The patella, or knee cap, is located in the centre of the knee joint.
The term "luxating" means out of place or dislocated. A luxating patella is
a knee cap that moves out of its normal location.
The muscles of the thigh is attach directly or indirectly to the top
of the knee cap. A ligament, called the patellar ligament runs from the
bottom of the knee cap to a point on the tibia (shin bone) just below
the knee joint. When the thigh muscles contract the force is sent
through the patella and through the patellar ligament and results in
straightening of the knee joint. The patella stays in the centre of the
leg because the point of attachment of the patellar ligament is on the
midline and because the patella slides in a groove on the lower end of
the femur (the thigh bone).
The patella luxates because the point of attachment of the patellar
ligament is not on the midline of the tibia. As the thigh muscles contract,
the force is pulled against the groove on the inner side of the femur. After
several months or years of this abnormal movement, the inner side of the
groove wears down and the patella is free to move out of the groove or
dislocate. When this occurs, the dog has difficulty bearing weight on the
leg. It may learn how to kick the leg and snap the patella back into its
normal location. However, because the side of the groove is gone, it
dislocates again easily.
Since the joint surfaces are bathed in a slippery joint fluid, there
is usually little or no discomfort early in the process. This can cause the
knee to be susceptible to other injuries, especially torn cruciate ligaments
which are very very painful to the dog . And as they get older the knee can
become arthritic and painful. The bones may actually curve in response to
the abnormal location of the kneecap thus leading to badly shaped legs and
your bully not being able to stand square...
Surgery should be performed if your dog has a persistent lameness or
if other knee injuries occur secondary to the luxation. The cost is quite
high for knee operations and can be a very long and painful recovery, as to
what kind of surgery is best you will be best discussed with your Veterinary
surgery. but a simple check up at the vets from your stud dog/broodbitch
perhaps whilst they have their annul boosters could rule this problem out as
it is inherited so a dog showing signs of Patella Luxation should not be
used in a breeding program
If the surgery is performed before arthritis occurs, the prognosis is
excellent. Your dog should regain full use of its leg. However, if arthritis
has already occurred, the joint will still be somewhat painful, especially
in cold weather.
INFORMATION SUPPLIED ON THIS PAGE IS FOR INFORMATION PURPOSES ONLY. IF
YOU SUSPECT YOUR DOG HAS ANY OF THE ABOVE SYMPTOMS OR PROBLEMS PLEASE
SEEK THE ADVICE OF YOUR VET.