Cost-Utility Analysis of Total Ankle Replacement Compared with Ankle Arthrodesis for Patients Aged 50-85 Years with End-Stage Ankle Osteoarthritis: The TARVA Study.

ABSTRACT

BACKGROUND: Patients with end-stage ankle osteoarthritis suffer from reduced mobility and quality of life and the main surgical treatments are total ankle replacement (TAR) and ankle fusion (AF). OBJECTIVES: Our aim was to calculate the mean incremental cost per quality-adjusted life-year (QALY) of TAR compared with AF in patients with end-stage ankle osteoarthritis, over 52 weeks and over the patients' lifetime. METHOD: We conducted a cost-utility analysis of 282 participants from 17 UK centres recruited to a randomised controlled trial (TARVA). QALYs were calculated using index values from EQ-5D-5L. Resource use information was collected from case report forms and self-completed questionnaires. Primary analysis was within-trial analysis from the National Health Service (NHS) and Personal Social Services (PSS) perspective, while secondary analyses were within-trial analysis from wider perspective and long-term economic modelling. Adjustments were made for baseline resource use and index values. RESULTS: Total cost at 52 weeks was higher in the TAR group compared with the AF group, from the NHS and PSS perspective (mean adjusted difference £2539, 95% confidence interval [CI] £1142, £3897). The difference became very small from the wider perspective (£155, 95% CI -  £1947, £2331). There was no significant difference between TAR and AF in terms of QALYs (mean adjusted difference 0.02, 95% CI -  0.015, 0.05) at 52 weeks post-operation. The incremental cost-effectiveness ratio (ICER) was £131,999 per QALY gained 52 weeks post-operation. Long-term economic modelling resulted in an ICER of £4200 per QALY gained, and there is a 69% probability of TAR being cost effective at a cost-effectiveness threshold of £20,000 per QALY gained. CONCLUSION: TAR does not appear to be cost effective over AF 52 weeks post-operation. A decision model suggests that TAR can be cost effective over the patients' lifetime but there is a need for longer-term prospectively collected data. Clinical trial registration ISRCTN60672307 and ClinicalTrials.gov NCT02128555.