Inter-Observer Agreement on the Radiographic Assessment of Canine Hip Dysplasia

In order to gain insight into the process of evaluating the hip quality of potential breeding dogs, we estimated inter-observer agreement on the assessability of radiographs, on the morphological observations and on the final scoring of canine hip dysplasia. One hundred radiographs were assessed in terms of their radiographic quality and the morphological traits of the hips by six individual observers and by two groups of two observers each. These six observers and two groups were also asked to evaluate the radiographs in accordance with the FCI (Federation Cynologique Internationale) instructions. There was no consistent pattern between observers in the evaluation of the technical quality of the radiographs. For some of the observers there was a small amount of agreement in the evaluation of the morphological characteristics. The agreement between the evaluations of the two groups was greater (harmonization between observers). The level of agreement in final scoring (FCI; A, B, C, D, E) was low between some observers, but acceptable between others. These results suggest that the assessment of the quality of ventrodorsal extended radiographs of hips, the assessment of the morphological traits of hips and the final scoring of the hip quality is highly variable between observers, ranging from total disagreement to nearly full agreement. Solutions must be found for maximizing the agreement between the different observers.