The president of The Danish Kennel Klub Jørgen Hindse Madsen opened the Conference and welcomed the participants.

Prof. Dr. W. Brass represented a welcome send by the President of FCI Hans W. Müller, thanking the participants for taking part and DKK, Dorte Hald Nielsen and Peter von Rosen Vange for the endless effort to make this seminar. Hans W. Møller pointed the universal position FCI has in regards to Hip Dysplasia evaluation and that this conference is a serious progress.

In the name of the FCI Scientific Commission Prof. Dr. W. Brass also thanked DKK and The Nordic Kennel Union for the effort of assuring better organisation of hip scoring. He furthermore made a historical view on the development in procedures of HD evaluation from the first meeting in Utrecht 1974 up to this seminar.

Dr. H.A.W. Hazewinkel gave an introduction to Hip dysplasia; what it is and how it develops.

Résumé is present in a paper copy kindly shared with us by Dr. H.A.W. Hazewinkel.

First sessions next speaker was Dr.O. Distl, Germany, on the subject of Genetics, future technologies and genetic marker.

Dr.O. Distl introduced the current research in inheritment of HD.

For a long time we have believed in a polygenetic model including many genes with no distinguishable effects.

Research are now working with major gene models in different breeds and coming up with a dominant major gene model in German Shepard with phenotypic scale for CHD.

In German Shepard study have been made on a common sire with clinical signs of HD and his progeny, looking what is transmitted in sire, what is different and what is common with HD effected and not effected progeny.

Studies have been made on Labradors, Rottweiler, Golden Retrievers, German Shepard and Greyhounds. These studies have been made from different HD-diagnose systems, Norberg Angel, signs of distraction or FCI score. Comparison has been made to se where there was agreement on found chromosomes, looking for allele to se transformation of chromosomes.

Conclusion. HD has a very complex gene trait, 90-95% is genetic, only 5-10% environment. HD is a genetic disease in some or all breeds. Different single genes influence CHD and are located on some chromosomes in some breeds.

Perspectives. We need more breeds included in such studies, establishment of DNA-banks and care-control studies.

For recording of CHD we need a good classification system.

Questions were made to the extent of false negative or positive diagnoses of HD influence on the result of the studies and to the time aspect in having a DNA-test available. To the last question the answer was “it depends on money”

Speaker was Prof. Dr. M. Flückiger, Schweiz on the subject “Requirements for official FCI scoring, age of the animal, sedation/anaesthesia, number and type of projections and submission of digital films.

Dr. M. Flückiger described the current criteria for making x-rays used to score hips by the FCI-system.

Age minimum 12 months, for giant breeds 18 months. Breed clubs may rise the minimal age. Giant breeds are decided to be breeds more than 50 kg.

Rumours have been that female oestrus may have influence on the laxity, but studies have shown no negative effect on laxity, neither on standard nor on distraction x-ray

Relaxation by sedation or anaestesia is important as laxity can be hide or masked in awake animals, witch gives false data. The difference on using relaxation is highly significant and we might miss up to 60% of the dysplastic dogs without relaxation

Projection: hind limbs extended, pelvis symmetrical, femora parallel to each other and to tabletop and patella centred.

The Swiss model includes an x-ray with hind legs abducted with femora pulled 90 degrees, as this picture gives good evaluation of the femoral head.

Examples on malpositions:

Pelvis, rotation over long or short axis.

Rotation over long axis makes unequal hip appearance; rotation over short axis makes almond shaped foramina oblongata and effects on the Norberg angle reading.

Femora abducted might mask a subluxation. A femora medial abducted makes subluxation pronounced.

Is femora outward rotated shows subluxation. A femora inward rotated makes a pseudo Morgan line, witch has nothing to do with HD.

Femora not parallel to tabletop can mask a subluxation.

Stick to proper position, it’s very important!

Digital Films. We have to consider some aspects before accepting these films.

Prerequisites:

Medical standard. X-rays must be produced and stored according to a standard ex. Dicom (digital imaging and communication medicine), but these are very big films that have to be stored.

Identification of animal and owner. The program does not accept any diffrenties.

Need of tool to measure Norberg angle on screen.

The quality is usual very good as contrast etc. can be manipulated. Problem occurs when the picture is manipulated, ex. Removement of arthrosis.

Dicom image cannot be manipulated.

Storage system. Storing images demands a big capacity. Therefore many clinics have to reduce the pictures to .jpg or .tif. They are only 10% of the size of a Dicom image and they can be manipulated, both id-information and the picture.

The archiving software might not be compatible with Dicom, refused radiographs can’t be marked and there is no tool for measurement of Norberg angel.

Current solution:

We do accept electronic image if it’s printed out on film or paper (minimal size 65%)

We make manual measurement of Norberg angle

Scoring criteria FCI:

Norberg angle, joint space width, position of femoral center, shape of craniolateral acetabulum edge, Morgan line.

Score: A-E

Swiss system:

Gives points to each of 6 individual criteria, score 0-5, best is 0, and worst is 30. Easy to translate to FCI-system

England:

9 criteria score 0-6, best is 0, and worst is 53 each side, total 106. Score on right and score on left side. Do not translate to FCI-system.

In England there is no grading, only score. There is no breeding ban for dysplastic dogs.

New better methods:

Comparison between FCI, British and Swiss scoring. Se article on:

Gutmann, Matthias 2003

Future:

Genetic markers, major genes.
Blood testing
Puppy screening
Preventive, measurements early and adequate.

The future is brainpower. Prevention is not al medical but also a psychological challenge.

Questions or comments were made to sedation, difficulties on position and the risk of getting a false positive or negative result and type of selections in breeding stock.

Speaker was Dr. B. Tellhelm, Germany on the subject: Hip scoring, for breeding selection only, FCI mode (A-E), limits and variations.

FCI diagnosis of CHD made by radiography. Primary criterias are laxity and deformation, secondary arthrosis.

Only in single cases comparable findings shows cause of trauma or inflammation. Differentiation is normally not possible.

FCI classify CHD in 5 categories depending on the present of dorsal acetabular rim, joint space, femoral neck, subcondral bone layer and center of femoral head.

Germany screen with points in 3 grades.

Must be able to se dorsal rand of acetabular rim. Grid can cause problems.

Asymmetry, tilting to left or right

Criteria for laxity, Norberg Angle < 105, correlation of femoral head center and acetabular rim, joint space, osteoarthrosis.

Hip arthrosis is seen by subcondral sclerosis, osteophylosis/enthesiophilosis, remodelling of femoral head and acetabulum, collar-line.

Collar-line is a line along the border of femoral head to the neck, a ringdeformation. This arthrotic change can be difficult to se, but is more easily seen in second x-ray position. Osteoarthrosis is degeneration, not an inflammation.

Some breeds have a different form of the femoral head, what makes the collar-line seen, without being an athrotic deformation.

Morgonline is new bone on the femoral neck

Sclerosis is seen as additional bone on the neck under the head.

Puppyline. In some dogs or breeds we find a small scarp line on the femoral neck what will disappear later. Seen on a good hip, I personally don’t take it in evaluation.

The femoral head deformation is not always clear. It is very important with positioning and no rotation.

We se more breed variations.

The femoral head-neck in some breeds like GSD has a special form, ex. seen as there is no real neck.

Is no real neck dysplasia? Is it too thick neck or too short neck?

These dogs get same score as dogs with normal neck.

Some other breeds have a special form of the hip

Scoring by the FCI system, decides the final result to be the score of the worst hip.

Score system A-E

No signs of HD: A

Congruent head and acetabulum, sharp and slightly rounded craniolateral rim, joint space narrow and even.

B: Slight incongruence with a Norberg Angle about 105 or the femoral head center medial and congruent head and acetabulum.

Comment: I would like us to rediscuss this definition. This is a normal joint. Where is the border to “slight”, there is only a minimal divergence, what is normal and what is scored as B?

Mild HD: C

Incongruent acetabulum, Norberg Angle ~100, slightly flattening of the craniolateral rim.

Comment: and/or laxity. Here is the quality of the x-ray very important, to detect small sign. Is it irregularities or only slight osteoarthrotic changes?

Moderate HD: D

Obvious incongruent/subluxated, Norberg Angle> 90. Flattening of the craniolateral rim and/or osteoarthrotic signs.

Severe HD: E

Marked dysplastic changes, luxation, Norberg Angel< 90, obvious flattening of craniolateral rim, deformation of femoral head, osteoarthrosis.

Limits of FCI system:

Estimation of laxity is uncertain.

Classification based on radiological arthrosis has a weakness, as arthrosis as result of a primary disease need time to develop. Furthermore it can be breed depending and can be caused by different genetic diseases.

Does arthrosis always mean laxity??

It’s subjective to a large extend, as it’s highly influenced by technique, quality and the person who evaluates.

Development of HD is a biological occurrence with lots of variations.

Different scrutinisers can score a dog’s hips differently. I think there should be only one expect for one breed, also international seen.

Consistency of screening is important.

Breeding advise:

Should the screening be as rigorous as possible?

Is it better to exclude a possible good dog than to include a possible bad dog?

It depends on the situation in the breed.

Phenotype is not the same as genotype. Hereditability of criteria should be considered.

Questions or comments were made to the 5 scoring categories, if they give enough information to selection of breeding stock and to the relevance of making different references for different breeds.

Speaker on this session was Dorte Hald Nielsen, Denmark. DHN introduced the Nordic Kennel Union and their suggestion to improvement of the FCI-scoring system.

The NKU HD-panel consists of persons who evaluate HD in Denmark, Sweden, Finland and Norway. Together we evaluate hips on 42.000 dogs a year. I hope to have an open discussion and exchange view and I hope we are able to reach consensus to be used on discussion on Scientific Commission FCI.

First I like to discuss some additions to the FCI protocol. In the protocol from 1991, we find the demand on technical quality to be very week. We would like to ad on this.

About the quality:

g) "The minimum size of the x-ray film must be such as to include the pelvis up to a level of os sacrum and both patellae. The technical quality of the radiographs has to be such as to allow accurate visualization of the hip joint. As a minimum the margo acetabularis must be clearly recognised...."

h) "If the above listed rules are not fulfilled the radiograph has to be rejected."

This lead to a discussion weather the films always must be rejected if the above mentioned are not fulfilled, even though the scrutiniser finds the evaluation of the hip clear. There were also views on the possibility of the problem of fitting both hip and patellae of a giant breed on same film and to witch is most important, lumbosacral or patellae. The scrutiniser is the person that rejects or accepts an x-ray, but it these rules are written down, it might be easier for the veterinarians to understand the rejection of a film.

There were also questions made to the choice of words and the seminar decided to focus on reaching agreement and leave the formulation to the English-speaking people.

The seminar accepted the suggestion g) if removed "as a minimum"

The participants discussed the problems of positioning some very muscular breeds as described and how much divagation from ideal to accept and also the possibilities of manipulating the pictures.

The participants agreed on the importance of having a clear definition on how the dogs shall be positioned and also to standardize and thereby harmonise the evaluations.

The participants also discussed the risk of not getting new pictures for evaluation if the x-rays were rejected and thereby having less dogs evaluated. Never the less it is the evaluators responsibility to decide if the x-rays are good enough to be evaluated and to explain why he/she chooses to evaluate a picture even though it did not fulfil the written rules.

The difficulties of measuring the Norberg Angle and the different tools available for measurement were discussed. Especially the problem to determine the center of the head and to find the acetabulum point.

Evaluation in plenum of the 20 pictures send in advance to the participants:

Pic. 1: 

Quality: 1
Position: 1
Congruent, joint space even, NA>105, center of head medial.
A/A

Pic. 2: 

Quality: 2
Position: 2, patella right femur not enough rotated
Incongruent, uneven joint space, NA<100, center of head outside dorsal rim, no arthrosis.
Discussion on size of NA and final evaluation C or D
D/C

Pic. 3: 

Quality: 1
Position: 2, patella right femur not enough rotated
Congruent, slight joint divagation, NA<105, Sclerosis on central cranial contour, not luxated, ringline
Discussion on the advantage of having a second position picture of this dog to estimate the ringline. This dog is between a B and C
B/B

Pic. 4: 

Quality: 1
Position: 1
Slightly incongruent on both sides, most on left side. Divergent joint space, NA<105, right side center of head on dorsal rim, left side slightly outside dorsal rim. No arthrosis.
Discussion on evaluation and NA. Opinions B/D, C/C as of flattening and NA~100, B/C
B/C or C/C = C

Pic. 5: 

Pic. 6: 

Quality: 1
Position: 2, asymmetry in pelvis tilted to right side, minimal rotation
Slight incongruent, NA right 105, left 100
Discussion: Because of pelvis rotated NA~100 both sides
A/B or B/B = B

Pic. 7: 

Quality: fair
Position: fair but slightly tilted to the left.
Incongruent, Malformation, deform head, osteofytes on femoral neck, Morgan line, flattened rim, subluxation, NA~90
E/E

Pic. 8: 

Quality: 1
Position: 2, because of left side where hind leg is pushed toward midline.
Unusual formation of neck, not well marked.
Congruent, NA 105, no signs of DJD.
Discussion on NA 105 or <105 right side = B/A. Pelvis bit tilted = A/A.
A/A

Pic. 9: 

Quality: 2, not clear dorsal left
Position: 2, not parallel with the axis and pelvis tilted to the left.
Incongruent bilateral, sclerosis, obvious signs of arthrosis on neck, center of head lateral to dorsal edge.
Discussion: Less on left side
D/C or D/D = D

Pic. 10: 

Quality: 1
Position: 2, Asymmetric pelvis, little rotated.
Sclerosis neck left side. Sclerosis acetabulum, luxation, NA left~90, right~95, center of head outside dorsal rim.
Discussion: C/D or D/D
C/D or D/D = D

Pic. 11: 

Quality: 1
Position: 2-3, femur not enough rotated, patella not centred. Shape of foramen body, but can evaluate these hips in spite the quality.
Congruent, even joint space, femur head ½ - 1/3 inside dorsal rim, NA>105
"The hips of my dreams"
A/A

Pic. 12: 

Quality: 1
Position: 2, stifle not included. Discussion as some would give pos: 1
NA normal, center of femur head just on dorsal rim, deformation both sides.
Discussion: Wider joint space on right side, slight sign of new bone formation – ringline, NA<105 and femoral head out of center. Slight deformation of right head. Is this a dysplastic hip?
B/B or C/B??

Pic. 13: 

Quality: 1
Position: 2 – 3, femur not parallel, Patella not centred. Shall these pictures be rejected?
Congruent, cranial rim thin and nice, no signs of osteofytes or sclerosis. Center of head almost on dorsal acetabular rim, NA~105.
Discussion: Correct position would show more luxation, Discussion on where on the acetabular edge to use for measurement of NA. End of edge or end of acetabular rim?
B/B or B/A = B

As result of this discussion was decided to develop a guideline on how to measure the Norberg Angle.

Richard C. Nap and 2 more people from the seminar will make a suggestion to a guideline.

Pic. 14: 

Quality: 1
Position: 1, even though patella is not quiet in the middle. Discussion about position = pos: 2. The picture will not be rejected.
Incongruent, Laxity, NA~90, artrotic changes on right side
Discussion D or E
D/D or E/E?

Pic. 15: 

Pic. 16: 

Quality: 1
Position: 1
Incongruent, broad joint space, flattened acetabular rim, maybe small osteofytes on edge, center of femoral head out on left side
Discussion: NA 95 or 105, dysplastic joint but femur head is not so damaged. Incongruent, then NA doesn’t matter. Congruency is the most important. The sclerosis on outer acetabulum shows that the head hides more on the outer side of acetabulum.
C/C

Pic. 17: 

Quality: 1, maybe 2 as the grid is not centred, not correct in focus
Position: 1
Congruent, NA~105
Discussion: Wide pelvis canal, but then as a result the acetabular rim is parallel and straight and often NA<105, the head is big and that often makes it difficult to reach NA 105. Conclusion is that NA 105 must only be a reference.
A/A

Pic. 18: 

Quality: 1
Position: 1, though bit rotated on long axis
Congruency good, not perfect, NA~105 right side, left NA<105, no secondary changes.
A/B = B

Pic. 19: 

Quality: 1 – 2 as bone structure is not clear on neck
Position: 2, patella not centred and pelvis slightly tilted
Not congruent, hardly any reactions, subluxation.
Discussion: We don’t need any degenerative changes to get a D, passive laxity.
D/D

Pic. 20: 

Quality: 1
Position: 2, asymmetric pelvis, iskias bigger on right side
Small diversion, no significant sclerosis. Right side clear sclerotic line on neck
Discussion: C/C or C/B, ringline thicker on right side
C/C or C/B = C

Last comments of Saturday’s workshop:

We have had no hipevaluation more than 1 score from each other

Discussion went about manipulation of the hip, remodelling of the bone, burning the growing cartilage and gold implantations.

A request was made, that all surgery done covering inherited disease must be reported to the kennel clubs by the veterinarian.

Make the owner sign to the information about earlier screening and surgery of importance at time of screening.

Suggestion was made to make measurement variability for each breed, as base for screening. This would make the evaluation a better tool for breeding, by making it possible to find a partner that compensates a specific problem. Now it’s all together in one score and unusable for breeding selection

Belgium participants referred to current belgium research on measurement of HD. Final presentation will be ready in 1 year and we will send you all a presentation.

Åke Hedhammer closed today’s discussion and thanked Dorte Hald Nielsen for a good program and a well-organised day.