PennHip --MAY--be a better indicator of hip dysplasia than OFA

[Jennifer Sider]

Link to the abstract; http://avmajournals.avma.org/doi/abs/10.2460/javma.237.5.532

Abstract;

Abstract

Journal of the American Veterinary Medical Association

September 1, 2010, Vol. 237, No. 5, Pages 532-541

doi: 10.2460/javma.237.5.532

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

Michelle Y. Powers, DVM, DACVS; Georga T. Karbe, Med vet; Thomas P. Gregor, BS; Pamela McKelvie, VMD; William T. N. Culp, VMD, DACVS; Hilary H. Fordyce, VMD; Gail K. Smith, VMD, PhD

Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104. (Powers, Karbe,
Gregor, McKelvie, Culp, Fordyce, Smith)

Dr. Powers' present address is Bulger Veterinary Hospital, 247 Chickering Rd, North Andover, MA 01845.

Dr. Culp's present address is the Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis,
Davis, CA 95616.

Dr. Fordyce's present address is Metropolitan Veterinary Associates, 2626 Van Buren Ave, Norristown, PA 19403.

Presented in abstract form at the Veterinary Orthopedic Society Conference, Val d'Isere, France, March 2000.

Address correspondence to Dr. Smith ([e-mail]).

Objective—To compare 2 screening methods for detecting evidence of hip dysplasia (Orthopedic Foundation for Animals [OFA] and PennHIP) in dogs.

Design—Diagnostic test evaluation study.

Animals—439 dogs ≥ 24 months of age that received routine hip joint screening from June 1987 through July 2008.

Procedures—Dogs were sedated, and PennHIP radiography was performed (hip joint– extended [HE], compression, and distraction radiographic views). The HE
radiographic view was submitted for OFA evaluation. A copy of the HE
radiographic view plus the compression and distraction radiographic
views were submitted for routine PennHIP evaluation, including
quantification of hip joint laxity via the distraction index (DI).

Results—14% (60/439) of dogs had hip joints scored as excellent by OFA standards; however, 52% (31/60) of those had a DI ≥ 0.30 (range, 0.14 to 0.61).
Eighty-two percent of (183/223) dogs with OFA-rated good hip joints had a
DI ≥ 0.30 (range, 0.10 to 0.77), and 94% (79/84) of dogs with OFA-rated
fair hip joints had a DI ≥ 0.30 (range, 0.14 to 0.77). Of all dogs with
fair to excellent hip joints by OFA standards, 80% (293/367) had a DI ≥
0.30. All dogs with OFA-rated borderline hip joints or mild, moderate,
or severe hip dysplasia had a DI ≥ 0.30 (range, 0.30 to 0.83).

Conclusion and 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.

[Christel Flink]

I disagree, I do however think that PennHip is probably the best indicator of the possibility of developing HD in the future.
I had a rehomed dog who came to me as an adult and he had a PennHip evaluation in his "luggage". That said he did not have HD or DJD at the time but I took him for an FCI evalutation so had new x-rays done which came up with quite a different result. He had D and C on his hips (on a scale of A = Normal hips Grade A, B = Normal hips Grade B , C = Mild Dysplasia, D = Moderate Dysplasia, E = Severe Dysplasia), with mild and moderate DJD if memory serves.
It was bad enough to cut his life short at 6.5 years of age when the arthritis had gone too far and had started affecting his spine as well as hips.

If I'd do a PennHip x-ray on my dog today, I'd pay the few bucks extra to have copies sent off for an FCI evaluation as well and get both.

[Jennifer Sider]

Hey Christel; what age was the Pennhip eval done? What was the distraction index on the eval? >30 is where the cut off is for HD down the road, wondering if he was indeed >30 at the time of Pennhip reading, in which case the eval did its job?

I know they advocate 16 weeks for a decent reading; however I'd think the dog should be done much older; besides; here we can have the one set of x-rays completed 2x and sent away for an OFA rating as well as the Pennhip.

[Christel Flink]

Hi Jennifer,

I think you are missing my point.

The subject line of this topic was that PennHip may be a better indicator of dysplasia (than OFA in this case) and I just don't think the PennHip is a good evaluator of actual dysplasia, but a good PREDICTOR for DJD, absolutely, especially in young dogs.
Ideally, in my opinion, you'd be best off with both PH and another (more traditional) evaluation.

The PennHip evaluation of my dog clearly stated he was free of HD and DJD, he was about a year old at his evaluation, I redid the x-rays about a year after that where he had mild and moderate dysplasia and DJD.
I know you can tell me that he may have developed both the HD and DJD in that years time between the age of 1 and 2 years old, others have in the past who are also proponent's of the PH eval.
I'll keep claiming that the dogs either have HD, or they don't, the DJD (Degenerative Joint Disease, as not everyone will know the abbreviation) is what can/will come later on due to wear and tear of a badly formed joint.

His PennHip result was 0.58 - 0.61.

We too can have one set of x-rays sent off for both PennHip and FCI eval here, it is the PH eval that requires most x-rays and I think they take a shot of the angle the FCI eval uses regardless, so that can just be sent off for eval at a small extra fee (for the people evaluating at the Swedish Kennel Club).

I may be misunderstanding here, but if my boy was scored lower than 0.30, then surely the eval had failed miserably as that is what they generally refer to as the safer cut off point, like you mentioned too. But then again, even with his higher score, I consider the PH eval in his case, failed.
He DID have HD, there's no question about that and a fairly bad one at that, as it ended his life prematurely. Like I said though, I could be misunderstanding you here.

[Jennifer Sider]

Okay; so what I understand is you had his Pennhip Report; either the original or the copy; on it was his microchip/tatoo # identifying him as the dog tested; and his results showed; 0.58 - 0.61 distraction index.

So one femoral head was 58% out of the joint and one femoral head was 61% out of the joint. Anything greater than 0.30 is at risk for developing DJD. According to Pennhip the closer the number is to 0.70 the higher the risk is.

Under the DJD box; it was marked NONE?

What weight did it indicate for him at 1 year? And then what was his weight at 2 years when you had him tested?

I'm not arguing with you; the results you have is the results you have; I'm having Dora done Pennhip and OFA; mainly because the OFA score is much less significant from a breeding standpoint; where Pennhip gives you a distraction index for each hip separately, and if you have consistent laxer hips on one side than the other; perhaps you should be breeding away from that, as well you can breed tighter to tighter with infinite numbers.

The reason I asked about his weight is I think perhaps that the earlier it is done (and btw OFA wouldn't have given you a rating at 12 mos. you would have only had a prelim) the less likely to be accurate; depending of course on the amount of weight gained.

Just curious as to why your results were so contrary to what is the norm?

[Christel Flink]

Not sure what you mean with contrary to the norm.
In my opinion 0.58 and 0.61 are pretty bad hips, not that I knew that at the time and I was even told he'd be good enough to breed from. In fact he was imported to Sweden with that purpose (not by me).
So the fact he received a score of mild and moderate dysplasia isn't really surprising.

But my point is that the PennHip did not tell me he had dysplasia or DJD. Like I said, the DJD is one thing as that will develop with time in a badly formed joint, but the HD should have shown - if PennHip was actually a good way of finding out about the prevalence of HD in dogs. Which I disagree with (and I thought that was the message of this post, that PH was a good predictor).
I think it's a good way of predicting DJD as the dog gets older, but like I said, it either has HD or it doesn't. I don't really see a lot of middle ground there.

As for his weight gain, he was always a tall, lanky type of Boerboel and he was at 55-56 kg at his maximum weight despite being on the taller side at 72 or so cm. He came to me as a 1.5 year old so I can't tell you exact weight gain between 1 and 2 but he stayed around the 55 kg mark through the 5 years I had him.

Yes, the box was marked none. Yes, it was indeed my dog, I wasn't scammed.

Not sure why his numbers are so confusing for you, help me here please - in your opinion do you think his scores are good, bad or in between?

[Sweet Pea]

Maybe I'm interpreting PennHip wrong, but isn't anything > 0.30 considered dysplastic to some degree? I don't understand why people put so much weight on the "no evidence of DJD" aspect. With scores like Christel's dog had, the dog will probably end up with DJD later on in life. My puppy was diagnosed with severe HD at 18 weeks old and had no DJD at that point, but come 9 months old, he had mild DJD. So I guess my point is, who really cares if it says they have no DJD, it can always develop down the road if the DI is > 0.30, right? Also, I'm curious to know why they would call Christel's results reported he was not dysplastic with those scores?