Hip Dysplasia

What is Hip Dysplasia?

Hip Dysplasia is basically a deformity of the hip joint in which the head of the femur (ball section of the joint) fits poorly into the acetabulum (the socket).

Due to the poor fit of the joint, the ball moves in the socket in an abnormal manner leading to wear and tear on the surfaces of the joint and the development of arthritis. The ligament and capsule around the joint become slack and the muscles of the hindquarters waste away.

Hip dysplasia is a largely inherited condition seen mostly in the bigger breeds of dogs, such as the Alaskan Malamute, although environmental factors also play a part in the soundness of the hip joint. The mode of inheritance is polygenic, meaning that a number of genes interact to determine the final physical characteristics of the hip joint.

Signs of Hip Dysplasia
The signs of hip dysplasia may develop in a pup as young as 3 - 4 months in age, but may not become apparent until the dog is older. A dog with hip dysplasia may not show any obvious signs initially, however the hips can degenerate with age and the dog may eventually suffer severe pain and difficulty in moving the back legs. Hip dysplasia may be indicated when a dog shows discomfort after exercise, a tendency to "bunny hop" when running, an awkward, rolling movement rather than a smooth gait, difficulty in jumping or getting up from lying down and a reduced level of activity. Hip dysplasia can only be confirmed by hip x-ray when the dog is over 12 months of age.

Prevention
Hip Dysplasia has been diagnosed in more than 100 breeds of dog. Fortunately, studies have shown that the chances of progeny being hip dysplastic are significantly decreased when both parents have normal hips.

Ventro-dorsal x-ray of a dog with good hips

The degree of Hip Dysplasia is indicated by a scoring system for each hip, the lower the score, the better the hips.  Dogs with hip scores 0 - 7 on either hip are considered to have normal hips and are suitable for breeding, while those with hip scores of greater than 7 on either hip are considered hip dysplastic and are therefore not suitable for breeding.  Hip dysplasia can be progressively eliminated by only using dogs with normal hips (as determined by x-ray) for breeding programs.  Dogs with hip scores closer to 7 should only be bred with dogs with lower hip scores, e.g. 0 - 4.

It should be remembered that, although both parents may be free of hip dysplasia, there is no guarantee that the progeny will not be hip dysplastic, however the chances of having pups with hip dysplasia will be greatly reduced.

When looking at a litter ask the breeder to see the hip evaluation reports for the sire and dam. The report must include:

• the kennel name of the dog which has been x-rayed

• the kennel names of the dog’s parents and grandparents

• a break down of how different aspects of the hip joint were scored

• a final score for each hip based on the cumulative scores
  (0 = excellent, 53 = worse possible score).

• the suitability of the dog for breeding based on the hip score obtained for the worst hip.

• the signature of the veterinarian who read the hip x-ray.

Puppy buyers can help reduce the incidence of hip dysplasia in the Alaskan Malamute by refusing to buy pups from breeders who have not had both parents hip x-rayed, or where one or both parents have not passed for hip dysplasia. If the breeder cannot show puppy buyers the hip x-ray reports, buyers should go elsewhere for their pups.

Produced by The Alaskan Malamute Club, Victoria Inc.

Normal hip                             A mildly dysplastic hip

Moderately dysplastic hip                 A severely dysplastic hip

Hip dysplasia can range from mild to severe
(top right to bottom right)

Hip Dysplasia Control Program

The Alaskan Malamute Club, Victoria Inc. has in place a Hip Dysplasia Control Program in which Malamutes have an "A" suffix added to their registered pedigree name to indicate that they have a hip dysplasia pass (score 0 - 7 on each hip).

Download Hip Dysplasia form & program

1.   The Alaskan Malamute Club, Victoria, Inc. (referred to as the Club or AMCV) will only accept hip X-ray results where the X-rays have been graded under the AVA (Australian Veterinary Association) Hip Dysplasia (HD) Scheme by approved readers.

2.  Dogs must be at least 12 months of age, and be identified in accordance with this program before being X-rayed for Hip Dysplasia. (see item 6)

3.  The program is open to all Alaskan Malamute owners in Victoria, whether members of the AMCV or not, and under the same conditions, and upon payment of the prescribed fee.

4. The AMCV has designated a maximum score of 7 on either hip as being acceptable for breeding, i.e. a maximum score from 0 to 7.

5.   (a) Dogs which have had their hips graded overseas will be accepted by AMCV only if the X-ray results are submitted to the Club, and the Club gains approval from the VCA HDC.

(b) Dogs which have been X-rayed prior to the commencement of this program may be accepted under this program if application is made to the AMCV and the results are acceptable to the VCA’s HDC.

(c) If there should be any question about the acceptability or otherwise of any HD result, the VCA HDC will make the final decision.

6. (a) At or before the time of X-rays being taken, dogs must be positively identified by either tattoo or microchip, and if microchipped the number should be recorded on the X-ray. If by tattoo, owners should apply to the AMCV HDO (Hip Dysplasia Officer) for allocation of a tattoo number which will be tattooed high on the left inner thigh of the dog, and this number will be included on the HD X-ray application form. Only dogs which have been correctly identified at the time of X-ray will be accepted by the Club, and will be included in the VCA suffix scheme.

(b) The allocated Tattoo Number will consist of three prefix letters for each Member and three numerals indicating the number of each individual dog with that prefix, e.g. AMC004.

7. The AMCV will, if requested by an owner, apply to the VCA for the suffix "[A]" to be added to the registered name of any Alaskan Malamute owned by them if the requirements of this policy are fulfilled and the dog passes the standard set.

8. The AMCV will actively encourage owners to have every Alaskan Malamute X-rayed and graded for HD, and the results submitted to the Club, before breeding from it.

9. The AMCV will actively encourage owners to breed for better hips. Ie. dogs with a high pass score should be bred to dogs with low pass scores.

10. The AMCV will strongly discourage the breeding together of 2 dogs with high pass scores. Failed dogs should not be bred from, i.e higher than seven on either hip.

11. For advertising or publication of a dog in any AMCV literature the club must publish the hip status by stating either (a) Pass, (b) No hip score provided or (c) Dog too young.

12. A Hip Dysplasia Officer shall be elected by the Members, to be responsible for the implementation and management of this program.

13. The Club will actively support any breeder who participates in the control program, yet, from parents both passed for breeding, still produces a puppy that scores higher than 7 on either hip (i.e. fails the hip X-ray). The Club may, via the HDO, assist by providing information about Hip Dysplasia, writing letters, and acting as a liaison between the owner of the dog, the breeder, and the VCA or other controlling interstate body, if the need arises.

14. The Club will actively support any person who owns an Alaskan Malamute who fails a hip X-ray, if the owner fails to obtain satisfaction from the breeder. The Club may, via the HDO, assist by writing letters, and acting as a liaison between the owner, the breeder, and the VCA or other controlling interstate body.

15. All hip passes will be published when recorded, and a list of passes will be made available to AMCV Members.

16. An annual report on the program will be prepared and forwarded to the VCA.

17. This program will come into effect on the first day of October, 1992. As from that date, all Alaskan Malamutes must comply with the requirements of this program before X-ray results will be accepted, and all dogs which had been previously accepted under the old AMCV HD Scheme will be included in the VCA suffix application.

18. For a litter to be eligible for advertising on the puppy register:

(a) the breeder must have been a member of the AMCV for 6 months and both parents of the litter must have been hip X-rayed and passed for breeding, and

(b) hip scores for both parents must be submitted with the application to the puppy registrar.

(c) Advertisements for litters will not be accepted unless advertised through the puppy register.

THE REASONS FOR A HIP DYSPLASIA SCHEME

Hip Dysplasia is a problem of medium and large breed dogs which may produce hind limb lameness. Because of the poor correlation between the severity of the clinical and radiological signs, radiographic examination of the hips is the standard method of assessment of a dog’s hip dysplasia status.

The OFA figures in 1986 showed that of the 4500 Alaskan Malamutes examined, 70% had either excellent or good hips. There had only been 25 dogs submitted to the BVA scheme up to June 1988 and these had an average score of 17 with a range of 2 - 66.

The current situation regarding the hereditary nature of hip dysplasia is that it has a polygenic mode of inheritance which contributes 20 - 50% of the factors involved in initiating the problem. Dr. Willis’s work with the GSDL/BVA Hip Dysplasia Scheme suggests that there is considerable benefit in running schemes providing club members are willing to co-operate.

This means that everyone should participate and submit radiographs of all dogs examined. It is just as important to have all the radiographs of dogs with poor quality hips as it is those with good quality hips if the scheme is to be of benefit to the breed as a whole.

The assessment of the hips will be made using a scoring scheme. The scoring system was revised in 2000 with a score of 0 to 7 on both hips being in the pass group and a score of 8 or greater on either hip indicating failure.

Because of the poor correlation of the clinical and radiographic signs, some owners of dogs that move well are going to be disappointed when their dog’s hip radiograph is graded as a fail. Unfortunately some dividing line has to be drawn if I am to give advice on those dogs whose radiographic hip dysplasia status is appropriate for breeding in the light of current knowledge. There should be no variation in the way the hips are scored over a period of time but it is certainly possible that the pass/fail line could vary in light of overall standard of hips sent for assessment.

Owners of dogs that fall into the fail category by one or two points on one hip might still consider using that dog for breeding if it is an ideal example of the breed in all other aspects. After all, there is little point in breeding from a dog with excellent hips that has poor construction or uncertain temperament. However, if the choice is between dogs of even construction and temperament, then it would be sensible to use the dog with the best hips.

If members have problems in understanding the interpretation of the hip radiographs, I would be pleased to try and explain their reports.

NEW AVA HIP DYSPLASIA SCHEME

Application forms for the new scheme are now available from the National Office and State Offices.

Care should be taken to ensure that the details requested on the form are completed accurately.

It should be noted that the radiographic examination must be undertaken with the aid of a general anaesthetic. This is the technique taught and required in all Australian veterinary schools and as well as assisting accurate positioning, it will ensure the most consistent repetitive results for the scoring system.

Any members with queries about the scheme should consult the AMCV Health Officer.

"A" Suffix application forms can be obtained from the AMCV Secretary or Hereditary Diseases Co-ordinator.