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-   -   Some interesting reading on PennHIP (http://www.germanshepherds.com/forum/breeding-general/456378-some-interesting-reading-pennhip.html)

hunterisgreat 06-02-2014 03:30 PM

Some interesting reading on PennHIP
 
The points I wish to discuss in this thread:
Quote:

2. The distraction index does not change significantly over time.

A study of large breed dogs showed that the distraction index stayed the same over time (within acceptable statistical limits) and was much more reliable over time than other methods such as the Norberg angle and the OFA scoring method.

Smith GK, Gregor TP, Rhodes WH and Biery D. Coxofemoral joint laxity from distraction radiography and its contemporaneous and prospective correlation with laxity, subjective score and evidence of degenerative joint disease from conventional hip-extended radiography, Am J Vet Res, 1993; 54: 1021-1042.
Abstract

5. 80% of dogs evaluated as “normal” by the OFA were found to have hip laxity by PennHIP testing that predisposed them to developing hip osteoarthritis in the future.

Dogs judged as normal by the OFA harbored clinically important passive hip joint laxity as determined via the PennHIP distraction index. Results suggested that OFA scoring radiographs (x-rays) underestimated susceptibility to osteoarthritis in dogs. The presence of these “normal” dogs in the breeding pool may slow the progress of decreasing hip dysplasia prevalence.

Powers MY, Karbe GT, Gregor TP, McKelvie PJ, Culp WT, Fordyce HH, Smith GK. Evaluation of the relationship between Orthopedic Foundation for Animals’ hip joint scores and PennHIP distraction index values in dogs. J Am Vet Med Assoc 2010; 237: 532-541.
Abstract

6. PennHIP Biomechanics

Biomechanical testing determined the optimal patient position for measuring hip laxity. Hip laxity was found to be maximal in the non weight-bearing position used in the PennHIP method and is actually masked in the conventional hip-extended position.

Smith GK , Biery DN and Gregor TP. New concepts of coxofemoral joint stability and development of a clinical stress-radiographic method for quantitating hip joint laxity in the dog, J Am Vet Med Assoc. 1990;196:59-70.
Abstract
Heyman J, Smith GK and Cofone MA. A biomechanical study of the effect of coxofemoral positioning on passive hip joint laxity in the dog. Am J Vet Res, 1993;54:210-215.
Abstract

9. Within and Between Examiner Repeatability

Studies have shown that the PennHIP method has a very high degree of reproducibility between examiners. In other words, your dog should have similar distraction scores no matter which PennHIP certified veterinarian performs the radiographs. This high degree of consistency is attributable to the inherent biomechanics of the canine hip joint and to the quality-assurance training that all PennHIP network veterinarians must successfully complete.

Smith GK , LaFond E, Heyman SJ, Cofone MA and Gregor TP. Biomechanical characterization of passive laxity of the canine coxofemoral joint, Am J Vet Res, 1997;58:1078-1082.
Abstract
Smith GK , LaFond E and Gregor TP. Within-and between-examiner repeatability of distraction indices of the hip joints in dogs, Am J Vet Res, 1997;58:1076-1077.
Abstract
number 2 was interesting simply because everyone rushes to do OFA at 2 years of age "hurry, get the hips xray'ed"

number 5 was a jaw dropper for me... so "normal" ofa hips can be actually bad... not good news.

considering 9 and how bad positioning can make a "good" hipped dog look "poor"... the fact that you can take 2 films of the same dog, the same day, one less well positioned, and get an "excellent" on one and a "fair" on another is a big issue... if the test were ideal you should get "excellent" on one, and "inconclusive, reshoot" on the other.

hunterisgreat 06-03-2014 11:03 AM

Really, not interesting to anyone but me?

Liesje 06-03-2014 11:12 AM

5. OK, maybe, but...."hip osteoarthritis" is not "hip dysplasia", right? So it's not all that earth-shattering that if you take an OFA x-ray and submit to OFA for an OFA rating regarding hip dysplasia, they aren't going to give you a full analysis of whether your dog may develop arthritis.

I had my mutt x-rayed when he was 4 years old, did not send results to OFA but trust my vet and we both agreed he does *not* have HD, but he probably *will* develop arthritis as he ages. When I have a vet or specialist look at a dog's hips I'm not just trying to position them such that we get the top rating we can, I really want to know! If there is laxity, or the joint is not completely smooth and they might develop arthritis over time, that's important for me to know and that's why I'm paying someone to take the pictures and "read" them for me, not just so I can say "Oh he's OFA Good" and never think about it again. People who really push PennHip seem to have this assumption that those who use OFA or a-stamp only care about getting a passing rating. Maybe that's true for some but most people I know really want to know about their dogs' structure and what it means for the future, not just breeding but for the dogs' activity levels and what sorts of training is appropriate.

hunterisgreat 06-03-2014 11:25 AM

Quote:

Originally Posted by Liesje (Post 5595650)
5. OK, maybe, but...."hip osteoarthritis" is not "hip dysplasia", right? So it's not all that earth-shattering that if you take an OFA x-ray and submit to OFA for an OFA rating regarding hip dysplasia, they aren't going to give you a full analysis of whether your dog may develop arthritis.

I had my mutt x-rayed when he was 4 years old, did not send results to OFA but trust my vet and we both agreed he does *not* have HD, but he probably *will* develop arthritis as he ages. When I have a vet or specialist look at a dog's hips I'm not just trying to position them such that we get the top rating we can, I really want to know! If there is laxity, or the joint is not completely smooth and they might develop arthritis over time, that's important for me to know and that's why I'm paying someone to take the pictures and "read" them for me, not just so I can say "Oh he's OFA Good" and never think about it again. People who really push PennHip seem to have this assumption that those who use OFA or a-stamp only care about getting a passing rating. Maybe that's true for some but most people I know really want to know about their dogs' structure and what it means for the future, not just breeding but for the dogs' activity levels and what sorts of training is appropriate.

My concern with 5 was, I'd assume that a pup out of two "excellents" should be excellent as well... we all know its always a roll of the dice, but this seems to make me far less confident in OFA films.

Isn't the whole point in evaluating to be grading from the best possible positioning?

Liesje 06-03-2014 12:28 PM

Yes, but to me at least the grading is not the whole point of the evaluation. I'm paying for my *vet* to take the picture and make the call, not the OFA. If the dog is 24+ months and a breed survey prospect, then I'll submit to OFA since it's pretty cheap and I'll get the rating that I already knew was coming, but I walk out of the vet's office knowing what I need to know without an OFA certificate. If anything is unclear, the vet refers me to a specialist (I like my vet, he's very honest about what he knows or doesn't know). The specialist I used to use actually did the research that PennHIP is based on and he uses OFA or a-stamp ratings, so that tells me something. PennHIP tries to make it sound like they're more thorough but my vet knows the full history of my dogs, he knows what I feed them, how I exercise them, what sorts of training and activities we do, whether they've had previous injuries, etc. I think all that info is valuable when looking at joints and trying to determine how the dog may age, whether they are a breeding prospect, and what activity level is appropriate.

hunterisgreat 06-03-2014 12:36 PM

Quote:

Originally Posted by Liesje (Post 5595994)
Yes, but to me at least the grading is not the whole point of the evaluation. I'm paying for my *vet* to take the picture and make the call, not the OFA. If the dog is 24+ months and a breed survey prospect, then I'll submit to OFA since it's pretty cheap and I'll get the rating that I already knew was coming, but I walk out of the vet's office knowing what I need to know without an OFA certificate. If anything is unclear, the vet refers me to a specialist (I like my vet, he's very honest about what he knows or doesn't know). The specialist I used to use actually did the research that PennHIP is based on and he uses OFA or a-stamp ratings, so that tells me something. PennHIP tries to make it sound like they're more thorough but my vet knows the full history of my dogs, he knows what I feed them, how I exercise them, what sorts of training and activities we do, whether they've had previous injuries, etc. I think all that info is valuable when looking at joints and trying to determine how the dog may age, whether they are a breeding prospect, and what activity level is appropriate.

Well OFA/a-stamp still dominates because its the incumbent method. Everyone knows what OFA is. People **** their head and say "huh" when I tell them my dog is "pennhip .26/.28". "Good" is a clearer warm and fuzzy. That being said, pennhip is more valuable to a breeder I'd think.

carmspack 06-03-2014 01:01 PM

I am interested , very much so , but haven't been able to organize my thoughts on the whole "hip" thing --- especially since , as in another thread "a gene has been found for hd" --- although it is not what most people think it is , or means what they think it does.

the vet that took care of all the PD k9s for a large city, out of friendship and to gain experience as it was very early days, offered to "penn-hip" all of my dogs at no expense to me.
I did not take him up on this offer. I was doing OFA AND OVC on the same animal .

the key is EPI-genetics . Knowing what the gene's are in a multi factorial disorder allows you to influence the gene expression through nutrition , providing the proper minerals for the codons , switches , for on or off at that location.
Laxity also can be influenced by generations of well nourished animals , particularly while in fetal development and then continued throughout the critical growth stages. This includes ligaments, cartilage, tendons, muscle , bone density .
Never one thing in isolation. Always the whole and entire body-system.

carmspack 06-03-2014 01:07 PM

every GSD should be endowed with the most competent immune system .

all the attention to hip x rays and breed selection "still" has the statistics , as it did in the 1970's Swedish study , that approximately 30 % will have some degree of HD . That seems to be "natural" to the breed. What has changed is that we have shifted the ratings to less severe, and more to the mild , borderline range.

Doc 06-03-2014 09:26 PM

I have a dog that scored .20 for both hips on PennHip and OFA rated him a Fair and they both used the same X-rays. I trust PennHip. OFA is a crap shoot.

gsdsar 06-03-2014 09:36 PM

I believe PennHIP is a better source of information in regards to total hip structure.

Unfortunately, as someone said, everyone knows what OFA is, so that seems to be what people want.

I had a dog OFA fair, but PennHIP was .19/.24. (I think it was a while ago).

It has also been shown that the same radiographs sent to OFA multiple times often get different ratings. OFA is totally subjective. PennHIP, is objective, in that it scientifically measures hip laxity. No guessing.


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