Case history: Two adult male dogs were separately presented for acute-onset, severe hind limb lameness isolated to the tarsus. There were no prior orthopaedic concerns and there was no significant trauma associated with the onset of lameness in either case.
Clinical findings: Pain and effusion of the affected tarsus were found in both cases. Lameness was not responsive to oral analgesia. Radiography was insufficient to fully determine the extent of the damage in the tarsus; the fracture was visible in one case only. CT imaging demonstrated an isolated, lateral, trochlear ridge talar fracture in both cases and contralateral talar abnormalities of comparable location and direction to the fracture.
Diagnosis: Isolated lateral trochlear ridge fracture of the talus without significant trauma or concurrent injury. Abnormalities of talus of the contralateral limb were demonstrated on CT imaging.
Clinical relevance: A previously unrecognised pathological process may affect the talus of adult dogs that could predispose them to develop fracture of the lateral talar ridge without significant trauma. Further investigations are required to determine the prevalence and risk of fracture associated with this abnormality.