Incomplete ossification of the humeral condyle in Vietnamese pot-bellied pigs

The purpose of this study was to evaluate the occurrence of humeral condyla r fractures in Vietnamese pot-bellied pigs and to postulate a possible pred isposing cause for these fractures. Thirteen Vietnamese pot-bellied pigs (G roup A) were evaluated over an eight year period (1990-1998), each with a h istory of either a unilateral or bilateral forelimb lameness. The cause of lameness was localized to the elbow region. Of the thirteen pigs, twenty-on e elbows were evaluated radiographically. Pigs ranged in age from six month s to four years old. All pigs over the age of seven months showed radiograp hic evidence of elbow degenerative joint disease, Fractures involving the m edial aspect of the humeral condyle were identified in 8/21 studies (38%). A well-defined linear intracondylar articular lucency was identified in 7/2 1 studies (33%) on the craniocaudal projection. The site of this lucency co rresponded to the location of the articular component of the fractures seen involving the humeral condyle, The elbows of five pot-bellied pigs with no known history of forelimb lameness or trauma (Group B) were evaluated radi ographically following euthanasia. All five pigs were of unknown age and ge nder. An intracondylar vertical linear lucency was identified bilaterally i n three pigs (60%). Concurrent degenerative joint disease was present in al l instances. The remaining two pigs were radiographically normal. Computed tomography of the elbows was performed in one affected pig from Group B, Th e radiographic findings in this pig were verified. Histopathology of the ri ght elbow of this affected pig was diagnostic for incomplete endochondral o ssification of the humeral condyle. A similar condition involving the humer al condyle has been previously described in Cocker and Brittany Spaniels. T hese canine breeds also have a high incidence of humeral condylar fractures . It is postulated that Vietnamese pot-bellied pigs are similarly prone to humeral condylar fractures, even in the absence of known trauma, due to inc omplete ossification of the humeral condyle.