RTG photo- base for diagnosis

[Liz P]

A few studies I was able to find online on short notice.

 

Early detection of canine hip dysplasia: comparison of two palpation and five radiographic methods

J Am Anim Hosp Assoc. 1998 Jul-Aug;34(4):339-47.

Distraction index measurement (PennHIP method) was the most accurate in predicting the development of DJD (p less than 0.001). Distraction index radiography in puppies six-to-10 and 16-to-18 weeks of age was the most reliable predictor of hip dysplasia.

 

Evaluation of the relationship between Orthopedic Foundation for Animals' hip joint scores and PennHIP distraction index values in dogs.

J Am Vet Med Assoc. September 1, 2010;237(5):532-41.

CLINICAL RELEVANCE: Dogs judged as phenotypically normal by the OFA harbored clinically important passive hip joint laxity as determined via distraction radiography. Results suggested that OFA scoring of HE radiographs underestimated susceptibility to osteoarthritis in dogs, which may impede progress in reducing or eliminating hip dysplasia through breeding.

 

An assessment of the agreement between the New Zealand Veterinary Association Hip Dysplasia Scoring System and the PennHIP Distraction Index in German Shepherd dogs.

N Z Vet J. December 2009;57(6):338-45.

CLINICAL RELEVANCE: The low level of agreement between NZVA and PennHIP results in the same dog precludes them being used interchangeably to guide breeding decisions. The higher heritability of distraction-index measurement in previous studies suggests that it is a better selection tool for breeding dogs when CHD is present within a population. The advantage of a hip-extended ventrodorsal view is its low cost and widespread availability but comparisons between individuals may not be accurate due to the poor sensitivity and the presence of false negatives.

 

Distraction index as a risk factor for osteoarthritis associated with hip dysplasia in four large dog breeds.

J Small Anim Pract. May 2010;51(5):264-9.

J J Runge¹; S P Kelly; T P Gregor; S Kotwal; G K Smith

CLINICAL SIGNIFICANCE: Results from this study support previous findings, that irrespective of breed, the probability of radiographic OA increases with hip joint laxity as measured by the DI.

[emilyfalk]

Liz,

 

You say 'work alone' doesn't expose HD in border collies. What does, then? A distraction index on a radiograph? If I raise my dog on appropriate nutrition and with appropriate puppy-related cautions and then it grows up to work sound it's whole life...what else would be relevant in exposing HD? Sure they have a great work ethic, but I bet a severely affected dog would still show gait abnormalities while working, would exhibit a change in work (slicing flanks, not lying down, or not covering), or while their guard is down (waking up from a post-exercise activity).

 

It seems to me that reading hip scores and not looking at the dog's soundness is like reading a CBC without looking at the patient's clinical signs. "Within normal limits" can be normal or abnormal, and vice versa, depending on the situation.

 

I want to know who goes lame from HD and therefore can not work. So I want to know who is showing signs and also has radiographic findings to support HD. Not the other way around. There are dogs who have HD and remain sound throughout their entire working career. I wouldn't necessarily remove such a dog from the breeding population.

 

And I did go to school at Penn and have been thoroughly versed in PennHip. I believe in it, but I'm not convinced it applies to working border collies.

[Liz P]

"Interesting, Liz, you may well be correct and not that I'm trying to diss your statements in any way, but is your observation a 100% correlation? Or just your impression?, because, unfortunately, impressions or small sample size can squew the real statistics (and... as you previous stated in this thread 'association does not prove 'causation')"

 

You are absolutely correct that I haven't owned enough dogs to have enough data for a reliable confidence interval. However, it's pretty easy to look at an 11 year old dog who could still run 15 miles on a dog sledding team, come home sound and still want more work and compare him to the 9 year old dog who was lame for weeks after a half mile walk to check the sheep in the far pasture.

[Liz P]

Emily, I've owned and worked my fair share of dysplastic dogs. For several of them, you would have had no idea until they were much older, old enough to have grand pups and great grandpups already. My most severely dysplastic dog was extremely flexible and hard working. Outruns were done at full speed, flanks were quick and clean, covered great and only refused a lie down when the dog disagreed with the command. That dog did not start to get lame after working until nearly 8 years old.

 

Of course I look at the whole picture, but are you saying you think it's ok to breed a dysplastic dog with abandon just because it can work hard? It's been done, and the results are sad.

[emilyfalk]

With abandon? Of course not.

 

You describe just what I'm talking about: if your severely dysplastic dog worked well into old age, is it's hip score *that* important? What I get from your other posts is that you would've first x-rayed the dog, found out it had a high DI or signs of HD, diagnosed it as dysplastic and written it off. Your example is the exact opposite of what you have been posting, so I am confused what point you are trying to make.

[Liz P]

I am not sure how it's the opposite of what I have been posting? I want dogs like the one that was still working at 12 years old. I consider my 5 year old trial dog to only be in the middle of her career, not at the end of it. Accurate hip scoring of breeding stock increases the odds of producing sound offspring that stay sound well into their senior years. I've had dysplastic dogs who were lame before their 5th birthday. I had one dysplastic pup that was bunny hopping at 8 weeks old. One friend had a BC with such sever HD as a pup that the choice was total hip replacement or euthanasia.

 

My point about the dog that wasn't lame until 8 years old, then declined very rapidly, was that I could have bred that dog many times had I not hip scored it. If I had made the mistake of breeding the dysplastic dog to another dog that was also dysplastic but appeared sound, I could have produced many pups like the one my friend euthanized. There was one such dog someone did breed. First litters were done without hip scores. Dog was scored after producing severely dysplastic pups that were unsound even as pets. Justification was made that the dog was producing so well that it was still bred, even after producing those dysplastic pups and being found to be dysplastic itself.

 

Would you buy one of those pups? How would you feel if you had been the person that bought a pup that wasn't even sound as a pet?

 

I buy pups from working parents to increase my odds of getting a dog that works. I buy pups from health tested parents to increase my odds of having a dog that is sound and healthy. If you want to take a risk and buy a pup from parents without scores or that are even dysplastic themselves, it's your choice.

[mum24dog]

ETA I also get the impression that in the UK there is much less emphasis placed on hip testing in working BCs (the general comment being that good hips are selected for by the nature of the work they do). when it is done, it is mainly some of the larger breeders and those individuals who have their dogs standing at stud for a lot of bitches...and I think both are aiming to send pups to the U.S...or maybe to the agility crowd who will probably be more willing to pay more than working stockmen/women

 

Risk's sire belongs to his breeder, is well used at stud and is hip tested.

 

His dam isn't but is one of the breeder's own well tried and tested line with a lot of offspring. Some litter mates were destined for the US, Canada and countries in Europe.

 

If the breeder buys in a bitch from another line with a view to possibly breeding if she shows working promise she will probably be tested before breeding.

 

I'm OK with that given the fact that hip testing provides no guarantees and the polygenic nature of the condition.

 

I also have a nearly 9 yo dysplastic dog that is competing in top class agility as well as ever without any signs of discomfort so the possibility of HD doesn't send me into a tailspin of panic. We only found out that he had HD by accident. I wouldn't have bred from him though even though he is currently functionally sound. (Well I wouldn't have bred from him anyway, but that's a different issue.)

[Eileen Stein]

Accurate hip scoring of breeding stock increases the odds of producing sound offspring that stay sound well into their senior years.

Theoretically yes, but what is accurate hip scoring of breeding stock?

 

Emily touches on what I think of as a major problem in most of the studies: they validate a method by comparing how well its score correlates to another score, rather than to the actual condition of the dog in later life. (Liz, you say you have informally used the actual condition of the dog in later life as a criterion, but only for a sample so small that no validity could be claimed for it. I'm sure you know that a different handful of dogs could have produced the opposite results.) I've also noticed that most PennHIP advocates cite instances of dogs' passing OFA but being found dysplastic by PennHIP as evidence that OFA is deficient. There's an obvious logical fallacy there -- It's a valid contention only if you ASSUME that PennHIP scores are "right." And what's the basis for assuming that? Circular reasoning.

 

You can do harm with a health test, if your premises are not correct. For example, you can exclude dogs from breeding for fear they will produce PRA, when in fact the "test" (exam) you are using to identify the dogs to exclude is actually mistaking an acquired retinopathy for a hereditary one. If Denise's hypothesis is correct -- and I do find it persuasive although certainly not proven -- we could be doing harm by accepting PennHIP's distraction index measurement to exclude border collies from breeding.

 

Actually, though, the OP's question did not concern using a hip test for breeding, but simply using it to predict the likely soundness of her own dog. And while I think Denise's article should be required reading for everyone, I mainly cited it for her comparison of OFA and PennHIP as screening tools:

 

. . . Some procedures are better at screening individuals for a disease but not as good as a selection tool, that is, predicting how that individual will pass on certain traits. OFA ratings are usually very reliable as a screening tool. A passing OFA rating on a dog at least two years old will determine within a 95% confidence limit the dog will not develop HD. Therefore, for a yes or no answer on that individual, OFA is statistically sound as a predictor for HD. . . .

. . . When PennHIP is used as a screening tool, it can predict with very good accuracy that dogs with values of 0.30 or lower will be unlikely to develop HD. And that many dogs at the other end of the range (DI of 0.70 or higher) with very loose hips will develop HD. However, most dogs of all breeds will fall somewhere in the middle or the "gray zone" for these predictions. So one cannot accurately predict whether one’s dog will develop HD or not in most instances using this technique. . . .

 

If there has been later specific research that contradicts this assessment of PennHIP (which is certainly possible, since the article is not a recent one), I would be interested in being referred to it.

[Pipedream Farm]

So what is the gold method for determining if a dog has HD? Is it the score given by one of the many methods discussed or is it the function of the hip?

 

 

 

 

 

Comparison of three radiographic methods for diagnosis of hip dysplasia in eight-month-old dogs

http://avmajournals.avma.org/doi/abs/10.2460/javma.2001.219.1242

 

Objective—To compare the accuracy of the extended- hip radiographic (EHR) score, the distraction index (DI), and the dorsolateral subluxation (DLS) score for identifying hip dysplasia in dogs at 8 months of age.

 

Design—Cohort study

 

Animals—129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhound crossbreds.

 

Procedure—Radiography was performed when dogs were 8 months of age. Dogs were euthanatized at 8 to 36 months of age; hip dysplasia was diagnosed at the time of necropsy on the basis of results of a gross examination of the articular cartilage of the hip joints for signs of osteoarthritis.

 

Results—The EHR score, DI, and DLS score at 8 months of age were all significantly correlated with degree of cartilage degeneration at necropsy. Sensitivity and specificity of using EHR score at 8 months of age to diagnose hip dysplasia (scores > 3 were considered abnormal) were 38 and 96%, respectively; sensitivity and specificity of using DI (values > 0.7 were considered abnormal) were 50 and 89%; and sensitivity and specificity of using DLS score (scores ≤ 55% were considered abnormal) were 83 and 84%.

 

Conclusions and Clinical Relevance—Results suggested that specificities of the 3 methods for diagnosing hip dysplasia in dogs at 8 months of age were similar. However, the DLS score had higher sensitivity, indicating that there were fewer false-negative results. (J Am Vet Med Assoc 2001;219:1242–1246)

[Liz P]

PennHIP gives 1) A report of the appearance of the hip, including a description of the fit, any changes seen and a note about whether or not the dog has DJD. This is similar to OFA but gives actual info about the dog. 2) A laxity rating. 3) A percentile that compares the individual dog to the other individuals within the breed that are in the database.

 

So, what you are essentially saying is that you don't like PennHIP because you don't know how to use the results (as you would OFA results) to make sound breeding decisions.

[mum24dog]

I am not sure how it's the opposite of what I have been posting? I want dogs like the one that was still working at 12 years old. I consider my 5 year old trial dog to only be in the middle of her career, not at the end of it. Accurate hip scoring of breeding stock increases the odds of producing sound offspring that stay sound well into their senior years. I've had dysplastic dogs who were lame before their 5th birthday. I had one dysplastic pup that was bunny hopping at 8 weeks old. One friend had a BC with such sever HD as a pup that the choice was total hip replacement or euthanasia.

 

My point about the dog that wasn't lame until 8 years old, then declined very rapidly, was that I could have bred that dog many times had I not hip scored it. If I had made the mistake of breeding the dysplastic dog to another dog that was also dysplastic but appeared sound, I could have produced many pups like the one my friend euthanized. There was one such dog someone did breed. First litters were done without hip scores. Dog was scored after producing severely dysplastic pups that were unsound even as pets. Justification was made that the dog was producing so well that it was still bred, even after producing those dysplastic pups and being found to be dysplastic itself.

 

Would you buy one of those pups? How would you feel if you had been the person that bought a pup that wasn't even sound as a pet?

 

I buy pups from working parents to increase my odds of getting a dog that works. I buy pups from health tested parents to increase my odds of having a dog that is sound and healthy. If you want to take a risk and buy a pup from parents without scores or that are even dysplastic themselves, it's your choice.

 

I'm a bit confused. You seem to have experienced an unfortunate number of dysplastic dogs but say you buy pups from health tested parents. Have you just been unlucky or is there another reason?

[Mark Billadeau]

Liz,

 

I'm saying that all of the radiographic methods provide the same useful information on the hip at the time the radiograph is taken (is it within normal limits or abnormal) and none is any more reliable than the other in making breeding decisions towards reducing the incidence of HD in the breed. I also suspect the hip score obtained at 24 months is best predicted when using the same method during the preliminary hip exam; PennHip does a better job at predicting PennHips scores than OFA would be at predicting PennHip scores.

 

What you seem to be forgetting is that a dog with passing hips scores (using any method) could be genetically "affected" with HD but a restricted caloric diet prevented the phenotype from being developed in a dog with the genotype. So how can any one of these methods be better than the others at selectively breeding out HD?

 

The problem in selectively breeding to yield certain hip scores is that hip scores have never been correlated to the functioning of that hip over a lifetime of working livestock. The hip evalautions should be used to exclude from breeding dogs with HD (a polygentic disease for which we have no genetic test).

 

 

Mark

 

 

 

BTW, we don't use OFA; we send in our radiographs to Cornell for a written report on the hips which is more than just a score.

[emilyfalk]

I'm still confused.

 

Of course I recommend hip screening radiographs of any sort for all breeding dogs. That provides useful information. But I don't really care if it is OFA excellent vs good, or if the DI is in the 99% or the 75% percentile. A functioning joint in a sound dog is good enough for me. Or, finding a dysplastic joint in a mature sound dog would tell me to pay extra attention in choosing a cross.

 

Besides, aren't we pretty certain that HD is polygenic? How many times do people say "you can still get a dysplastic pup from 2 excellent parents"?

 

In other breeds, they have so little criteria for breeding a "quality" dog (ie they're all pets already and many have ridiculous health problems from birth), so it makes sense to use the hip scores to improve the breed. If there was a "nose score" for brachycephalic dogs, I'd be all over that!

 

I wonder if border collies aren't like sheep: we are now recognizing that selecting for parasite *tolerance* is another way to tackle the dewormer resistance problem. There are sheep that are resistant to worms (don't carry a heavy worm burden) and sheep that for whatever reason thrive while tolerating a high worm burden. There is some protective factor we don't know about. Maybe our dogs could be the same? HD resistant dogs and HD tolerant dogs? I don't think one is necessarily "right" and the other "wrong", just different.

[Liz P]

First dysplastic dog I called the breeder, let her know. Got another pup (kept the first though) because I wanted something to compete with. Replacement pup (unrelated) was also dysplastic. Turns out I was lied to. First dog's sire had a prelim normal but was later found to be dysplastic himself. Second dog I was also lied to. Turns out grandparents were dysplastic. After the first dog I wanted several generations of clear hips, so I was really unhappy. I didn't learn this until a friend with a littermate who was also dysplastic called me.

 

Had another dysplastic dog out of an OFA Fair x Cornell normal breeding. Different breeder.

 

Got a pup by a sire whose hips were supposedly normal x a bitch who is Cornell normal. After I noticed a problem I asked to see the actual score of the sire. Owner skirted the issue and wouldn't show them to them.

 

Over a period of 20 years and owning 15 Border Collies that I hip scored, I've had 4 with HD. Bad luck? Partly luck, partly being naive and stupid with the purchase of my first few dogs.

 

Recently I had a conversation with human genetics councilor who said the gene for HD in people is dominant with incomplete penetrance. He suspects we might be seeing the same in dogs based on pedigree analysis.

[Maxi]

Recently I had a conversation with human genetics councilor who said the gene for HD in people is dominant with incomplete penetrance. He suspects we might be seeing the same in dogs based on pedigree analysis.

 

Liz there are several genes that are associated with HD in humans that map to different chromosomes. You can check this out in OMIM (Online Mendelian Inheritance in Man).

http://www.ncbi.nlm.nih.gov/omim/?term=hip+dysplasia

[Maxi]

 

 

I wonder if border collies aren't like sheep: we are now recognizing that selecting for parasite *tolerance* is another way to tackle the dewormer resistance problem. There are sheep that are resistant to worms (don't carry a heavy worm burden) and sheep that for whatever reason thrive while tolerating a high worm burden. There is some protective factor we don't know about. Maybe our dogs could be the same? HD resistant dogs and HD tolerant dogs? I don't think one is necessarily "right" and the other "wrong", just different.

 

I think this is very interesting, & possibly correct, notion.

 

Although this paper relates to Alaskan Sled Dogs. It does indicate that there may be specific genomic profiles associated with speed, endurance and work ethic. It is plausible that some of the markers identified may link to factors that confer a protective effect on joint structure.

[Klaudia945]

Yes, it's ring in the corner.

In our law there is a mention that employees can't be inside RTG workroom, while doing photo. So if you want to do photo of your dog bones, you just have to bring two adult people (of course healthy, not pregnant etc.) with you to hold dog (this is what vet said to me).

I will need a little time to read the whole discussion

She's 15 months old, so I don't want to do registration of score in pedigree yet (this can be a reason, why vet done a bad photo... because this isn't photo for registration... ).

 

[Maxi]

I buy pups from working parents to increase my odds of getting a dog that works. I buy pups from health tested parents to increase my odds of having a dog that is sound and healthy. If you want to take a risk and buy a pup from parents without scores or that are even dysplastic themselves, it's your choice.

 

This link from the Institute of Canine Biology may be of interest for those who wish to chose pups which are genetically predisposed to have a reduced risk for HD. However, it should be noted that this article states

' Hip dysplasia has a heritability of about 20%, which means that 80% of the variation among dogs is influenced by the "environment" (which includes anything that is NOT genetic) - nutrition of the mother, how much exercise the puppy got, what substrate is in the kennel - ANYTHING that could influence the quality of the hip. So a dog might not have great hips, but if it has a low EBV for hips, that tells you that it has good GENES for hips.

 

The author (Dr Carol Beuchat PhD) has also posted this blog entry that provides some additional links to relevant research papers

[Mark Billadeau]

Below is a quote from a retrospective study on hip and elbow dysplasia in the USA. While this study talks about hip scores from one radiographic method I have seen the same conclusion drawn about other radiographic methods: hip scores (phenotype assessments) are insufficient to decrease the prevelence of HD and ED in breeds.

 

 

 

 

 

Monitoring Hip and Elbow Dysplasia Achieved Modest Genetic Improvement of 74 Dog Breeds over 40 Years in USA

 

The complex inheritance patterns of both ED and HD have been extensively investigated [1], [3]–[7], which supports the argument that in order to reduce the incidence of HD and ED, selection for breeding should be based on estimated breeding values (EBVs) and not simply the phenotype of antecedent generations [3]. The genotype of a dog with a complex trait cannot be revealed from its phenotype. This is particularly relevant for dogs with borderline or unaffected hips that can harbor deleterious mutations that are not apparent from their phenotypes

[Liz P]

But when selection pressure is applied and a high percentage of dogs are screened, meaningful data can be gathered and used to improve hip scores. If everyone hip scored their dogs, we might actually have some success at reducing the rate of HD in the breed.

J Am Vet Med Assoc. 1997 Jan 15;210(2):207-14.

Prevalence and inheritance of and selection for hip dysplasia in seven breeds of dogs in Sweden and benefit: cost analysis of a screening and control program.

RESULTS:

Decreasing prevalence of hip dysplasia corresponding to selection of breeding stock and high heritabilities was found. Sex differences were documented in 3 of the breeds. This was interpreted as breed differences in the distribution of genes related to hip dysplasia.

 

 

Genetics of canine hip dysplasia

J Am Vet Med Assoc. May 1997;210(10):1474-9. 16 Refs

RESULTS: In < 5 generations of selection, the percentage of German Shepherd Dogs with canine hip dysplasia at 12 to 16 months of age decreased from 55 to 24%. Among Labrador Retrievers, the percentage decreased from 30 to 10%. CLINICAL IMPLICATIONS: This report gives practitioners documented proof that genetic selection will work to improve hip quality.

[Pipedream Farm]

To use one of your arguments.....

Those studies are much older than the one I posted and the more recent study includes many more dogs (A total of 1,264,422 dogs from 74 breeds) making it more statistically significant.

 

Mark

[emilyfalk]

I'd be interested in a study that used a large number of working border collies. No other breeds, no anecdotal information.

 

Hmm, maybe I could start that, get back to you in 10 years or so

[Maxi]

I'd be interested in a study that used a large number of working border collies. No other breeds, no anecdotal information.

Hmm, maybe I could start that, get back to you in 10 years or so

Would be nice.. and it's possible that places like Cornell who are collating this info may be able to provide some details (certainly the paper that Mark cites has a figure that lists information pertaining to BCs).

 

,,,but unfortunately I personally reckon that most repositories of either hip scores or DNA (for genomic screens) will not distinguish between working BCs and the Barbie variety. JMO

[Mark Billadeau]

The ABCA had a long running hip study (ca. 8 years) of working bred Border Collies with Cornell to compare a new (at the time) radiographic hip evaluation method called DLS to OFA and the Norberg angle. We ended with 60 dogs in the study where the hips were evaluated around 8-12 months and then just after 24 months. The problem with the data set is we had only 60 dogs AND that none of the dogs volunteered for the study by owners or breeders had abnormal hips.

 

 

 

Hip studies take a long time (waiting for puppies to mature) and require a statistically large enough sampling of dogs (100s) with a wide range in hip quality (HD to perfect) in order to evaluate the predictive information of the method being evaluated. This means breeders/owners of working bred Border Collies must be willing to submit their pups to the study, allow the study to follow the progress of these pups past the point where many trainers will have made decisions about keeping the dogs (based upon what they see in training), and be able to obtain access to working bred pups with HD. Then there are the logistical issues about collecting data from dogs that live all over the country; will they be required to go to one location for data collection or will multiple data collection locations have to be equipped and trained such that the collected data is not biased by those collecting the data.

[emilyfalk]

I think it's doable. If I ever held a trial with a really large entry I could do the physical exam and offer rads of 1-2yo's and then 10yo's at a significantly reduced rate (time is free, equipment is not). Could maybe get a decent sample size. And now with the use of digital rads, it's really easy to send and store them. Results could be skewed by the selling of dogs who would get lost from the study (part of the reason for the sale due to lameness?), but if one were to focus an investigation on looking at young dog rads and clinical signs and comparing to the old dog rads and clinical signs, I think some useful information could be gained.

 

I'm not sure a university would get behind such an investigation, but an individual...maybe?

 

Or maybe a week of bed rest has me feeling overly industrious!