The Arthroplasty Pain Experience (APEX) studies are two randomised controlled trials in primary total hip (THR) and knee replacement (TKR) at a large UK orthopaedics centre. APEX investigated the effect of local anaesthetic wound infiltration (LAI), administered before wound closure, in addition to standard analgesia, on pain severity at 12 months. This abstract reports results of the within-trial economic evaluations. Cost-effectiveness was assessed from the health and social care payer perspective in relation to quality adjusted life years (QALYs). Resource use was collected from hospital records and patient-completed postal questionnaires, and valued using unit cost estimates from local NHS Trust and national tariffs. Missing data were imputed using chained equations. Costs and outcomes were compared per trial arm and plotted in cost-effectiveness planes. The economic results were bootstrapped incremental net monetary benefit statistics (INMB) and cost-effectiveness acceptability curves. One-way deterministic sensitivity analyses explored any methodological uncertainty.Background
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