Bilateral epiphysiolysis of the femoral heads in two dogs.

Two Shetland Sheepdogs that did not have a history of trauma were referred because of a gradual onset of lameness in the hind limbs. Bilateral slipped capital femoral epiphysis was diagnosed. Separation of the proximal femoral epiphysis that is not associated with trauma is recognized as a distinct clinical syndrome in adolescent human beings and swine, causing a condition called epiphysiolysis. The precise cause of this type of injury is unknown. Histologic lesions observed in the growth plates could have been the result of an abnormally high mechanical load imposed by obesity. It is not known whether cartilaginous lesions observed in the physis of 1 dog represented a preexisting cartilaginous defect (dyschondroplasia) or a late stage of repair after separation of the capital femoral epiphysis.