Here is the design of a clinical trial:

Official Title: Treatment of Periprosthetic Joint Infections Guided by Minimum Biofilm Eradication Concentration (MBEC) in Addition to Minimum Inhibitory Concentration (MIC); a Prospective Randomized Clinical Trial

Included conditions:
- Prosthetic Joint Infection
- Prosthetic Infection
- Hip Prosthesis Infection
- Knee Prosthesis Infection

Study Armgroups:
- {'label': 'MBEC and MIC susceptibility testing', 'type': 'EXPERIMENTAL', 'description': 'For all administered antimicrobials staphylococcal strains must be susceptible in disc diffusion tests/MIC, regardless of MBEC-level. Antibiotic combinations will be selected from 5 already recommended non-cell wall active anti-staphylococcal antibiotics with high per-oral bio-availabilities and acceptable bone penetration used in the treatment of PJIs: rifampicin, fusidic acid, ciprofloxacin/levofloxacin and clindamycin.\n\nMBEC cut-off for replacement with 2nd or 3rd line antibiotic: RIF MBEC/MIC \\> 8; LEV MBEC/MIC \\> 5; FUS MBEC/MIC \\> 3; CLI MBEC/MIC \\> 4; LIN MBEC/MIC \\> 2; T/S MBEC \\> MIC\n\nSecond line of treatment:\n\nRIF and Fusidic acid 500 mg TID (ter in die) RIF and Clindamycin 450 - 600 mg TID LEV and Fusidic acid 500 mg TID LEV and Clindamycin 450 mg TID\n\nThird line of treatment:\n\nLinezolid 600 mg BID (bis in die) Sulfamethoxazole/Trimethoprim 800/160 mg TID Clindamycin 450 mg TID and Fusidic acid 500 mg TID', 'interventionNames': ['Diagnostic Test: MIC or MBEC+MIC based treatment algorithm']}
- {'label': 'MIC susceptibility testing', 'type': 'ACTIVE_COMPARATOR', 'description': 'If the causative bacterium is susceptible according to MIC diagnostics, the patient will follow the first line of treatment: Rifampicin 750-900 mg/day + Levofloxacin 750 mg BID', 'interventionNames': ['Diagnostic Test: MIC or MBEC+MIC based treatment algorithm']}

Interventions:
- {'type': 'DIAGNOSTIC_TEST', 'name': 'MIC or MBEC+MIC based treatment algorithm', 'description': 'i) Non cell wall active standard of care antibiotic combination (MIC-guided) for 6 weeks.\n\nii) Non cell wall active antibiotic combination according to a MBEC-based decision algorithm for 6 weeks.', 'armGroupLabels': ['MBEC and MIC susceptibility testing', 'MIC susceptibility testing']}

Primary Outcomes:
- {'measure': 'Number of changes in antimicrobial regimen other than standard of care', 'description': 'Proportions of antimicrobial regimens other than standard of care through application of proposed MBEC-algorithm.', 'timeFrame': '6 weeks'}

Please estimate the sample size based on the assumption: 
1:1 randomisation allocation, power 80%, alpha set to 5%, intention to treat analysis.
Sample size calculation
        We consider the diagnostic tool clinically useful if it guides treatment differently than standard scheme in more than 25% of the decisions, according to the MBEC cut-off for replacement. Change of treatment decision other than first-line treatment is considered as an event. Sample size calculation is based on two independent study groups comparing proportions of events. Based on our previous work,41 we anticipate that MIC alone will guide to other than first-line treatment in 40% of the staphylococci PJI. We anticipate that the MIC and MBEC in combination will guide to other than first-line treatment in at least 75% of cases. With 1:1 randomisation allocation, power 80% and alpha set to 5%, the study requires 60 patients, 30 in each group. We will include 64 patients to account for dropouts. Analyses will be undertaken according to intention to treat.