Hip Dysplasia & PennHIP Radiographs for Dogs
Early Screening & Assessment
What is Hip Dysplasia?
Hip dysplasia is the most common, heritable orthopaedic problem seen in dogs. It affects almost all breeds of dogs but is especially common in large and giant breeds.
The normal hip consists of the femoral head, which is round like a ball and connects the thigh bone (“femur”) to the socket of the pelvis (“acetabulum”).
When a dog has hip dysplasia, the ball and socket do not fit smoothly. The socket is flattened and the ball is not held tightly in place. This makes for an unstable joint and leads to arthritis and pain in the joint.
Clinically, the disease manifests itself in one of two ways:
- A severe form that typically affects younger dogs and is usually characterised by significant pain and lameness.
- A more chronic form with more gradual onset of clinical signs such as mild intermittent pain, stiffness and a restricted range of motion in the hips as a dog ages. This progresses to long term inflammation and pain.
Changes that can be noticed with hip dysplasia include:
- Reduced activity
- Difficulty rising or lying down, or going upstairs
- A characteristic sway of the hips is seen from behind
- Stairs are taken in a bunny hop fashion
What Causes Hip Dysplasia?
The primary cause of hip dysplasia is genetic but inheritance of this trait is not straight forward. Puppies with hip dysplasia can have parents with “normal” hips as the condition can skip generations. Other factors such as level of exercise at an early age, nutritional factors, hormonal/neutering factors, and other environmental situations can play a role.
How can I find out if my puppy is at risk of developing hip dysplasia in the future?
PennHIP radiographs are a screening process to assess the laxity in a puppy’s hip joint (aka the tightness of the ball and socket). This determines if a puppy is at risk of developing hip dysplasia later in life and allows us to implement strategies early to minimise the severity of this condition before it progresses.
These radiographs are performed in-house by one of our dedicated PennHIP accredited veterinarians. The procedure is performed under a general anaesthetic in order to correctly position the hips for x-ray. A measurement called a distraction index is calculated from these radiographs, the idea being that a tighter-fitting hip – one allowing less distraction – is less likely to develop dysplasia. Each dog breed has a different range of distraction that is considered acceptable. Puppies can be screened as young as 16 weeks of age with this system.
What if my puppy is found to be at risk of developing hip dysplasia?
Juvenile Pubic Symphysiodesis (JPS) surgery is a preventative procedure performed on puppies before the age of 20 weeks old. This is done once hip laxity has been detected (by PennHIP screening radiographs), but before it is known if the puppy will indeed have hip dysplasia.
The pubic symphysis is the cartilage seam connecting the right side of the pelvis to the left side. As an individual matures, this cartilage converts to bone and the two halves of the pelvis fuse permanently. The JPS surgery prematurely seals the symphysis, and as the puppy grows this results in rotating the developing hip sockets into a more normal alignment. Because this procedure relies on growth of the pelvis to rotate the hip sockets, it must be performed at an early age while the puppy is still growing. The window is very narrow for this procedure, so if a puppy is a predisposed breed it is worth considering screening radiographs at 16 weeks of age so we can plan for this procedure before 20 weeks of age.
Have the conversation with your vet now – before the window closes!
What else can we do?
In dogs at risk of hip dysplasia, other preventative strategies can be implemented early to support aging joints. These include:
- Weight management
- Nutritional supplements and/or prescription diets
- Joint injections to promote cartilage production and repair