The pelvis is rotated with the right hemipelvis farther away from the imaging plate. The right stifle should be moved axially (medially) so the femurs are parallel. The right femur/stifle should be further internally rotated (so the patella is more centrally located over the femur). In this example, there are multiple positioning errors. Pelvic radiographs must be assessed for adequate positioning and should be repeated if the pelvis is oblique, as in Figure 2A. Ensuring that both limbs are positioned similarly allows side-to-side comparisons. This can be useful when radiographic changes are equivocal. Figure 1C shows an example of the pelvis correctly positioned.Īltering the degree of limb extension or flexion and changing the degree of internal or external rotation can significantly affect the appearance of the femoral head and neck. Ideally, the sacrum, ilial wings, and entire 7th lumbar vertebra should be included in the image. Note the uniform and equal size of the obturator foramen on this well-positioned radiograph. In this image the femurs are parallel with each other and parallel with the imaging plate. If the stifles are kept internally rotated, the patella should be centrally located over the distal femurs, as seen in the normally positioned radiograph ( Figure 1B). The limbs are then extended, maintaining the internal rotation, until the femurs are parallel with the table. While in a flexed position, the limbs are internally rotated and abducted so that the stifles are almost touching. All but the pelvis and hindlimbs are within the trough. This view is best obtained with the dog placed in dorsal recumbency, which is done by using a foam positioning trough. It is also advised to take into account the hip scores of a dog's relatives.Step-by-Step: Pelvic Radiography Positioningįigure 1A demonstrates the normal positioning for the ventrodorsal hip-extended view (the view that should be submitted to the Orthopedic Foundation for Animals). Where EBVs are available these should be used. You can find out the median score of your dog's breed here.ĬHS recommends only breeding dogs with hip scores below or close to the published breed medians. These scores are collected together and used to create breed-specific statistics, including an average (median) score across the breed. The lower the primary changes score, the less evidence of hip dysplasia there is, and the lower the total score, the less evidence of hip dysplasia and secondary osteoarthritis there is. They are likely to increase as the dog ages and the arthritis progresses. These are the assessments of the arthritic response to the underlying dysplasia in various parts of the joint. The second 6 components are known as the ‘Secondary Changes’. The poorer the fit of the femoral head (“ball”) to the acetabulum (“socket”) the more dysplastic the hip, the lower the score, the less dysplastic the hip appears. These are assessments of the conformation of the hip joint. The first 3 components are known as the ‘Primary Changes’. The minimum score for each hip is 0 and the maximum is 53, giving a range for the total score of 0 to 106. Each hip joint is scored on nine parameters, generating a total score representing the severity of the condition.
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