HIP DYSPLASIA

 

Hip dysplasia is the most commonly discussed problem of the breed.

 

To briefly explain what Hip Scoring is— The term refers to the shape and

fit of the Ball of the Femur with the Socket in the Hip.  The ball is to ideally fit

snuggly within the socket of the hip, with a good smooth range of movement.  

There are varying degrees of hip dysplasia, from mild to extreme, the lowest

score being 0 and the highest being 106. 

 

Hip Dysplasia is a combination of genetic predisposition and environment. It

can be caused by genetics and passed on from parents, as well as being also

contributed to by a number of environmental factors such impact, trauma,

mineral deficiencies, over nutrition,  etc.  There is no such thing as solely

‘environmental’ hip dysplasia.

 

Hip Dysplasia is evidenced by signs of discomfort when running, standing or

rising.  The dog may be reluctant to rise or rises with difficulty, swaggers or

sways its rear end while walking and may avoid excessive exercise, jumping

or other use of its hind legs. 

 

DV Scoring is done on 9 different points of the hip joint anatomy and it is

necessary for the dogs pelvis to be xrayed in the correct position for scoring

by experienced Veterinarians.  The xrays are then forwarded to a recognised

veterinary radiographer for scoring.  The score is expressed as two numbers

eg. 3:6 Being the total for the right hip, then left hip.  Both left and right scores

are added together to give an overall hip score for the dog,

eg. 3+6 = Total Hip Score of 9.  The LOWER the score THE BETTER the hip.

 

The breed average for hip scoring is around 18.45 in Australia.

 

There are certainly a number of breeders who are hip scoring their animals.

However there are also  breeders who still refuse to X-ray their animals. 

 

Unless your dog shows signs of pain or discomfort, hip dysplasia does not always mean the end for your dog.  While dogs with very high score should not be used in a breeding program, they can still live a long and happy life, some without any evidence of pain. 

 

Common questions on Hip Dysplasia (See below)  Please scroll down.

 

Below are XRAYS of some “severely hip dysplastic” Dogue de Bordeaux — Photo A and B

and in comparison an excellent “Hip Dysplasia free” Dogue de Bordeaux — Photo C and D

 

 

 

 

PENN HIP SCORING or ‘Traditional’ DV HIP SCORING

 

Basically the normal hip score is a DV view scoring the basic 'hip conformation' done by approved scorers (humans) while the PennHip method is based on the different measurements from 3 different views of the hips said to show the passive laxity of the joint (believed to be the basic cause of hip dysplasia ie. tighter hips = less joint travel = less percussive damage = less hip dysplasia).  The PennHip score is computer generated. While the measure of laxity (Distraction Index) doesn't change the dogs ranking within the breed group can and the idea is that dogs in the better half of the ranking should be used to push selection pressure towards 'tighter hips' (lower DI's).  Suluxation is the 'passive laxity' of the joint while the PennHip measure is interested in both the passive laxity and the measure of the laxity under force. X-rays showing both these and the normal DV view are all submitted and they use them to determine what the Distraction Index (or difference) is between the two and the presence of DJD.

Both methods can reduce the incidence of HD over time it seems (of course this is dependant on the action taken by breeders) but PennHip is scientifically proven more accurate at an earlier age than either the DV score or OFA grading as used in the US.

There are different size 'distractors' for different breeds which are also adjustable and they must be set at a uniform width covering the same anatomical landmarks on the hips which are used to provide the 'force' view. There is not a great deal of force involved, just the distractors are positioned just outside the acetabular rim and the femoral heads are 'folded' around them.  If the force is excessive enough to cause 'cavitation' (air bubbles within the joint space) then the x-rays have to be done again at a later date. The vets are trained to only use the force and widths required and they don't want excessive forces to result in cavitation as then it is done again at a cost to them. If the distractors are not set wide enough then the x-ray has to be done again, the same if too wide. The distractors are also heavily padded so between the padding and muscles I would think it is not possible to place enough force on them to cause dislocation.  The strength of the ligaments are what is assumed holds the joint together with the different x-rays views giving as near as possible the amount of joint travel that that strength allows in natural movement. The theory being the looser the joint, the higher the joint travel and the more banging around and then joint changes occur.  The force required to dislocate a joint is very large (as is the force required to put it back in). That said on some breeds the DI is large enough that the ball does almost come completely out of the socket but that is because they have very lax hip joints. The DI is a measure of the difference between the 'passive' space and the 'forced' space so some hips can appear to have larger forced spaces but when compared to the passive view, the spaces on this (relative to the acetabular rim) are also large so the DI is not as high as you might expect. It is interested only in the difference between the 2 (the actual joint travel) rather than a measurement based off what might be considered 'normal'.

 

The science behind the method is found at

http://www.pennhip.org—then go to research on the left hand side

Breeders are now observing that dogs with better PennHip scores seem to be throwing offspring with both better PennHip scores and Hip scores.  

 

Penn Hip results at 4 months are highly likely to correlate to that found at 12 months and 2 years of age.  This is important in a breeding program.  Some breeders are now doing both DV Hip Scoring and Penn Hip Scoring.

 

The mean for our breed is currently given as 0.69 (50th percentile), the 75th percentile is currently 0.60 and 25th 0.78. The minimum at approx 500 dogs was 0.28 and the max was 1.08. There is a dogue which has a much lower DI on one hip but the other is a lot higher so theoretically there can/will be a dogue with hips tighter than 0.28 eventually. Results are updated quarterly. Both the minimum and maximum can go lower and higher but what this all basically means at the moment is the breed as a whole has very poor hips!

 

While you don't recieve new ranking certificates the results are published and the dogs are all ranked. These can be viewed by any person - they are not privately kept records.

 

 

Common questions on Hip Dysplasia:-

 

What is a good score?
Ideally, you want to breed with dogues who are both low scored, as close to zero as possible.
This is not always possible, so a basic rule followed by many of the top breeders is - of course to breed together Dogues who are as close to zero as possible - but at the maximum, the sum of the two scores of the parents, should be no more than 30, or within a few points.

 

Or to put it another way—In order to see real improvement in hip conformation that the hip scores of any matings should not add up to more than 1.5 x the breed average ie. approx. 30.

Eg. If one parent has a score of 25, you would want to use a mate with a score of around 5 or less.

However in most cases nowadays, many breeders are able to work with much lower scores. But to breed together two high scores, is very irresponsible, as is breeding with UNSCORED DOGS.

Eg. A low score is between 0-10, a good score between 11-15, and acceptable being between 16-20. If the score is over 20, then you have to be even more careful to breed with a mate who has a low score and preferably also low scores throughout the pedigree.

It is not advised to breed with a Dogue over 30 and anything in the late 20's should be bred with a very low score, say between 0 and 5.

The breed average is currently 18, but that is only an average based on Dogues who's hip x-rays have been submitted for scoring. There are people who have not submitted x-rays due to the poor hips being obvious on the x-rays. So while the average is 18, it does not mean we should be aiming for 18 as being a "good" score, we should be aiming alot lower.

How do you read the hip score report?

The hip joint reading is made up of the following, and scored for the left and right joints:

Norberg Angle
Sublaxation
Cranial acetabular edge
Dorsal acetabular edge
Cranial effective acetabular rim
Acetabular fossa
Caudal acetabular adge
Femoral head/neck exotosis
Femoral head recontouring

And the total of all these readings is added together to form the total hip score, out of a maximum of 106.

So it's not just a matter of taking two Dogues each with say a hip score of 10. You need to look at the analysis of the hip joint and match up any high scoring areas, with a low scoring mate.
Eg. If a female scores a left 4 and right 5 in Sublaxation, you would want to breed her to a male who has 0:0 in Sublaxation on both left and right, same goes for the other measurements.

Sublaxation is the tightness of the ball within the socket. A loose joint can cause problems, so if you continue to breed Dogues with high Sublaxation, you will perpetuate the space between the ball and socket, whereas the fit is supposed to be tight.

ALWAYS ASK TO SEE A COPY OF THE HIP SCORE REPORTS FOR THE PARENTS WHEN BUYING A PUPPY AND TRY AND ANALYSE THE COMPATIBILITY OF THE PARENTS.  EVEN ASK YOU VET FOR GUIDANCE.

 

GREAT EASY TO READ DIAGRAMS OF GOOD AND BAD HIPS

Link to International Vet Report on Hip Dysplasia— http://www.grsk.org/Fluckiger_Scorig.pdf

 

 

What if they don’t own the stud dog?

Any breeder to correct health assessments on their Dogues when planning to breed, should be assessing all aspects of both the dogs hip score reports.  Even if the stud dog is from another kennel or owned by someone else, it is recommended to always view a copy of the hip score report in full.  Reputable breeders should be able to provide you with a copy of hip score reports for both parents, even if they don’t own the stud dog.  Xrays are not sufficient.  

 

 

Doesn’t a hip score around the breed average mean the dog has excellent hips?

Many people still believe that hip scores in the 20’s or around the average are excellent but that is not the case.

 

Scores in the 20's show dogs with very poor hip conformation and from a veterinary point of view this is considered a very dysplastic dog.

Dogs that score in the teens are still quite dysplastic dogs.

Breeding together dogs with high scores is very irresponsible. People who practice this may argue that you can do this and still get good scores (which really just equals good luck) but they are also the same people who ignore their pet owners who are crying out about their dog that requires surgery. They'll also be the ones who are first to say it's environmental which is not true.

What is selective breeding?

Breeders need to analyze scores so they are not breeding dogs together that have both scored high in the same aspects of hip conformation and also consider the scores of parents/siblings/relatives. A score of 30 is generally considered the combined number which would see generational improvement in hip dysplasia.

Selective breeding has been proven to improve the overall hip health within breeds which at the same time proves the genetic basis of Hip Dysplasia.

 

Doing matings where dogs are unscored or in the 20's is very irresponsible. With a lot of information and experience you could conceive of breeding together 2 dogs in the higher range (around the average) BUT that would mean having many generations of good to exceptional scores behind both parents (with maybe only 1 or 2 dogs above the average in 4 or 5 generations) and still have a very low probability of producing severely dysplastic dogs but you would also need to take into account scores of litter mates and relatives. If one of those dogs around the average had an extremely dysplastic littermate or had produced extremely dysplastic offspring then you just couldn't justify doing it.

Myths          -          “The dog has bad hips because he is big and grew quickly.”

                      -          “The dog as bad hips because the dog was a terror as a youngster and either                                  jumped fences or crawled under them.”

 

How much does it cost to hip score my dog?
In Australia, the AVA hip scoring will cost anywhere from $200 to $500 depending on where you are and what vet you use. That is for hips and elbows as well.  Xrays can be sent to either an AVA assessor in your state or to the Aust. Vet Radiology Service.  There will be another smaller cost to pay (around $100) for the hip and elbow score report and postage of xrays, etc. 

 

Very small costs for the peace of mind, and the priceless knowledge that health testing can give to you as a Dog owner and especially as a breeder.

 

What age should I hip score my dog?

DV Hip scoring is usually done between 12-14 months of age, but even up to 18 months in males to allow for growth plate closer is normal.  Penn Hip can be done as young as 4 months of age. 

 

 

Link to AVA Hip/Elbow Dysplasia information website. 

http://avacms.eseries.hengesystems.com.au/AM/Template.cfm?Section=Hip_and_Elbow_Dysplasia_Analysis&Template=/CM/HTMLDisplay.cfm&ContentID=6751

 

Or Australasian Veterinary Radiology Service , Dr. RS Wyburn, Western Australia

Email — wyburn@netserv.net.au

 

Hip Dysplasia

NORMAL HIP JOINT                          DYSPLASTIC HIP JOINT