Repeatability of dorsolateral subluxation scores in dogs and correlation with macroscopic appearance of hip osteoarthritis

Objective-To determine whether dorsolateral subluxation (DLS) scores in you ng dogs could be used to reliably predict which dogs would develop evidence of hip osteoarthritis and whether DLS scores measured at various ages corr elated with each other. Animals 129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhou nd crossbreds. Procedures-DLS scores were measured on radiographs taken at 4, 8, and 12 mo nths of age and at necropsy (8 to 36 months of age). At necropsy, the hip j oints were examined macroscopically and a score assigned for degree of cart ilage degeneration. Results-DLS scores at 4 (n = 35, r(s) = -0.62), 8 (n = 106, r(s) = -0.54), and 12 (n = 15, r(s) = -0.87) months of age were significantly correlated w ith cartilage degeneration scores, and DLS scores at 8 months of age were s ignificantly correlated with scores obtained at the time of necropsy (n = 3 9, r(s) = 0.87). The DLS scores at 4 months of age were significantly diffe rent from scores at 8 months of age, but scores did not differ significantl y thereafter. Likelihood ratios for cartilage lesions for low (< 45%), inte rmediate (greater than or equal to 45 but less than or equal to 55%), and h igh (> 55%) DLS scores at 8 months of age were 8.0, 2.6, and 0.2, respectiv ely. Conclusions and Clinical Relevance-Results suggest that DLS score at 8 mont hs of age was a reasonable, albeit imperfect, predictor of the condition of the hip joint cartilage at necropsy. Thus, the DLS method might be useful for early identification of dogs with hip dysplasia.