A retrospective study of dogs with cranial cruciate ligament rupture: 32 cases (2006-2012)

Rupture of the cranial cruciate ligament (RLCCr) is one of the most common injuries in the dog and the leading cause of degenerative joint disease (DAD) of the knee. Untreated animals exhibit degenerative joint changes in a few weeks and severe changes within a few months. The severity of degeneration appears to be directly proportional to body size and age. Systemic inflammatory joint diseases are associated with the rupture of this ligament. The aim of this study was to characterize the population of dogs suffering from RLCCr according to the following factors: type of lameness, unilateral or bilateral ligament rupture, breed, age, sex, reproductive status, diet, body weight, presence of DAD and patellar luxation prior to RLCCr. The data base was created from information from medical records of 32 dogs diagnosed with RLCCr in Companion Animals Hospital Uninity, Catholic University of Parana in the period from January 2006 to December 2012. The results showed that most of dogs (56.25%) had weight bearing lameness on initial presentation. The unilateral RLCCr was the most frequent (90.62%), 13.8% of these cases presented RLCCr in the contralateral limb, after an average period of 2 years and 4 months. The most frequent breeds were Toy Poodle (21.9%) and Pitbull (18.75%); mixed breed dogs accounted for 12.5% of cases. The most frequent ages were 2, 3, 4 and 7 years (average = 5.7 years). With respect to sex and reproductive status, females (68.75%) and non-castrated animals (69%) were most affected. As for diet, the majority (59.38%) ate commercial dog food. Regarding body weights, the majority (25%) weighed between 26 and 35 kg. DAD and patellar luxation prior to RLCCr were seen in 53.12% and 21.88% of the patients, respectively. It could be observed that the data in our environment tend to be similar to those of the literature: RLCCr occured in large adult dogs, weighing between 26 and 35 kg with unilateral rupture and weight bearing lameness and affected females more than males. Animals receiving commercial dog food and entire dogs were the most affected. Patellar luxation before RLCCr occurred in a minority of animals, different from the DAD preceding RLCCr, that was seen in most cases.