Canine Hip Dysplasia (HD) is the abnormal development of the hip joint such that there is not a proper fit between the ball and socket. The hip joint may be loose (laxity), the ball may be partially dislocated from the socket (subluxation), or the joint can erode to the point where the ball is no longer round and the socket is flattened (shallow acetabulum). Improper fit leads to excessive wear and tear with damage to the cartilage, loss of joint lubrication and inflammation. It gets worse with age and affected dogs eventually develop osteoarthritis (degenerative joint disease) which can be very painful.
Signs and Symptoms
- Not wanting to exercise or go up stairs
- Audible click when walking
HD is polygenic and multifactorial. This means it is genetic and controlled by multiple genes, but also influenced by environmental factors such as weight and age.
Related dogs with hip dysplasia.
If a dog presents with pain or lameness, a veterinarian may do a physical examination, looking for joint laxity or pain, but the definitive diagnosis of HD in a dog with symptoms is by X-ray (radiograph). X-rays can also detect HD prior to a dog exhibiting symptoms. Because HD is genetic, common (11% of Samoyeds evaluated) and very undesirable, X-rays are frequently used to screen dogs prior to breeding.The X-rays can be sent to an organization that provides an independent evaluation of the dog’s hips. In the United States, the Orthopedic Foundation for Animals (OFA) has been providing this service for many years; they issue an OFA number if the dog has normal hips (excellent, good or fair). PennHIP is an another well-established organization. There are similar organizations in other countries. Each organization evaluates x-rays, but there are differences in how the dog is positioned for the x-rays, how they are evaluated, and at what age the dog can be evaluated. X-ray evaluations of young dogs do not always accurately predict whether or not a dog will develop CHD later in life. Although HD is genetic, a DNA test is not yet available.
Note: Treatment of animals should only be performed by a licensed veterinarian. Veterinarians should consult the current literature and current pharmacological formularies before initiating any treatment protocol.
Several surgical treatments are available to treat HD, including total hip joint replacement.Which surgery may be recommended depends on the age of the dog, the condition of the hips, and the willingness of the owner to accept the costs and risks. There is also a procedure, juvenile pubic symphysiodesis, that can be performed on young puppies to prevent the development of hip dysplasia. This is used when the risk of HD is high, or the hip joints show laxity at a very young age. The dog is typically spayed/neutered at the same time so that the HD is not passed on. If surgery is not performed, anti-inflammatory medications may be used to relieve the pain (only use canine medications prescribed by your veterinarian; do NOT give human painkillers). Glucosamine and chondroitin sulfate, nutritional supplements, also appear to help although this has yet to be proven in stringent scientific studies.
Management techniques include ensuring the affected dog is not overweight (to reduce stress on hips) and moderate exercise to maintain muscle tone. HD should also be managed in a breeding program. Selecting dogs for breeding based on x-ray screening has reduced, but not eliminated, hip dysplasia, because some dogs can be “carriers” without exhibiting HD. If only dogs with the best hips are bred (for example, OFA excellent) , that would only be 10% of Samoyeds which would limit the overall Samoyed gene pool too severely. The following OFA article discusses how to use available information, including a “vertical pedigree,” to help make breeding decisions.
Dr. Bell’s Genetics Lecture presented to the Samoyed Club of America October 15, 2002
Research article in the Veterinary Journal for anyone interested in the genetic methods used to evaluate HD: The long (and winding) road to gene discovery for canine hip dysplasia. Zhu et al, Vet J. 2009: 181: 97-110