HIP DYSPLASIA EVALUATION - WHICH SHOULD I USE:  OFA OR PENNHIP

Dear Jubilee:

I want to certify that my dogs hips are sound and free of canine hip dysplasia. Which should I use: OFA or PennHIP?

Concerned

Dear Concerned, 

We use both PennHip and OFA, and since the PennHip requires an OFA view, we often have a copy made of that for OFA or for a preliminary OFA reading.

I found out last year that there is a mathematical formula for OFA, and somewhere I have it. It requires the reader to take precise measurements of different parts of the hip construction, and calculate the formula to determine the precise depth of how well the ball is covered by the hip joint. Whether the three readers do or not, I don't know. But it does seem to me that readers can and do make subjective calls at times. And I do know of situations where dogs failed OFA but passed a few months later on a second x-ray.

Our own reservation about OFA is based on what the two registries measure: OFA only tells you that on the day the x-ray was taken, there was or was not any sign of hip dysplasia. It makes no prediction for the future of that particular dog. PennHIP, on the other hand, measures joint laxity, and depending on how much laxity there is in the hip joint, makes a prediction about the likelihood of that dog ever getting hip dysplasia.

We have reservations about both PennHIP and OFA given the way they manipulate the hip joint during the exam. But they are the only two established ways to find out just what the condition of the hip joint is, so we have to use one or the other or both. Recently, someone suggested that it might be a good idea for the dog to have a chiropractic adjustment after going through either or both of these procedures. We think that is an excellent idea.

OFA is the one most breeders rely on. It has not only been around longer and used more than PennHIP, but it has an OPEN registry of the dogs that have passed. So a breeder can go to the OFA web site and search on a dog that they are thinking of breeding to and the dogs behind that dog to get a historic picture of the hips in a particular dog's line. If you want to look up a specific dog, you can go to http://www.offa.org/, click on search OFA records, and find that dog's results if he (1) was evaluated by OFA and (2) if he passed.

PennHIP has a closed registry, so the only way to get the information is from the owner of the dog.

We have noticed that the PennHIP readings tend to be similar in a line. In one of our lines, there is more laxity than in the other so the hips in the other line are tighter and therefore get lower scores (good) with PennHIP. Both lines get OFA readings of OFA Good, and both lines are deemed acceptable for breeding stock by PennHIP. This is just my own observation on specific dogs: there was no PennHIP done on earlier generations.

I have known of OFA excellent dogs who got high PennHIP scores and OFA Fair dogs that got very low PennHIP scores. So there is NO parallel between the two approaches to evaluating the hips.

Since we now do both PennHIP and OFA, our dogs have to be anaesthetized to do the x-rays. Before doing both, we did have a very good OFA vet who did not use to anaesthetize the dogs. And we got beautiful x-rays of the three dogs that he did without the anaesthesia. When the x-rays are sent to OFA, the vet makes a notation about whether anaesthesia was used, so that is factored in to the OFA review. All PennHIP x-rays have to be done under anaesthesia.

What we like about PennHIP is that we can check the hips earlier than two years of age, so we can find out what the hips are like before we start showing a dog, etc. with a good idea of how good the hips will be throughout the dog's life. And once, someone wanted to breed to one of our dogs before he was two. So we did his PennHIP at 18 months because we would not let him be bred without knowing the condition of his hips. If we get a good PennHIP on a female that we have done before she is two, we do not usually have her put under a second time to do an OFA certification when she turns two since we do not need it to breed her.

So there are different reasons for using the two different approaches, and we do feel very comfortable with the predictive value of the PennHIP. They are not parallel results since they evaluate different things, but PennHIP does give you feedback on the wear and tear on the hip joint and whether there is any visual evidence of arthritis in the joint. And since it measures laxity, it does let you know how deeply the ball is set into the hip socket.

One thing that we always do, regardless of which approach we take, is have a copy made of the OFA view for our records. So we have the x-rays of all of our dogs that have been x-rayed so we can compare the dogs, have vets read them, etc.

Jubilee