Case Study: Bilateral fractures a common complication in toy breeds

Meet Merlin, the Chihuahua cross whose magical skills weren’t enough to prevent injury when he jumped out of a car!

Merlin was referred to Dr Peter Young for management of bilateral non-union fractures of the distal radius and ulna; a not uncommon complication of such fractures in toy breed dogs.

Merlin, an 8-year-old male Chihuahua cross presented with a history of jumping out of a car 2 months prior. Immediately after the incident, he was taken to a local clinic, where bilateral radiographs of radius and ulna were taken. They showed fractured bilateral tibia and ulna in the distal 1/3 of the diaphysis. Both legs were splinted at the local clinic.

2 months after the incident Merlin presented to the referral vet with bandages on both front legs. Merlin was unable to bear weight on either front leg. When palpated both front legs felt unstable. Radiographs of the tibia and ulna were taken of both legs in lateral and dorsopalmar position. These showed signs of delayed bone healing and malalignment. There were signs of decalcification of the ulna and radius distal to the fractures.

Clinical and radiographic examination showed that the fractures had not healed, the fracture ends had not been retracted to normal position and there was still instability around the fractures.

The left radius and ulna were hypertrophic with a fragment overriding, and the right radius and ulna were atrophic, also with a fragment overriding. Surgery was recommended in order to obtain complete bone healing.

The surgical procedure chosen was external fixation of the atrophic non-union mid shaft fracture of the left radius.

The dog was placed in dorsal recumbency. The intercarpal joint was located by inserting 2 needles in the medial and the dorsal joint space and detecting joint fluid. A k-wire was drilled through the distal radius in a lateromedial direction just proximal to the joint space. A ring fixator was applied on the wire and another k-wire was applied in a dorsopalmar direction. The carpal joint was manipulated to confirm that there was no accidental articular insertion of wires. A 2 cm incision was made over the dorsomedial part of the fracture. The cephalic vein was identified and protected at all times. A transverse osteotomy was made at the location of the chronic fracture and the distal and proximal parts were aligned. The distal part was rotated 30 degrees so the supination was neutralised. 2 positive threaded pins were applied 11 and 40 mm proximal to the osteotomy in a lateromedial direction and 2 pins were applied 7 and 27 mm proximal to the osteotomy. Each pin was locked on to a bar with clamps connecting the two pins and the fixation ring. Alignment was checked. A 10-degree medial angle at the osteotomy site is detected and an adjustment on the fixating configuration was made to correct that. All bolts were tightened, and the skin was sutured with Premilin 3-0.

A soft dressing was applied to control swelling.

Radiographs were planned for 3-4 weeks post op; these will determine when the external fixation can be removed.

The right leg went on to heal spontaneously once Merlin could ambulate on the left.
With the increasing popularity of toy breed dogs in our densely populated cities, cases like Merlin are not uncommon.

VetPrac is excited to offer a workshop that will equip you to appropriately manage cases like Merlin and hopefully reduce the risk of complications such as non-union fractures.

The Fine and Fiddly Fracture Workshop will be held at UQ Gatton on April 12-13, 2019. To register for this amazing workshop, click here. For more information, check out the brochure.