We have two vets in the UK who take plates under the PennHip method.

Looking at their study which dicates the level of laxicity present in order for Osteo-Arthrtis to develop wasn't borne out in their trial (the average age of the dogs was 20 months - probably older than the UK now, but younger than other methods in the States and Europe) - with only one dog above 0.30 within the sample group going on to develop OA.

It stands to reason that poorly 'fitting' joints, when subject to above average wear and tear will be susceptible to arthritis. However, there is also a lot of evidence to show that if you have a dog with poor joints - walk it HARD in a controlled manner - the muscles start to take over the job of of those joints whilst protecting them.

Where it is known that a dog has poor joints, actually, because of the way the owner then takes that dogs exercise, coupled with various supplements (which evokes efficacy discussions in itself) - could mean that poor doggie with dodgy hips at 18 months, may potentially suffer less arthritis than the really good hipped dog who has regular but uncontrolled exercise.

The clinic I worked with for my girl's injured knee (she also has really bad hips) have had notable success in conservatively treating young dogs with HD (i.e. before they are old enough to have surgery) - this involves using an underwater treadmill, supplements, ultrasound and acupuncture, plus a strict regime of hard on lead walking - only one dog has subsequently returned for surgery - the remainder building their muscle to a level where it compensates for poor joint formation.

I can certainly see the logic in the PennHip argument - but the same could easily be said for the UK hipscoring scheme which is more comprehensive - but it will take many years to formalise the facts of using this method involving constant monitoring of all dogs tested throughout their lives to say beyond doubt that by breeding from dogs within a certain DI - they can prevent OA in the Hips (it also takes no consideration of OA / OCD in the shoulder, hock, elbows, stifle )

Just like humans - knees can be shot to b&ggary - and their hips fine, or their knees and hips shot, but their back fine, or like me - their back shot to pieces at a young age - yet their hips and knees fine.

During their life, knees and shoulders in larger dogs are subject to a lot more trauma than hips - yet - we are seeing more hip problems in smaller dogs it seems (if breed scoring numbers are indicative of a problem - which they usually are) and not such widespread elbow issues.

Even if you could guarantee no susceptibility to OA and therefore bad hips in dogs, it means little unless you can guarantee no susceptibility in their other joints - as hips typically remain one of the most straightforward to treat.

Also - as a slight afterthought - OA (which is wear and tear) in humans is typically thought to be environmentally caused - but quite clearly a genetic tendency to susceptibility to OA must exist, otherwise you wouldn't have parents and children living very different lives / activity levels etc yet developing.

And that follows through for HD from what I can see as well - as no gene has been isolated and no mode of inheritance known, whatever the PennHip method might tell us about the joints - we are still looking at many years and several generations with a significant sample size to prove the hypothesis.

You know my view on this - I've long said we should have vet panellists for hipscoring in the same manner we do for eye testing - because although a bad vet won't make a difference to an average within a numerically high breed, it could ruin their future potential as a dam / sire - and in numerically small breed where only a few dogs are tested, it could seriously skew breed averages.

__________________
What you need to know before buying a Labrador puppy