Breed susceptibility for common surgically treated orthopaedic diseases in 12 dog breeds.

Background: A retrospective case-control study was conducted to estimate breed predisposition for common orthopaedic conditions in 12 popular dog breeds in Norway and Sweden. Orthopaedic conditions investigated were elbow dysplasia (ED); cranial cruciate ligament disease (CCLD); medial patellar luxation (MPL); and fractures of the radius and ulna. Dogs surgically treated for the conditions above at the Swedish and Norwegian University Animal Hospitals between the years 2011 and 2015 were compared with a geographically adjusted control group calculated from the national ID-registries. Logistic regression analyses (stratified for clinic and combined) were used to calculate odds ratios (OR) and 95% confidence intervals. Mixed breed dogs were used as reference.

Results: Breeds found at-risk for ED were the Labrador retriever (OR = 5.73), the Rottweiler (OR = 5.63), the German shepherd dog (OR = 3.31) and the Staffordshire bull terrier (OR = 3.08). The Chihuahua was the only breed where an increased risk for MPL (OR = 2.80) was identified. While the Rottweiler was the only breed predisposed for CCLD (OR = 3.96), the results were conflicting for the Labrador retriever (OR = 0.44 in Sweden, 2.85 in Norway); the overall risk was identical to mixed-breed dogs.

Conclusions: Most results are in concordance with earlier studies. However, an increased risk of CCLD was not identified for the Labrador retriever, the Staffordshire bull terrier was found to have an increased risk of ED and some country-specific differences were noted. These results highlight the importance of utilising large caseloads and appropriate control groups when breed susceptibility is reported.