HIP DYSPLASIA IN DOGS A GUIDE FOR DOG OWNERS BY JOHN FOSTER
HIP DYSPLASIA IN DOGS A GUIDE FOR DOG OWNERS BY JOHN FOSTER

DEVELOPMENTAL DEMANDS It is argued that dogs are not barn with hips affected by dysplasia (unlikehumans suffering from the disease). Hip modelling, otherwise termed development, can worsen with the passing of time, most particularly during the rapid growth phase between 14 and 26 weeks of age. Unwelcome changes in anatomic relationships within the joint start in early puppy hood with first usage and continue through into young adult hood. Wear and tearfrom exercise of the distorted joint is followed by varying amounts of inflammation and degeneration resulting in remodelling change.

 
Normal hips. Note that the photographicimage is clear and the structures shownare distinct. The projection of the pelvis,the spine, the tail and the legs straightwith one side of the anatomy being amirror image of the other.

THE BVA/KC HD SCHEME All radiographs submitted to the BVA/KC Hip Dysplasia Scheme are assessedby means of scoring. The hip score is the sum of the points awarded for each of nine radiographic features of both hip joints. The lower the score the less the degree of hip dysplasia present. The minimum (best) score for each hip iszero and the maximum (worst) is 53, giving a range for the total of 0 to 106. The average score of the breed, or the 'breed mean score', is calculated from all the scores recorded for a given breed and is shown alongside its range there by giving a representation of the overall hip status of the breed. All breeders wishing to try to control HD should breed only from animals with hipscores well below the breed mean score.Sires (fathers) to be bred from should only be ones whose progeny (offspring) have achieved consistently low scores. The same selection procedure shouldbe used for bitches for breeding, since the use of animals with higher than ideal scores may make the risk of producing offspring with high scores much greater. This circumstance is not only disappointing and potentially costly interms of compromised breeding plans, but may lead to subsequent civil courtaction.

For the hip scoring scheme to be meaningful and successful in the attempt to control this serious disease it is important that all radiographs taken under the scheme are submitted for scoring, whatever the apparent state of the hips, in order that the information gathered is as relevant as possible. It is only by this means that proper conclusions may be drawn by the scheme's statistitians, geneticists and veterinary advisers. It is not hard to understand why things happen so quickly and how critical awhole series of factors in the dog's life are, when realising some animals treble their size and weight during a three- month period of adolescence. Getting all the many nutritional needs in the right quantity, to the right placeand at the right time requires a mastery of logistics. However, it has to be realised that this apparent basic requirement overlays the parts played by inheritance and other factors, for example the type of exercise taken and the degree of body weight.

 
SIGNS, APPEARANCE AND PATHOLOGY Hip dysplasia, because it can be made up of a picture of joint looseness, new bone formation or bone loss and inflammation and pain, can show up in arange of signs from apparent soundness through lameness to degrees of exercise intolerance. Combine these findings with the fact that some breeds and some individuals are more stoical than others and there is no predicting, just by looking from the outside, to what degree a particular dog has or hasn't got HD. More reliable is the clinical examination which is likely to reveallimitation of movement of the affected hip, probably reduction in muscle mass of the limb and some degree of pain. Remember, a dog with HD in the normal course of life does not show discomfort by, say, yelping, mainly because the pain is likely to be continuous as opposed to sudden and unexpected. The only way to assess properly the presence or relative absence of HD is by radiography. This is an accurate photographic way of showing the position ofthe ball of the joint in relation to the socket and the presence and degree of any secondary changes.
 
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