What is PennHIP?
The PennHIP method is a different way to assess, measure, and interpret hip joint status in dogs. It consists of three separate radiographs: the distraction view, the compression view, and the hip-extended view. The distraction view and compression view are used to obtain accurate and precise measurements of hip joint laxity and congruity, respectively. The hip-extended view is used to obtain supplementary information regarding the existence of osteoarthritis in the hip joint.
PennHIP is a service provided in conjunction with a worldwide network certified PennHIP-trained veterinarians. Through this network of veterinarians implementing the method, PennHIP is amassing a large scientific database on the etiology (cause), prediction, and genetic basis of canine hip dysplasia with a goal of helping to reduce the frequency and severity of hip dysplasia in all breeds of dogs.
Why use PennHIP?
A growing body of scientific information from multiple independent laboratories confirms that the PennHIP method surpasses other diagnostic methods in its ability to measure hip joint laxity and accurately predict the onset of the osteoarthritis (OA) of canine hip dysplasia (CHD). Osteoarthritis is also known as degenerative joint disease (DJD).
The PennHIP method can be performed on dogs as young as sixteen weeks of age, compared with two years using the standard technique.
The data generated by PennHIP allows breeders to confidently identify the members of their breeding stock with the tightest hips and the best breeding potential. PennHIP interpretation will also permit breeders to assess the progress they are making with their breeding program. Pet owners are able to obtain an estimate of their dog’s risk for developing DJD and at the direction of their veterinarian, make lifestyle adjustments for their dog to enhance the quality of their pet’s life.
What is the rationale behind PennHIP?
Through sophisticated biomechanical studies, it was found that the canine hip is loosest when positioned in a neutral or “standing” orientation (also called the stance-phase of weight bearing). It was reasoned that this point is also the optimal patient position for measuring maximal hip joint laxity on a radiograph. Ironically, the standard hip-extended patient positioning was found to put the hip in one of its tightest configurations thereby masking the inherent hip laxity of the dog.
Passive hip laxity measured in the neutral position was radiographically monitored in dogs as they matured. It was shown that 1) the radiographic measurement of passive hip joint laxity by the PennHIP method was accurate in dogs as young as sixteen weeks of age, and 2) hip laxity was the primary risk factor to predict the development of OA. Specifically, the looser the hip joint according to the PennHIP method, the greater the chance that it will develop OA.
The PennHIP method also incorporates the hip-extended radiograph to evaluate for evidence of OA.
How was PennHIP developed?
In 1983, while at the University of Pennsylvania School of Veterinary Medicine, Dr. Gail Smith began to research and develop a scientific method for the early diagnosis of CHD. Multiple scientific disciplines – including biomechanics, orthopedics, clinical medicine, radiology, epidemiology, and quantitative genetics – were incorporated during the development of PennHIP. This research resulted in a diagnostic method capable of estimating the susceptibility for CHD in dogs as young as sixteen weeks of age.
In 1993, Dr. Smith established PennHIP, a program that initially conducted clinical trials of the new hip dysplasia diagnostic technology and quickly grew. PennHip was acquired from the University of Pennsylvania by Antech Diagnostics in 2013.
What happens to my dog during a PennHIP evaluation?
To obtain diagnostic radiographs, the patient and the surrounding musculature must be completely relaxed. For the comfort and safety of the animal, this requires sedation and/or general anesthesia. Typically, three separate radiographs are made during an evaluation: compression view, distraction view, and hip-extended view. The PennHIP procedure has been safely performed on thousands of patients.
At what age can my dog have a PennHIP radiograph?
The PennHIP method can be reliably performed on a dog as young as 16 weeks old. Passive hip laxity at 16 weeks correlates highly with later hip laxity. In other words, a dog’s hip laxity at 16 weeks will be much the same at one year, two years or even three years.
There are obvious advantages to screening dogs for hip joint laxity at 16 weeks of age (or six months, one year, etc.) as opposed to waiting until two years of age. The reliability of the PennHIP method slightly improves with age, with one year being marginally superior to 6 months, which in turn is marginally better than 16 weeks. For all dogs, we recommend, when possible, to use the average of repeated evaluations to get a more reliable estimate of a dog’s hip laxity status.
Does this procedure require sedation and/or anesthesia?
To obtain diagnostic quality radiographs, the musculature around the hip joint must be completely relaxed. For the comfort and safety of the animal, this requires either heavy sedation or general anesthesia.
Is it possible the procedure will hurt my dog’s hips?
After many studies, both in the PennHIP laboratory and in independent laboratories, there is no evidence to suggest that the PennHIP procedure is any more harmful than the standard hip-extended procedure. PennHIP is aware of only a handful of cases of dogs that have exhibited discomfort after the procedure. All such claims are followed up and no long-term pain or untoward effects have been observed.
Is the PennHIP procedure more expensive than the OFA procedure?
The total fee for a PennHIP evaluation is determined by the veterinarian providing the service. Your PennHIP veterinarian will likely charge more for PennHIP testing than for an OFA evaluation. PennHIP analysis consists of three radiographs rather than one. Also, a certified PennHIP veterinarian incurred costs of training, quality assurance testing, and purchase of the necessary equipment.
How can I find a PennHIP veterinarian or get answers to additional questions?
Search for a PennHIP veterinarian in your area here.
How does PennHIP differ from evaluation methods that use the hip-extended position?
PennHIP differs from other methods in some very fundamental and important ways:
Scientific Protocol
PennHIP was developed and tested following strict scientific protocols and the results of these studies have been, and continue to be, published in peer-reviewed scientific journals. As with all diagnostic tests, PennHIP’s accuracy is not 100%, but in direct comparisons it is far superior to any other available hip dysplasia diagnostic methods.
Will PennHIP replace other commercially available systems?
PennHIP has been received enthusiastically as a major step toward reducing the frequency of CHD, particularly among working and service dog organizations. We encourage and welcome continued scientific examination and comparison of PennHIP to any available or new methods of canine hip dysplasia diagnosis. As technology advances, the veterinary professional community will utilize the most effective 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. Today, with it’s strong scientific foundation, the PennHIP method is the most effective hip screening tool available for dogs.
Will AKC and other breed registration organizations “recognize” PennHIP?
In 1996, the AKC board of directors announced plans to remove all health and genetic information from the official AKC registration and to include it along with PennHIP information in the “Information and Health Database” known as CHIC. This database is managed by the Orthopedic Foundation for Animals and breeders and dog owners may apply to enter PennHIP information. We continue to work with other organizations, nationally and internationally to present the PennHIP technology and the positive impact it holds for reducing CHD.
How does PennHIP testing benefit me as an owner or breeder of dogs?
Research has shown that the PennHIP method surpasses other diagnostic methods in its ability to accurately predict a dog’s susceptibility to developing OA of CHD. The PennHIP 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 is for breeding, for working or service use, or as a family pet. The data amassed and analyzed by PennHIP will allow breeders to confidently identify the members of their breeding stock with the tightest hips and assess the progress they are making with their breeding program in reducing the amount of hip laxity in their dogs. And for pet owners, understanding their pet’s risk of developing hip OA will enable them to make lifestyle changes for their dog to lower that risk and enhance quality of life.