Diagnosis and surgical repair of patellar luxations in a flock of sheep.

Eleven sheep with a common ancestry were evaluated for clinical signs of hind limb lameness. Physical examination revealed advanced forms of patellar luxation. Radiography confirmed the diagnosis of patellar luxation; flexed dorsoproximal-dorsodistal radiographic views were obtained and revealed hypoplasia of the femoral trochlea. Because of the advanced form of patellar luxation and trochlear hypoplasia, surgical intervention was recommended in the form of recession trochleoplasty and a modified tibial tuberosity transposition, along with imbrication and releasing incisions. Sheep may have a genetic predisposition for patellar luxation.