Paracetamol, ibuprofen and dexamethasone for pain treatment after total hip arthroplasty: protocol for the randomised, placebo-controlled, parallel 4-group, blinded, multicentre RECIPE trial

INTRODUCTION: Multimodal analgesia with paracetamol, non-steroidal anti-inflammatory drug and glucocorticoid is recommended for hip arthroplasty, but with uncertain effects of the different combinations. We aim to investigate benefit and harm of different combinations of paracetamol, ibuprofen and dexamethasone following total hip arthroplasty. METHODS AND ANALYSIS: RECIPE is a randomised, placebo-controlled, parallel 4-group, blinded trial with 90-day and 1-year follow-up performed at nine Danish hospitals. Interventions are initiated preoperatively and continued for 24 hours postoperatively. Eligible participants undergoing total hip arthroplasty are randomised to:group A: oral paracetamol 1000 mg × 4+oral ibuprofen 400 mg × 4+intravenous placebo; group B: oral paracetamol 1000 mg × 4+intravenous dexamethasone 24 mg+oral placebo; group C: oral ibuprofen 400 mg × 4+intravenous dexamethasone 24 mg+oral placebo; group D: oral paracetamol 1000 mg × 4+oral ibuprofen 400 mg × 4+intravenous dexamethasone 24 mg. Primary outcome is cumulative opioid consumption at 0–24 hours. Secondary outcomes are pain at rest, during mobilisation and during a 5 m walk and adverse events. Follow-up includes serious adverse events and patient reported outcome measures at 90 days and 1 year. A total of 1060 participants are needed to demonstrate a difference of 8 mg in 24-hour morphine consumption assuming an SD of 24.5 mg, a risk of type I errors of 0.0083 and a risk of type 2 errors of 0.2. Primary analysis will be a modified intention-to-treat analysis. With this trial we aim to verify recommendations for pain treatment after total hip arthroplasty, and investigate the role of dexamethasone as an analgesic adjuvant to paracetamol and ibuprofen. ETHICS AND DISSEMINATION: This trial is approved by the Region Zealand Committee on Health Research Ethics (SJ-799). Plans for dissemination include publication in peer-reviewed journals and presentation at scientific meetings. TRIAL REGISTRATION NUMBER: NCT04123873.