Background: End-stage ankle osteoarthritis causes severe pain and disability. There are no randomized trials comparing the 2 main surgical treatments: total ankle replacement (TAR) and ankle fusion (AF).
Objective: To determine which treatment is superior in terms of clinical scores and adverse events.
Design: A multicenter, parallel-group, open-label randomized trial. (ISRCTN registry number: 60672307).
Setting: 17 National Health Service trusts across the United Kingdom.
Patients: Patients with end-stage ankle osteoarthritis, aged 50 to 85 years, and suitable for either procedure.
Intervention: Patients were randomly assigned to TAR or AF surgical treatment.
Measurements: The primary outcome was change in Manchester-Oxford Foot Questionnaire walking/standing (MOXFQ-W/S) domain scores between baseline and 52 weeks after surgery. No blinding was possible.
Results: Between 6 March 2015 and 10 January 2019, a total of 303 patients were randomly assigned; mean age was 68 years, and 71% were men. Twenty-one patients withdrew before surgery, and 281 clinical scores were analyzed. At 52 weeks, the mean MOXFQ-W/S scores improved for both groups. The adjusted difference in the change in MOXFQ-W/S scores from baseline was -5.6 (95% CI, -12.5 to 1.4), showing that TAR improved more than AF, but the difference was not considered clinically or statistically significant. The number of adverse events was similar between groups (109 vs. 104), but there were more wound healing issues in the TAR group and more thromboembolic events and nonunion in the AF group. The symptomatic nonunion rate for AF was 7%. A post hoc analysis suggested superiority of fixed-bearing TAR over AF (-11.1 [CI, -19.3 to -2.9]).
Limitation: Only 52-week data; pragmatic design creates heterogeneity of implants and surgical techniques.
Conclusion: Both TAR and AF improve MOXFQ-W/S and had similar clinical scores and number of harms. Total ankle replacement had greater wound healing complications and nerve injuries, whereas AF had greater thromboembolism and nonunion, with a symptomatic nonunion rate of 7%.
Primary funding source: National Institute for Health and Care Research Heath Technology Assessment Programme.