Ankle Arthrodesis After Failed Total Ankle Replacement

While ankle fusion has long been considered the standard treatment for ankle arthritis, advancements in total ankle replacement (TAR) are offering new options for patients. TAR procedures have improved over time with better surgical techniques and implant designs, leading to an increase in their popularity. In the United States, the number of TAR surgeries has grown significantly over the years.

However, it’s important to note that as more TAR surgeries are performed, the rate of complications has also risen. Complications can vary widely, ranging from minor issues to more serious problems like implant fracture, infection, technical errors, implant shifting, dislocation, wound complications, and others. These complications can occur in anywhere from 1.3% to 50% of cases.

In cases where a TAR cannot be revised or salvaged, alternative options include ankle fusion (tibiotalar arthrodesis), fusion involving the ankle and heel bone (tibiotalocalcaneal arthrodesis), or in extreme cases, amputation. It’s essential for patients to discuss the potential risks and benefits of TAR surgery thoroughly with their orthopedic surgeon to make informed decisions about their treatment options.

Ensuring there’s enough healthy bone in the ankle is crucial for successful fusion after a total ankle replacement (TAR) surgery. Depending on the amount of remaining bone, different bone grafting techniques may be recommended. If the bone stock in the talus (the bone in the ankle) is greater or less than 2 cm, there are specific strategies to consider.

For small bone defects (<2 cm) where limb length shortening isn’t a concern, a fusion procedure can be done in place, with the option of adding graft material from nearby bones or the hip. It’s important to watch out for any impingement between the bones during fusion. If the bone defect is larger than 2 cm, a fusion using structural grafts is preferred. This method not only provides stability but also helps maintain proper limb length and keeps ankle muscles and tendons working effectively.

Structural graft options may include bone from the hip (iliac crest), the femur, or the lower leg (distal tibia). If there’s arthritis in the subtalar joint or the talus has collapsed due to bone death (osteonecrosis), a fusion involving the ankle and heel bones may be necessary. Your orthopedic surgeon will determine the best approach based on your specific condition and needs.

 

Result

As ankle replacement surgery becomes more common, orthopedic surgeons are increasingly challenged with managing complications and failures that may arise. When severe issues like bone loss, implant shifting, tissue problems, infection, or significant bone damage occur, the standard approach is to consider either a direct or staged fusion of the ankle joint.

When converting from ankle replacement to fusion, surgeons must address two key concerns: filling the void left by the removed implant and ensuring proper fixation of the fused bones. Various techniques have been explored, but there isn’t one universally perfect method.

Around two years post-surgery, more than 90% of patients showed radiographic evidence of successful fusion, regardless of the specific technique used. Moreover, overall patient satisfaction rates were high, with approximately 91.5% reporting positive outcomes. It’s important to note, though, that complications were seen in about 22% of cases. Your surgeon will discuss these findings with you and help determine the most suitable treatment approach based on your individual circumstances.

Among 193 patients who underwent revision surgery to fuse either the ankle or the tibiotalocalcaneal (TTC) joint, 84% successfully fused after their first fusion attempt. Importantly, they experienced significant improvements in their foot and ankle function, as measured by the AOFAS score. Notably, those who received bone grafts for ankle fusion had a 100% fusion rate after their initial surgery, while those undergoing TTC fusion had a lower rate of 50%.

For patients who required a second fusion attempt, the overall fusion rate was 62.5%, leaving only a small number without fusion. However, some patients chose not to undergo a second surgery despite successful pain relief, even though X-rays showed incomplete fusion. Notably, complications were rare in these cases, likely due to the absence of hardware.

In patients with bone defects smaller than 2 cm, the authors suggest using either bone from the hip (iliac crest) or donated bone with sturdy internal fixation, based on promising study results. However, it’s essential for surgeons to carefully evaluate this approach before proceeding, as it’s based on older studies with limited patient numbers and hasn’t been consistently replicated in current research. This technique is typically reserved for specific cases with good bone quality and minimal health issues, requiring precise surgical preparation and bone graft placement to ensure stability.

For patients with larger bone defects exceeding 2 cm, the recommended approach involves using hip bone grafts with internal fixation using screws, with additional plating if necessary for added stability.

The review included patients who were managed with varied techniques to arthrodesis the ankle and, at times, included the subtalar joint. The tibiotalocalcaneal arthrodesis fused in only 43% of patients. Of this group, the subtalar joint fused in 65% of patients (at first attempt), thus contributing to 10% of the failure rate.

Overall, these patients had lower satisfaction scores and higher complication rates, though it could not be said with statistical power that fusing the subtalar joint is a negative prognostic factor. This may indicate that perhaps the techniques to address the subtalar joint are inadequate; perhaps the subtalar fusion should be staged after the ankle has fusion. Alternatively, the patients who require a TTC fusion may be set up for failure by host factors (bone mineral density, medical comorbidities), the severity of their arthroplasty failure, and the large amount of tibia and talar bone loss.

 

Conclusion

When a total ankle replacement (TAR) doesn’t work out as expected, salvaging the ankle through fusion surgery can lead to positive outcomes and high satisfaction levels in the short term, provided that fusion is successful. Using bone graft fusion technique tends to have the best initial fusion rates with minimal complications.

In the future, it’s important for studies to include prospective comparisons between different surgical approaches or control groups. Using standardized outcome measures will make it easier to directly compare results and understand which methods work best for patients.

A seasoned orthopedic surgeon and foot and ankle specialist, Dr. Mohammad Athar welcomes patients at the offices of Complete Orthopedics in Queens / Long Island. Fellowship trained in both hip and knee reconstruction, Dr. Athar has extensive expertise in both total hip replacements and total knee replacements for arthritis of the hip and knee, respectively. As an orthopedic surgeon, he also performs surgery to treat meniscal tears, cartilage injuries, and fractures. He is certified for robotics assisted hip and knee replacements, and well versed in cutting-edge cartilage replacement techniques.
In addition, Dr. Athar is a fellowship-trained foot and ankle specialist, which has allowed him to accrue a vast experience in foot and ankle surgery, including ankle replacement, new cartilage replacement techniques, and minimally invasive foot surgery. In this role, he performs surgery to treat ankle arthritis, foot deformity, bunions, diabetic foot complications, toe deformity, and fractures of the lower extremities. Dr. Athar is adept at non-surgical treatment of musculoskeletal conditions in the upper and lower extremities such as braces, medication, orthotics, or injections to treat the above-mentioned conditions.