Objective—To determine the effect of pelvic tilt on the Norberg angle (NA) measured in ventrodorsal radiographic views of a hip joint in a canine femoral-pelvic bone model.
Sample Population—Radiographic views of a femoral-pelvic bone model with 1 articulated hip joint (without evident laxity).
Procedures—The bone model was placed on a radiography table. With the joint fully extended, the pelvic coronal plane was tilted from 0— in 5— increments caudally and cranially to a maximum of 30— in each direction (femoral frontal plane was maintained parallel with the radiograph cassette); a digital ventrodorsal radiographic view was obtained at each tilt position. In each image, the NA was measured 3 times by 2 observers (operators). The effect of pelvic tilt on the NA was evaluated by use of a repeated-measures analysis; within-and between-operator variances were also assessed.
Results—Within-operator repeatability was excellent for assessments of hip joint NAs in radiographic views obtained when cranial or caudal tilt was applied to the femoral-pelvic model; replicate measurement variation was < 2.5% (coefficient of variation < 5%). Mean NA values determined by the 2 operators in cranial or caudal tilt views did not differ. Mean between-operator difference in caudal tilt measurements was —0.55— (95% confidence interval, —1.69— to 0.59—) and in cranial tilt measurements was —0.13— (95% confidence interval, —1.33— to 1.06—). Cranial or caudal pelvic tilt did not affect measurement of the NA.
Conclusions and Clinical Relevance—Model-derived results indicated that pelvic tilt during acquisition of ventrodorsal radiographic views of the hip joints of a dog should not affect measurement of the NA.
A 6-year-old neutered male domestic shorthair cat was evaluated for left pelvic limb lameness of 3 months' duration. The cat lived indoors but had access to the outside. Conservative management with meloxicam and a glucosamine-chondroitin sulfate product resulted in apparent resolution of the lameness. Two weeks prior to evaluation, the lameness recurred and a mass was detected on the medial aspect of the left tarsal region. The cat's vaccination status was adequate, and results of tests for FeLV and FIV were negative.
A weight-bearing lameness of the left pelvic limb was detected during physical examination. Palpation of the left