Hip dysplasia is a common and often debilitating orthopaedic condition characterised by instability of the hip joint which affects many larger breed dogs. It is generally considered that puppies are born with normal conformation of the hip joint i.e. a smoothly fitting ball-and-socket joint comprising of the femoral head (ball) and the acetabulum (the socket). See Figure 1.
The mechanism by which dysplastic hips become lax and unstable is due to many factors but these include both genetic and environmental. The underlying cause is a laxity of the soft tissues supporting the hip joint; in severe cases this can be detected by your vet at first vaccination. However, because it occurs in young dogs when the bones are still partly cartilaginous so therefore soft instead of ossifying into a normal hard boney well fitting ball-and-socket conformation, the femoral head and acetabulum form a shallow, less congruous joint. Arthritic new bone also forms due to stresses on the soft tissue components of the joint and further remodelling changes occur. See Figure 2.
||The degenerative process then becomes a vicious
cycle, exacerbated by obesity and over-exercise.
In 1984 The British Veterinary Association (BVA) in association with the Kennel Club instituted the BVA/KC hip dysplasia scoring scheme to replace the earlier Pass/Breeder’s Letter/Fail Scheme. Many countries have their own scoring scheme but in the UK, a single radiographic hip view is used. Best X-rays are achieved with a relaxed dog using either sedation or general anaesthesia.
The skeletally mature dog, over 12 months old, is usually laid in a trough on his/her back and the hind limbs are extended with the stifles parallel to each other, this is achieved by the strategic use of sellotape and ties! It is essential to have a marker to mark left or right together with the date and the dog’s kennel club registration number, which will show on the film. This can be the fiddly bit as there are strict rules governing the suitability of an X-ray. There must be no rotation of the pelvis, and this can be difficult sometimes in very thin, bony dogs.
|A diagnostic X-ray (See Figure
3) can then be submitted to the BVA together with the scoring fee and
a part-completed certificate. The vet then signs to certify the radiograph
was taken on the date indicated and may check and add the dog’s
microchip or tattoo number. Until the latter becomes mandatory the substitution
of dogs with known good hips could occur by unscrupulous breeders. One
could consider this may be a case for DNA profiling to become more the
The radiograph is then examined by two scrutineers, randomly paired, from a panel of (currently) thirteen, all who have been trained in hip dysplasia assessment. Each year they set a quality control exercise to check each scrutineer. Under the scoring scheme, nine radiographic features for each hip are assessed with a numerical score given to each (0-6). Points are given to each undesirable feature with zero being a perfect example of that feature.
The individual scores are then summated giving a total for each hip and a total score for the dog. One feature is scored between 0-5 (caudal acetabular edge) so with the other eight scoring 0-6, the total parameters for each hip may range from 0-53 and for a given dog so giving a possible total score of between 0 and 106. See Table 1.
This means that meaningful comparisons between dogs may be achieved.
As with most things, this system has it’s limitations and is by no means foolproof.
As a summary of the scoring system the lower the score the better. Hips scores of 0,0 (Total=0) being perfect and 53,53 (Total = maximum 106) devastatingly dreadful. For each breed there is an average score obtained, which is continually being updated, this is known as the breed mean score (BMS). The BMS for Hungarian Vizslas is at present a total of 12.
As breeders and as potential puppy purchasers how is the scheme best used?
Temperament and ability obviously all count in choosing the right match but remember, it is theoretically possible for people who purchase a pup which develops hip dysplasia to sue a breeder who bred from affected parents.
In practice, the number of clients who continue to breed from their dogs either without hip scoring or who worse, ignore the score indication staggers me. Likewise there are the new puppy owners who look blankly when you ask what the parents hip scores were. Too often have I had to euthanase an otherwise healthy puppy which can’t bear it’s own weight or suffers pain. See Figure 4. I would prefer not to be put in this situation so I strongly urge responsible breeding in any breed let alone my own , the Hungarian Vizsla.
I strongly recommend breeders advise prospective owners to insure their animals because should the problem arise. As vets can do so much more when there are no financial constraints. In addition, I recommend the use of nutriceuticals e.g. glucosamine and chondroitin sulphate, during the skeletal development stage. This can be administered either in feed or ideally one of the veterinary prescribed extremely pure formulations such as Synoquin®, Seroquin® or Cortiflex®. There are others on the market but I tend to subscribe to the thought that quality and purity comes at a cost.
|Where do I go to get my Dog Hip-Scored?|
|Your vet is the first port of call. Specialist orthopaedic
vets would be contactable by referral through your vet but often a practice
has a vet with a keen interest in orthopaedics and who has done further
learning in the subject.
|What does it cost?|
British Veterinary Association rates for hip scoring as of 1st January 2006:
In addition there is the charge by your vet to include sedation/G.A.
and X-ray, this cost varies according to the surgery charges. The author’s
practice, for example charges an inclusive fee of £100 inc VAT.
The anaesthetic issue is a hangover from "the good old days/James Herriot era". Modern anaesthetics are extremely safe, the Gold standard most often used in practice being propofol induction and isofluorane gaseous maintenance. These have come from the medical field where they are routinely used on 90 year olds having hip replacements! As long as a dog is fit and healthy there is minimal risk with any anaesthetic procedure.
The author’s practice routinely uses a reversable sedation for
hip scoring, which takes 7 minutes to standing after reversal. This combination
is medetomidine (Domitor) and butorphanol (Torbugesic) which is reversed
by atipamezole (Antisedan). Again this combination is exceedingly safe
in young fit animals i.e. the healthy breeding animal!
This should not be an excuse for not hip-scoring your dog.
By Verity J. Griffiths B.Sc(Hons).,M.A., VetM.B., M.R.C.V.S.