General Anaesthesia Versus Spinal Anaesthesia for Outpatient Total Hip and Knee Arthroplasty: A Randomised Trial Protocol

INTRODUCTION: Same-day discharge after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) is increasing, but the optimal anaesthetic technique for outpatient pathways remains uncertain. Neuraxial anaesthesia is widely recommended based on observational evidence, whereas fast-track programmes using short-acting total intravenous anaesthesia may facilitate early mobilisation and discharge. No randomised controlled trial has compared general anaesthesia (GA) with spinal anaesthesia (SA) specifically in outpatient primary THA/TKA using a same-day discharge target. METHODS AND ANALYSIS: GASPS is a pragmatic, multicentre, parallel-group superiority randomised controlled trial. Adults scheduled for outpatient primary THA or TKA will be randomised 1:1 to GA or SA, with stratification by site and procedure (THA/TKA). The primary outcome is successful same-day discharge (discharge on the day of surgery) without readmission within 48 h after discharge. The five key secondary outcomes are time to fulfilment of hospital discharge indicators, quality-of-recovery (QoR-15) trajectories over postoperative Days 1-35, patients' qualitative experiences of anaesthesia and recovery, cost per quality-adjusted life-year and safety (adverse events); all remaining outcomes-including pain, postoperative nausea and vomiting, opioid consumption, mobilisation and patient-reported outcomes (EQ-5D-5L and HOOS/KOOS)-are exploratory. An embedded qualitative study will explore patient experiences using semi-structured interviews, and an economic evaluation will compare costs and outcomes from healthcare and societal perspectives. Analyses will follow the intention-to-treat principle; a group sequential design with O'Brien-Fleming boundaries is planned for an interim analysis. Approval has been obtained from the Swedish Medical Products Agency. Written informed consent will be obtained from all participants. Results will be disseminated through peer-reviewed publications, conference presentations and reporting in the EU Clinical Trials Information System (CTIS). CONCLUSION: This study is designed to determine the most effective anaesthetic method for same-day discharge after primary TKA and THA. With increasing outpatient surgeries, this study will be helpful for optimisation of outpatient processes. TRIAL REGISTRATION: EU CT/CTIS: 2024-520127-89-00. CLINICALTRIALS: gov: NCT07334132.