Vascular changes in induced abnormal bone growth in lambs.

In lambs, unilateral hip excision arthroplasty induced angular and torsional deformities in the contralateral limb and the vascular changes associated with abnormal bone growth in distal tibiae and metatarsi have been studied. Eosinophilic septa separating physeal cartilage columns were more frequent and prominent in association with physeal osteochondrosis. Epiphyseal vessels traversed thickened physeal cartilage to an abnormal depth and resulted in protrusions of epiphyseal bone and an irregular epiphyseal bone plate. In some cases, epiphyseal vessels crossed the whole physis and arboresced after turning through 180 degrees. This vascular pattern appears to occur as a reparative response.