Palpation and dorsal acetabular rim radiographic view for early detection of canine hip dysplasia Part 1: Standardization and measurement repeatability on six-month-old dogs

The objectives of this study were to standardize a palpation technique and to determine within and between examiners, the repeatability in interpretin g the angle of reduction, subluxation and the acetabular slope measurements . Also it was desired to ascertain the effect of pelvis positioning on the acetabular slope measurement on six-month-old dogs. On palpation examinatio n fifty-three (53) dogs had their angles of reduction and subluxation measu red. A radiographic examination including, a standard hip-extended view, a compression and a distraction view and a dorsal acetabular rim view were pe rformed on each dog. The within examiner repeatability was excellent for both the angle of reduc tion and subluxation (r = 0.975, p = 0.82 and r = 0.977, p = 0.81 respectiv ely). The between examiners repeatability was good for the angle of reducti on (r = 0.843, p = 0.51) but only a fair correlation was found for the angl e of subluxation (r = 0.652, p = 0.83). For the acetabular slope measuremen t, an excellent within examiner correlation was observed (r = 0.940, p = 0. 52). However, though a good correlation was found between examiners, a sign ificant difference was found in the measurements of the three examiners (r = 0.780, p < 0.0001). The under- or overrotation position slightly changed the slope measurement but a fair correlation was still observed with the pe rfect position (r = 0.769, p = 0.074 and r = 0.684, p = 0.061 respectively) . If the pelvis is turned to one side, a correlation was not found (r = 0.0 90, p = 0.847). The high repeatability of the angle of reduction measuremen t in six-month-old dogs suggests that it may be used by multiple examiners, with the expectation of comparable and consistent results. The modified me thod of the acetabular slope measurement improved the correlation, but a si gnificant difference was still observed between examiners.