Osteochondral Fragmentation (Osteochondrosis) of the Canine Patella

Abstract

SummaryThree four-month-old female grey-hound siblings with osteochondral fragmentation of the lateral aspect of the patella are presented. One dog was affected unilaterally and two bilaterally. The dogs exhibited mild weight-bearing lameness, slight flexion of the stifle, and discomfort during full flexion and extension of affected stifles. A non-palpable, mild synovial effusion was cytologically consistent with chronic inflammation and compatible with osteochondrosis and degenerative joint disease. The hallmark clinical sign was a characteristic prominence of the patella. Cranioproximalcraniodistal oblique (skyline) radio-graphs and transverse CT scans revealed osteochondral fragments and defects of the patella. The osteochondral fragments were surgically excised in two dogs and one dog was necropsied. The osteochondral fragments and patellae were evaluated histologically. Macroscopic and microscopic features of the osteochondral tissues were characteristic of osteochondrosis.Osteochondrosis of the patella was diagnosed in three sibling Greyhounds. The hallmark clinical sign was enlargement and prominence of the patella. Radiographic examination, cranioproximal-craniodistal oblique view, demonstrated the fragmented lateral border of the patella. Findings from computed tomography and histopathological examination are described. Surgical excision of the fragment in two dogs restored satisfactory function.