By Joe Spoo DVM

Say the words “hip dysplasia” and most hunting dog owners have a vague idea of this arthritis causing disease. We all know of an old campaigner that just can’t go anymore because of “arthritis” or the young dog whose career was cut short by too much pain. Say the same two words to a breeder and you likely will get a defensive answer about not having it in their lines and that their dogs are guaranteed, but what does that mean? It is my hope that after reading this article you will have a better understanding of this complicated disease.

So what is hip dysplasia? It is an inherited developmental disorder of the hip joint resulting in abnormal function of the ball and socket. Basically it is a problem that is based on a combination of the genes from mom and dad as well as the nutrition and environment the dog grows up in. These combine to make a joint that doesn’t work smooth and efficiently. The changes that result from this abnormal function can range from minor changes to the joint with no outward signs, all the way to complete destruction of the joint and a crippled dog. Canine hip dysplasia is an extremely prevalent disease (as high as 74% in some breeds). Most dogs, though, have a mild form that doesn’t seem to affect performance until the dog is into its latter years. For dogs with more than the mild form, their peak years can be plagued with discomfort, disability and decreased work longevity.

What makes this disease so difficult to control in the dog population is the number of factors that go into determining how a dog’s hips will perform. First, there are multiple genes that determine the conformation of the hip joints, thus you can’t always expect that when you breed ‘good-hipped’ dogs to ‘good-hipped’ dogs that you’ll get ‘good-hipped’ pups. Secondly numerous environmental factors also influence the development of the hips, such as early nutrition, weight control, exercise and muscle mass.

So what about breeders’ claims of having certified hips? Currently the most widely used all-breed hip dysplasia registry is the Orthopedic Foundation for Animals (OFA). The OFA currently grades hips based on a standard x-ray view. The x-ray is sent to three randomly selected board-certified radiologists who grade the hips. The scores are combined and the dog is given a rating, excellent, good, fair or poor. To be officially graded dogs must be at least 24 months of age and permanently identified (i.e. microchipped, tattoed, etc.).

The downfalls of this particular system stem from the subjective nature of the scoring, and the wide variety of interpretation from radiologist to radiologist. The x-ray itself can be misleading as it takes just one look at the hips with no outside influences, such as those exerted when the hip is in motion. Lastly, one must consider the environmental influences as well. Will those normal hips at two years of age still be normal looking 5 years and 20 pounds down the road? Also many x-rays are pre-screened by the veterinarian taking the films, thus only hips likely to get a good rating are sent on to OFA.

So, am I anti-OFA? Absolutely not, currently it is only one of two choices, and is by far the most widely used, that we have when selecting breeding dogs as far as hips are concerned. Just realize there are no guarantees built into this system. When a breeder guarantees hips on OFA scores they are still taking a risk, albeit an educated risk. There are still other factors at work.

The other major method of measuring canine hips is the method known as PennHIP. This method requires the dog to be sedated (with OFA x-rays the dog usually is sedated but not always). Then three x-rays are taken of the hips, a standard view, one with compression applied to the hip joint and one with distraction applied. The x-rays are then evaluated for degenerative changes and a quantitative number is reached based on hip distraction. The owner is given a report on the findings discussing the distraction index and a laxity ranking relative to other members of the breed. It is not a pass/fail system. However, dogs that have already developed degenerative changes are given a designation of confirmed hip dysplasia.

Sounds like a good method right? Well, yes and no. Although a little complicated it is a method based on numbers and not opinions. Once you get away from metro areas and universities currently there are not a lot of veterinarians trained in the PennHIP method. Whereas, any vet with an x-ray machine can take OFA film. Secondly, the numbers are calculated based on other members of the breed. This is great for the popular breeds like labs and goldens where there are a lot of dogs to compare. The laxity numbers may not play such an important role to those of us owning dogs of lesser popularity; however, the distraction index might.

What does this boil down to for the average dog owner? Make sure your breeder is doing their job by having their dogs’ hips evaluated by at least one of the above methods. Also find out what is really involved in the guarantee on the hips. Some breeders require different things to exercise the guarantee, from neutering to returning, while others will require the dog to be euthanized to get a refund.

Once you get your new hunting partner home, get to work on the environmental factors that influence the hips. Feed a quality diet at correct amounts. Rolly-polly pups are cute in pictures, but extra weight early can start the wheels turning for development of hip dysplasia. Controlled feeding and keeping your pup at a lean body weight are probably the most important things you can do for your dog to give him the best shot at a long healthy life. Also give the pup plenty of controlled exercise to start in the development of good muscle mass. These guys are athletes and need to be treated as such.

How about the dog that already has clinical signs of hip dysplasia? Options range from hip replacement to conservative management. Here again, weight is a big influencing factor. Less weight equals less stress equals less discomfort. It’s the viscous cycle of the dog not exercising thus getting heavier thus not exercising that needs broken. Start by reducing the food to take the weight off and slow and easy leash walks to build up the muscle mass. As far as mild dogs go, don’t let them sit around all summer and take them on a week-long pheasant hunt in November. Every year I see these dogs after the trip because they can hardly move. Make their outings shorter with longer periods of rest in between and work on conditioning throughout the year.

There also are numerous anti-inflammatories for dogs. Which one to use will be up to you and your veterinarian. One word of caution, do NOT give your dog your anti-inflammatory medication (i.e. aspirin, Tylenol, or ibubrofen), as serious consequences can result. Please consult your veterinarian first and let him or her decide. Dogs’ livers metabolize drugs differently than ours with varying side-effects.

So there you have it, a crash course in hip dysplasia. A complicated and frustrating disease for dog owners, but when armed with knowledge, a disease that can be attacked head on.