Hip Dysplasia (HD)
HD refers to an abnormally shaped hip joint which has a basic ball and socket setup.
HD usually means the ball (femoral head) is not sitting in the socket (acetabulum) as well as it should. With time, the ball and socket "bump" and "grind" into each other, leading to arthritis and joint pain.
HD can occur in any breed, but is most common in medium to large pure breeds such as:
- Alaskan Malamutes
- German Shepherds
- Golden Retrievers
HD is usually seen where there has been poor breeding practices e.g. mating relatives. It is carried in the genes (DNA) of the parents.
Signs can develop from as young as 6-8 weeks of age in severe cases. Affected dogs have a wobbly hind leg walking action when viewed form behind. They have trouble rising from rest, and as the disease progresses, pain when trying to get up. There is a reduction in exercise tolerance.
Ortalani Sign in Young Pups
Young pups can have their hip joint manipulated in a certain way by a vet to determine if there is any looseness in the hip joint. This is usually done when in for their first lot of vaccines.
A positive result indicates the pup has HD and may get associated arthritis problems later in life. The good news is if the pup is less than 20 weeks of age, it can have a relatively minor operation performed to "re-shape" the hip joint while it is still growing. This is called a Juvenile Pubic Symphyodesis (JPS)
Hip Scoring and Penn Hip Evaluation
In an effort by conscientious breeders to remove HD from their breeding line, a national Hip Scoring system was set up.
An X-ray of the hips is performed under general anaesthetic and referred to a specialist veterinary radiologist for reporting.
A low score means that a pet has excellent breeding potential. Breeders then look for a breeding partner with similar low scores to ensure the litter has the best chance of being free from Hip Dysplasia. For a small additional fee, an Elbow Dysplasia X-ray can be performed at the same time.
The standard Hip Score technic has been around for some time and there are breed averages to compare the dog's score with. Its accuracy has been questioned though, and newer technics are now available which are more accurate.
If the breeder has been lucky to have a Penn Hip certified vet, a more accurate set of radiographs can be taken. The Penn Hip technic involves the use of a special device which gently pulls the hips out of their sockets (if loose), whilst taking the x-ray with the dog lying on its back.
Juvenile Pubic Symphyodesis (JPS)
A specialist veterinary surgeon can use a cautery tool to burn a particular part of the pelvis in young pups with loose hip joints. This halts growth in this section of the pelvis whilst allowing other remaining growing parts to change the shape of the hip joint, making it much more stable.
A JPS has to be done before 20 weeks of age, ideally before 15 weeks. Success rates if performed early are as high as 90%.
This operation can save the dog from major orthopaedic operations later in life e.g. Total Hip Replacement (THR) or a Triple Pelvic Osteotomy (TPO).
Triple Pelvic Osteotomy (TPO)
This operation is performed in slightly older dogs but has some limitations.
- Done in mild to moderately loose joints and not those that are very loose.
- Dogs in this category usually have hindleg lameness and hip pain on full flexion and forward movement of the leg.
- Less than 10-20 months of age, ideally less than 10 months.
- No evidence of arthritis in the hip joint
Surgery involves cutting the pelvis into 3 sections on the affected side and re-positioning the 3 fragments so the hip socket sits move "over" the femoral head (the "ball"). Post operatively, it can take 5-6 weeks before the hip goes back into place.
Total Hip Replacement (THR)
Just like in humans, dogs with bad hips can have artificial ones installed. There are cement-based and cementless (more expensive) types of artificial hips. Surgery is performed in dogs less than 10-12 months of age with severe laxity in the hip joint and very early signs of arthritis. A cementless hip joint can last up to 10 years.
Purchasing a new pup- avoid the pitfalls
If purchasing a new pup, ask the breeder to give you copies of the hip scores (or Pen Hip reports if lucky) of both parents (as well as eye examination and elbow dysplasia scores).
If the breeder has some excuse for not having some sort of hip score, be wary of proceeding with the purchase as it could mean big veterinary bills down the track. Have the pup examined within 24 hours by your vet to check for any other problems eg heart murmurs, hernias. Ask the breeder if you can return the pup if it fails this vet examination.
These are great tips for avoiding "back yard breeders" - the scourge of organised and well run kennel clubs who have registered breeders in their ranks.