Comparison of susceptibility for hip dysplasia between Rottweilers and German shepherd dogs.

Passive laxity of the coxofemoral joints, as measured quantitatively by radiographing the joints under stress, has been shown to be an accurate measure of the risk for developing degenerative joint disease (DJD) of the coxofemoral joints. Seventy-four Rottweilers between 12 and 40 months old were evaluated subjectively for radiographic evidence of DJD, using the ventrodorsal view of the pelvis with the coxofemoral joints fully extended and the knees internally rotated (standard hip-extended view). Effect of age, sex, weight, and distraction index on the risk of developing DJD was evaluated by use of a logistic regression model. Results were compared with those from a group of German Shepherd Dogs. Results indicated that in Rottweilers the distraction index was the only statistically significant predictor of the risk of developing DJD of the coxofemoral joint. When German Shepherd Dogs were included in the model, they had a significantly greater risk of developing DJD than did Rottweilers. This finding provides further support for the theory that there are differences in disease susceptibility among breeds and emphasizes the need to develop disease susceptibility curves for all breeds affected by hip dysplasia to facilitate accurate, scientifically based recommendations for breeding or treatment.