Hip dysplasia is a medical condition found in many breeds of dogs, but more prevalent in large breed dogs such as the German Shepherd. The word “dysplasia” means abnormal growth, so hip dysplasia is abnormal development of the hips.
The femur is the long bone above your knee that ends with a structure that resembles the shape of a ball. This ball normally fits tightly into a “socket” that is nestled in the pelvis so when the dog walks, there is a smooth rotating motion within the socket.
In dogs with hip dysplasia, the ball does NOT fit tightly within the socket, so it starts to bang into the smooth protective cartilage of the pelvic socket and flattens it out over time. As the joint deteriorates, arthritis sets in and the condition continues to worsen eliciting a great deal of pain with every step.
The primary cause of hip dysplasia is genetic, but there are many other factors that are involved such as exercise level as puppies, nutrition, gonadectomy at an early age, and environmental situations.
We discussed the CHIC in the last blog and the testing for hip dysplasia is one of the items listed for many breeds. There are currently 2 procedures for testing hip dysplasia in dogs. One method is called PennHip and this procedure is done on young puppies at least 16 weeks of age as a tool to “predict” the chances of the puppy developing hip dysplasia as it ages. The puppies are sedated and the hip joint is distracted, or pulled out of the socket as far as comfortably possible, and assigned a number called a distraction index indicating the level of laxity in the joint.
The second method more commonly done is to take an X-ray of the hips to assess the condition and laxity of the hip joint. The X-ray is then sent to the Orthopedic Foundation of America, or OFA, where they compare the hips of dogs within the same breed and assign each dog an evaluation rating. Dogs can have the radiographs done when they are younger but the results are called Preliminary. The dogs must be over 2 years of age in order for the OFA to assign the dog a final certification rating. The hips that pass and are normal are rated as either Fair, Good, or Excellent depending on the condition and tightness of the joint. Those hips that do NOT meet a passing rating are then assigned a level of hip dysplasia such as Borderline, Mild, Moderate or Severe. Dogs that do NOT receive a passing score should NOT be bred so they do not pass this trait on to puppies.
We perform these X-rays here at the University Veterinary Specialists and we typically do them without sedation. Once the radiographs are taken, we send the images via the computer to the OFA for evaluation, so the results are back in about 10-14 days. The breeder needs to plan accordingly as these X-rays cannot be done when a bitch is in season.
Note that the round “ball” at the end of the femur is tightly seated in the “socket” of the pelvis. This dog has excellent hips with NO hip dysplasia.
Now look at the rough “ball” on the end of the femurs of these hips. There are a lot of arthritic changes here causing pain. The “socket” on the side of the dog marked with an R is really worn down and the hip ball is actually sliding out of the socket when the dog walks. This dog is severely dysplastic.
If you check the CHIC listing on the AKC website and find that your breed needs a hip dysplasia radiograph, please give us a call for an appointment. You will need to also bring in a copy of your dogs AKC registration as this will be required for the application.
Being a responsible breeder will pay off with healthy puppies for your families waiting for their new puppies!!!!