Quantification of measurement of femoral head

coverage and Norberg angle within and among four breeds of dogs (original) (raw)

Abstract

Objective—To report values for percentage coverage of the femoral head (PC) and Norberg angle (NA) in 4 common breeds of dogs and to determine values for each that distinguish between normal and dysplastic hip status on the basis of Orthopedic Foundation for Animals (OFA) hip evaluation.

Animals—1,841 dogs 24 to 48 months of age that were Labrador Retrievers (455), Golden Retrievers (423), Rottweilers (545), or German Shepherd Dogs (418).

Procedure—Retrospective analysis of NA and PC measured from standard OFA ventrodorsal pelvic radiographs from 4 breeds of dog.

Results—Norberg angle ranged from 67.4 to 124.4° for Labrador Retrievers, 59.7 to 128.6° for Rottweilers, 70.2 to 119.4° for Golden Retrievers, and 55.3 to 121.3° for German Shepherd Dogs. The PC ranged from 6.5 to 79.9% for Labrador Retrievers, 5.7 to 79.5% for Rottweilers, 8.3 to 79.3% for Golden Retrievers, and 5.4 to 83.7% for German Shepherd Dogs. On the basis of logistic regression modeling for determining normal versus abnormal hip status for all 4 breeds, cutoff points for NA were < 105° and PC were < 50%.

Conclusions and Clinical Relevance—Results of our study indicate that cutoff points of NA of 105° and PC of 50% do not differentiate normal versus dysplastic hip status. Each of the 4 breeds had different values for NA and PC that distinguished normal from dysplastic hip status. (Am J Vet Res 2000;61:1492–1500)