsal bone. Fixation was planned with 10-minute fast-setting epoxy putty. In order to assess the temperature of polymerization of the epoxy dough and the possibility of heat-bone necrosis, the temperature was recorded every 30 seconds for 12 minutes with three different amounts of the epoxy material in an ex vivo test. The temperature of the pieces reached a peak of 50-60ºC, where the highest peak corresponds to the highest amount of material. When approximately 6g of putty were used, the peak temperature reached only 51ºC. This peak changed to 58ºC when 4 times more epoxy was mixed and measured. If the temperature of the pins inserted in the bone exceeds 70ºC, bone necrosis could occur. In light of these results, the fracture was treated with 6 g of epoxy putty that was allowed to polymerize over a 1A 2/2 external skeletal fixation, with 1-mm pins bent at 90º and joined together with cerclage wire. At 6 weeks after surgery the bird had formed a good primary bone callus, and the external fixators were therefore removed. With this approach a satisfactory recovery of the patient was achieved with normal use of the affected limb.

Highlights

Free-range wildlife birds may suffer traumatic injuries when venturing into urban territories
Because both polymers show an increase in temperature during the polymerization reaction, the danger of heatrelated bone necrosis must be taken into consideration when the temperature of the pins exceeds 70°C (Fukushima et al, 2002). This is especially true with PMMA that yields maximum PMMA surface temperatures that range from 101 to 110°C with a 2-minute plateau of >100°C. (Preininger et al, 2012). In this case report we tested the exothermic peak of epoxy putty polymerization and show for the first time the use of fast-setting epoxy putty to achieve a 1A 2/2 external skeletal fixation with 90° bent 1-mm pins joined together with cerclage wire to treat a tibiotarsal fracture in a wild Slender-billed Parakeet (Enicognathus leptorhynchus)
Because distal limb fractures in birds are especially prone to rotation, simple casts will not oppose these forces and would be subject to damage by the parakeet’s powerful beak, which is capable of destroying most materials

Summary

Introduction

Free-range wildlife birds may suffer traumatic injuries when venturing into urban territories. À luz desses resultados, a fratura foi tratada com 6g de massa epóxi deixada polimerizar sobre uma fixação externa, em configurações 1A 2/2 usando pinos de Recebido em 17 de março de 2014 Aceito em 20 de outubro de 2014 E-mail: joarias@uchile.cl

Results

Conclusion