PennHIP is an alternative method of evaluating hips used by some breeders. It is controversial in the veterinary community and it’s validity is not universally accepted. With English Setters it has little practical value for selecting breeding dogs. We believe that due to the way PennHIP has been marketed as the “magic pill” substitute for OFA evaluations, it has in all likelihood set back progress in reducing hip dysplasia. Because the method does not reliably diagnose the disease some breeders who rely exclusively on PennHIP will unknowingly use dysplastic dogs in their breeding programs, and others are using PennHIP because they know their dogs won’t pass an OFA. Understanding why we say this requires an in depth look at PennHIP
PennHIP Reports and What They Mean
PennHIP is not a pass/fail screening and there is no such thing as “PennHIP Certified”, or “PennHIP’ed clear” of hip dysplasia. PennHIP only addresses two criteria:
1 – Laxity Dogs are given a score called the Distraction Index, or DI, which measures the amount of laxity (also called subluxation) in the hip and compares it to other dogs from the same breed. A score of 0 would mean no laxity, a score of 1 indicates a hip that can be forced completely out of the socket. Based on the dog’s DI the report will show where the dog lies in relation to the rest of the breed in the PennHIP database. For instance, a dog in the 90th percentile indicates hips that are in the tightest 10% of the breed. Breeders are told that using breeding dogs that score better than the median score for the breed will decrease the overall incidence of dysplasia. According to PennHIP, a DI of .3 or LESS almost always indicates good hips. Dogs with a DI of .7 or greater virtually always have dysplasia. Also according to PennHIP’s research, scores between .4 and .6 are not meaningful enough to be useful. Most English Setter scores are higher than .4.
2 – Presence or absence of Degenerative Joint Disease (DJD) Hip Dysplasia is abnormal conformation of the hip joint. DJD is arthritic changes to the joint that are a symptom of Hip Dysplasia, not the disease itself. Presence of DJD confirms that the dog has Hip Dysplasia, but absence of DJD does NOT mean the dog is clear of Hip Dysplasia.
The Problem With PennHIP
Because arthritic changes often take years to develop and there are multiple aspects of hip joint conformation that can be abnormal, it is entirely possible for a dysplastic dog to have a fairly good looking PennHIP report. An example would be a dog with a middle of the road DI score like .45, which would be better than average for an English Setter, and shows no DJD at the time of evaluation. Many dogs like this would fail an OFA evaluation due to subluxation or one or more of the other abnormalities in the hip joint that PennHIP does not consider. Unfortunately such dogs would also meet PennHIP’s recommended breeding criteria. This is a major short coming of the PennHIP method. Unless the hips are very tight, very loose, or arthritic, there is NO way to tell from the report whether a dog has good or bad hips. We don’t use PennHIP because of this and for the following reasons:
- There is no breeding study or data which shows whether selecting for lower DI’s decreases the incidence of HD in offspring. The last time we talked to PennHIP (personal comments from Dr. Gail Smith, the founder of PennHIP) they indicated no interest in pursuing a breeding study.
- All of the published studies that fully support the PennHIP method were authored or coauthored by Gail Smith.
- Independent studies contradict PennHIP’s claims.
- PennHIP does not allow independent access to, or review of, it’s database.
- In English Setters, a breed which has a very high median DI score, simply following PennHIP’s recommendation of picking breeding dogs better than the median for the breed would guarantee using a high percentage of dysplastic dogs in a breeding program. The median score is so high because the database contains only a few hundred English Setters, a large percentage of which are from one kennel that has an exceptionally high incidence of HD (personal comments Dr. Pamela McKelvie/PennHIP), making the median score useless for this breed.
- Because there is no pass/fail, and because buyers do not understand how PennHIP works, using PennHIP as the ONLY hip screening method gives dishonest breeders a way to hide the fact that they are using dogs in their breeding program that would fail OFA evaluation. This does not mean we believe all breeders who use PennHIP are intentionally dishonest. In fact, a breeder who also has OFA certifications may be especially conscientious. PennHIP DOES NOT, as has sometimes been claimed, do an OFA – like evaluation for anyone, so any “certification” of this type must come from the OFA to be meaningful.
- PennHIP’s database is fully closed and there is no way to verify DI’s for an individual dog.
If you are considering buying a pup from a litter out of parents with PennHIP evaluations and no OFA’s, here is what you need to look for: You need to see the actual PennHIP reports for both parents. The DI’s of both hips of both parents need to be .3 or less. Both reports must show no DJD present. Both parents should be at least 2 years old at the time of the evaluation. If all of these criteria are met it is very likely the parents of the litter have normal hips.