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Objective—

To determine whether the composition of cartilage from the shoulder joints of dogs varied with the risk of developing canine hip dysplasia (CHD).

Design—

Observational study.

Animals—

12 skeletally mature (approx 1 year old) Labrador Retrievers.

Procedure—

Dogs were classified as having a low, moderate, or high risk of developing CHD on the basis of distraction indices. Cartilage was harvested from the craniolateral and weight-bearing regions of the humeral heads, and wet weight per unit area and dry, glycosaminoglycan, and fibronectin contents were determined.

Results—

Glycosaminoglycan and dry contents did not vary among risk groups. For cartilage from the craniolateral region of the humeral head, wet weight per unit area and fibronectin content increased as risk of developing CHD increased. Wet weight and fibronectin content of cartilage from the weight-bearing region of the humeral head did not vary among risk groups.

Clinical Implications—

Dogs that have a high risk of developing CHD are also more likely to develop osteoarthritis of the shoulder joint. The observed increases in wet weight per unit area and fibronectin content in cartilage from the craniolateral region of the humeral head in dogs at a high risk of developing CHD may be early signs of incipient osteoarthritis. (J Am Vet Med Assoc 1997;210: 1483-1485)

Free access
in Journal of the American Veterinary Medical Association

Objective—

To determine whether onset of mineralization of the femoral and proximal tibial epiphyses and age at closure of the femoral and acetabular triradiate growth plates was different for Labrador Retrievers that were radiographically normal or that had canine hip dysplasia (CHD).

Design—

Cohort study.

Animals—

36 Labrador Retriever puppies.

Procedure—

Puppies were radiographed every other day from the time they were 8 to 10 days old until ossification of the femoral heads was apparent. Radiographs were then obtained weekly until puppies were 1 month old and then monthly until puppies were 8 to 12 months old. Age at which mineralization was first observed in the proximal and distal femoral and proximal tibial epiphyses and at which the femoral capital, triradiate acetabular, and distal femoral growth plates were no longer radiographically visible were recorded. Fifteen dogs were euthanatized and necropsied to determine whether dogs had CHD.

Results—

There were 26 radiographically normal left and right hip joints and 10 dysplastic left and right hip joints. Onset of mineralization of the proximal femoral epiphyses and of the right proximal tibial epiphysis was significantly later in dysplastic than in radiographically normal puppies. The left femoral capital growth plates closed significantly later in dysplastic than in radiographically normal joints, but other differences in growth plate closure were not detected.

Clinical Implications—

Endochondral ossification may be abnormal in dogs with CHD. The disease appears to affect multiple joints, even though it is most evident clinically in the hip joint. (J Am Vet Med Assoc 1997;210: 1458–1462)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether dorsolateral subluxation (DLS) scores in young dogs could be used to reliably predict which dogs would develop evidence of hip osteoarthritis and whether DLS scores measured at various ages correlated with each other.

Animals—129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhound crossbreds.

Procedures—DLS scores were measured on radiographs taken at 4, 8, and 12 months of age and at necropsy (8 to 36 months of age). At necropsy, the hip joints were examined macroscopically and a score assigned for degree of cartilage 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 with cartilage degeneration scores, and DLS scores at 8 months of age were significantly correlated with scores obtained at the time of necropsy (n = 39, r s = 0.87). The DLS scores at 4 months of age were significantly different from scores at 8 months of age, but scores did not differ significantly thereafter. Likelihood ratios for cartilage lesions for low (< 45%), intermediate (≥ 45 but ≤ 55%), and high (> 55%) DLS scores at 8 months of age were 8.0, 2.6, and 0.2, respectively.

Conclusions and Clinical Relevance—Results suggest that DLS score at 8 months 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. (Am J Vet Res 2001;62:1711–1715)

Full access
in American Journal of Veterinary Research

SUMMARY

We investigated whether stromelysin activity in the medium of canine articular cartilage explants is associated with proteoglycan degradation in these explants. Cartilage explants were treated with recombinant human interleukin 1α (rh-il-lα), lipopolysaccharide, or canine monocyte-conditioned medium. Proteoglycan synthesis and degradation were measured. Metalloproteinase activity (inhibitable by tissue inhibitor of metalloproteinase 2) in the culture medium was measured by use of fluorimetry with a quenched fluorescent substrate. Western blots of the medium were probed with polyclonal antibodies to human stromelysin, collagenase, and gelatinase.

Neither metalloproteinase activity nor proteoglycan degradation were inducible in canine cartilage explants treated with rh-ll-1α. However, proteoglycan synthesis was significantly (P < 0.05) decreased by concentrations of 10 and 100 ng of rh-il-1α/ml. Metalloproteinase activity in the medium accompanied proteoglycan degradation of cartilage treated with lipopolysaccharide and monocyte-conditioned medium. The metalloproteinase released into the medium was identified as prostromelysin by results of western blotting.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To compare the accuracy of the extended- hip radiographic (EHR) score, the distraction index (DI), and the dorsolateral subluxation (DLS) score for identifying hip dysplasia in dogs at 8 months of age.

Design—Cohort study

Animals—129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhound crossbreds.

Procedure—Radiography was performed when dogs were 8 months of age. Dogs were euthanatized at 8 to 36 months of age; hip dysplasia was diagnosed at the time of necropsy on the basis of results of a gross examination of the articular cartilage of the hip joints for signs of osteoarthritis.

Results—The EHR score, DI, and DLS score at 8 months of age were all significantly correlated with degree of cartilage degeneration at necropsy. Sensitivity and specificity of using EHR score at 8 months of age to diagnose hip dysplasia (scores > 3 were considered abnormal) were 38 and 96%, respectively; sensitivity and specificity of using DI (values > 0.7 were considered abnormal) were 50 and 89%; and sensitivity and specificity of using DLS score (scores ≤ 55% were considered abnormal) were 83 and 84%.

Conclusions and Clinical Relevance—Results suggested that specificities of the 3 methods for diagnosing hip dysplasia in dogs at 8 months of age were similar. However, the DLS score had higher sensitivity, indicating that there were fewer false-negative results. (J Am Vet Med Assoc 2001;219:1242–1246)

Full access
in Journal of the American Veterinary Medical Association