What is hip dysplasia?
Hip dysplasia is an abnormal development or growth of the hip joint, usually affecting both sides. It is caused by varying degrees of looseness of surrounding tissues, instability, malformation of the ball and socket joint, and osteoarthritis.
Hip dysplasia is the most common cause of osteoarthritis of the hip in dogs. Large breed dogs, like St. Bernards, are the most commonly affected dog, with German Shepherds and working breeds also commonly affected. Hip dysplasia rarely affects small dogs.
What are the main causes of hip dysplasia in pets?
- environment factors, such as weight gain and exercise
- an imbalance between the muscle mass and the skeletal development which leads to joint laxity (looseness)
- the ball and socket joints pull apart, which initiates the other changes
- soft tissues failing to keep the joint surfaces together
The symptoms of hip dysplasia
Often, young dogs will show a sudden onset of hind limb lameness. They may be unwilling to exercise, jump, or climb stairs, and have difficulty getting up from a lying position. They may develop an unusual gait or stride, or show signs of pain or discomfort when handled around the hip area.
The sudden onset of clinical signs is thought to be associated with micro-fractures of the socket, as this area is overloaded with pressure from the displaced joint. As the animal reaches maturity (12-18 months old) these fractures heal, usually resulting in symptoms of the condition subsiding. Most dysplastic dogs between 12 and 14 months of age walk and run soundly and are free of significant pain.
Senior pets show all of the classical signs of degenerative osteoarthritis. There is lameness after heavy exercise, a waddling gait, and difficulty rising after laying down. The signs may come on suddenly, or you could notice a gradual decline in your pet’s usual activity. Pain may be evident when handling the hips.
How is Hip Dysplasia diagnosed?
Your vet will perform a thorough physical examination and ask you questions about your pet’s lifestyle. This will require your pet to be placed under a general anaesthetic to minimise discomfort and allow for a thorough examination. The hip is rotated through a range of movements, checking for the common signs of dysplasia. Additionally, an X-ray will provide further, more accurate diagnosis.
X-rays are examined for the presence of new bone formation (spurs or osteophytes), and to check the shape of the bones.
Many dogs are not overtly affected by this problem despite having an advanced stage of the disease. Young dogs with acute signs may respond to conservative therapy and then require no further treatment after they mature.
Conservative therapy includes:
- dieting if the dog is overweight
- avoiding strenuous exercise
- swimming and supervised exercise
- analgesic and anti-inflammatory medication (as prescribed by your vet)
Dogs with more advanced hip dysplasia may require surgery. There are a number of surgical techniques routinely used in these cases. Each case must be examined and treated individually. A thorough assessment of the history, clinical signs, and X-rays is essential before embarking on the correct course of treatment.