Abstract
AIMS: The aim of this study was to estimate the additional cost per quality-adjusted life-year (QALY) of robotic-assisted total knee arthroplasty (rTKA) compared to manually performed total knee arthroplasty (mTKA). METHODS: An economic evaluation was undertaken from the UK NHS and personal social services perspective, alongside a randomized controlled trial comparing rTKA and mTKA. Costs were estimated individually using a top-down approach and included all healthcare resources incurred during the trial. Costs were presented in 2021 GBP sterling (£). Responses to the EuroQol five-dimension three-level questionnaire were used to estimate QALYs for each participant. The incremental cost-effectiveness ratio (ICER) was evaluated against the current willingness-to-pay threshold recommended by the National Institute for Health and Care Excellence. Stochastic sensitivity analysis was performed using bootstrapping techniques, and results were shown through the cost-effectiveness acceptability curve and cost-effectiveness plane. Cost-effectiveness over one- and ten-year time horizons were explored using a decision model. RESULTS: There were 100 participants randomized: 50 rTKA and 50 mTKA. Overall, 37 participants (39.4%) had some missing data on either costs or utilities, or on both. Multiple imputation was used for the base case results. The intervention was associated with incremental mean per-patient costs of £1,829 (95% CI 421 to 3,238) and an incremental QALY gain of 0.015 (95% CI -0.05 to 0.0796) at one year. The ICER at one year was £123,770. However, rTKA was likely to be cost-effective over a ten-year time horizon, with an ICER of £11,109. All except one of the scenarios (QALY gain reduction to 0.005) explored supported the cost-effectiveness of rTKA over a ten-year time horizon with an ICER below a £20,000 threshold. CONCLUSION: Over a short one-year time horizon, rTKA was not a cost-effective procedure compared to mTKA. However, when results were extrapolated out to a ten-year time horizon, which would need to be confirmed in future research, rTKA was likely to be cost-effective.