Here is the design of a clinical trial:

Official Title: Effect of Combinations of Paracetamol, Ibuprofen, and Dexamethasone on Patient-Controlled Morphine Consumption in the First 24 Hours After Total Hip Arthroplasty. The RECIPE Randomized Clinical Trial

Included conditions:
- Pain, Acute
- Hip Arthropathy
- Analgesia
- Postoperative Pain

Study Armgroups:
- {'label': 'Group A', 'type': 'EXPERIMENTAL', 'description': 'Paracetamol 1000 mg + Ibuprofen 400 mg administered orally 1 hour before surgery and given with 6-hour intervals to a total of 4 times the first postoperative day.\n\nPlus placebo (matching DXM) IV administered after induction of anaesthesia', 'interventionNames': ['Drug: Paracetamol', 'Drug: Ibuprofen', 'Drug: Placebo IV']}
- {'label': 'Group B', 'type': 'EXPERIMENTAL', 'description': 'Paracetamol 1000 mg and placebo (matching ibuprofen) orally 1 hour before surgery and given with 6-hour intervals to a total of 4 times the first postoperative day.\n\nPlus DXM 24 mg IV after induction of anaesthesia', 'interventionNames': ['Drug: Paracetamol', 'Drug: Dexamethasone', 'Drug: Placebo oral capsules']}
- {'label': 'Group C', 'type': 'EXPERIMENTAL', 'description': 'Placebo (matching paracetamol) + ibuprofen 400 mg orally 1 hour before surgery and given with 6-hour intervals to a total of 4 times the first postoperative day.\n\nPlus DXM 24 mg IV after induction of anaesthesia', 'interventionNames': ['Drug: Ibuprofen', 'Drug: Dexamethasone', 'Drug: Placebo oral capsules']}
- {'label': 'Group D', 'type': 'EXPERIMENTAL', 'description': 'Paracetamol 1000 mg + ibuprofen 400 mg orally 1 hour before surgery and given with 6-hour intervals to a total of 4 times the first postoperative day.\n\nPlus DXM 24 mg IV after induction of anaesthesia', 'interventionNames': ['Drug: Paracetamol', 'Drug: Ibuprofen', 'Drug: Dexamethasone']}

Interventions:
- {'type': 'DRUG', 'name': 'Paracetamol', 'description': '1g x 4 p.o.', 'armGroupLabels': ['Group A', 'Group B', 'Group D'], 'otherNames': ['Acetaminophen']}
- {'type': 'DRUG', 'name': 'Ibuprofen', 'description': '400mg x 4 p.o.', 'armGroupLabels': ['Group A', 'Group C', 'Group D']}
- {'type': 'DRUG', 'name': 'Dexamethasone', 'description': '24mg IV x 1 after induction om anaesthesia', 'armGroupLabels': ['Group B', 'Group C', 'Group D']}
- {'type': 'DRUG', 'name': 'Placebo oral capsules', 'description': 'p.o. x 4', 'armGroupLabels': ['Group B', 'Group C']}
- {'type': 'DRUG', 'name': 'Placebo IV', 'description': 'IV x 1', 'armGroupLabels': ['Group A']}

Primary Outcomes:
- {'measure': 'Cumulative opioid consumption in the first 24 hours after surgery', 'description': 'Cumulative opioid consumption in units of intravenous morphine equivalents in the first 24 postoperative hours. This includes opioids administered as (a) patient-controlled analgesia (PCA); (b) supplemental opioid administered at the post-anaesthesia care unit the first hour after end of surgery (general anaesthesia) or the first hour after ceasing of spinal anaesthesia; and (c) any supplemental opioid given at the ward', 'timeFrame': '0-24 hours after end of surgery'}

Please estimate the sample size based on the assumption: 
The significance level is Bonferroni-adjusted to 0.0083 for six pairwise comparisons, with a power of 0.80. A surplus of 15% is added to adjust for presumed non-normal distribution of data. Missing data is expected to be less than 5%, and multiple imputation will be used if necessary.
Sample size estimation and power calculation
          Due to the four intervention groups in this trial, six comparisons, comparing each individual treatment group, will be of interest (A vs B, A vs C, A vs D, B vs C, B vs D and C vs D). To preserve a maximum family wise error rate of less than 0.05, the threshold for type 1 error rate is Bonferroni-adjusted for the pairwise comparisons to 0.05/6=0.0083.
          The PANSAID trial15 reported a mean of 28âmg (SD 24.5âmg) morphine over 24 hours for the combination of paracetamol 1000âmg+ibuprofen 400âmg. Furthermore, a recent systematic review with network meta-analysis found a mean morphine consumption of 22.8âmg/24 hours when combining paracetamol and ibuprofen in major surgical procedures.45
          A persisting challenge in clinical research on postoperative pain is the fact that the quantification of a minimal important difference (MID) in morphine consumption is uncertain. A newly published systematic review of 570 RCTs on differences in MID after total knee and hip arthroplasties reported an investigator perceived median MID of 10âmg intravenous morphine equivalent as absolute reduction.46 The MID chosen for this trial is prompted by previous results and has been thoroughly debated: with a reduction of 8âmg morphine/24 hours the percentage-reduction (28%â35%) in morphine consumption will be similar to those previously reported in trials investigating multimodal postoperative analgesia.15 45 47 In addition, this trial also investigates the addition of a third adjunct non-opioid analgesic component. Hence, it is expected that the reduction in morphine consumption will be less than with addition of a second non-opioid analgesic. In the PANSAID trial investigating two non-opioids, an MID of 10âmg was chosen, and thus, the 8âmg MID of the RECIPE trial corresponds to a 20% smaller MID, as would be expected for an addition of a third non-opioid analgesic.
          Consequently, to detect or to discard a mean MID of 8âmg in 24-hour morphine-consumption, with an SD of 24.5âmg and a power of 0.80, enrolment of 920 (230 in each group) participants is needed. To adjust for a presumed non-normal distribution of data a surplus of 15% is added.48 Hence 265 participants will be included in each group, adding up to a total of 1060 included participants. In two previous large trials with a similar setup and design, missing data on the primary outcome was limited to less than 5%.15 24 Furthermore, if missing data will unexpectedly occur, we plan to use multiple imputation to minimise the power loss due to missing data. Consequently, we have not adjusted our sample size per missing data. Sample size is calculated with PS Power and Sample Size Calculations (V.3.0, January 2009, William D. Dupont and Walton D. Plummer) and double controlled with Stata.49