Are you worried that your puppy might be predisposed to hip dysplasia? At BEVS we are offering the PennHip screening for hip laxity. A test that can be performed as early as 16 weeks of age and will allow us to predict the chances and development of future hip dysplasia.
PennHip evaluation is the best test for early detection of hip laxity, which is the key factor in the development of canine hip dysplasia. The hip joint is a ball-and-socket joint, with the ball of the femur (femoral head) fitting into the hip socket (acetabulum). Hip laxity refers to the degree of “looseness” of the ball in the hip socket.
It has been proven that dogs with loser hips are at higher risk of developing hip dysplasia than dogs with tight hips. PennHip evaluation allows us to identify hip laxity as early as 16 weeks of age, helping breeders make decisions on breeding strategies and allowing us to advise dog owners on life style adjustments and preventive approaches to minimize pain and progression of the disease.
PennHIP screening includes three separate radiographs (x-rays): 1. extended view, 2. compression view and 3. distraction view. For the distraction view, a custom distraction device is applied to reveal the maximum amount of hip laxity. To achieve this, the dog’s muscles are completely relaxed by administering sedation or general anesthesia. Below are examples of the three PennHIP radiographs of a 4 year old Labrador Retriever.
Traditional hip screening methods rely solely on the hip-extended view (picture 1) to evaluate both the presence of hip arthritis and joint laxity (subluxation). Using traditional systems many dogs hips would be considered normal because the hip-extended view might not show evidence of arthritis or subluxation (laxity). While the hip-extended view can detect existing arthritic changes, it often conceals hip laxity thereby giving a false impression of joint tightness. So, in the absence of arthritic changes, the hip-extended view does not reliably distinguish between dogs that are disease susceptible and those that are not.
For the compression view, the dog’s hind legs are positioned in a neutral, weight bearing orientation and the femoral heads (balls of the femur) are gently seated into the acetabulum (hip sockets). This view can identify critical anatomic landmarks of the hip and determine how well the femoral head fits into the acetabulum.
For the distraction view (picture 3) the dog’s hind legs are positioned in the same neutral position as the compression radiograph and a distraction device is used to reveal the dog’s inherent joint laxity. This exclusive feature of the PennHIP procedure permits accurate measurement of maximal hip laxity. When comparing this dog’s hip-extended view (photo 1) to the distraction view (photo 3), the distraction view reveals much greater joint laxity, if present. The PennHIP method uses the amount of joint laxity revealed in the distraction view (photo 3) to tell us if a dog is actually susceptible to developing hip dysplasia and hip arthritis later in life.
We will submit the films to Antech Imaging Services and a PennHip certified radiologist will evaluate the images and provide us with a Distraction Index (DI). The DI is a measurement of hip laxity which is expressed as a number from 0-1. It represents how far the ball of the femur can be distracted from the socket. It has been established that a value less than 0.3 would indicate uncommon occurrence of hip dysplasia.
The report also includes a full description of arthritic changes and a breed laxity profile ranking. Based on the DI, dogs are ranked within their breed. For the dog breeder this ranking helps in the selection of breeding candidates—dogs in the tighter half of the population are recommended for breeding. By selecting breeding dogs with tight hips (lower DI), meaningful progress toward better hips can be made within a few generations.
For breeders: Information compiled in PennHIP’s international database permits informed selection of breeding stock based on hip tightness relative to other members of the same breed. Breeders can reduce the incidence and severity of Canine Hip Dysplasia (CHD) in future generations of dogs by applying selection pressure towards tighter hips. Among current hip screening methods, PennHIP has the highest heritability value to bring about these genetic changes.
For service and working dog organizations: Service and working dog organizations were the first to adopt PennHip as their main method for hip screening. The investment in training service/working dogs is enormous. The ability to prescreen the dog’s genetic predisposition to CHD is an invaluable tool when evaluating a future service/working dog’s hip integrity.
For companion dog owners: If your dog is identified to be at risk for CHD, your veterinarian can recommend, at an early age, appropriate strategies (diet, medication, and/or activities) to delay or diminish the ultimate course of the disease.