Interobserver Variation in Canine Hip Dysplasia Evaluation

Canine hip dysplasia (CHD) is a common disease representing an important problem for many dog breeds worldwide. The screening for CHD and breeding programs have been ongoing for many decades but the incidence of disease have failed to be reduced to the expected level. The early diagnosis of CHD is paramount in order to facilitate the early management strategies and to prevent the breeding of the affected individuals. Generally in this area, the emphasis is placed on the radiographic evaluation process, however this is partly a subjective process suggested to be influenced by the experience of the observers. This study was designed to evaluate the interobserver agreement in CHD evaluation based on the Federation Cynologique International system (FCI system). Ten original radiographs were sent to five different groups of observers, from students to certified veterinarians. They were asked to evaluate the ventro-dorsal radiographs according to the FCI system which is the most common system used in Europe to give the final grades (A, B, C, D, E). The grades were converted to numbers and the data were analysed using a one-way ANOVA test. The results showed that only in 20% of the cases, the interobserver agreement was statistically higher in the group of the most experienced observers when compared to the less experienced group of observers. This means that the level of experience does not always lead to a higher agreement. This could be a problem of widespread objective evaluations of CHD. In addition, there are several different systems of evaluation used in various countries. It is necessary to understand the intention of dog owners, who when buying a dog may be planning its first breeding. Therefore, the “correct” or “incorrect” assessment of the CHD radiographs may not always result in the elimination of affected individuals. We do not know exactly the situation of the development of the hip in some breeds, because scrutineers are receiving only “negative radiographs” for evaluation. Many owners are very educated about hip and elbow dysplasia. It is a time to tell the scientific truth.