by Scott A. Krick D.V.M.
Reprinted from Delaware Valley Golden Retriever Rescue Golden Opportunities newsletter (DVGRR, Sinking Spring, PA)
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Dysplasia is a "catch all" term used to describe a hip joint in which some or all of the signs associated with joint instability are present radiographically. Many factors can contribute to "hip dysplasia." For the most part, dysplasia is an inherited instability of the joint. This instability can be compounded by environmental factors such as injury to the joint and by dietary factors such as pushing rapid growth in puppies. It is my opinion that if a dog is predisposed to joint instability, you can aggravate the condition by overfeeding high protein diets and by excessive exercise, but you cannot create problems if the dog is not already genetically predisposed. Conversely if the dog is genetically predisposed it would be wise to encourage slow growth by switching to adult food at six months of age, not using high protein foods and by discouraging excessive stress on the hip joint during exercise.
Most people find it surprising that physical examination of the hips by a veterinarian is, itself, not a very reliable way to evaluate the hip joint status. There are several reasons why this is true. Perhaps the greatest reason is that there is a substantial amount of muscle mass surrounding the hip, making palpation of the joint itself virtually impossible. Another significant factor is that pain associated with degenerative joint disease will vary considerably among individuals, making assessment based on resentment of manipulation very subjective. This is not to say, however, that physical examination and observation are useless.
A thorough history and examination often reveal that the dog experiences difficulty when rising from a lying position. Many dogs exhibit reluctance to jump up or to climb stairs (actions that place greater weight and stress on the hip joints). Some dogs show a "bunny-hopping' gait in which they run using both back legs together. While this can also be normal, it commonly suggests that the dog is unconsciously "sharing" the weight between the legs rather than using them alternately. Some individuals show marked lameness (limping). A veterinarian may also note atrophy (loss of muscle mass) of the thigh muscles suggesting that the dog is not using the limb as athletically as usual. This is not specific to the hip joint, but may support a diagnosis of hip joint problems. Additionally, a dog who resents full extension of the rear limbs may be experiencing degenerative problems with its hips. The final complicating factor is that hip joint pain is often episodic. The dog may be physically "normal" some or most of the time, and therefore may appear to be normal on physical examination even in the presence of substantial degenerative changes.
The most widely used methods of evaluating the hips are the OFA and the PennHip technique. Both rely on radiography (x-rays) of the hip joint to assess its conformation and stability. OFA evaluation is performed entirely through subjective interpretation of observation, while PennHip evaluation relies on actual measurements of laxity. As you are probably aware, there is a great deal of controversy as to which of the methods of evaluation is better. I personally feel that the PennHip method is much more accurate, repeatable and predictive of future degenerative joint disease. Using its information and recommendations, it is possible to actually improve hip status in succeeding generations through selective breeding. The arguments against it most frequently arise from individuals who are apparently afraid to find out the truth about their dog(s) or breeding lines, because rarely are there legitimate reasons for distrusting the results.
Once a diagnosis of hip dysplasia is made, there are several options for the dog and owner. In "mild" cases, no treatments may be indicated. One of the "nutriceuticals" (products used in treatment which are not considered drugs) such as Glycoflex, Inflammex, glucosamine sulfate, chondroitin sulfate or Cosequin may be recommended. This class of products is claimed to increase joint fluid viscosity and provide nourishment for the joint surfaces. Until recently no controlled studies had been done to document the effectiveness of the nutriceuticals. A study of a similar injectable product (Adequan) suggested marked improvement in the joints of dogs treated versus the untreated control group. I have been very impressed with the effects of Glycoflex in particular in reducing or alleviating the symptoms of discomfort associated with joint problems. Another option available is the use of non-steroidal-antiinflammatory drugs. This category of medication includes aspirin, phenylbutazone, Rimadyl, Etogesic, Arquel and other drugs. While they may give relief from the symptoms of joint pain, they do not improve the joint in any way. A third choice is steroids such as prednisolone and methylprednisolone. Steroids are, for me, the drug of last resort for joint pain. Like the non-steroidals, these drugs do nothing to improve the joint. They are strictly used to reduce inflammation. Long term use of either steroidals or non-steroidals may actually contribute to degeneration of the joint. I have found that the neutriceutical products may decrease or eliminate the need for other classes of medications in many cases.
Another consideration for the treatment of dysplasia involves surgical intervention. There are several procedures used to restore some or all of the function of the joint. Total hip replacement is the "gold standard" by which other procedures are measured. Like in humans, a new metal alloy "ball" and an acrylic "socket" are installed to replace the damaged one(s). Success rates are high in the 90 percentile for nearly perfect return to function. Many surgeons have found that replacement of only one affected hip often returns the dog to soundness even if initially both legs are affected, so rarely does the other hip require replacement. This is appealing since the surgery costs in the $1,800 to $ 3,000 price range. Pectinectomy involves cutting the tendons attachment of the "groin" muscle known as the Pectineus. This relieves the immediate tension on the hip joint and tends to diminish pain. Unfortunately, this procedure is often only a temporary solution to the chronic problem. This procedure has become less frequently used because of this fact.
The other commonly used surgical options included the Triple Pelvic Osteotomy (TPO) and the Femoral Head and neck Excision (FHO). The TPO involves cutting the supports for the "socket" and realigning it so as to reduce stress on the hip joint. The FHO involves completely removing the femoral head ("ball'), allowing the gluteal muscles to support the weight of the rear leg and thus avoiding any bone on bone contact. Both techniques can restore good to excellent function to the dog, depending on the underlying problem and the dog's age and weight.
Ideally, it is best to avoid the problem altogether. The only way to do that is to screen all potential breeding animals and breed only dogs of "better" hip conformation, so as to eliminate affected animals from the breeding population. Until a concerted effort is made to accomplish this, however, the tragedy of hip dysplasia will remain a common occurrence.
Postscript from YGRR
The best way to treat hip dysplasia is to prevent it. Before buying a puppy, be sure the sire and the dam have been certified free of hip dysplasia. But certified-free parents are not guaranteed to have dysplasia-free pups. Some veterinarians postulate that if more than 25 percent of the pup's ancestors developed hip dysplasia, it is more likely to develop the disease.
New evidence shows that hip dysplasia can be delayed or prevented by restricting the growth rate of susceptible puppies. Dogs predisposed to hip dysplasia may benefit from a conservative diet until 2 years of age. One study showed that feeding a 24 percent smaller ration to puppies, beginning at 8 weeks of age, resulted in a 46 percent lower occurrence of hip dysplasia. Check with your veterinarian for an appropriate diet. Boisterous play can aggravate dysplastic joints. Keep your puppy from any kind of jumping or sustained activity until it is 1 year old. Thereafter, avoid activities involving strenuous jumping or sudden momentum changes. Swimming, which puts little stress on the joints, is recommended.
Acupuncture, homeopathy, therapeutic massage and chiropracty may relieve inflammation, pain and stiffness. Holistic veterinarians are most likely to turn to acupuncture because it seems to slow joint degeneration, even in severe cases. Acupuncture and massage also increase circulation throughout the body. Chiropracty readjusts the spine and other bones that may have been thrown out of balance by limping, favoring one leg or other attempts to relieve the pain.
The most successful alternative treatments appear to be supplements that
stimulate the body to lubricate the afflicted joint and rebuild damaged
cartilage. Holistic veterinarians often prescribe shark and bovine
cartilage, glucosamine, chondroitin sulphate, proanthocyanidins, super
oxide dismutase and glycosaminoglycans to relieve inflammation, nourish the
cartilage and increase the joint lubrication fluid, which reduces pain and
inflammation. It may be necessary to try several different supplements (one at a time of
course) until you find the one that helps your dog. One YGRR member found
that neither Cosequin nor Glycoflex helped her adopted Rottweiler, but
Joint Care from the Foster & Smith catalog and Osteo-Biflex (a product made
for humans) did help him. The principal ingredients in Joint Care are
glucosamine hydrosulfate and chondroitin sulfate plus Ascorbic Acid and
some minerals. Osteo-Biflex contains the same amounts of the glucosamine
and the chondroitin but no vitamins or minerals. Osteo-Biflex is available
over the counter.
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