Tibial Tuberosity Advancement (TTA)

The Tibial Tuberosity Advancement (TTA) is a relatively new procedure designed to perform on dogs to stabilize the stifle (knee) after a rupture of the Cranial Cruciate Ligament (CrCL).  Success and effectiveness of this procedure are reportedly equivalent to the Tibial Plateau Leveling Osteotomy (TPLO) procedure.  The TTA, is a specialized surgery and should be performed by a board certified veterinarian surgeon.

Dogs that suffer an injury to the cranial cruciate ligament will lose stability of the knee joint. The result is a reduction in mobility and range of motion, and the progression of chronic arthritis begins. The TTA, Tibial Tuberosity Advancement, is used to resolve cranial tibial thrust, resulting in a stable stifle joint.  In essence this means that the cranial cruciate ligament normally prevents the tibia from sliding forward.  When the cranial cruciate ligament is torn this movement needs to be prevented.  A TTA procedure effectively advances the front of the tibia (shin bone) where the quadriceps tendon (tendon that attaches to the knee cap) inserts, so forces are shifted forward and the tibia no longer slides forward with respect to the femur (thigh bone).

In more technical terms, the TTA involves an osteotomy (bone cutting and moving procedure) of the non-weight bearing portion of the tibia. The patellar tendon is aligned perpendicularly to the common tangent of the stifle joint, eliminating cranial (forward) tibial thrust. This new alignment eliminates the need for the CrCL and results in a stable joint.

  • The required advancement of the patellar ligament insertion at the tibial tuberosity is measured from a radiograph of the stifle in extension;
  • With a frontal plane osteotomy, the tibial tuberosity is advanced and held in position by:
  • A cage transferring the compression component of the patellar tendon force from the tuberosity to the proximal tibia;
  • A tension band plate transferring the patellar ligament force to the proximal diaphysis of the tibia;
  • The open osteotomy, distal to the cage, is grafted with autologous cancellous bone or other graft material such as allograft or hydroxyapatite (HA) to accelerate healing.

Either an arthroscopy (examination and cleaning of the joint by a camera), or arthrotomy  (cleaning of the open joint) is performed. Arthroscopy or an open arthrotomy performed before TTA will allow for a clear view of the injury and the ability to clean the joint of debris.

Because the TTA is an osteotomy (bone cutting and moving procedure), a qualified orthopedic surgeon also has the ability to make some additional corrections to a malformed knee during the procedure that may prevent future problems for the patient as well.

Whenever your pet is showing signs of a health issue your first step is to contact your primary care veterinarian. If it is indicated that your pet may suffer from a rupture of the Cranial Cruciate Ligament (CrCL) or another serious condition, a veterinary specialist is available at an ExpertVet certified hospital.