Canine Hip Dysplasia
Information About Canine Hip Dysplasia (CHD)
"Hip dysplasia is a painful condition of the hip joint in dogs. It is believed to be caused by a combination of genetics, environment, rapid growth, and nutrition," says Dr. Mary K. Quinn, veterinarian and surgery resident formerly with the University of Illinois Veterinary Medicine Teaching Hospital at Urbana. It occurs most often in Labrador retrievers, German shepherd dogs, and golden retrievers but can affect almost any breed of dog. Large-breed dogs are most frequently affected because they can grow too rapidly for their bones to grow in synch. Diets that encourage rapid growth, such as an early high-protein diet or puppy chow fed for a prolonged time, are thought to contribute to the problem.
The hip is a ball and socket joint. The ball is the head of the femur or thighbone. The cup in the pelvis, or hipbone, is called the acetabulum. Normally the head of the femur fits snugly into the acetabulum and forms the pivot point from which the hind leg swings.
In hip dysplasia, this joint is loose. Instead of rotating smoothly, the femoral head bangs around the inside the acetabulum. The dog may show signs of pain around 6 to 12 months of age, the period of most-rapid physical growth. The dog may be lame, may not want to run and play as hard as usual, may be reluctant to jump, or may experience pain when the hips are handled.
Bones respond to stress by growing thicker. This works well to make a tennis player's arm stronger but extra bone in the hip joint worsens the fit of the joint. The extra bone that results from the stress of hip dysplasia is referred to as arthritic change. Dogs with hip dysplasia may suffer from arthritis after they are a few years old.
Diagnosis of hip dysplasia is based on signs of pain in the hip joint and X rays showing poor hip structure. Unfortunately, X rays alone can't predict the progression of the disease or the secondary arthritic changes. Some dogs with very poor hip structure suffer very little pain. Others dogs, with only subtle abnormalities, will suffer a great deal. "Treatment of hip dysplasia is indicated if the dog is in pain," explains Dr. Quinn.
If hip dysplasia is detected early, before the dog is a year old and before there are any arthritic changes, it can be surgically corrected by a triple pelvic osteotomy (TPO). In this procedure, the pelvis is cut in three places and the acetabulum is rotated over the femoral head, making a snug fit. This procedure restores the normal anatomy and, for many dogs, restores normal function.
Sometimes it is possible to manage pain from hip dysplasia with non-steriodal anti-inflammatory drugs, such as aspirin or carprofen. These dogs should be kept fit and trim. Any excess weight will aggravate arthritis. Fit muscles will reduce the load on the joint and help support the dog's weight. Low-impact exercise, such as swimming or leash walking, will build up muscles without pounding on the joint. In some dogs, however, the joint eventually becomes so arthritic that the pain can't be controlled medically.
"Salvage" surgical procedures can be done on older dogs to relieve pain caused by arthritis. In one such procedure, called a femoral head osteotomy, the head and neck of the femur are removed so that there is no bone-to-bone contact. Fibrous scar tissue forms a "false" joint. These dogs must be exercised regularly beginning right after surgery. Their muscles must be strong enough to support the dog's weight on the false joint. The other salvage option is a total hip replacement. The diseased joint is removed and an artificial replacement joint is inserted, as in a human hip replacement.
Before buying a large-breed puppy, ask the breeders whether their dogs are certified "hip dysplasia free" by the Orthopedic Foundation for Animals. This will not guarantee a puppy free of hip dysplasia, but it will reduce the likelihood. If you notice problems in your growing pup, have it checked right away. The TPO is a wonderful corrective procedure but has to be done early in the dog's life.
"Hip dysplasia is not always the crippling disease owners perceive it to be," says Dr. Quinn. "There is a lot that can be done to keep the dog functional and free of pain."
For more information on hip dysplasia, contact your local veterinarian.