Emerging Insights With The Ankle Implant Arthroplasty

Robert W. Mendicino, DPM, FACFAS, Alan R. Catanzariti, DPM, FACFAS, and Kyle S. Peterson, DPM

   Lastly, one would perform a physical therapy evaluation preoperatively to assess the patient’s ability to maintain a non-weightbearing gait. We consider this a key factor in obtaining a successful outcome.

What We Have Learned From Our Experience

We started performing ankle replacement surgeries at our institution in 1998. Since that time, we have performed over 100 total ankle replacement surgeries. The initial implanted device was the Buechel-Pappas implant (Endotec). Although this implant never received FDA approval, we did see early patient satisfaction with this device.

   We began using the Agility total ankle device shortly after its approval by the FDA. With minimal data available at the time, we were uncertain of the implant’s long-term durability. Within the first two to three years following surgery, patients were satisfied with decreased pain and a preservation of ankle motion. We experienced some hardware problems at three to four years following surgery. Common complications we encountered included: talar and tibial component subsidence and osteolysis; prosthesis loosening; and periprosthetic fracture. These complications lead to poor patient satisfaction and increased failure rates. As a result, we decreased the number of TARs in the early 2000s and performed more ankle arthrodesis procedures.

   Recently, with the approval of the STAR system in the U.S., we have increased the number of TAR procedures at our institution. The STAR has now become our preferred device. The advancements of the improved device include a cementless, low profile design requiring minimal bone resection and a modification of the instrumentation set.

   The reproducible stepwise surgical approach facilitates the ability to effectively and accurately prepare the joint for implantation. First, the surgeon ensures the tibial component is tightly seated into dense subchondral bone. This allows stronger fixation.
Secondly, the talar component is designed to bear weight on five surfaces. This increases the weightbearing surface area and allows for increased bony in-growth.

   Lastly, because the STAR implant is the only mobile-bearing device on the market, it effectively reduces torsional stress against the tibial and talar components. This significantly reduces the possibility of loosening.

   We have also found the Salto Talaris total ankle to be promising because it also requires minimal bone resection. The STAR and Salto Talaris devices are our current ankle implants of choice. The Agility total ankle still remains a viable option but we have relegated its use to revision surgery rather than using it as a primary implant.

In Conclusion

Although total ankle replacement surgery had less than desirable outcomes in the past, newer designs and extensive patient follow-up allow a compelling argument for total ankle replacement versus ankle arthrodesis. Similar to other foot and ankle procedures though, one must ensure careful patient selection and employ appropriate preoperative planning.

   In addition, surgeons should have the proper training and experience to perform these technically demanding procedures. Researchers have reported that the percentage of complications decreases significantly with greater surgeon experience.17,18 With four ankle implants available, one must consider each device’s specific designs and the consideration for revision surgery, if necessary. In the U.S., total ankle replacement surgery is safe, efficacious and a more cost-effective alternative to ankle fusion.19

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