Tibial Tuberosity Advancement TTA Cruciate Repair
Damage to the Anterior or Cranial Cruciate Ligament (ACL) 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 ACL 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 ACL. 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.
Ten 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.
In this technique, the front edge of the tibia 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 neutralizes the shear forces and eliminates the problem in the joint.
Post Operative View of Implants
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, our veterinarians have chosen to use this technique for our ACL injuries. Dr. Shufer recently completed a certification course in this surgical technique under the tutelage of Drs. Montavon and Tepic. Our veterinary team is confident that this surgery will offer greatly improved recovery for our patients.