(3) Regarding PennHIP DJD diagnosis, and the CI. QUESTION (a) Is the PennHIP diagnosis of DJD on the standard hip extended radiographic view based on the same criteria used by board certified vet radiologists?
This is a difficult question to answer, as not all board certified radiologists read for DJD in the same manner. For example, some radiologists read the caudolateral, curvilinear osteopyte (CCO) or Morgan’s line, as an early sign of DJD in the hip, while others choose to ignore it. Radiologists trained at the University of Pennsylvania follow the former criteria, whereas those reading for the OFA follow the latter. The CCO has been statistically associated with contemporaneous and longitudinal development of DJD. Specifically, a dog showing a CCO is 7.9 times more likely to have hip DJD on the same radiograph, and 3.7 times more likely to have obvious radiographic signs of DJD later in life, compared to dogs without a CCO (Evaluation of radiographic caudolateral curvilinear osteophyte on the femoral neck and its relationship to degenerative joint disease and distraction index in dogs. JAVMA 2002; 220: 472-476 and Caudolateral curvilinear osteophyte (CCO) as a risk factor for degenerative joint disease: A life-long study in Labrador retrievers. Vet Ortho Soc, 29th Annual Conference 2002 (abstract)). At the PennHIP analysis center, we attempt to interpret the hip extended radiograph for DJD similar to OFA radiologists. However, clients receiving PennHIP evaluations at the University of Pennsylvania are educated about the CCO. Presently, we feel that it may be best to exclude these dogs from the breeding program, given the information learned from the above studies. The ultimate decision, however, is left to the breeder. A paper from our laboratory was recently accepted for publication by JAVMA, and addresses the CCO and its implication on hip dysplasia prevalence. This paper should be published some time this summer.