Perceived by patients to cause the same extent of impairment as congestive heart failure and end-stage kidney disease, ankle arthritis affects about 1% of the United States population and mostly occurs from post-traumatic ankle injuries.
Although ankle fusion has historically been the gold standard treatment for ankle arthritis, sources who spoke with Healio/Orthopedics Today said the use of total ankle replacement (TAR) for this indication has increased in the past decade.
“Total ankle replacement is definitely growing, and it has particularly grown over the last 15 years as we have had new and better implants,” Scott J. Ellis, MD, professor of orthopedic surgery at Hospital for Special Surgery and Weill Cornell Medical College, told Healio/Orthopedics Today.
Outcomes of ankle fusion
According to Lew C. Schon, MD, FACS, FAAOS, director of orthopedic innovation in the Institute of Foot and Ankle Reconstruction at Mercy Medical Center, the main benefit of ankle fusion is that it can provide patients with good pain relief, stability and a decent gait, and can lead to a comfortable and functional life. Although patients with an ankle fusion can sometimes walk 10,000 to 15,000 steps per day, Schon said many of his patients with fused ankles can only walk up to 5,000 steps per day.
“There is a range of activities they can do, but certain things that they cannot do,” Schon said. “For example, going up and down hills, operating foot pedals, sliding on boots, getting up from a squatted position and kneeling can be difficult for them.”
While ankle fusion and TAR provide equal pain relief for patients, James K. DeOrio, MD, professor of orthopedic surgery and director of the foot and ankle fellowship at Duke University, said patients experience more comfort from a functional standpoint after TAR. He uses the Vantage ankle replacement (Exactech), which he helped design.
“From a functional standpoint, [ankle replacement] is more comfortable to be able to move around your apartment, your house, go for walks or go for a 5-mile hike,” DeOrio told Healio/Orthopedics Today. “Without that movement, it is awkward," he said.
Ankle fusion vs. replacement
Compared with ankle fusion, Schon said his patients who undergo TAR can anticipate achieving 5,000 to 15,000 steps a day.
“We have not had trouble with people operating any pedals, foot controls. Squatting is easier, kneeling is easier, patients can go up and down hills better, their cadence is more normal, their symmetry between the legs is usually more normal than with the fusion and we have not seen any hindfoot or midfoot arthritis significantly advance,” Schon, who utilizes the Trabecular Metal Total Ankle (Zimmer Biomet) implant, said.
David I. Pedowitz, MD, MS, chief of the division of foot and ankle surgery and associate professor of orthopedic surgery at the Sidney Kimmel Medical College, Thomas Jefferson University, Rothman Orthopaedic Institute, said patients who undergo TAR may have a quicker recovery compared with ankle fusion and more patients report feeling that their ankle is more normal after a replacement.
“It also allows them to keep the motion that they have in their ankle,” Pedowitz, who is an Orthopedics Today Editorial Board Member, said. “Some people are under the false assumption that an ankle replacement will give them motion, but an ankle replacement does not give anyone motion. It hopefully allows you to keep the motion you already have.”
Risk for additional surgery
Another similarity between ankle fusion and ankle replacement is the procedures both come with the risk of needing additional surgery, according to sources.
Ankle fusion places stress on the subtalar joint which can lead to arthritis and the need for subtalar arthrodesis, according to DeOrio.
“If you fuse an ankle joint, patients can get along well, but when you get arthritis in the subtalar joint, then the only treatment for that is to do a subtalar arthrodesis,” he said. “That locks down even more motion, and it feels more like a peg leg than it does a real ankle.”
While the joints around the ankle do not experience as much stress with an ankle replacement as they do with a fusion, patients who undergo TAR may need to undergo a revision, depending on patient and anatomic factors, according to Pedowitz.
“Essentially, most patients under the age of 70 [years] will require a revision at some time in their lives just because ankle replacements are expected to last 10 to 15 years with, of course, exceptions,” Pedowitz, who utilizes the Cadence Total Ankle System (Smith & Nephew), said.
Ellis said a second procedure may also be needed among patients with a TAR if they develop cysts in the bone or experience loosening or an infection.
“If the implant becomes loose or it becomes infected, then you have to take it out and revise it and we know that the results of revision are never as good as the primary total ankle,” Ellis said. “You could also convert the total ankle replacement to a fusion, but the problem is then you take out the implant and there is a hole there, essentially, because of the bone that you have taken out plus the implant, and so it is not easy to get an ankle to fuse at that point.”
Revision ankle replacement
If a patient with a TAR presents with a loose tibia, sources who spoke with Healio/Orthopedics Today agreed they would prefer to perform a revision over a fusion.
W. Hodges Davis, MD, who said a big part of his practice consists of performing revision TAR, said he has not fused a failed replacement in 7 years.
“A fusion with big bone defects has a high complication rate and a high nonunion rate, and I feel like I have a lower complication rate with the revision than with doing the fusions,” Davis, of the OrthoCarolina Foot and Ankle Institute and Atrium Health, told Healio/Orthopedics Today.
When a revision procedure cannot be performed in a patient with a loose tibia, Schon said another option is a tibiotalo or tibiotalocalcaneal fusion. However, these fusions may have trouble healing, he said.