Joint laxity in canine hip dysplasia assessed using the hip flexed not distracted ventrodorsal view

Abstract

Objectives The ventrodorsal hip extended standard view is conventionally used for radiographic screening of canine hip dysplasia. However, because the ventrodorsal hip extended standard view minimises hip joint laxity, several alternative views have been proposed. Our aim was to evaluate a new ventrodorsal hip flexed and not distracted view to assess joint laxity, by comparing it with the ventrodorsal hip extended standard and ventrodorsal hip flexed and distracted views. Materials and Methods Between April 2013 and March 2017, all dogs referred to the University of Naples “Federico II” for the diagnosis of canine hip dysplasia were studied using the ventrodorsal hip extended standard, ventrodorsal hip flexed and not distracted and ventrodorsal hip flexed and distracted views. The Norberg angle and the laxity index were measured for each view. Results Overall, 102 dogs, 67 males and 35 females, mean age 15 months, were included. The mean (±standard deviation) Norberg angles were 99.77° (±10.42°), 89.29° (±14.32°) and 91.80° (±13.50°) for the ventrodorsal hip extended standard, ventrodorsal hip flexed and not distracted and ventrodorsal hip flexed and distracted views, respectively. The mean (± standard deviation) laxity indices were 0.19 (± 0.14), 0.39 (± 0.25) and 0.36 (± 0.21), respectively. The ventrodorsal hip flexed and distracted and ventrodorsal hip flexed and not distracted views had lower Norberg angle and higher laxity index values compared with the ventrodorsal hip extended standard view. The ventrodorsal hip flexed and distracted and ventrodorsal hip extended standard views are in strong agreement for the measurement of both Norberg angle and laxity index, as confirmed by Bland‐Altman analysis and the intraclass correlation coefficient. Clinical Significance The ventrodorsal hip flexed and distracted and ventrodorsal hip flexed and not distracted views obtained with the hip in a neutral position reveal joint laxity better than the ventrodorsal hip extended standard view. Unlike the ventrodorsal hip flexed and distracted view, the ventrodorsal hip flexed and not distracted view does not require human operators or special devices for positioning the dog. The wide age range of the dogs enrolled might have influenced the laxity index measurements, since capsular fibrosis in older dogs reduces laxity.

B-mode ultrasonography and ARFI elastography of articular and peri-articular structures of the hip joint in non-dysplastic and dysplastic dogs as confirmed by radiographic examination

“…Although the gold standard of CHD diagnosis is radiographic examination [ 8 , 10 ], the results of this study demonstrated that ultrasonographic evaluation can be used as a screening method and diagnostic aid for CHD and that the association of both imaging methods can bring greater accuracy in disease investigation.…”

“…Radiographic examination of the hip is the gold standard for diagnosing dysplasia [ 5 , 7 , 8 ]. Numerous radiographic approaches can be employed to assist in the investigation of secondary disease [ 9 ].…”

Imaging techniques in Veterinary Medicine. Part I: Radiography and Ultrasonography

“…This view was first proposed by Schnelle [4] in an effort to reproduce the radiographic features of human being's coxo-femural dysplasia, however this positioning is not natural in the dog. B) Same dog studied with a ventro-dorsal view in which the coxo-femural joints are flexed and positioned in a more natural positioning: both the hip joints show now a severe laxity with lateral subluxation of the femural heads [13]. performed to rule out lung metastasis, it is reccomended to perform it on animals in general anestesia and during a positive ventilation [18].…”

“…fractures or luxations), the patient has to be sedated or anaesthetized in order to better visualize a lesion, when it is necessary to obtain a more stressed positioning, ( Fig. 2 ) [ 13 ].

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