# PennHip - Understanding Results?



## FOM (Jan 17, 2003)

Okay I got Ranger's PennHip results but it makes no sense to me - can some one explain what I'm looking at....

FOM


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## Franco (Jun 27, 2003)

Both hips will be scored.

Ideal would be upper 20 percentile in both.
Upper 40% in both is good.

I read where that when a dog had hip issues, it is on the left side most of the time.

Labs are rated against a lab database.


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## FOM (Jan 17, 2003)

Okay what do the numbers mean on the form?

How do you know what precentile? I see the DI index....does it mean anything?

The laxity profile puts him in the 80th.....but does it go any more specific ranking? Or just in 10% groupings?

FOM


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## windycanyon (Dec 21, 2007)

The lower the DI, the better. The DI's are more important than percentile because the percentile ranking is constantly changing if I remember right. IOW, labs that started out at the 90th percentile back when PH started may only be at the 60th or less now that they've got more data.

I think the lowest DIs for labs was about 0.19 a year or so ago and that was a field dog. Anyone have the current data? I'm thinking 0.3 is not too shabby still. I really wish PH would have a database online.


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## Franco (Jun 27, 2003)

I wish I had my report here from the Lab I gave away. He was the bottom 20% on the left and bottom 40% on the right.

I seem to remember a 62 on the right, which was not good. 

I seem to remember that most of it is explained on the report. Maybe they didn't send you that info. The D1 index is how your dog's hip compare to other Labs. 

Anne, jump in here cause I know you can put it in better tech terms.


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## FOM (Jan 17, 2003)

"There is an increasing risk of developing DJD as the DI increases; low risk when the DI is close to 0.30, high risk when DI is close to 0.70 or above."

Rangers is 0.37 for both hips = we are looking good?! And in the 80th percentile...

FOM


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## FOM (Jan 17, 2003)

Just making sure I'm reading the report correctly - this is only the 2nd dog I had PennHip and the results for the first dog went directly to Aussie (aka Julie) and I never got to see his........so if I'm looking at this correctly, we should not be stressing about Ranger's hips....

FOM


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## windycanyon (Dec 21, 2007)

FOM,

If you have a few moments, go into the Labradata.org database, click on Certification Search, and then find the Pennsylvania Hip Improvement Program and hit Search. There are several dogs entered w/ PH numbers. 
It appears, based on the most recent PH submissions to Labradata, that the mean DI for labs right now is ~.46.

You can then click on a dog, click on Certs/Tests, and then "View Doc" and you'll see how that Percentile ranking relates to the DI in general. Your .37 seems to be great based on what I see! Several dogs that scored in that range were also OFAd and came back Excellent (I think one Good).

I noticed one dog's DI was .6 or so (w/no DJD present), and the dog had a corresponding "Fair" rating by OFA. It's all pretty interesting!

ETA: My instructions may be meaningless if the database is changed a lot after tonight's updates as announced by Maureen earlier!


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## YardleyLabs (Dec 22, 2006)

A DI of 0.3 or smaller is pretty much the gold standard since, at that level, there is virtually no chance that a dog will ever develop dysplasia. With both hips at 0.3, the dog would basically be in the 90th percentile (best 10%) or better. With DI of 0.5 or less, the dog will be in about the top 50% of Labs. PennHIP uses that as its standard for breeding, arguing that if only better than average dogs are bred, hips will continue to improve over time. 

I disagree. That logic would exclude many dogs that would be the equivalent of OFA Good and essentially every dog that would be rated Fair. While that may make mathematical sense, it disregards the other qualities that need to be considered in making breeding decisions. I also wonder how much, if any, research has been done on whether or not there is a level at which hips are too tight in a manner that might contribute to other injuries.


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## JusticeDog (Jul 3, 2003)

Sounds like good news, Lainee....


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## Lady Duck Hunter (Jan 9, 2003)

In my opinion... this is why Penn Hip hasn't ever taken off like it should have. It is easy for us and the general public to understand terms like Excellent, Good, Fair but looking at the clinical results and measurements doesn't mean a thing to the majority of us. Gotta keep things simple.


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## ErinsEdge (Feb 14, 2003)

Lady Duck Hunter said:


> In my opinion... this is why Penn Hip hasn't ever taken off like it should have. It is easy for us and the general public to understand terms like Excellent, Good, Fair but looking at the clinical results and measurements doesn't mean a thing to the majority of us. Gotta keep things simple.


I agree. It also leaves room for those that do not pass OFA to give numbers that people can't interpret (and I know this happens). OFA has worked for me just fine and now that they are hedging on the early interpretations of PH in the 4-8 month range, I'll stick to what works for me.


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## windycanyon (Dec 21, 2007)

ErinsEdge said:


> I agree. It also leaves room for those that do not pass OFA to give numbers that people can't interpret (and I know this happens). OFA has worked for me just fine and now that they are hedging on the early interpretations of PH in the 4-8 month range, I'll stick to what works for me.


I agree. I know of a lab that failed OFA but got a pass from PH at the 50th percentile, way back when. I bet the dog wouldn't be at the 50th percentile now and in fact, I believe it produced some HD...

I noticed one dog in the labradata database that was PH'd at ~4mos. Had a relatively high DI at that time (.5 or so if I remember right) which greatly improved as an adult... I think to the .3 or .35 level. Isn't that interesting? Almost everyone I know who does prelims has said their dogs had better hips at 2 than at 1.


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## J Connolly (Aug 16, 2007)

Penn Hip is actually very easy to understand. First of all it gives you an actual measuement of the laxity of the hips. The DI ( or distraction index ) is simply the % the femoral head can be distracted from the hip at a given pressure. A DI of .38 means that the femoral head can be distracted 38 % out the acetabulum ( hip socket) .Your dog has excellant hips as his distraction index is better than 80% of all the labs ever submitted to Penn Hip. We should always use dogs that are above the 50th percentile for their breed. Tighter hips are always better. Dogs with a DI of .3 or less will probably never have DJD and that is the goal. Many breeds have very few if any dogs with DI's less than 0.3. The important thing to understand is that Penn Hip is an objective measurement vs. a subjective measurement in the case of OFA. Many dogs that OFA good at 2 years of age will have significant DJD when the are 5-6 years of age. Penn Hip also has a higher coefficient of heritability (using Penn Hipp evals will make more improvement over time) than OFA and is better tool to use in improving hip conformation. This explains the why so many of us have dogs with 5 generation pedigrees of OFA "Good" dogs only to have our pup turn out to be dysplastic.

The last thing I want to add is that the veterinarian that radiographed and submitted your dog's hip films to Penn Hip has been specially trained to perform this procedure and is more competent than most folks on a website to discuss the results with you so that you understand them. Take a minute and call him, I am sure he will be glad to discuss the results and breeding implications with you.


Mike Connolly


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## Gerry Clinchy (Aug 7, 2007)

J Connolly said:


> First of all it gives you an actual measuement of the laxity of the hips. The DI ( or distraction index ) is simply the % the femoral head can be distracted from the hip at a given pressure. A DI of .38 means that the femoral head can be distracted 38 % out the acetabulum ( hip socket) .
> 
> [Gerry] My understanding is that the DI (Distraction Index) is the measurement of the difference between the radii of the "compressed" hip view and the "distracted" hip view. Imagine two circles set directly over each other with their centers in the same spot. Then you draw the radius of each circle (a straight line from the center to the edge of the circle). If the two circles are perfectly aligned the radius of each circle will be exactly over the other one. The "DI" will be zero. As the angle between those two radii increases, the DI goes upward from zero.
> 
> ...


In the end, we are breeding dogs ... not test results. We have to learn as much as we can about the evaluation tools we are using. To say a dog has "excellent" hips without understanding the tool used to evaluate, is like saying "this dog is field trial calibre" to someone who has never seen a field trial.


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## J Connolly (Aug 16, 2007)

Poor choice of words. I did not mean to infer that this dog's hips would OFA "Excellant", but compared to other dogs in his breed his hips have less laxity than 80% of the dogs evaluated. I would consider that an "excellant" result. 

Mike Connolly


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## Gerry Clinchy (Aug 7, 2007)

J Connolly said:


> Poor choice of words. I did not mean to infer that this dog's hips would OFA "Excellant", but compared to other dogs in his breed his hips have less laxity than 80% of the dogs evaluated. I would consider that an "excellant" result.
> 
> Mike Connolly


I think that's exactly why PennHIP chooses to talk in numerical terms about their ratings. Different people might say that top 20% is "very good", but "excellent" might be reserved for the top 5%. 

I don't focus on that percentile as much as I do on the actual DI #. If I want to improve hips within my own breeding program, then I have to look at improving my own DI #s over time. For all I know, the rest of the population could get better or worse, so the percentile rating would change based on things other people are doing, not what's happening within my own breeding program. 

Also worth noting, that PennHIP does not "pass" or "fail" your dog. They are providing you with "data" to include in your breeding program ... and telling you what impact that data may have on your final decisions. They tell you what you can do to improve hips, but it is up to the breeder to incorporate this information into their overall breeding decisions.

If Lean Mac had a PennHIP # of .60/.60 should he have not been bred? I don't think many would agree with that! It would just have meant that one should use that information to match up his mates wisely.

This kind of breeding "advice" takes more thought on the part of the breeder than black-and-white answers like "pass" and "fail". 

This is especially true because PennHIP gives you separate evaluations for each hip. There is evidence, admitted to even by OFA, that the left and right hip may be inherited separately! 

Thus, you might be able to improve overall hip production by breeding a better right hip to better left hip, and produce progeny who had better ratings in both hips. The UK system has long used that hypothesis.


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## J Connolly (Aug 16, 2007)

"If Lean Mac had a PennHIP # of .60/.60 should he have not been bred"

What it would mean is that you would be breeding to a dog that has a lot of joint laxity and therefore if you wanted to try to improve hips in your pups you could do better by choosing another dog. If you had a female with a DI of 0.38 you would be going backward in terms of hip laxity.

While it may be practical to talk interms of ones own breeding program most people have to go outside of their own dogs to find a mate so I think to be able to see how a dog compares within the breed is helpful. If Penn Hip is successful then a dog today that ranks in the 80th percentile might only be in the 60th percentile 10 years from now.

Hips aren't everything, I have a GR bitch with a DI of 0.38 ranking her in the 90th percentile and I spayed her. We refer to her as the "other sister". 

I have been certified to take Penn Hip films for several years and I think it is a great tool although most people won't take the time to learn about it and use it. They mainly want a number so they can breed their dog.

Mike Connolly DVM


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## windycanyon (Dec 21, 2007)

Pennhip would be alot more breeder friendly if it had a database. It's really hard to do an analysis on the vertical ped/offspring of a dog if there is no database available. I thought it was coming but couldn't find it recently when I checked again. Also if they read elbows too... 

That said, due to the special training required, very few vets in my area are certd. One in Wenatchee, about 100 miles but last I checked, he wanted the dog all day due to not using reversible anesthesia. WSU is about twice that distance, so either way, there goes an entire day. I am really pleased w/ my OFA vet, and so far, so good.


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## Last Frontier Labs (Jan 3, 2003)

Looking for this...
http://www.vet.upenn.edu/RyanHospital/SpecialtyCareServices/PennHIP/tabid/448/Default.aspx
Follow the sub menu on the left for more info.


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## windycanyon (Dec 21, 2007)

Are you saying they have a database of dogs' info? I sure haven't located it. I'm talking one like OFA.... results, vertical peds, etc.


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## Last Frontier Labs (Jan 3, 2003)

According the this info under "What's New?", it is coming soon.
*Open-optional Database*
As mentioned above, we have upgraded the PennHIP database. Along with this upgrade we are working to establish an “open-optional” database to facilitate sharing important genetic information. Under this new voluntary program, *owners will have the choice of including their dog’s hip results in the open-optional database, the results of which will be made available to the public through this website*. The open-optional database will provide the distraction index and laxity rankings for dogs free of degenerative joint disease and in the top 40 percent of their breed.


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## Aussie (Jan 4, 2003)

YardleyLabs said:


> I also wonder how much, if any, research has been done on whether or not there is a level at which hips are too tight in a manner that might contribute to other injuries.



"Too tight? Contributing to other injuries?" Never heard that train of thought. 

Lainee I think the Ranger's Penn hip result bode well.


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## YardleyLabs (Dec 22, 2006)

Aussie said:


> "Too tight? Contributing to other injuries?" Never heard that train of thought.
> 
> Lainee I think the Ranger's Penn hip result bode well.


I'm not a vet but have read the variety of material available on the PennHIP website. It concerns me that the presumption is made that tighter is always better but I did not see any research concerning the relationship, if any, between hip distraction indices and the frequency of other structural problems such as ligament injuries. 

From a mechanical perspective, some degree of elasticity (or looseness) might actually reduce stress on other structural systems. That's conjecture based on ignorance. However, based on my limited sample of five dogs with PennHIP results, the one with the tightest hips (0.22/0.22 or about 99th percentile for Labs) also seemed to be the most likely to suffer general muscle strains during training. This observation is clearly anecdotal and without statistical merit. However, I would be more comfortable if the "tighter is always better" approach were documented through research. If anyone knows of articles on this, I would be very interested.


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