Primary total ankle replacement surgery is a cost-effective intervention.

• PTAR is a very cost-effective intervention. • Poor pre-operative EQ-5D-3L significantly predicts the most cost-effective patients. • Patients with pre-operative EQ-5D-3L of 0.57 or higher were not cost-effective. The primary aim was to assess the cost-effectiveness of primary total ankle replacements (PTAR) in the UK. Secondary aim was to identify predictors associated with increased cost-effectiveness of PTAR. Pre-operative and six-month post-operative data was obtained over a 90-month period across the two centres receiving adult referrals in the UK. The EuroQol general health questionnaire (EQ-5D-3L) measured health-related Quality of Life (HRQoL) and the Manchester-Oxford Foot Questionnaire (MOXFQ) measured joint function. Predictors, tested for significance with QALYs gained, were pre-operative scores and demographic data including age, gender, BMI and socioeconomic status. A cost per QALY of less than £20,000 was defined as cost effective. The 51-patient cohort [mean age 67.70 (SD 8.91), 58.8% male] had 47.7% classed as obese or higher. Cost per QALY gained was £1669, rising to £4466 when annual (3.5%) reduction in health gains and revision rates and discounting were included. Lower pre-operative EQ-5D-3L index correlated significantly with increased QALYs gained (p < 0.01), all other predictors were not significantly (p > 0.05) associated with QALYs gained. PTAR is a cost-effective intervention for treating end-stage ankle arthritis. Pre-operative EQ-5D-3L was associated with QALYs gained. A pre-operative EQ-5D-3L score of 0.57 or more was not cost effective to operate on. [ABSTRACT FROM AUTHOR]