This is by far the most common of defects in large-breed dogs. The more common the breed, the more commonly you will come across this defect. A dysplastic dog is one whose hip joint is not properly formed. The hip joint consists of a ball and socket. In normal, healthy hips, the ball is seated tightly in the socket of the hip. In a dog with hip dysplasia, the hip joint does not fit together well due to poor placement of the aligning structures or shallowness of the socket. The poor placement causes uncomfortable movement and often friction from constant bone-to-bone contact or because the joint is too loose.

Effects on the Dog

The resulting effects on the dog can often be devastating. Dogs with bad hips often experience bouts of lameness, have trouble getting up after lying down, and have trouble maneuvering stairs and jumping. As these dogs age, the problem can progress to the point where they are in severe pain and euthanasia is the kindest option. Because the joint does not work correctly, it is prone to develop arthritis and worsens with age and excessive weight gain. In the past, it was advised that dysplastic dogs not be exercised a lot and not be allowed to run or do anything strenuous. Though their activity level may be severely impaired, it is actually better for dogs with hip dysplasia to be as active as possible so they can develop the proper muscle compensation they will need to remain mobile.

Though hip dysplasia has a main genetic component, there are several environmental factors that can exacerbate the problem in dogs with a predisposition. Obesity is a serious one. Dogs that carry around extra weight put stress on all of their joints. They are much more prone to injury than dogs that are fit. Dogs with hips that are not well formed are even more prone to problems from excessive weight, which puts way too much stress and strain on a joint that is already compromised. Rapid growth spurts, often seen around adolescence, can also be a problem, as can physical stress from sports involving repetitive jumping or jarring, like disk catching or flyball. These factors would not trigger problems in a dog with normal hips, but in a dog that is predisposed to hip dysplasia it can cause major problems. It is always best to have your dog examined by a veterinarian before starting any new sport or activity that involves a lot of jumping and twisting.

Genetic Screening for Hip Dysplasia

The most common diagnostic tool for evaluating a dog's hips are X-rays. These must be taken and then read by a board-certified veterinary orthopedist. The Orthopedic Foundation for Animals (OFA) operates as a voluntary diagnostic service and registry of hip status for all breeds of dogs. Based on evaluations of hip X-rays, dogs over two years old are rated as follows: excellent, good, fair, borderline, mild dysplastic, or severely dysplastic.

Most informed breeders will not breed any dog with less than a fair rating. Doing so would almost certainly pass along at least some traits of malfunctioning hips to at least some of the off-spring, thus making the incidence of hip dysplasia far more likely in future dogs.

Another way to evaluate hips has been developed recently. A procedure called Penn Hip evaluates a dog's hips by the laxity as well as the tightness of their fit. The values are given in percentages within each breed. After the evaluation, you get a value that tells you where this particular dog falls within his breed. If, for instance, your dog fell in the 30 percentile, his hips would be considered better than 30 percent of the Goldens who have had Penn Hip measurements taken, but worse than 70 percent of the overall dogs tested. Each breed has an average range that careful, knowledgeable breeders try to stay within to prevent the occurrence of hip dysplasia from rearing its ugly head in their breeding programs.