|Like most large, heavy
breeds, the Labrador has a problem with Canine Hip Dysplasia (CHD). Canine
hip dysplasia has puzzled researchers for the past 50 years. Although certain
aspects of this degenerative, sometimes painful condition are now understood
(or at least agree upon in theory), much must still be learned about helping
afflicted dogs and preventing the increasing incidence of the disease.
Originally, the only means at the breeder’s disposal was to look at the
dog’s movement in order to judge whether the hips seemed sound. But many
dogs with wretched movement never develop hip problems, and dogs with excellent
movement can develop degenerative joint disease (DJD) of the hip joint.
Hip dysplasia is one of the most over-diagnosed and misdiagnosed conditions.
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. It may or may not be bilateral (affecting both the right and left hip joints) .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.
Hip dysplasia is a
developmental condition and is not considered a congenital anomaly.
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. As stated earlier dysplasia
is not caused by factors in the environment but they can influence whether
a dog develops the disease. In other words, how you raise your puppy won't
determine whether or not he is dysplastic, but it can affect when and perhaps
if, he begins to develop symptoms. Some of these factors which have been
proposed to worsen, but not cause CHD are types of food fed (diets low
in protein are best), avoiding excess exercise during puppy hood (i.e.
forced running for any distance, pulling weights, mushing, running with
owner on bike, etc.), not using calcium supplementation (may increase the
bone remodeling). Reduced caloric intake and glucosamine products in immature
animals genetically predisposed for hip dysplasia may lessen the pathologic
changes associated with hip dysplasia. 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. Studies have been done on supplementation
with mega doses of vitamin C. These studies showed that dogs receiving
the supplements were least likely to develop the disease. Vitamin C is
important for the healthy development of bones, muscles and blood vessels.
It has been implicated as having a therapeutic role in the treatment and
relief of pain associated with hypertrophic osteodystrophy. In more recent
years, therapeutic effect of vitamin C has been indicated in treatment
of hip dysplasia. Because vitamin C also functions to maintain integrity
of connective tissue cells, accordingly, it has been observed to slow down
the progression of osteoarthrosis and relieve pain in dysplastic dogs.
Breeders for years have used vitamin C as prophylaxis for hip dysplasia
in growing puppies. Vitamin C is a fairly safe drug; overdosage, unlike
other vitamins, is not possible since any of the drug not used by the body
is quickly excreted. In dogs at higher genetic risk of developing hip
dysplasia (i.e. offspring of one or more dysplastic parents), vitamin C
treatment may serve as a possible conservative alternative to surgical
Guided by Berge's success with degenerative syndromes in dogs, Dr. L. Phillips Brown conducted a similar study with dogs housed at the Best Friends Animal Sanctuary in Kanab, Utah, USA. Dr. Brown administered Ester–C® calcium ascorbate, ordinary ascorbic acid, or a placebo twice daily to each group of dogs for three weeks. Response to treatment was graded with the Average Mobility Improvement Score (AMIS), using a four-point scale, with "0" representing no response and "3" representing a very good response. Treatment was then discontinued for three weeks and the groups were crossed over, so that each group received a different treatment. Treatment and scoring were performed two more times in this fashion. When all improvement scores were added up, Dr. Brown found that dogs receiving the Ester–C® ascorbate showed an AMIS score of 1.5, while dogs receiving plain ascorbic acid showed an AMIS score of 0.5. The average score of the placebo was 0.1, indicating that no significant improvement can be expected if no intervention is performed. Dr. Brown concluded that Ester–C® calcium ascorbate was more effective than ordinary ascorbic acid for improvement of mobility difficulties (Brown, 1994a, b, c).
Ester–C® calcium ascorbate or NOW's Ascorbate
Mineral-C, is a mineralized form of vitamin C that aids in the
absorption and retention in the body’s tissues, and because it has a neutral
pH it does not cause gastric upset. Ascorbic acid, the vitamin C we are
most familiar with, is too rapidly excreted to be effective, can irritate
the lining of the digestive tract, and at the higher dosage recommended
will cause the formation of crystals in the urinary tract.
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 Orthopaedic 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
When a puppy is 5-7
weeks old, a veterinarian experienced in the Bardens Palpation technique
can make a subjective determination of a tendency toward hip dysplasia.
Palpation to estimate the amount of laxity of the hip joints is not an
accurate method for prognosis; however, it has been observed that puppies
having tight hip joints at an early age have a better chance of developing
sound hip joints.
news about Canine Hip Dysplasia is that most cases can be treated to help
eliminate or decrease pain, allowing fairly normal levels of activity.
Very few dogs today have to be put to sleep to alleviate suffering. There
are always choices to be made, but the vast majority of affected animals
can live quite comfortable lives.
Pectineus Tenotomy was popular in the early 1970's. The procedure involves cutting a section of the pectineus tendon and / or muscle. We do not know exactly how this process relieves pain, although it does seem to, in some cases. It does not however, affect the amount of arthritis that will form over the years. A disadvantage is that the relief it provides may be only temporary. Although it is still performed by some veterinarians, it is generally regarded as an obsolete procedure.
of the hip joint (Triple Osteotomy of the Pelvis) 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
In Femoral Head
Excisions, the ball portion of the hip is removed. Because arthritis
develops from the ball rubbing abnormally in the socket, removing 1/2 the
hip joint, and thus the bone to bone contact, relieves the pain. Once the
ball is removed, a piece of muscle or joint tissue is placed between the
thigh bone ( femora) and the socket. This causes scar tissue to form which
in turn supports the leg.
Once the discomfort
subsides after surgery, the dogs personality and activity level improve
dramatically. We are often told by pet owners that their dogs play and
act like puppies again.
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.
OFA's latest news release contains some good news, but it should be read with a "filter" for fuller understanding. The intertwining of valid and accurate information with some that could be called (by the skeptics) misleading is unfortunate, but not too much of a problem. The announcement that in the 30 years of OFA's existence there has been "dramatic" improvement in dogs' hips must be expanded upon... salted before swallowing.
The opening statement that, "Breeders working with the OFA have reduced HD by 29% and increased the rate of 'excellent' by 56%" is certainly good news, but let's look at it more closely.
Remember that such figures as the 29% above are definitely skewed. As more vets get to see the good breeders' dogs, and X-ray more dogs, they get a little better at reading the films and giving you a better diagnosis or prediction. Some years ago OFA surveyed the readings of private practitioners and found that more than half read the radiographs WRONG... and in both "directions"; i.e., some read good hips as being bad, and some read dysplastic hips as being normal. Some dogs have even been put down as a result of erroneous readings. Don't let vets euthanize a dog unless YOU can easily see the dysplasia on the film and the dog is in obvious, continued or chronic intermittent pain. The skewing of statistics results from more films NOT being sent to OFA because the vet has become more adept at spotting HD, and saving you the OFA reading fee. Thus, the worst hips don't get reported to and recorded by OFA; of the films that DO go in, these are the better hips and naturally the picture will look rosier than before.
The increase in percent graded "excellent" is indeed good news. As OFA executive director Dr. Greg Keller admits, "the decreasing percentage of dysplastic hips can be due to prior screening" (the skew we mentioned), but he also maintains that the "percent-excellent" is a good barometer of progress (WITHIN THAT COMMUNITY REGULARLY USING OFA, REMEMBER). Say, your vet sends only films of normal hips because people aren't paying OFA for confirmation of obvious dysplasia anymore. If those "normals" have more in the "excellent" category than used to be the case, that means his clients are conscientiously selecting for good joints, because the entire spectrum of hip quality has been shifted toward the normal end of the random range.
Thus, more hips are going to fall into the far (best) end of the bell curve and fewer into the really bad end. It is known that breeding selection for normal hips results not only in fewer cases of HD, but also in lower average severity. And this is why we have cause to rejoice: the higher relative numbers for "excellents" is indeed a sign of progress.
Is the rate of progress satisfactory? For some, who use only the best OFA grades (Good and Excellent), probably, but then they have always been the "A and B students" anyway. The average doesn't really apply to those folks any more than average intelligence has much meaning for Mensa members, or average body fat has for the marathon runner. Those leaders in their fields are unaffected by what the hoi polloi do. For breed clubs and the sport in general, perhaps the rate of progress is much too slow.
There are factors which influence the rating of hips. Some temporary physiological and exogenous factors may influence the appearance of hips in radiographs. Among them are the estrus cycle of the female and anesthesia administered for the purpose of taking the radiographs. Fluctuating hormone levels and anesthesia have an effect on pelvic muscles and may cause an increase in visual subluxation of the hip joints. In such a case, a rating may be lowered by these factors.
The OFA method is still the only method used in many European countries. Although this uniformity looks good, results cannot be compared easily, because of the difference in interpretation. For example, some dogs have been evaluated by both the Dutch and the German system. Differences were large: always the Dutch evaluation indicated an inferior result. There are many examples of dogs being rated CHD Free in Germany and CHD Tc or even Mild Positive in the Netherlands. The Netherlands are considered to have the most demanding test of Europe. Fair enough, if the OFA method would be reliable. But it isn't.
One last word about the OFA method: If you use OFA, don't screen dogs below the age of two years and above 5-6 years of age. Below the age of two years it is difficult to draw the line between what is normal and abnormal; above 5-6 years of age, primary arthritis of old age may be impossible to differentiate from slight hip dysplasia.
PennHIP (from University of Pennsylvania Hip Improvement Program) is a closed registry that was developed by Dr. Gail Smith at the University of Pennsylvania School of Veterinary Medicine. In studies of the mechanics of the hip joint, Dr. Smith found that the hip extended view could actually mask some of the hip laxity. He determined that a neutral position, where the hips are positioned as though the dog were standing, best showed maximum laxity. An additional benefit of this position is that it produces a much more consistent reading.
The PennHIP method
is a novel way to assess, measure and interpret hip joint laxity. It
consists of three separate radiographs: the distraction view, the compression
view and the hip-extended view (see below). The distraction view and compression
view, developed by Dr. Smith, are used to obtain accurate and precise measurements
of joint laxity and congruity. The hip-extended view is used to obtain
supplementary information regarding the existence of degenerative joint
disease (DJD) of the hip joint. (The hip-extended view is the conventional
radiographic view used to evaluate the integrity of the canine hip joint.)
The PennHIP technique is more accurate than the current standard and it
has been shown to be a better predictor for the onset of DJD.
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.
For now, the best chance of avoiding the disease is still to select puppies from parents who both have normal hip joints, but this doesn't guarantee the puppy won't have dysplasia. Normal puppies may also be born to parents who have hip dysplasia. Like all of life, it's a crap shoot, but it still pays to get the best odds you can.
Line breeding or inbreeding
dogs can actually decrease the incidence of dysplasia in a line. The more
inbreeding, the lower the heritability index because inbreeding reduces
the total genetic variability, that is, the gene pool is smaller. Inbreeding
is not really a bad thing, in fact all purebred dogs are inbred or they
would not resemble their breed and would look more like feral dogs. Inbreeding
only becomes problematic when undesirable genetic traits are concentrated
within the gene pool. This is why a strict culling program along with excellent
record keeping is necessary in a breeding program that decides to use this
Proceedings of the 1994 American Holistic Veterinary Medical Association Annual
Conference, Orlando, FL. pp. 119–125.
Brown, LP. 1994b. Vitamin C. New forms and new uses in dogs. New Editions Health World, Nov/Dec 1994, pp. 44–45.
Brown, LP. 1994c. Ester–C® for joint discomfort – a study. Natural Pet 3 (#6): 25–27.
Smith G.K., Gregor T.P., Rhodes W.H. Biery D.N. "Coxofemoral joint laxity from distration radiography and its contemporaneous and prospective correlation with laxity, subjective score, and evidence of degenerative joint disease from conventional hip-extended radiography in dogs."" Am J Vet Res. 1993 July;54(7):1023.