*What is hip dysplasia?
The word “dysplasia” means “abnormality of development”. Hip dysplasia is a canine genetic condition in which there is a tendency towards development of hip laxity early in life. Hip dysplasia is not congenital, because affected dogs are born with morphologically normal hips. The soft tissues (ligaments and joint capsule) that normally stabilize the hip joint become loose within the first few weeks of life. The consequence of this laxity is that the normally very congruent ‘ball and socket’ hip joint becomes much less congruent. The ball becomes flattened and deformed and the socket becomes more saucer-shaped. All dogs with hip dysplasia develop secondary osteoarthritis of the affected joint. The vast majority of affected dogs have dysplasia of both hips.
*What is the cause of hip dysplasia?
This condition is primarily of genetic cause, although environmental factors such as obesity during puppyhood may influence whether an animal with the genes coding for hip dysplasia will develop a clinical problem. Current estimates state that more than one hundred genes code for hip dysplasia. It is important to recognize that environmental factors are unable to cause hip dysplasia, although they can influence whether an animal with the genes that code for hip dysplasia will develop a clinical problem.
*How can I tell if my dog has hip dysplasia?
Hip dysplasia is the commonest orthopaedic condition in dogs. It most frequently affects large rapidly growing dogs, although small dogs and cats can also be affected. The onset of clinical signs is variable, but hip dysplasia is most commonly diagnosed between 6 and 12 months of age. The clinical signs are very variable, and include stiffness, exercise intolerance, difficulty getting up or lying down, problems climbing stairs, and gait abnormalities, including limping on one or both back legs. It is rare for dogs to demonstrate overt signs of pain at home, although clinically affected dogs are often very painful when their hips are extended by a veterinary surgeon.
*What is happening inside an affected joint?
Pain is caused initially by repetitive strain injuries to the lax hip stabilizers, and microfracturing of the bone and cartilage surfaces that are rubbing past one another. As cartilage erosion progresses, pain is the result of the global joint disease known as osteoarthritis.
*How is hip dysplasia diagnosed?
Hip dysplasia is diagnosed, in most cases, following a multimodal evaluation process between you, your primary care vet and a specialist orthopaedic surgeon.
In the first instance you may have noticed your dog exhibiting some or all of the following clinical signs;
Difficulty rising, sitting or lying
Difficulty climbing stairs or getting in and out of the car
Abnormal gait – Sometimes described as a ‘swaying’ gait during walk
Limping on one or both hindlimbs
Protective of hip region during grooming or bathing
Pain – not necessarily in all dogs
Your primary care vet may have recognised an abnormal gait or noticed hip pain in your dog during routine health checks or following concerns raised by you. If your primary care vet has a suspicion of hip dysplasia, they may perform radiographs of your dogs hip joints. Radiographs will usually show changes in affected dogs, although this is not always the case. More often than not your dog will be referred to have a consultation with a specialist orthopaedic surgeon