Ciubotariu, Cosmin Lucian

Abstract Background Prosthetic joint infection (PJI) represents an important complication of total joint arthroplasty, affecting approximately 2% of patients. However, considerable heterogeneity in outcome definitions renders cross-study and clinical comparisons challenging. Methods We performed a meta-epidemiological study and systematic review of cohort studies and randomized controlled trial (RCTs) reporting clear definitions of PJI outcomes. Relevant data regarding outcome definitions of treatment success or failure were extracted and categorized into 7 outcome domains: clinical signs and symptoms, imaging, microbiology, mortality, antibiotics-related, surgical-related, and histology. A network plot was generated to visualize domains combinations. Data on patient-reported outcome measures (PROMs) were also collected. Based on these results, we finally proposed a working definition of PJI core outcome set. Results The literature search identified 7585 references, leading to 461 studies. The majority were retrospective (416/461, 90.2%), with limited representation of prospective studies (37/461, 8.0%) and RCTs (8/461, 1.7%). Outcome reporting was highly heterogeneous, with the clinical criterion being the most frequently used domain, combined with microbiological, surgical, and mortality-related outcomes. In contrast, histopathological, imaging, and antibiotic-related criteria were rarely reported. Thirty-six PROMs were included in only 111 (24.1%) studies, most commonly the Knee Society Score (26%) and Harris Hip Score (23%). Conclusions We showed substantial heterogeneity in PJI outcome definitions, with inconsistent reporting across key domains, limiting comparability and evidence synthesis. Standardized, consensus-based outcomes incorporating patient-reported and antibiotic-related measures are needed, and the proposed core outcome set may support harmonized research and clinical practice aligned with the new PJI definition.