Internal Radioulnar Fixation for Treatment of Nonunion of Proximal Radius and Ulna Fractures in a Toy Breed Dog

Luca Vezzoni,Paolo Abrescia,Aldo Vezzoni

doi:10.1055/s-0041-1723831

Abstract

AbstractIn this case report, we describe an alternative surgical procedure to treat proximal radius and ulnar nonunion in a toy breed dog. A 14-month-old, Maltese cross-breed dog was referred after previous treatment with external and internal fixation had failed, resulting in a nonunion of a fracture of the proximal radius and ulna with the proximal radius fragment too small and friable to be used for fixation. A craniomedial approach was made to debride the radius nonunion site and a second approach to the lateral aspect of the ulna was made. The fracture was realigned and a titanium locking plate was applied in bridging fashion, fixed to the proximal ulnar fragment with three locking screws in the most proximal plate holes, a fourth screw was inserted in the mid-shaft of the distal ulnar fragment and three locking screws were inserted in the distal most holes of the plate through the distal ulna to engage the distal radial fragment. A recombinant bone morphogenetic protein 2 graft was inserted into the radius and ulna fracture sites. The dog had a successful clinical and radiographic outcome with bridging of the defect 4 weeks postoperatively and complete callus formation 8 weeks postoperatively. Implants have undergone dynamization and then removal. Use of a locking plate as an internal fixator achieving fixation of the proximal ulna and distal radius can be considered an option for the treatment of proximal radioulnar nonunions with a small proximal radial fragment.

Highlights

Fractures of the radius and ulna are common in dogs, in miniature and toy breeds,[1–4] and many fixation methods have been described
Conservative treatment using rigid bandages in toy breed dogs commonly results in complications including malunion or nonunion in up to 80% of fractures.[5,6]
Bone plating is a popular method for fixation of radius and ulna fractures[10–13]; complications can occur in up to 54% of dogs that weigh less than 6 kg.[14,15]

Summary

Introduction

Fractures of the radius and ulna are common in dogs, in miniature and toy breeds,[1–4] and many fixation methods have been described. Bone plating is a popular method for fixation of radius and ulna fractures[10–13]; complications can occur in up to 54% of dogs that weigh less than 6 kg.[14,15]. These complications include delayed union, nonunion, re-fracture after implant removal and osteopenia due to stress protection.[16,17]. Nonunion fractures are characterized by formation of fibrous or cartilaginous tissue between fragments This is a serious complication in small animal orthopaedics, in the treatment of radius and ulna fractures in toy breed dogs. Fractures and nonunion of the proximal radius occur infrequently but are challenging because of the anatomic constraints to surgical approach and limited bone stock for implant fixation.[4]. When the proximal fragment of the radius is too small to achieve adequate fixation, treatment options include use of an interlocking nail or a bone plate on the ulna only, or the use of an external skeletal fixator with fixation pins applied to the olecranon and to the distal radius fragment.[4,31,32] The purpose of this report was to describe the use of a locking plate fixed to the proximal ulna and distal radius for treatment of nonunion of proximal radius and ulna fractures in a toy breed dog

Case Report

Findings

Discussion