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Understanding How TTC Fusion Differs from Traditional Ankle Fusion: The Difference is in the Implant

When conservative methods of relieving pain or deformities in the ankle do not provide lasting relief, a surgical procedure known as ankle fusion is sometimes considered. Because of the wide range of patient needs, surgeons can choose from many different options for fusion surgery. One such option, called TTC fusion (TTC stands for tibiotalocalcaneal), is one type of ankle fusion.

The choice of primary ankle fusion or TTC fusion is made by the surgeon, based on many clinical factors. Only a surgeon trained in foot and ankle surgery can determine which method is best for a given patient. Either way, the goal is to reduce pain.

In primary ankle fusion surgery, the ankle joint is removed, allowing the tibia (shinbone) to grow together, or fuse, with the talus bone (the first large bone of the foot). Pins, plates, screws or rods are inserted through the bones to hold the bones together until they heal.

Image showing traditional ankle fusion. 

In TTC fusion, the tibia, talus and calcaneal bones are fused together using sophisticated metal implants called intramedullary nails (intramedullary means within the bone). DePuy Orthopaedics offers a TTC implant called the VersaNail® made of high-tech metals (titanium alloy). Using this system, surgeons can adapt the implant for the specific size and anatomy of each patient, and help achieve optimum alignment of the bones of the foot and ankle. TTC fusion is considered for certain patients with advanced osteoarthritis or rheumatoid diseases, injuries from accidents, ankle deformity, and complications from diabetes (Charcot), as well as to treat conditions such as avascular necrosis. (See related article on medical conditions for which TTC is considered.)

TTC is generally used in advanced cases (called “end-stage ankle disorder”) where more conservative treatments like medication and other surgical treatments have not worked. It is also indicated for some patients who have had prior surgeries with inadequate results.

In TTC fusion, special screws help eliminate rotation, preventing the calcaneus, the largest bone in the heel, (the one that forms the round part of the heel) from “rocking” on the implant when the patient puts weight on it.

TTC Fusion with the VersaNail System

The system is designed to allow surgeons to insert the implant and the locking screws from the position in the anatomy that best suits the needs of the patient, and to make ultra-fine adjustments during surgery.

Whether the surgeon chooses traditional fusion or TTC fusion, the goal is to alleviate the pain that is felt either when bone rubs on bone after cartilage has worn away significantly or due to other disabling deformities.

Though some loss of movement of the foot and ankle joints does occur in both TTC and traditional fusion, fusion can be very effective in reducing pain, correcting deformities and stabilizing the joints. The recovery period can extend for three to six months, but the patient can usually begin to put weight on the foot around six weeks after surgery.

Fusion is not for every patient, and only a surgeon trained in foot and ankle surgery can determine the right treatment for you. As with any surgery there are risks, and results will vary from patient to patient.

Last Updated: 10/16/2007