Unicortical condylar fracture of the Thoroughbred fetlock: 45 cases (2006-2013).

Abstract: Fracture of the metacarpal/tarsal condyle is usually preceded by prodromal pathology. Early recognition of injury is desirable to minimise the risk of serious breakdown; however, the clinical and diagnostic characteristics of unicortical condylar fractures have been poorly documented to date. Objective: To describe the clinical, imaging and outcome features of racehorses in first opinion practice diagnosed with short unicortical fracture of the metacarpal/tarsal condyle. Methods: Retrospective case series. Methods: All flat racehorses sustaining a unicortical condylar fracture while under the primary care of a single first opinion UK veterinary practice (2006-2013) were identified from imaging records and histories analysed for clinical presentation, lesion location, treatment, rehabilitation guidance and outcome. Results: Forty-five cases were identified during the period of study. Forelimb injuries predominated (35/45, 77.8%). Mean age of cases was 3.4 ± 1.3 years. Palpable clinical abnormality referable to the fetlock region was not a feature. The majority (35/45, 77.8%) of injuries were diagnosed with radiography (flexed dorsopalmar/plantar projection), with the remainder requiring magnetic resonance imaging (MRI) for diagnosis. Seven horses underwent surgery either at the time of original diagnosis or following reinjury. Twenty-eight of 30 horses (93.3%), not retired for unrelated reasons, returned to racing, with 5 (16.7%) conservatively managed horses sustaining reinjury at a median of 305 days. Misdiagnosis resulted in progression to catastrophic fracture in 2 cases. Conclusions: Clinical findings associated with unicortical condylar fractures can be mild and appropriate diagnostic imaging is necessary for injury detection. Failure to detect injury can lead to catastrophic fracture. Most cases respond to conservative management and return to racing, but risk of reinjury merits consideration of surgery in selected cases. Veterinary vigilance and timely intervention has the potential to considerably reduce the incidence of complete condylar fracture of the fetlock in the racehorse. The Summary is available in Chinese - see Supporting information.