CANINE HIP DYSPLASIA
WHAT IS CANINE HIP DYSPLASIA?
Dysplasia means "abnormality of development" but in more simple terms that is easy to understand, dysplasia means "doesn't fit together properly", a bit like a square peg in a round hole.
WHAT CAUSES CANINE HIP DYSPLASIA?
Hip dysplasia in dogs is a genetic disease. It is passed from parents to puppies. There is no evidence to suggest that exercise causes hip dysplasia. Environmental factors such as obesity will make the condition worse however. This causes great confusion amongst breeders and veterinarians. The reason for this confusion is that all dogs are born with normal hips and hip dysplasia develops with growth.
The joint capsule and ligament that attaches the femoral head in the acetabulum become loose within the first few weeks of life. The ball joint (femoral head) becomes unstable. This "looseness" is called laxity. Laxity of the femoral head causes changes to the shape of the joint as the animal grows.
This photo shows a developing femoral head (ball joint) that is loose in the acetabulum (socket).
The photo above shows displacement of the femoral head from the acetablulum ie the ball joint is loose. This can be felt as a "clunk" and is called a positive Ortolani test. The femoral head (ball joint) wobbles around and as the dog grows, this becomes deformed. The head becomes mushroom shaped and the socket becomes shallow like a saucer.
SURGICAL MANAGEMENT OF CANINE HIP DYSPLASIA
Surgery for canine HD falls into two categories
- Early treatment
- Salvage procedure - when severe osteoarthritis has developed
EARLY TREATMENT -
JUVENILE PUBIC SYMPHYSIODESIS - JPS
This is a wonderful preventatitve surgery but HD needs to be diagnosed between 4-5 months for this operation to be effective. Radiographs would preferably be taken at 4 months and your dog tested at the same time for any Ortolani signs.
The growing pelvis has cartilage along the ventral midline of the pubic bones which is where the pelvis grows. This line of cartilage is cauterised to make it fuse early. As the pelvis grows, the femoral heads are pushed back into the joint making the ball joint and socket develop more normally again.
EARLY TREATMENT -
OSTEOTOMY TPO AND DPO
If this crucial window between 4-5 months is missed during development and it is not possible to do a JPS, unfortunately, more advanced surgery is then required. A Triple Pelvic Osteotomy (TPO) or a Double Pelvic Osteotomy (DPO).
These techniques are only helpful if there is no osteoarthritis developing. Whilst theoretically this technique can be done at any time if no OA has developed, there is a window between eight and ten months when it is the best time to do an osteotomy procedure. Again, it is crucial to have an early diagnosis of HD.
SALVAGE PROCEDURE -
FEMORAL HEAD EXCISION
If osteoarthritis has started to develop, it is only possible to manage the condition medically using analgesia, non steroidal anti-inflammatory drugs, PRP, stem cell therapy, neutroceuticals, Antinol and laser therapy. If pain cannot be controlled, it is possible to do a femoral head excision where the ball joint is removed. Whilst this takes away the source of pain, dogs don't have a joint to stand on. It is an affordable option for many people however. The alternative is a total hip replacement.
SALVAGE PROCEDURE -
TOTAL HIP REPLACEMENT
This involved having a new artificial hip.
This photo shows the socket that is placed into the acetabulum.
A new hip is created by first replacing the acetabulum with an artificial socket.
The femoral head (ball joint) is removed and replaced with an artificial head that locks into the socket. It has a full range of motion like a normal joint. The older THR prosthetic hips were glued in place with a high level of disasters unfortunately. KYON has made a new cementless implant that is screwed on like a bone plate. We are monitoring this new procedure to see if the results are good.