Postoperative complications occur in 5-15% of patients undergoing elective primary total hip arthroplasty (THA), including periprosthetic joint infection (PJI), thrombosis, wound healing disorders, and metabolic dysregulation. The gut microbiome and the systemic immune profile have both been implicated as modifiable contributors to perioperative complication risk. Preoperative therapeutic fasting has been shown to remodel the gut microbiome, lower proinflammatory cytokines, and improve metabolic parameters.
This single-center, prospective, randomized, two-arm controlled trial at Charité - Universitätsmedizin Berlin investigates whether a structured 20-day preoperative fasting intervention (alternating cycles of the Buchinger Fastenbox and intermittent fasting) modulates two co-primary endpoints - plasma IL-8 (a central proinflammatory marker) and gut microbial alpha-diversity (Shannon index) - compared with standard preoperative care. Secondary endpoints include further immune markers (TNFα, IL-10, T-/B-/NK-cell subsets, activation/exhaustion markers, monocyte HLA-DR), microbiome composition and function, continuous glucose-monitoring and daily metabolic measures, patient-reported outcomes (HOOS, PROMIS-33, infection self-report), and clinical outcomes (postoperative complications per EBJIS criteria, length of stay).
Adults aged 18-75 undergoing elective primary THA are stratified by metabolic status (metabolically healthy vs. metabolically unhealthy according to harmonized metabolic-syndrome criteria) and randomized 1:1 to the fasting intervention versus standard care. Stool and whole-blood samples are collected at baseline (Day -21), and at Day +7 post-operatively for shotgun-metagenomic sequencing and multiparameter flow cytometry, with additional cytokine blood samples at Day -1 and 6 h / 24 h / 72 h post-operatively. Continuous glucose monitoring is performed in all participants from Day -21 until surgery. Planned enrollment is 130 participants.
Adults aged 18-75 years (inclusive)
Scheduled for elective primary total hip arthroplasty (THA)
Able and willing to provide written informed consent
Able to follow the 20-day preoperative fasting protocol independently at home (if randomized to the fasting arm) or willing to be randomized to either arm
Resorption disorder due to bowel disease (e.g. inflammatory bowel disease, short-bowel syndrome, active celiac disease)
Antibiotic therapy within the last 2 months before baseline (T0)
Probiotic, prebiotic, or symbiotic supplementation within the last 2 months before baseline (T0)
Inability or unwillingness to provide informed consent
Parallel
Buchinger Fastenbox + intermittent fasting (20-day preoperative schedule)
Other interventionTwo 5-day cycles of the Buchinger Wilhelmi Fastenbox (hypocaloric, low-carbohydrate, plant-based vegetable broths) alternating with two 5-day cycles of intermittent fasting (time-restricted feeding), totaling 20 days immediately preceding surgery. Self-administered at home; participants receive structured instructions, daily symptom and metabolic logs, and contact options with the study team for the duration of each cycle.
Change in plasma interleukin-8 (IL-8) concentration from baseline to Day +7 post-operatively
IL-8 plasma concentration (pg/mL), measured by validated immunoassay
Change in gut microbial alpha-diversity (Shannon index) from baseline to Day +7 post-operatively
Shannon diversity index from shotgun-metagenomic stool sequencing
Perioperative kinetics of plasma cytokines (TNFα, IL-10, IL-6, IL-8)
Serial plasma concentrations of TNFα, IL-10, IL-6, and IL-8 measured by validated immunoassays.
Serum C-reactive protein (CRP)
Serum CRP concentration (mg/L).
T-cell subsets (CD3+, CD4+, CD8+) by flow cytometry
Absolute and relative frequencies of CD3+, CD4+, and CD8+ T cells in whole blood.
B-cell frequency (CD19+)
Frequency of CD19+ B cells.
Click on the lead sponsor to view all of their trials.
Charite University, Berlin, Germany
Lead sponsor
Schulthess Klinik
Collaborator
Buchinger Wilhelmi Clinic
Collaborator
