HIP DYSPLASIA

                                                     

WHAT IS HIP DYSPLASIA?

Both cats and dogs can suffer from Hip Dysplasia.

Hip Dysplasia is a genetic disease characterized by abnormally formed hip joints.  Abnormally developed hips are lax (loose) leading to abnormal wear of the hip joint.   Hip Dysplasia creates degenerative joint disease, osteoarthrosis arthrosis (types of arthritis) leading to pain and debilitation.

Over time articular cartilage (the cartilage that cushions the joint) is worn away. The cartilage is prematurely destroyed because the hip is abnormally shaped.  Traumatic articular fracture (fracture within the joint capsule) can also occur. (Click to see joint anatomy.)

Once the cartilage is damaged enzymes, that further degrade the joint, are released into the joint. The enzymes molecularly degrade the characteristics of cartilage thickness and elasticity.   The result is cartilage that no longer absorbs loads placed on the joint when the animal moves.   The destruction continues in a cycle with debris and enzymes continuing to contaminate the joint fluid and cartilage.  The enzymes destroy the ability of the cartilage to regenerate.  So the joint continues to degrade, lose lubrication, and can no longer protect itself from inflammation.

 The synovial membrane (fluid found in the cavities of synovial joints. Synovial fluid reduces friction between the articular cartilage and other tissues in joints to lubricate and cushion them during movement.) is invaded by the degrading enzymes and inflammatory cells enter the joint.

As a result of lost cartilage synovial fluid contacts nerve endings in the bone, resulting in pain.  The body's reaction is to attempt to stabilize the joint and decrease the pain by producing new bone (bone spurs) at the edges of the joint surface, muscle attachments, joint capsules, and ligaments.  The joint capsule thickens and range of motion becomes limited.

As each animal is an individual there is now way of predicting when it will begin experiencing pain and loss of movement or the severity of symptoms.  Factors that can influence onset are exercise level, weight, and weather.

SYMPTOMS OF HIP DYSPLASIA

Dogs:

• Difficulty walking and/or climbing
• Limping
• Reduced appetite
• Lagging behind on walks
• Hesitancy or slowness rising when from a lying position
• Slow or stiff movements on waking, getting up, or in cold weather
• Decreased activity, especially play
• Hopping with hind legs, rather than running normally
• Swollen joints that feel warm when touched
• Licking or chewing a joint
• Yelping in pain when touched
• Personality changes -i.e. aggressiveness when touched
• Resting more than usual

Cats:

Symptoms of hip dysplasia in cats are similar to those seen in dogs. But cats are stoic creatures. It is their nature to hide or mask their pain well. But your dysplastic cat may refrain from certain movements or particular activities that cause pain. A cat in pain may not jump as high as it once did.  Or it may move more and more slowly as the pain increases. The gradual decreasing movement may go undetected the disease has progressed to the point that it is obvious that the cat in in pain. Even at that point some people may not realize the source of the problem. 

WHAT CAUSES HIP DYSPLASIA?

The major factor is heredity.  Dogs and cats known to have hip dysplasia should never be bred.

Generally speaking large and giant breed dogs are more prone to dysplasia than smaller breeds but there are exceptions.  Some susceptible breeds are:
Bulldog, Pug, Otterhound, Mastiff, St. Bernard, Clumber Spaniel, Sussex Spaniel, Basset Hound, French Bulldog, American Bulldog, Norfolk Terrier, English Shepard, Newfoundland, Bloodhound, American Staffordshire Terrier, Catahoula, Pit Bull , Chesapeake Bay Retriever, Rottweiler, Golden Retriever, Gordon Setter, Norwegian Elkhound, Chow Chow, Shih Tzu, Old English Sheepdog, German Shepard, Giant Schnauzer, Welsh Corgi, Beagle, English Setter, Black and Tan Coonhound.

Cat breeds known to have hip dysplasia:

Main Coon

When purchasing a puppy or kitten breed that is prone to dysplasia look for a breeder that screens their animals it.  This is not a guarantee that your puppy or kitten will have no problems but it does improve the odds against it.

WHAT TO DO WITH A PUPPY OR ADULT DOG OR CAT THAT IS PRONE TO HIP DYSPLASIA

Check Ups - Have your puppy examined immediately after purchase. Do not assume your puppy has been tested before you purchase it.  None of the currently available tests are valid for puppies under the age of four months. After 4 months ask us whether your dog should have x -rays to detect possible problems.

Diet - Slow the puppy's growth rate by limiting fat and protein in its diet.  We may recommend using a food specifically developed for large breed puppies.  A puppy that should be a large dog will still become large but its growth rate will be slower, which will probably result in a healthier dog than one that grew too fast.

Supplements - Supplementing the dog or cat's diet with Glucosamine, Ester C (a form of Vitamin C) and other supplements may be recommended. Talk with us about an appropriate treatment plan.

Weight - Maintain your pet at a healthy weight.  Excess weight puts undue strain on all joints including hips.  Regularly monitor your pet's weight.  You should be able to easily feel its ribs under its coat.  Ask us to show you how to determine whether your dog or cat is a healthy weight.

Exercise - Exercise your dog or cat appropriate to its age.  Puppies should be allowed to exercise and stop at will.  Excessive exercise (like taking your puppy for long walks or runs) should be avoided.  Repetitive movements should be avoided.  Do not jog with your dog till its at least one year old and be sure to build the dog's stamina gradually. 

The right amount of exercise helps maintain muscle tone and strength and helps stabilize that dysplastic joint. Exercise also improves joint range of motion keeping your dog more comfortable. Swimming is a non-weight bearing exercise that can be a good means of maintaining muscle tone and range of motion.  It spares the joint from weight borne concussion.  

Avoid putting your young puppy or kitten in situations where it could fall (i.e. top of stairs, on tables, in the back of pickups, etc.

Temperature - Keep your pet warm at all times.  Do not expose it to temperature extremes.

Bedding - Provide a well padded and warm bed to help alleviate some of the pain associated with osteoarthritis. Foam beds for dogs and cats are commercially available.

Other Non Surgical TreatmentS

There are a number of drugs that help control symptoms of osteoarthritis secondary to Hip Dysplasia.

Non Steriodal Anti Inflammatory Drugs (NSAIDS) - Inhibit the release of prostaglandins (Prostaglandins are unsaturated carboxylic acids.  Physiological effects of prostaglandins include the activation of the inflammatory response, production of pain, and fever. When tissues are damaged, white blood cells flood to the site to try to minimize tissue destruction. Prostaglandins are produced as a result.) decreasing the inflammatory process and reducing pain.

Alternative Drugs or Neutraceuticals for Dogs and Cats- According to the manufacturers, these drugs work provide the raw materials to enhance the synthesis of glycosaminoglycan (Family of carbohydrates is essential or important for the life of vertebrates that form an important component of connective tissues.) and hyaluronate (Hyaluronan is an important component of articular cartilage, where it is present as a coat around each cell.), two factors that are  not produced adequately in the diseased arthritic joint. These drugs may also enhance the synthesis of other macromolecules by cartilage cells that inhibit degradative enzymes produced within the arthritic joint.

Glucosamine appears to be a promising treatment for hip dysplasia and osteoarthritis.   Glucosamine is a dietary supplement that has been shown to be effective in the treatment of hip dysplasia, osteoarthritis, and joint pain in both pets and humans.

Used in the correct form and quality, glucosamine can treat pain and rehabilitate damaged cartilage. It is safe to use and does not have any of the side effects associated with NSAIDs.

Studies have shown positive effects in people with osteoarthritis. No controlled studies have been performed showing efficacy in dogs and cats but many owners report positive responses. Be sure to ask us about the use of glucosamine and other neutraceuticals for your pet.

Disease Modifying Osteoarthritis Agents - Drugs that are injected into the joint, vein or muscle have been a useful treatment for osteoarthritis in dogs. Injection allows the drugs to reach more rapid therapeutic levels than when taken orally. These drugs may be used along with oral neutraceuticals.  Response to these drugs varies from animal to animal.  There are side effects so animals must be observed closely.

SURGICAL TREATMENTS

Triple Pelvic Osteotomy (TPO) - Performed on young dogs, usually less than eighteen months old. The pelvis is cut in three places and the socket rotated.  The surgery improves the fit of the femoral head and the acetabulum. The pelvis is fixed into its new position with orthopedic plates and screws. TPO cannot be done after there are arthritic changes in the joint because the arthritis will most likely progress despite surgery.

Total Hip Replacement (THR) - The most effective treatment in that it gives the animal the most anatomically correct and sound hip joint. Most dogs need to have only one hip surgically repaired.  The procedure gives them one sound leg to stand on taking the pressure off the other leg.  This surgery is performed on older dogs (over 10 months) with osteoarthritis that can no longer be medically managed.  THR surgery has a high rate of success.

Femoral Head and Neck Ostectomy (FHO) - Performed when there is significant osteoarthritis and the owner cannot afford THR. FHO eliminates hip pain by removing the femoral head and neck initiating the development of a fibrous false joint that permits the animal to ambulate. The false joint is not as stable as a true joint and the animal will have an altered gait but pain relief and adequate function are the positive results. FHO is performed in all dogs of all sizes, but better long term success rates occur in smaller dogs (under 44 pounds). The presence of preoperative muscle mass and early postoperative physical therapy are two important factors in determining how successful the surgery will ultimately be. FHO  surgery is usually not as successful in dogs with severe muscle wasting (atrophy) and/or obese animals.

In cats, FHO is the surgery of choice.  Recovery time is relatively short, about 3-4 weeks.  Post operative complications are uncommon.  In most cases, once the cat is fully healed the post operative hip works nearly as effectively as the normal hip.  FHO is also done in traumatic fractures of the femoral head and neck.