Hip dysplasia literally
means an abnormality in the development of the hip joint. It is
characterized by a shallow acetabulum (the "cup" of the hip
joint) and changes in the shape of the femoral head (the "ball"
of the hip joint). These changes may occur due to excessive
laxity in the hip joint. Hip dysplasia can exist with or without
clinical signs. When dogs exhibit clinical signs of this problem
they usually are lame on one or both rear limbs.
Severe arthritis can develop as a result of the malformation of
the hip joint and this results in pain as the disease
progresses. Many young dogs exhibit pain during or shortly after
the growth period, often before arthritic changes appear to be
present.
It is not unusual for this pain to appear to disappear for
several years and then to return when arthritic changes become
obvious.
Dogs with hip
dysplasia appear to be born with normal hips and then to develop
the disease later. This has led to a lot of speculation as to
the contributing factors which may be involved with this
disease. This is an inherited condition, but not all dogs with
the genetic tendency will develop clinical signs and the degree
of hip dysplasia which develops does not alway seem to correlate
well with expectations based on the parent's condition.
Multiple genetic factors are involved and environmental factors
also play a role in determining the degree of hip dysplasia.
Dogs with no genetic predisposition do not develop hip dysplasia.
At present, the
strongest link to contributing factors other than genetic
predisposition appears to be to rapid growth and weight gain. In
a recent study done in Labrador retrievers a significant
reduction in the development of clinical hip dysplasia occurred
in a group of puppies fed 25% less than a control group which
was allowed to eat free choice. It is likely that the laxity in
the hip joints is aggravated by the rapid weight gain.
If feeding
practices are altered to reduce hip dysplasia in a litter of
puppies, it is probably best to use a puppy food and feed
smaller quantities than to switch to an adult dog food. The
calcium/phosphorous to calorie ratios in adult dog food are such
that the puppy will usually end up with higher than desired
total calcium or phosphorous intake by eating an adult food.
This occurs because more of these foods are necessary to meet
the caloric needs of puppies, even when feeding to keep the
puppy thin.
If clinical signs
of hip dysplasia occur in young dogs, such as lameness,
difficulty standing or walking after getting up, decreased
activity or a bunny-hop gait, it is often possible to help them
medically or surgically. X-ray confirmation of the presence of
hip dysplasia prior to treatment is necessary.
There are two techniques currently used to detect hip dysplasia,
the standard view used in Orthopedic Foundation for Animals (OFA)
testing and X-rays (radiographs) utilizing a device to
exaggerate joint laxity developed by the University of
Pennsylvania Hip Improvement Program (PennHIP).
The Penn Hip radiographs appear to be a better method for
judging hip dysplasia early in puppies, with one study showing
good predictability for hip dysplasia in puppies exhibiting
joint laxity at 4 months of age, based on PennHIP radiographs.
Once a
determination is made that hip dysplasia is present, a treatment
plan is necessary. For dogs that exhibit clinical signs at less
than a year of age, aggressive treatment may help alleviate
later suffering.
In the past a surgery known as a pectineal myotomy was advocated
but more recent evidence suggests that it is an ineffective
surgical procedure. However, administration of
glycosaminoglycans (Adequan Rx) may help to decrease the
severity of arthritis that develops later in life.
Surgical reconstruction of the hip joint (triple pelvic
osteotomy) is helpful if done during the growth stages. For
puppies with clinical signs at a young age, this surgery should
be strongly considered. It has a high success rate when done at
the proper time.
Dogs that exhibit
clinical signs after the growth phase require a different
approach to treatment. It is necessary to determine if the
disorder can be managed by medical treatment enough to keep the
dog comfortable. If so, aspirin is probably the best choice for
initial medical treatment. Aspirin/codeine combinations,
phenylbutazone, glycosaminoglycosans and corticosteroids may be
more beneficial or necessary for some dogs.
It is important to use appropriate dosages and to monitor the
progress of any dog on non-steroidal or steroidal
anti-inflammatory medications due to the increased risk of side
effects to these medications in dogs. If medical treatment is
insufficient then surgical repair is possible.
The best surgical
treatment for hip dypslasia is total hip replacement. By
removing the damaged acetabulum and femoral head and replacing
them with artificial joint components, pain is nearly
eliminated. This procedure is expensive but it is very effective
and should be the first choice for treatment of severe hip
dyplasia whenever possible.
In some cases, this surgery may be beyond a pet owner's normal
financial resources (Good quality health insurance is a must)
An alternative surgery is femoral head ostectomy. In this
procedure, the femoral head (ball part of the hip joint) is
simply removed. This eliminates most of the bone to bone contact
and can reduce the pain substantially. Not all dogs do well
following FHO surgery and it should only be considered as a "second
choice".
Hip dysplasia may
not ever be eliminated by programs designed to detect it early
unless some effort is made to publish the results of diagnostic
tests such as the OFA evaluation or PennHIP evaluations, openly.
This is the only way that breeders will be able to tell for
certain what the problems have been with hip dysplasia in a
dog's ancestry.
When an older dog
is exhibiting signs of pain associated with this condition it is
often possible to help them dramatically through medication and
simple steps like providing a warm bed or warm spot to rest
during the day.
There is no advantage to pain and steps should be taken to
ensure that the older dog is not in pain. Regular exercise can
be very helpful and weight loss can have dramatic effects on the
amount of discomfort a dog experiences.
Working with your
vet to come to the best solution for your dog and your situation
will enable you and your dog to enjoy life to its fullest,
despite the presence of hip dysplasia.
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