Hip Dysplasia
What is hip dysplasia and how is it caused?
Hip dysplasia is a deformity of the coxofemoral (hip) joint that occurs during the growth period.
Certain dogs are genetically predisposed to developing hip dysplasia.
Other contributory factors are overweight and overfed puppies and excessive
exercise in a young immature dog. As the dog grows the joint malforms, arthritis
may develop or the hip may even become dislocated. This all causes pain in
the hip joint. The degree of lameness that occurs is dependent on the extent of arthritic changes in the hip joint.
Is this found in certain breeds of dogs?
Most breeds of dogs can be affected with hip dysplasia although it is predominantly seen in the larger breeds of dogs, such as the German Shepherd, St. Bernard, Labrador Retriever, Old English
Sheepdog etc. There is equal distribution of the disease between male and female dogs.
What are the clinical signs, and when do they occur?
The typical clinical signs of hip dysplasia are lameness, weakness and pain in the hind legs, lack of co-ordination, and a reluctance to rise. Wasting of the large muscle groups in the hind legs may eventually develop. Most owners report that the dog has had difficulty in rising from a lying position for a period of weeks or
months. Clinical signs can occur as early as 4-6 weeks of age, but most dogs
start to show signs of lameness at around 1 to 2 years of age. Dogs with mild hip dysplasia and minimal arthritis may not become
lame until 6-10 years of age.
How is it diagnosed?
Tentative diagnosis of hip dysplasia is made on the basis of history, breed, and clinical signs.
Because the clinical signs may mimic other diseases, final diagnosis of hip dysplasia can only be made
by radiographing (x-raying) the hips. To obtain an accurate radiograph the
dog must be anaesthetised or heavily sedated to enable the correct positioning
for the hips to be evaluated. On examining the radiographs we look for an abnormal shape
to the hip joint and for degenerative changes (arthritis).
How is it treated?
The degree of clinical signs and arthritic changes in the joints determine the specific approach to therapy. Treatment of hip dysplasia may involve the use of drugs or surgery, or both. The options are as follows:
l. Anti-inflammatory drugs:
Several drugs will give relief from pain. Early in the course of the disease drugs which protect the cartilage lining of joints may be effective in limiting pain. Also
non-steroidal anti-inflammatory drugs (NSAIDs) work well in most dogs. There are
several types available, some work better in some dogs than others. It may
be a matter of trying several drugs to see which is the most effective one for
your dog. Anti-inflammatory drug therapy is most often used in older dogs,
in dogs that did not get good relief from surgery, or in dogs for which surgery
is not feasible.
2. Cartilage modifiers:
These
drugs are especially useful early in the course of the disease before there are
major degenerative changes in the joint. There are several forms of this
type of medication. Feed supplements are available that promote healthy
cartilage growth and joint fluid production. There is also a product
called Cartrophen. This is a drug which is given as a course of 4
weekly injections by your vet. It is designed to improve the functioning
of the joint fluid and improve the health of the cartilage, thereby reducing
inflammation and pain.
3. Glucosamine Sulphate
4.
Surgery:
There are four main procedures:
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Pectineal myotomy is a relatively minor procedure that involves cutting a small muscle that puts pressure on the hip joint. It results in no loss of leg function and gives good to excellent relief in 80-90% of dogs. If both hips are abnormal, both hips may be operated
on at the same time. The dog recovers from surgery in 1 to 2 days. However, this procedure does not stabilise the hip joint or prevent progression of arthritic changes. Within a few months to several years, pain and lameness will return. |
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Excision Arthroplasty
(EA) The hip is a ball and socket joint. EA is the removal of the ball part of the joint. This gives excellent results in small dogs
particularly as they have less weight bearing on their limbs. This procedure is
only used in large dogs if arthritis is very severe, if the hip dislocates, or if the expense of the other procedures is prohibitive. |
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Triple osteotomy is a procedure in which the pelvis is cut in three places around the hip joint. The bone is rotated to create better alignment with the femoral head (the ball). It is reattached so that the joint functions in a more normal fashion without looseness and pain. This should only be performed in a dog with no arthritic changes in the joint and is generally reserved for younger patients. |
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Total Hip Replacement is possible, as is done in humans. The hip joint is replaced with an artificial ball and socket often made of plastic and stainless steel attached to the pelvis and femur in place of the abnormal joint. It is
an expensive procedure, but it should give many years of pain-free use of the hips. Although the intent is for the transplant to be permanent, the new joint may loosen after a period of time. |
5.
Rest and weight control:
It
is important that your dog is not over-exercised. Severely affected dogs
may need to be restricted to lead exercise only. It is better to have
frequent, short walks than infrequent, long walks. It is also very
important to ensure your dog is not over-weight. Often losing weight is
all that is required in dogs with mild hip dysplasia to improve clinical signs
significantly. You may need to put your dog on a special veterinary
prescription diet food designed for weight loss. We can help you follow a
specific programmed tailored to your dog's specific needs.
I am considering breeding my dog. Can anything be done to prevent hip dysplasia
in the puppies?
Research has shown that the cause of hip dysplasia is related to a combination of genetic and environmental factors. The disease is known to be an inherited condition and the genetics of hip dysplasia are extremely complicated. In addition, environmental factors such as overfeeding and excessive exercise can predispose a dog (especially growing puppies) to developing hip dysplasia.
There are several practical things you can do to ensure that the incidence of the disease is reduced.
1. Have your dog or bitch hip scored - The British Veterinary Association runs a scheme (The
BVA/KC Hip Dysplasia Scheme). This scheme gives your dog a Hip
Score. A panel of experts examine an x-ray of your dog's hips and measure
9 aspects of the hip joint. They then give each hip a score to a maximum
of 81. The lower the score the better the hips are. The advice is
that you should only breed from a dog that has a lower hip score than the breed
average. In this way the chances of reducing the incidence of the disease are greatly increased. The procedure is as follows:
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the dog must be at least 12
months old and Kennel Club registered
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the radiographs can be taken by your own veterinary surgeon.
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general anaesthesia is necessary
to obtain correctly positioned radiographs
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the radiographs are then submitted to the
British Veterinary Association Hip Scoring panel together with the appropriate fee
to be assessed. A report of the Hip Score awarded is sent to your veterinary surgeon.
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the higher the score, the worse the hips.
2. When purchasing a puppy ask to see the parents hip scores - it is
obviously best to purchase a puppy that was born from parents that had low hip
scores. Even if you did not get this information at the time you purchased
the puppy it is worthwhile contacting the breeder to obtain it if you are
contemplating breeding from your dog. However it should be borne in mind that because heredity is not the only factor involved, there is still a chance of parents with normal hips
producing a puppy with hip dysplasia. Once you have obtained the necessary information, including the hip score, do discuss any breeding programme with your veterinary surgeon.
3.
Consider a feeding programme to slow growth - there is evidence that dogs that grow very rapidly are more likely to
develop hip dysplasia. Many pet food manufacturers now sell puppy
food designed for large and giant breeds that is lower in energy than regular
puppy food. These foods are formulated to ensure the puppy reaches their
full adult size and potential but without rapid growth. It is also
important not to supplement puppy food with extra vitamins and minerals as this
can also cause accelerated growth and damage to developing bone and cartilage.
4.
Avoid excessive exercise in a growing puppy - any abnormality in the structure of the hip joint is magnified if excessive running and jumping occur. It is
best to avoid long sessions of running or chasing thrown objects as this can be detrimental to joints.
Regular, controlled lead exercise will be adequate to keep the puppy exercised
and the bones developing correctly.
