Navicular disease in the horse: risk factors, radiographic changes, and response to therapy.

In a retrospective study, 74 horses met defined historical and clinical features indicative of navicular disease. Most of the affected horses were 4 to 9 years old. Males had a greater risk of navicular disease than females, geldings had a greater risk than stallions, and Quarter Horses had a greater risk than other breeds. Diagnostic radiographic changes were found in 42 of 70 horses examined. The distribution of diagnostic radiographic changes between the right and left fron feet was equal. There was no correlation between the finding of diagnostic radiographic changes and the horse's response to therapy or the type of work for which the horse had been used. A questionnaire regarding the current status of the horses in the study was mailed, and 51 replies were received. Of the 38 horses that were alive at least 6 months after treatment and for which the current status was known, 9 were sound at the time of follow-up (from 7 to 91 months after treatment). Three of these horses had been treated medically, 4 surgically, 1 by corrective shoeing, and 1 not treated. No advantage for medical or surgical therapy was demonstrated. The poor response to therapy in this group of horses suggests that the prognosis for horses with navicular disease should be guarded, and that the probability of a return to a prelameness capacity for work is slight.