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 Damage to the Anterior or Cranial Cruciate Ligament (CCL) is the most
common injury to the canine stifle (knee) joint. Research over the past
10 years has led to the understanding that the cause of this injury is
directly related to the tendency of tibia (shin bone) to slide forward
under the femur bone due to shearing forces exerted on the joint during
weight bearing. It turns out that the joint surface of the tibia
(tibial plateau) tends to be angled in such a way that the femur slides
backwards and down the slope and the tibia moves forward (cranial) and
up during weight bearing.
Historically, our attempts to repair damaged CCL revolved around
attempting to recreate the function of the ligament. This has been done
with grafts of tissue from the body as well as by the use of external
suture material to reproduce the effect of the CCL. These techniques
have been used for years with varying degrees of success. They have had
particular difficulty maintaining stability in the larger breed dogs,
since the forces exerted on the stifle increase dramatically with the
increased weight of the pet.
Recently two techniques have been developed to alter the angles
between the femur and tibia in order to neutralize the shear forces
which are causing the dislocation of the bones and the rupture of the
ligament. The first technique described is called the Tibial Plateau
Leveling Operation (TPLO). This technique was developed and patented by
Dr. Barclay Slocom some years ago and has been successfully performed on
thousands of pets throughout the world. The technique involves cutting
the tibia in a circular manner and rotating the tibial plateau to an
angle which neutralizes the shear forces we have been talking about.
The bone is then maintained in place with a special bone plate. The
recovery for this surgery takes about 8 weeks and the results are
generally very good with over 90% of the pets returning to acceptable
function as judged by owners and force plate analysis (which determines
the amount of weight bearing done by each limb during walking and
running. The TPLO surgery has gained wide acceptance, however it is a
very technically demanding surgery and is performed only in certain
veterinary specialty centers.
Five years ago, a group in Switzerland, led by Dr. Pierre Montavon
and Slobadon Tepic developed a simpler surgical technique called the
Tibial Tuberosity Advancement (TTA) surgery. Using complex force
analysis, they found that if the angle between the patella ligament and
the tibial plateau can be brought to 90 degrees, the forces leading to
shear would be eliminated.
Normal angle between patella tendon and tibial
plateau Angle corrected to 90 degrees
by tibial tuberosity advancment
In this technique, the front edge of the tiba is cut and a titanium
wedge is placed between the body of the bone and the tuberosity. This
movement changes the angle of the patella ligament to the stifle and
this, in turn neutralizes the shear forces and eliminates the problem in
the joint.
The results from this surgery on over 1000 dogs has been similar if
not better than the TPLO. The time to recovery is slightly better than
the TPLO surgery and for these reasons, we have chosen to use this
technique for our CCL injuries. Dr. Shufer recently completed a
certification course in this surgical techniques under the tutelage of
Drs. Montavon and Tepic. We are confident that this surgery will offer
greatly improved recovery for our patients.
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