Hip dislocation in dogs
THE hip joint is a strong ball and socket joint joining the hind limb to the pelvis.
As such, any accident that dislocates the hip joint must cause significant damage to the muscles, joint capsule and ligaments that keep the hip joint together.
In some cases if the dog is lucky the head of the femur (ball) can be put back in the acetabulum (socket) promptly and with support for several weeks the damaged tissues heal sufficiently to allow the joint to stay together and for normal use to return.
Unfortunately in many cases of hip dislocation, either failure to seek prompt treatment or the degree of damage to the supporting structures leads to a situation where the joint remains unstable and re-dislocates.
In these cases a surgical approach is required to help keep the joint in place.
There are various techniques that can be employed to help put the hip joint back together and keep it that way.
The most useful in medium to larger dogs is the toggle pin technique that uses a metal toggle and suture to replicate the round ligament’s job of attaching the head of the femur to the hip.
A small hole is drilled through the hip socket and a metal toggle with attached suture is pushed through.
This toggle is long and narrow and can be fed through the hole then jiggled 90 degrees to make it unable to pass back through the small hole (this is the same concept as placing a button through a buttonhole).
The suture is then fed through a hole drilled in the femoral head and fixed to the femur thus forming a solid retainer for the ball in the socket.
In medium to larger dogs where the cartilages of the ball and socket have not been badly damaged this method usually leads to normal function after recovery from the surgery.
This technique can be employed in smaller dogs, but is much more difficult due to the smaller size of the hip joint.
In smaller dogs (under 10kg) the usual approach is to perform a procedure called an excision arthroplasty where the head of the femur (ball) is removed and soft tissues are stitched between the smoothed off upper part of the femur and the socket on the hip.
Over time with some fibrous tissue deposition a “false” joint or fibrous joint is created that works well in lighter patients throughout their life.
If there has been significant damage to the hip joint or if the dislocation has been partly due to a poorly formed hip joint then total hip replacement surgery is a possibility to fix the hip dislocation.