Fractures of the central and third tarsal bones occur most commonly in Standardbred or Thoroughbred racehorses. Fractures usually cause acute-onset severe hindlimb lameness. Lameness is exacerbated by hock flexion. Acute fractures may be associated with heat, swelling, and pain on palpation over the distal tarsal bones; there may be tarsocrural joint effusion. Diagnosis is made by radiography, but fractures may not be visible until 7–14 days after injury when fracture line bone resorption has occurred. CT or bone scintigraphy can be useful for diagnosis if fracture is suspected but not evident radiologically. Variable fracture configurations can occur. Horses can be treated surgically with lag screw fixation or conservatively, depending on configuration of fracture. Prognosis depends on fracture configuration.
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