Evaluation of risk factors for degenerative joint disease associated with hip dysplasia in German Shepherd Dogs, Golden Retrievers, Labrador Retrievers, and Rottweilers.

OBJECTIVE: To determine whether age, breed, sex, weight, or distraction index (DI) was associated with the risk that dogs of 4 common breeds (German Shepherd Dog, Golden Retriever, Labrador Retriever, Rottweiler) would have radiographic evidence of degenerative joint disease (DJD) associated with hip dysplasia. DESIGN: Cross-sectional prevalence study. ANIMALS: 15,742 dogs. PROCEDURE: Hips of dogs were evaluated radiographically by use of the ventrodorsal hip-extended view, the compression v ew, and the distraction view. The ventrodorsal hip-extended view was examined to determine whether dogs had DJD. For each breed, a multiple logistic regression model incorporating age, sex, weight, and DI was created. For each breed, disease-susceptibility curves were produced, using all dogs, regardless of age, and dogs grouped on the basis of age. RESULTS: Weight and DI were significant risk factors for DJD in all breeds. For German Shepherd Dogs, the risk of having DJD was 4.95 times the risk for dogs of the other 3 breeds combined. In all breeds, the probability of having DJD increased with age. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the probability of having hip DJD increased with hip joint laxity as measured by use of DI. This association was breed-specific, indicating that breed-specific information on disease susceptibility should be incorporated when making breeding decisions and when deciding on possible surgical treatment of hip dysplasia.

Relationships between results of the Ortolani method of hip joint palpation and distraction index, Norberg angle, and hip score in dogs.

OBJECTIVE: To determine whether results of the Ortolani method of hip joint palpation in dogs were related to distraction index (DI), Norberg angle, or radiographic hip score. DESIGN: Cross-sectional study. ANIMALS: 459 clinically normal dogs. PROCEDURE: Dogs were sedated for radiography and palpation of the hip joints. Results of hip joint palpation were classified as negative, mild positive, moderate positive, or severe positive. Distraction indices were measured for all dogs. Norberg angles were measured for 380 dogs for which ventrodorsal hip-extended radiographic projections were available. Hip scores assigned by the Orthopedic Foundation for Animals (OFA) were available for 95 dogs. RESULTS: Age, weight, and sex were not significantly associated with results of hip joint palpation. There was moderate correlation between results of hip joint palpation and DI (r = 0.636), low-moderate correlation between results of hip joint palpation and OFA hip scores (rs = 0.437), and weak negative correlation (r = -0.236) between results of hip joint palpation and Norberg angle. For joints without degenerative joint disease (DJD), there was a significant linear relationship between results of hip palpation and DI; however, for joint with DJD, there was not. Results of hip joint palpation were 5.3-fold as likely to be negative for dogs with DJD as for dogs without. CLINICAL IMPLICATIONS: Results of hip joint palpation were at best moderately correlated with radiographic measures of hip joint laxity. Therefore, hip joint palpation should be combined with hip-extended and stress radiography when assessing hip joint quality.

Synovial fluid cavitation during distraction radiography of the coxofemoral joint in dogs.

OBJECTIVE: To determine risk factors for, and prevalence and short- and long-term effects of synovial fluid cavitation during distraction radiography. DESIGN: Multicenter prevalence survey. ANIMALS: 6,649 purebred dogs comprising 129 breeds. PROCEDURE: Radiographs from the PennHIP (University of Pennsylvania Hip Improvement Program) Laboratory were subjectively evaluated for evidence of cavitation. Multiple logistic regression was used to determine whether sex, breed, age, weight, distraction index (DI), or examining veterinarian was associated with cavitation. Short-term effects of cavitation were assessed by comparing DI for the hip with cavitation with DI for the contralateral hip in dogs with unilateral cavitation. Long-term effects of cavitation were assessed by comparing DI before and after cavitation was detected. RESULTS: Cavitation was detected in 279 (4.2%) of the radiographs analyzed. Male dogs, Golden Retrievers, and heavier dogs were at a decreased risk for cavitation. Irish Wolfhounds, Irish Setters, Rhodesian Ridgebacks, and Weimaraners had an increased risk for cavitation. Age and DI were not risk factors for cavitation. Mean DI was 0.08 greater in hips with cavitation than in paired hips without cavitation. Significant differences were not detected between DI before and after cavitation, but only 7 dogs were included in this analysis. CLINICAL IMPLICATIONS: Cavitation is rare during distraction radiography and can increase measured DI. Radiographs should be routinely examined to ensure accurate reporting of DI.