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rec.pets.dogs: PennHip FAQ

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Archive-name: dogs-faq/medical-info/pennhip
Last-modified: 13 May 1997

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                               PennHIP FAQ Sheet
                                                                ICG 03/95
                    Questions and Answers about PennHIP
    A New Scientific Method for Early Screening for Canine Hip Dysplasia
     * Introduction
     * What Exactly Is PennHIP?
     * How Was PennHIP Developed?
     * How Does PennHIP Differ from Evaluation Methods Which Use the Hip
       Extended Position?
     * What Happens to My Dog During a PennHIP Evaluation?
     * What Is the Cost of Having My Dog Evaluated?
     * Is PennHIP Going To Replace Other Commercially Available Systems?
     * Will AKC and Other Breed Registration Organizations "Recognize"
     * Are the Results Confidential?
     * How Does This Benefit Me as an Owner or Breeder of Dogs?
     * How Can I Get the Name of a PennHIP Veterinarian or Get Answers to
       Additional Questions?
   Canine Hip Dysplasia (CHD) is the most common, heritable orthopedic
   problem seen in dogs. It affects virtually all breeds of dogs but is
   especially problematic in large and giant breeds. Clinically, the
   disease manifests itself in one of two ways:
    1. a severe form that typically afflicts the younger animal and is
       usually characterized by marked pain and lameness, or
    2. a more chronic form with more gradual onset of clinical signs such
       as mild intermittent pain, stiffness and restricted range of
       motion in the hips as the dog ages. In many cases, the chronic
       form may be clinically silent.
   Breeders and veterinarians have long sought a reliable method to
   determine the likelihood of a dog developing CHD and passing that
   genetic trait to any offspring. It was generally recognized that the
   current diagnostic methods of hip evaluation were associated with
   disappointing progress in reducing the frequency of CHD. In 1983, Dr.
   Gail Smith, a veterinary orthopedic surgeon and bioengineer from the
   University of Pennsylvania School of Veterinary Medicine, began to
   actively research and develop a new scientific method for the early
   diagnosis of Canine Hip Dysplasia. Research in his laboratory resulted
   in a diagnostic method capable of estimating the susceptibility for
   CHD in populations of dogs as young as sixteen weeks. The method has
   shown distinct advantages over the standard CHD diagnostic method that
   evaluates dogs at two years or older. The university of Pennsylvania
   Hip Improvement Program (PennHIP) was founded as an extension of Dr.
   Smith's laboratory research. Below are answers to some commonly asked
   questions about the PennHIP method.
    What Exactly Is PennHIP?
   PennHIP is a scientific method to evaluate a dog for its
   susceptibility to develop Hip Dysplasia. The radiographic procedure
   involves a special positioning of the dog so that the dog's "passive
   hip laxity" can be accurately measured. In simple terms, passive hip
   laxity refers to the degree of looseness of the hip ball in the hip
   socket when the dog's muscles are completely relaxed. Research has
   shown that the degree of passive hip laxity is an important factor in
   determining susceptibility to develop Degenerative Joint Disease (DJD)
   later in life. Radiographic evidence of hip DJD, also known as
   osteoarthritis, is the universally accepted confirmation of CHD.
   PennHIP is being marketed by International Canine Genetics, Inc. (ICG)
   of Malvern, PA.
    How Was PennHIP developed?
   The development of PennHIP has involved multiple disciplines including
   biomechanics, orthopedics, clinical medicine, radiology, epidemiology
   and population genetics. The first phase of development involved
   sophisticated biomechanical testing to determine the optimal patient
   position for measuring hip laxity. By monitoring passive hip laxity in
   dogs as they matured, it was discovered that hip laxity was the
   primary factor in the development of the DJD characteristic of CHD.
   That is, the radiographic expression of DJD was statistically
   significantly correlated with the degree of measured passive hip
   laxity. In addition, the CHD prediction was shown to be acceptably
   accurate in populations of puppies as young as sixteen weeks of age.
   Moreover, the correlation between passive hip laxity and subsequent
   hip DJD was shown to increase over the four-month figures when hips
   were evaluated at six months and twelve months of age. In the same
   studies, it was shown that there was no statistically significant
   correlation between laxity and DJD when the standard hip extended
   position was used. In addition, no other method used to evaluate for
   CHD has undergone similar rigorous testing through controlled
   scientific studies to determine diagnostic accuracy.
    How Does PennHIP Differ from Evaluation Methods Which Use the Hip Extended
   PennHIP differs in some very fundamental and important ways. First,
   PennHIP was developed and tested following strict scientific protocol
   and the results of these studies have been published (and continue to
   be) in peer-reviewed, scientific journals. More than a decade of
   research and analysis has produced a body of information in support of
   PennHIP's effectiveness. As with all diagnostic tests, PennHIP's
   accuracy is not 100 percent, but in direct comparisons it is far
   superior to any other available diagnostic method. Second, passive hip
   laxity is objectively measured and the resulting Hip Evaluation Report
   is not issued in a pass/fail framework. PennHIP specifically measures
   passive joint laxity and includes the quantitative measurement in its
   report. Based on the degree of laxity, the individual dog is then
   ranked relative to other members of the same breed. (Note: Breed
   specific rankings are given when there are twenty or more evaluations.
   If there are fewer than twenty evaluations - ranking is made to the
   general dog population.) For Example, a dog receiving a ranking in the
   70th percentile means that thirty percent of its breed members have
   hips that are tighter. This allows breeders to easily identify those
   animals with tighter hips within each breed. As shown in our studies,
   dogs with tighter hips are less likely to develop CHD and pass that
   genetic tendency on to future generations. Third, because PennHIP is
   measuring maximal passive hip laxity, the position of the patient is
   very different from the hip-extended position. The hip-extended
   position has been used for more than thirty years to screen hips for
   either DJD, laxity or both. Laboratory studies, however, have
   indicated wide diagnostic variability among radiologists in
   interpreting this view. Further, through biomechanical testing, the
   hip-extended view was found to mask the underlying true joint laxity
   and through direct comparison, the predictive value for CHD was shown
   to be inferior to the PennHIP procedure. Most importantly, the
   heritability of the diseased phenotype scored in the hip-extended view
   has not been studied in most breeds of dogs. A knowledge of
   heritability is critical to determine whether the selection pressure
   will produce genetic change. Estimates for the heritability of passive
   hip laxity drawn from analysis of full pedigrees for the breeds
   examined thus far in the studies show high values (for German Shepherd
   Dogs, heritability = 0.61). Fourth, the PennHIP method is based on
   strict quality control. To take PennHIP radiographs, veterinarians
   must undergo training and a certification process to demonstrate
   competency. The data generated from PennHIP undergoes regular review
   and statistical analysis so that useful information, by breed, is
   available to judge progress toward reducing CHD. For optimal validity,
   it is mandatory that all PennHIP radiographs be submitted for analysis
   and inclusion in the PennHIP database. This policy eliminates the
   practice of prescreening radiographs and sending only the best for
   evaluation, resulting in biased hip data for any given breed.
    What Happens to My Dog During a PennHIP Evaluation?
   To obtain diagnostic radiographs, it is important that the patient and
   the surrounding hip musculature be completely relaxed. For the comfort
   and safety of the animal, this required sedation, however some
   veterinarians prefer general anesthesia. Typically, three separate
   radiographs are made during an evaluation. The first is a compression
   view where the femurs are positioned in a neutral, stance-phase
   orientation and the femoral heads are pushed fully into the sockets.
   This helps show the true depth of the hip socket and gives an
   indication of the "fit" of the ball in the socket. The second
   radiograph is the distraction view. Again, the hips are positioned in
   a neutral orientation and a special positioning device is used to
   apply a harmless force to cause the hips to displace laterally. This
   position is the most accurate and sensitive for showing the degree of
   passive laxity. Passive laxity has been shown to correlate with the
   susceptibility to develop DJD. A hip extended view is also included
   for the sole purpose of examining for any existing joint disease such
   as osteoarthritis. The PennHIP procedure has been safely performed on
   thousands of patients.
    What Is the Cost of Having My Dog Evaluated?
   The total fee for a PennHIP evaluation is determined by the
   veterinarian providing the service. It is important to remember that
   the total service includes sedation/anesthesia, three radiographs,
   office consultation and all charges associated with mailing and film
   evaluation. You will not find it necessary to write a separate check
   for evaluation fees or mail your dog's films. The veterinarian
   performing the procedure is responsible for payment and film
   submission. The film evaluation charge (currently $25.00) will be
   included in the total cost of a PennHIP evaluation.
    Is PennHIP Going To Replace Other Commercially Available Systems?
   As technology advances, the veterinary professional community will
   offer and utilize improved methods of disease diagnosis. The dog
   breeding community will also endorse those methods that help them
   achieve their goals of reducing the frequency of hip Dysplasia in dogs
   while maintaining other desirable traits and features. The PennHIP
   technology and research have been and will continue to be, fully
   presented to the veterinary medical community for its review. PennHIP
   has been received enthusiastically as a major step toward reducing the
   frequency of CHD. We encourage and welcome continued scientific
   examination and comparison of PennHIP to any available or new methods
   of canine hip Dysplasia diagnosis.
    Will AKC and Other Breed Registration Organizations "Recognize" PennHIP?
   ICG is working with many organizations to present the PennHIP
   technology and the positive impact it holds for reducing Canine Hip
   Dysplasia. It is conceivable that at some point a PennHIP reference
   might be included as part of the dog's registry information. However,
   all hip evaluation reports are considered confidential medical
   information and are released only to the PennHIP veterinarian and the
   owner of the dog (unless the owner requests otherwise).
    How Does This Benefit Me as an Owner or Breeder of Dogs?
   Scientific data confirms that the PennHIP method surpasses other
   diagnostic methods in the ability to accurately predict susceptibility
   to developing CHD. The method can be performed on dogs as young as
   sixteen weeks of age compared with two years using the standard
   technique. The ability to receive an early estimate of a dog's hip
   integrity is important whether the dog's intended purpose will be for
   breeding, for working or as a family pet. The data generated by
   PennHIP will allow breeders to confidently identify the members of
   their breeding stock with the tightest hips. The PennHIP
   interpretation will also permit breeders to assess the progress they
   are making with their breeding program as they strive to reduce the
   amount of hip laxity in their dogs. Pet owners are able to assess
   their pet's risk of developing CHD, and make lifestyle adjustments for
   their dog, if necessary, to enhance the quality of their pet's life.
    How Can I Get the Name of a PennHIP Veterinarian or Get Answers to
    Additional Questions?
   To obtain the name of a veterinarian near you who is trained and
   certified to perform the PennHIP procedure, call ICG at
   1-800-248-8099. If there is not a veterinarian near you presently,
   additional veterinarians are being trained throughout the country. If
   your veterinarian would like to learn more about PennHIP, please have
   him/her contact ICG directly.
                            For more information
                            Call 1-800-248-8099
          or inquire via email to ICG at
                       International Canine Genetics
                271 Great Valley Parkway, Malvern, PA 19355
    PennHip FAQ
    Internet Version kept by Bill Faulk,

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