No statistically significant difference
Overall, the mean MOXFQ-W/S scores improved significantly from baseline to 52 weeks for both groups, with average improvements of 49.9 in the TAR group and 44.4 points in the AF group. The average scores at 52 weeks were 31.4 in the TAR group and 36.8 in the AF group.
The adjusted difference in score change from baseline was –5.56, showing a slightly greater degree of improvement with TAR, but this difference was not clinically or statistically significant, the researchers noted.
Adverse event numbers were similar for both procedures, with 54% of TAR patients and 53% of AF patients experiencing at least 1 adverse event during the study period. Of those, 18% of TAR patients and 24% of AF patients experienced at least 1 serious adverse event.
However, the TAR patients experienced a higher rate of wound healing complications and nerve injuries, while thromboembolism was higher in the AF patients, the researchers noted.
A prespecified subgroup analysis of patients with osteoarthritis in adjacent joints suggested a greater improvement in TAR, compared with AF, a difference that increased when fixed-bearing TAR was compared with AF, the authors wrote.
“This reinforces previous reports that suggest that the presence of adjacent joint arthritis may be an indication for ankle replacement over AF,” the authors wrote in their discussion.
“Many of these patients did not have any symptoms in the adjacent joints,” they noted.
“The presence of adjacent joint arthritis, meaning the wear and tear of the joints around the ankle joint, seemed to favor ankle replacement,” Dr. Goldberg said. Approximately 30 joints in the foot continue to move after the ankle is fused, and if these adjacent joints are not healthy before surgery [as was the case in 42% of the study patients], the results of fusion were less successful, he explained.
A post hoc analysis between TAR subtypes showed that patients who had fixed-bearing TAR had significantly greater improvements, compared with AF patients, but this difference was not observed in patients who had mobile-bearing TAR, the researchers noted.
Dr. Goldberg said it was surprising “that, in a separate analysis, we found that the fixed-bearing ankle replacement patients [who accounted for half of the implants used] improved by a much greater difference when compared to ankle fusion.”
The study findings were limited by several factors including the short follow-up and study design that allowed surgeons to choose any implant and technique, the researchers noted.
Other limitations include a lack of data on cost-effectiveness and the impact of comorbidities on outcomes, they wrote. However, the study is the first completed multicenter randomized controlled trial to compare TAR and AF procedures for end-stage ankle osteoarthritis and shows that both yield similar clinical improvements, they concluded.
Data can inform treatment discussion
The take-home messages for clinicians are that both ankle replacement and ankle fusion are effective treatments that improve patients’ quality of life, and it is important to establish the health of adjacent joints before making treatment recommendations, Dr. Goldberg said.
“Careful counseling on the relative risks of each procedure should be part of the informed consent process,” he added. Ideally, all patients seeking surgical care for ankle arthritis should have a choice between ankle replacement and ankle fusion, but sometimes there is inequity of provision of the two treatments, he noted.
“We now encourage all surgeons to work in ankle arthritis networks so that every patient, no matter where they live, can have choice about the best treatment for them,” he said.