Diagnosis of metaphysitis in foals.

Acute metaphysitis was induced in the third metacarpal bone of five foals by injecting lipopolysaccharide intraosseously adjacent to the growth plate, and synovial fluid was collected from the metacarpophalangeal joint 6 hours later. A control injection of an equal volume of physiological saline was given in a similar site in the opposite limb. Mild transient lameness, fever, depression and anorexia occurred after the lipopolysaccharide injection. On the lipopolysaccharide-injected side there was an increased leucocyte count in the synovial fluid, with neutrophil predominance; this did not occur on the control side. From this study in foals we conclude that in cases of suspected bacterial metaphysitis, arthrocentesis of the joint adjacent to the metaphysitis should be conducted immediately.