Hip Dysplasia in Dogs

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There may be few more joyous sights than a dog running free, unable to stop as the thrill of tearing around a yard overtakes him. It's this joy that hip dysplasia robs from our dogs, and from us as we watch them age and struggle with their own limitations.

Hip dysplasia is the leading cause of lameness in the rear legs of dogs, especially in large breeds such as Newfoundlands, Saint Bernards, Chesapeake Bay Retrievers, and German Shepherds. It's estimated that 20 to 40 percent of large-breed dogs are afflicted. Even more heartbreaking, this genetic condition can onset from birth, rendering some very young dogs lame. For others, it's a long road toward less and less mobility. But for many dogs there are ways to treat or prevent--or at least lessen the impact of--hip dysplasia.

Causes

Simply put, hip dysplasia is a hereditary bone and joint disorder that causes abnormal hip joint development.

The design, structure, and functionality of the canine hip are all strikingly similar to that of a human. The hip is a ball-and-socket joint: the ball is the round head of the femur (thighbone) and the acetabulum (socket) is the concave indentation of the pelvis. In a normal hip, the smooth, rounded head of the femur fits deeply and snugly into the acetabulum. Durable ligaments allow for a wide range of motion and collectively hold the joint together.

In a dysplastic hip, the head of the femur fits loosely or--depending upon the severity of the condition--it may be entirely dislocated from the socket. The bone separating from the joint causes friction and, as the condition worsens, painful arthritis.

Symptoms

In dogs born with hip dysplasia, hip development may appear normal at first. However, the first sign of a problem typically arises when the dog is as young as four months to a year. Dogs may begin to show pain in the hips when walking or running. Their gait may change, they may have difficulty standing up, and when you press down on the rump you may see the pelvis drop.

Due to the abnormal wear and tear of the hip joint, the condition may deteriorate progressively as the dog's skeletal system fully develops. In the worst cases, it can prohibit the dog from walking.

When it's time to see a vet

If you notice your dog having difficulty with normal walking or running activities over a period of time (not just for a day or two), it's time to see a vet.

Vets generally rank the health of the hip, and the extent of dysplasia, as follows:

• Excellent. The hip is normal and fully operational; the femoral head fits tightly into a well-formed hip socket with minimal space between the head of the femur and the acetabulum.
• Mild hip dysplasia. The distance between the ball and socket of the hip increases as the ligaments that hold them together develop tears and begin to stretch, reducing the stability of the joint.
• Moderate dysplasia. The rounded femur head barely rests inside the socket and arthritic changes become evident, such as partial or occasional lameness, or pain when running or moving.
• Severe dysplasia. The head of the femur is completely dislocated from the joint. The dog may be unable to walk, or only with great difficulty.

The only foolproof method of diagnosing hip dysplasia in your pet is through an X-ray of the hip and pelvis to examine the hip structure. Because a puppy born with a genetic predisposition to hip dysplasia will appear to have normal hips in the early stages of development, your vet will likely advise waiting until the age of two for a full X-ray examination. Of course each situation is different, so ask your vet as soon as you notice a problem.

What's next

Taking an effective X-ray that allows the vet to make a proper diagnosis will require your dog to be heavily sedated or anesthetized.

It's difficult to outline a "typical" course of treatment even after the condition has been diagnosed, because there is such a range of possible severity of the problem. Treatments vary from modified diet and exercise routines to surgical procedures such as hip replacements--which, as you can imagine, are highly invasive and require long recovery times. However, in some puppies early surgery can help prevent degenerative joint disease. And for dogs older than nine months, new advances in total hip replacement (replacing the old joint with a new, artificial one) have led to extraordinary recoveries in as many as 95 percent of cases.

In a less severe case, your vet may prescribe anti-inflammatory medication and perhaps the use of Adequan, a drug that can relieve pain and inflammation and help repair damaged cartilage.

How to prevent hip dysplasia

The only true method of prevention is selective breeding. Obviously, this is also the one option that is off the table for owners of an affected dog. But there many steps that can help. Proper care can actually delay the onset of hip dysplasia in dogs that are genetically predisposed, perhaps resulting in a less severe form of the disease. In the best scenario, your dog may never develop any clinical symptoms.

• Proper weight management is critical. Excess weight puts undue stress on the hip joints, so be well versed in the proper amount of food for your dog's breed and age (this varies greatly according to your brand of dog food).
• Puppyhood provides special challenges for weight gain. Because it's such a critical time for bone and joint development, you must take special care to ensure that your dog does not gain too much weight. The best place to start is with a high-quality dog food that provides proper nutrition without requiring excessive amounts per serving. It's a great time to train yourself that offering table scraps is not a good habit.
• During stages of rapid bone growth, discourage young puppies from jumping from heights or standing on their hind legs--it simply puts too much stress on the joints.
• If your dog is experiencing lameness, it's important to keep him on a leash and not allow him to run or jump as he plays.
• Swimming is wonderful exercise for a dog with hip dysplasia, because it allows him to build muscle mass without overstressing the joint.
• As dogs age, exercise remains very important, but you may need to adapt to your dog's changing ability and mobility.