History
A 5-year-old 37-kg (81.4-lb) sexually intact male Doberman Pinscher was evaluated at the emergency department of Alameda East Veterinary Hospital because of an acute onset of non–weight-bearing lameness of the left hind limb after jumping over a drainage ditch. On physical examination, there was a grade IV of IV lameness in the left hind limb, with detectable crepitus on palpation of the medial aspect of the tarsus. Findings on tarsal radiographs were interpreted as consistent with soft tissue injury. A mild improvement in comfort was seen with administration of tramadol (2 mg/kg [0.9 mg/lb], PO, q 12 h), although the dog was still non–weight bearing on the limb. The dog was brought to the surgery service 1 week later. Physical examination revealed non–weight-bearing left hind limb lameness with considerable left tarsocrural joint effusion. Fracture of the talus was suspected from the original radiographs, and additional views were obtained (Figure 1).
Lateral (A) and dorsoplantar (B) radiographic views of the left tarsus of a 5-year-old sexually intact male Doberman Pinscher evaluated because of persistent left hind limb lameness.
Citation: Journal of the American Veterinary Medical Association 244, 7; 10.2460/javma.244.7.787
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
A fractured lateral ridge of the left talus is present with the fracture fragment proximally displaced (Figure 2). Severe tarsocrural joint effusion is seen with swelling of the adjacent soft tissues. Review of the radiographs taken at initial evaluation indicated that the fracture segment could also be seen at that time but had been interpreted as normal anatomy.
Same lateral image as in Figure 1. Notice the plantaroproximally displaced lateral trochlear ridge (arrows). Severe soft tissue swelling is seen surrounding the tarsus.
Citation: Journal of the American Veterinary Medical Association 244, 7; 10.2460/javma.244.7.787
To better evaluate the fracture site and for surgical planning purposes, CT was performed on both tarsi (Figure 3). The lateral ridge of the left talus is fractured and displaced in a plantaroproximal direction. Several small osseous fragments are visible surrounding this fracture site. Severe swelling of the adjacent soft tissues is seen.
Transverse CT images (bone algorithm; window width, 2,500 Hounsfield units; window level, 480 Hounsfield units; slice thickness, 2 mm) of the right and left tarsi taken at the level of the talus of the same dog as in Figure 1. Notice the fractured lateral trochlear ridge segment (arrow). C = Cranial. L = Left. P = Plantar. R = Right.
Citation: Journal of the American Veterinary Medical Association 244, 7; 10.2460/javma.244.7.787
Treatment and Outcome
A lateral approach to the plantar aspect of the tarsocrural joint was performed, and the fracture segment was reduced with two 0.045-inch Kirschner wires and a 2.0-mm screw. The patient recovered uneventfully and was managed in a cast for 6 weeks, a splint for 2 weeks, and a soft-padded bandage for an additional week. At recheck examination 4 months after surgery, all lameness had resolved. Brief lameness with soft tissue swelling in the tarsal area was seen 6 months after surgery following aggressive exercise at a park. Lameness resolved with rest and 5 days of NSAID administration.
Comments
Fractures of the trochlear ridge of the talus are rare in dogs and infrequently reported in the veterinary literature.1 Standard orthogonal radiography to evaluate the lateral trochlear ridge is complicated by superimposition of the medial trochlear ridge, calcaneus, and distal aspect of the tibia and fibula on the mediolateral view and by the calcaneus on the dorsoplantar view.1,2 A number of radiographic techniques have been recommended to help avoid summation of these bony structures, including the flexed dorsoplantar, plantaromedial-dorsolateral, plantarolateral-dorsomedial, and flexed dorsoplantar skyline views.1,2 The increasing use of CT in veterinary medicine has shown this diagnostic imaging modality to be more accurate in the identification of bony abnormalities of the lateral trochlear ridge.2 In addition, CT is superior to simple radiography in identifying fractures of the other tarsal bones as well as evaluating displacement and comminution of these fractures, which can aid in guiding treatment for these injuries.3,4
1. Maley JR, Dvorak LD & Bahr A. Diagnosis and management of a fracture of the lateral trochlear ridge of the talus in a dog. Vet Comp Orthop Traumatol 2010; 23: 284–288.
2. Gielen IM, van Ryssen B & van Bree H. Computerized tomography compared with radiography in the diagnosis of lateral trochlear ridge talar osteochondritis dissecans in dogs. Vet Comp Orthop Traumatol 2005; 18: 77–82.
3. Galateanu G, Aizenberg I, Hildebrandt TB, et al. Computed tomographic demonstration of central tarsal bone plantar process occult fracture in a dog. Vet Rec 2011; 169: 442.
4. Hercock CA, Innes JF, McConnell F, et al. Observer variation in the evaluation and classification of severe central tarsal bone fractures in racing Greyhounds. Vet Comp Orthop Traumatol 2011; 24: 215–222.
