Feline hip dysplasia

I stopped working in veterinary medicine three years ago after being employed as an emergency technician for thirteen years. During that time I saw many dogs of varying breeds come through the doors with all the classic symptoms of canine hip dysplasia. Not once did I ever hear of there being an instance of FELINE hip dysplasia.

The reason for this is simple: until recently, cats were thought to be free of this possibly crippling condition. Now research has begun looking into feline hip dysplasia and like its canine counter part, it is thought to be a hereditary disorder. No single gene has yet to be linked to the problem and researchers feel it is the result of several genetic factors working together. It is a known fact that if a cat (or dog) has hip dysplasia, BOTH parents must have the disorder or are carriers for it.

“Dysplasia” simply means the abnormal development of some type of tissue. Hip dysplasia is the result of the abnormal formation of the hip socket and head or “ball” at the top of the femur.

The femoral head fits into the depressed area (acetabulum) of the hip. In a normal hip the acetabulum fits closely to the femoral head so there is an ease of movement and the joint moves smoothly. The femoral head doesn’t “snap” into place, it is held there by the large muscles that surround the hip and pelvis.

In an abnormal or dysplastic hip, the various parts of the hip are malformed and the femoral head can’t fit properly into the acetabulum. This creates a serious freedom in the joint that allows the head of the femur to “come out of joint” or subluxate. In some cases the acetabulum is excessively shallow, in others the “ball” itself is malformed or the neck area that leads from the ball to the femur itself.

Usually, but not always, both hips will be affected by the disorder. As the condition continues to cause subluxations, grinding or popping in the hip joint, degenerative joint disease often occurs.

Feline Hip Dysplasia often goes unnoticed because of many reasons. Cats are normally less active than dogs and when they are out exercising, an owner is seldom attached to the end of the leash where limping or unusual movement may be noticed. Cats are normally lighter and more agile than dogs as well. Those cats that are allowed to become morbidly obese are more likely to show the signs of hip dysplasia. Conscientious breeders are now screening their breeding stock for hip dysplasia. More often than not though, the disease is found by accident when the cat is being x-rayed for some other, unrelated conditions. Some readers may wonder just how often a cat would be x-rayed, it happens on a regular basis at any busy veterinary clinic. On emergency we used radiographs to check for retained kittens, Feline Urinary Syndrome, fractures due to some type of trauma like being hit by a car or in one case, a cat that was put into a trash compacter by a ten year old child.

As in dogs, hip dysplasia isn’t apparent at birth. It develops as the kitten matures and may wait six months or more to appear. When they are brought in and the veterinarian suspects it may be Feline Hip Dysplasia, the cat will usually show obvious signs of pain, be unwilling or unable to walk, climb or jump. They may have “phantom” limps that come and go.

To give an actual diagnosis of Feline Hip Dysplasia, the veterinarian will take x-rays. These are normally done with the cat asleep by general anesthesia after it had been sedated with acepromazine or some other tranquilizer. The reason for the anesthesia is that the cat must be fully relaxed so it can be fully stretched out on its back with the rear legs opened wide and laid flat upon the x-ray table. This opening of the hips is necessary to receive a clear image of each bone and joint in the hip.

A second x-ray will also be taken with the cat on its side. One rear leg will be pulled down at a ninety-degree angle from the body and the other will be pulled back and downward. Both x-rays are needed to see all angles of the hip joint.

As in dogs, the larger, heavier breeds are most likely to suffer from hip dysplasia. Persian, Maine Coon and Himalayan are just three of the breeds commonly affected. Owners must realize that Feline Hip Dysplasia can occur in any cat. They can be any size, breed or even mixed breeds.

Breeders interested in eliminating the problem in their stock will have screening x-rays taken and submitted to the Hip Dysplasia Registry of the Orthopedic Foundation for Animals commonly known as OFA. The OFA is located at the University of Missouri, Columbia, Missouri.

The OFA has a panel of orthopedic specialists that look at the x-rays and then assigns a grade to the animal. If the dog or cat is found to be clear of hip dysplasia, they are given OFA certifications. Cats can be initially evaluated before they are two years old but will not receive final certifications until over that age.

Although OFA is the most well known screening locations, the University Of Pennsylvania has developed a method they call PennHip. Their program measures the looseness in the hip joint. PennHip isn’t as readily available to breeders as OFA but they are looking into more cases of Feline Hip Dysplasia than the OFA.

If a cat is diagnosed with Feline Hip Dysplasia and is over weight, the veterinarian will set up a weight loss program. Cats being placed on a diet should be done under the supervision of a veterinarian because drastic, quick weight loss can cause serious problems in the overall health of the cat. Hills and the Iams/Eukanuba companies both produce excellent quality foods that are specifically formulated to help the cat lose weight.

Since most cats will only be diagnosed with Feline Hip Dysplasia AFTER exhibiting clinical signs of pain and lameness, they will usually be prescribed anti-inflammatory and pain medications. Owners should NEVER, NEVER attempt to quack their cat and give Tylenol (Acetaminophen), Aspirin or Advil. Acetaminophen is highly poisonous to cats and won’t take long to become deadly. Aspirin and Advil are metabolized very slowly and one dose can take up to three days to leave the body. Over dosing of Aspirin or Advil can cause bleeding and death as well. Again, NEVER give any of these drugs to your cat!

Another treatment recommendation your veterinarian will make is the restriction of exercise. This will mean limiting access to outdoors and discouraging the cat from climbing and/or jumping.

In the cats that are in severe pain, there is a surgery called a femoral head ostectomy (FHO) that can often prove helpful. During this procedure, the veterinarian will go shave the hip area, make an incision and gently dissect the connecting tissues surrounding the hip. He or she will then remove the femoral head and neck.

Strange as this may seem, cats that go through this surgery usually regain full hip function and once the area has healed, be able to move without pain. I must admit I was totally amazed the first time I assisted in a FHO and then had to chase the cat a few weeks later after it had escaped its owner’s hold. If it hadn’t used a paw and opened a cabinet door to enter, I may never have gotten a hold of it!

Feline Hip Dysplasia can be an excruciatingly painful condition for the cat but with proper diagnosis and treatment, there is no reason he or she can’t go on and live a long and happy life.