Penn HIP Radiographs
We are pleased to offer Penn HIP radiographs to our clients and their pets. Veterinarians must complete specialized training and quality control exercises prior to becoming certified to perform Penn HIP radiographs. Currently, there are only 24 veterinarians in the state of Oregon certified to perform Penn HIP radiographs. Dr. Rebecca Bozarth, one of our staff doctors, is certified to perform Penn HIP radiographs.
Penn HIP is the most accurate method to measure hip laxity. Hip laxity refers to whether the ball of the femur fits into the hip socket loosely or tightly, and it has been shown that dogs with looser hips are at a higher risk to develop hip dysplasia. We are now able to accurately determine if a pet is susceptible to developing hip dysplasia as early as 16 weeks of age. This allows us to address the problem earlier than with OFA x-rays (which are performed at 2 years of age), and offers an opportunity to minimize the chronic pain and progression of hip dysplasia.
Penn hip radiographs allow puppies with loose hips to be identified. Some of these puppies are good candidates for a minimally invasive procedure called the “Juvenile Pubic Symphysiodesis” or JPS procedure. This procedure involves use of electro-cautery to fuse the cells of the growth plate at the front half of the pelvis where the two sides of the pelvis come together. Fusion of these cells effect the growth pattern of the pelvis, causing a rotation of the pelvis to better cover the head of the femurs as the puppy grows. Better coverage of the head of the femur results in less laxity of the hip joint and less development of the osteoarthritis changes associated with hip dysplasia, so therefore less pain and fewer symptoms of hip pain. Adult dogs with hip dysplasia are sometimes treated with a much more invasive surgery called a “Triple Pelvic Osteotomy” (TPO). To perform a TPO, an orthopedic surgeon performs osteotomies (cuts the bone) of the pelvis in 3 locations per side, then rotates and plates the pelvis to better cover the hip joint. The end result of a TPO is similar to that of the JPS procedure, but the TPO is much more invasive, has a much longer recovery time, and is much more expensive. JPS patients are up walking the same day as the surgery. JPS is a very elegant repair that uses a minimal change to redirect the growth of the pelvis into a better configuration, but must be performed by 20 weeks of age. Dr. Bozarth is trained and experienced in performing the JPS procedure.
The Penn HIP radiographs must be performed under general anesthesia to allow the patient’s muscles to be completely relaxed. The evaluation includes hip extended, compression, and distraction views. The hip-extended radiograph is obtained by extending the patient’s hind legs to identify if there are any radiographic signs of hip arthritis. The OFA style radiographs rely solely on the hip-extended view. However, if a patient has no signs of arthritic changes and has laxity in the hip, the hip-extended view is not able to reliably distinguish between those who are disease-susceptible or not. If an owner would like to submit their information for both Penn Hip and OFA certification, this radiograph is available for use for the OFA reading. The compression view involves placing the legs in a normal standing neutral position compared to the pelvis. The femoral heads are placed gently in the most normal weight bearing position to show maximal tightness of the hip joints. The distraction view is obtained by positioning the hind legs in a neutral weight-bearing orientation and a special device is positioned to reveal joint laxity. The hip distraction views are compared to the hip compression views, measurements are performed, and hip laxity is calculated. The hip laxity number is quite reliable and repeatable.
The radiographs are submitted to the Penn HIP Analysis Center for laxity evaluation and calculation of the distraction index. We then receive a report based on the distraction index (the percentage distance the ball of the femur can be distracted from the hip socket), the evidence of degenerative joint disease (arthritis), and where your pet ranks within its breed to help in the selection of breeding candidates. You will also receive a copy of the report in the mail. Dr. Bozarth will contact you to discuss the results and answer any questions, as well as to make any recommendations regarding further care.
Penn HIP is now recognized by the American Kennel Club, and has been included in the Canine Health Information Center. The veterinary community has also recently determined that Penn HIP evaluation is the preferred way of identifying hip dysplasia in dogs and cats. For more information, visit the Penn HIP website at www.pennhip.org.
