Canine hip dysplasia is the most commonly inherited orthopedic disease. Hip dysplasia in our companion dogs is prevalent, especially in the medium to large breeds. Hip dysplasia essentially means that the hip ball and socket aren’t or haven’t developed properly causing severe hip laxity or subluxation. This laxity is the abnormal movement of the femoral ball out of the hip socket. Ideally this ball and socket joint is tight. The laxity (inappropriate movement) in the hip joint causes pain, dysfunction and arthritis. In some cases puppies are lame as early as 9-12 weeks of age. Complaints by the owner are that the puppy is unable to unwilling to jump up or go up stairs, that the puppy has an abnormal gait in the hind limbs and that the puppy is in pain. Early detection of hip dysplasia is essential for lifelong decisions for the puppy and the owner. Diagnosis of dysplasia is determined through clinical signs of lameness or pain and with x-rays. Usually one view of the pelvis and hips is diagnostic. Many puppies are hip guaranteed by the breeder so some puppies will go back to the breeder if hip dysplasia is detected early. Some puppies are candidates for early intervention using surgical techniques to slow the progress of the dysplasia. After 10 months of age these early surgical interventions aren’t recommended. GVH recommends survey hip x-rays at spay and neuter time. Your dog is already under anesthesia and it’s a great time to assess your dog for hip dysplasia.
There are currently two certification methods for canine hips. Both require heavy sedation and x-rays of the pelvis and hips.
OFA (Orthopedic Foundation of America) is the most recognized hip certification method known to the public. OFA will certify hips after the age of 2 years when the skeletal frame is mature. By the age of two if the dog is dysplastic the only interventions are a total hip replacement, femoral head Osteotomy (surgical removal of the head of the femur, the ball of the joint), or using pain medications to make the dog more comfortable. OFA is one view of the pelvis with the hips and knees in internal rotation and the hind limbs in hyper extension. This requires heavy sedation or anesthesia. Often times the internal rotation and hyper extension of the hips can cause an artificial tightening of the hip joints, thus leading a radiologist to call the hips good when in fact there is laxity associated with the joints and the dog will develop dysplasia and arthritis.
Researchers at the University of Pennsylvania’s School of Veterinary Medicine have pioneered a better diagnostic method to assess hip laxity and therefore the propensity of developing dysplasia and arthritis. This procedure is called PennHIP and has proven to be the most accurate and precise method to measure hip laxity. It can identify dogs that are susceptible to developing hip dysplasia. The PennHIP procedure can be done as early as 16 weeks of age. This detection at a young age offers breeders the opportunity to make early decisions on breeding stock, and allows veterinarians to advise pet owners on the lifestyle adjustments and preventative strategies to minimize the pain and progression of the disease. PennHIP requires three x-ray views of the pelvis and hips. From these views a distraction index of each hip is measured. The distraction index is measured by using a compression and distraction view of the hips and measuring the movement of the hip within the socket (laxity). The index is used to assess hip laxity for each individual dog. Each individual is given a percentile ranking compared to the breed for the risk of developing dysplasia and arthritis. Early detection can permit the owner and veterinarian to make well informed decisions on early surgical intervention, controlling progression of the dysplasia, taking the dog out of the breeding pool and minimize the pain of the disease. Early surgical intervention like JPS (juvenile pubic symphysiodesis) is most successful if done before 20 weeks of age.
Dr. Kari Swenson is trained in PennHIP. She’s one of only seven veterinarians in Montana that have been trained and passed vigorous control exercises to be certified in PennHIP. For more information go to www.pennhip.org.
Please discuss hip dysplasia with your veterinarian to make informed decisions for your puppy or adult dog.
For further information regarding hip dysplasia surgical procedures such as JPS, total hip replacement, FHO, or Triple Pelvic Osteotomy (TPO) please visit this article at www.veterinarypartner.com and this article at www.peteducation.com.