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Fig. 1 Outcome scores at baseline and at time of latest follow-up in total ankle replacement (TAR) and ankle arthrodesis (fusion), graphed as the mean with confidence interval. The number of patients who answered individual questions ranged from 18 to 20 in the arthrodesis cohort and was consistent at 19 in the TAR cohort. AOS, Ankle Osteoarthritis Scale; SF-36, Short Form 36; PCS, Physical Component Score; MCS, Mental Component Score
AOS, Ankle Osteoarthritis Scale; SF-36, Short Form 36; PCS, Physical Component Score; MCS, Mental Component Score Courtesy of Bernard Burgesson, MD

AAOS Now

Published 6/1/2020
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Terry Stanton

RCT Compares Ankle Arthrodesis with Total Arthroplasty

Editor’s note: The following content was published in the AAOS Now Special Edition and distributed in June 2020. The content was originally scheduled for the AAOS Now Daily Edition, which publishes each year onsite at the AAOS Annual Meeting but this year’s meeting in March was canceled due to COVID-19. Despite the cancellation, members can access virtual content from the Annual Meeting by visiting the Academy’s Annual Meeting Virtual Experience webpage.

A first-of-its-kind, multicenter, randomized, controlled trial (RCT) compared the clinical outcomes of ankle arthrodesis (AA) versus total ankle arthroplasty (TAA) in managing end-stage ankle arthritis and demonstrated statistically significant improvements in all Ankle Osteoarthritis Scale (AOS) scores from baseline to time of last follow-up independently for both TAA and AA, with large effect sizes. “Although not statistically significant, we found patients who underwent AA reported better AOS scores (pain, disability, and total) at latest follow-up compared to patients in the TAA arm,” the authors noted. The pilot trial was presented by Bernard Burgesson, of the Department of Orthopaedic Surgery at Nova Scotia Health Authority in Halifax, Canada, as part of the Annual Meeting Virtual Experience.

“AA has been the gold standard and widely accepted in managing end-stage ankle arthritis,” the authors observed. “However, with recent advancements in surgical technique and TAA implant design, there are now data from more recent studies showing equivalence between the two procedures. Consensus on which operative intervention is superior has not been reached.”

The study enrolled 39 ankles from 39 patients from the four centers involved in the Canadian Orthopaedic Foot and Ankle Society multicenter Ankle Arthritis Outcome Study. Nineteen were randomized to TAA and 20 to AA. The overall mean follow-up was 5.1 years (TAA, 5.6 years; AA, 4.6 years). The average age at time of surgery was 65 years, with the TAA group being slightly younger (63.2 years) than the AA group (66.9 years). Body mass index (BMI) was similar between the two groups, with an average of 28.6 kg/m2. Approximately 50 percent of patients in each subgroup were nonsmokers. The overall incidence of diabetes was low, at 10 percent.

Fig. 1 Outcome scores at baseline and at time of latest follow-up in total ankle replacement (TAR) and ankle arthrodesis (fusion), graphed as the mean with confidence interval. The number of patients who answered individual questions ranged from 18 to 20 in the arthrodesis cohort and was consistent at 19 in the TAR cohort. AOS, Ankle Osteoarthritis Scale; SF-36, Short Form 36; PCS, Physical Component Score; MCS, Mental Component Score
AOS, Ankle Osteoarthritis Scale; SF-36, Short Form 36; PCS, Physical Component Score; MCS, Mental Component Score Courtesy of Bernard Burgesson, MD
Table 1. P values and effect sizes for comparisons of AOS scores within and between subgroups. AOS, Ankle Osteoarthritis Scale; TAR, Total Ankle Replacement; Fusion, Ankle Arthrodesis. *Represents Not Statistically Significant. Effect Size of 0.2 Equals Small Effect, 0.5 Equals Medium Effect, > 0.8 Equals Large Effect
Courtesy of Bernard Burgesson, MD

AOS pain, disability, and total scores improved significantly between the preoperative period and latest follow-up in both groups. As seen in Fig. 1, the average baseline AOS total score for TAA went from 59.4 to 38.0 at last follow-up (P < 0.05), whereas the AA group saw an improvement from 64.6 to 31.8 (P < 0.05). Additionally, there were slight improvements in Short Form 36 scores from baseline to last follow-up; however, they were not statistically significant. Table 1 outlines P values and effect sizes for all AOS scores.

Overall postoperative complications requiring revision occurred in six patients (15.3 percent). “Two major complications (10.5 percent; n = 2/19) were observed in the TAA cohort; both were revisions of metal components with one due to implant failure and the other secondary to infection,” Dr. Burgesson told AAOS Now. “The ankle arthrodesis cohort saw four major complications (20 percent; n = 4/20), including one amputation and three revisions due to nonunions/malunions. We did not assess statistical significance given the overall small sample size and number of events.” The patient in the AA arm who went on to have an amputation had persistent nonunion after multiple revisions over a five-year period.

The clinical takeaway, he said, is, “Clinical outcomes of TAA and AA, with average follow-up time of 5.1 years, were comparable. The AA cohort held a slight advantage over TAA in degree of improvement of AOS scores, although not statistically significantly.”

Future studies comparing the clinical outcomes of the interventions should strive for larger sample sizes, Dr. Burgesson said. “Additionally, future studies should explore the use of gait analysis in examining how each treatment affects patient gait patterns,” he said.

Dr. Burgesson’s coauthors of Paper 452, “Clinical Outcomes of Total Ankle Arthroplasty and Ankle Arthrodesis: A Pilot Randomised Controlled Trial,” are Mark Glazebrook, MD, FRCSC, PhD; Alastair Young, MB, ChB, MSc, ChM, FRCSC; and Tim Daniels, MD, FRCSC.

Terry Stanton is the senior medical writer for AAOS Now. He can be reached at tstanton@aaos.org.