P-99. Defining Success and Failure in Prosthetic Joint Infections: A Meta-epidemiologic Study Towards a Core Outcome Set

Abstract Background A unified definition of prosthetic joint infection outcomes (PJI) is crucial for consistent data, study comparisons, and better care. This study systematically reviews how PJIs outcomes are defined, building on our prior research on native vertebral osteomyelitis and postoperative spinal infection.Figure 1Network plot illustrating the co-occurrence of outcome criteria in prosthetic joint infection studies. Edge thickness reflects the frequency of the co-occurrence of each criterion. Each plot highlights one criterion, namely (1) clinical signs, (2) imaging, (3) microbiology, (4) histopathology, (5) antibiotics-related, (6) surgical-related, (7) mortality. Methods We conducted a comprehensive search of the Cochrane, Embase, Medline, and Scopus databases for studies published after 2005 that clearly defined outcomes for PJI. Eligible studies included randomized controlled trials and cohort studies with a minimum of 10 patients diagnosed with PJI. Our methodology adhered closely to the PRISMA guidelines. Using a saturation approach, we extracted and grouped explicit definitions of PJI outcomes into thematic criteria. A network plot (Figure 1) was used to visualize how frequently these criteria appeared and how they co-occurred across the included studies. Results Out of 7,584 screened studies, 552 (7.3%) met the inclusion criteria. This pilot analysis included 49 randomly selected studies (8,162 patients), mostly retrospective (48/49, 98%), focusing on mixed joint replacements (25/49, 51%), two-stage exchanges (15/49, 31%), or mixed surgeries (24/49, 49%). Only 6/49 (12.2%) applied a society-endorsed definition, and 13/49 (26.5%) cited a reference for their outcome definitions. Overall, 32/49 (65.3%) explicitly defined "success," 35/49 (71.4%) defined "failure," and 16/49 (32.7%) defined both. Most studies (25/49, 51%) had follow-up periods over two years, and 14/49 (28.6%) included patient-reported outcomes, identifying 14 unique PROMs (most commonly UCLA, HHS, and KSS scores). Functional outcomes were assessed in 13/49 (26.5%) studies. We identified 16 distinct outcome criteria across seven categories: clinical signs, microbiology, imaging, histopathology, antibiotics-related, surgical-related, and mortality. Network analysis revealed strong links among clinical signs, microbiology, surgical factors, mortality, and imaging. Conclusion Our pilot study found major variation in PJI outcome definitions, with few standardized criteria. A consensus-driven approach is needed to strengthen evidence synthesis and advance patient care in PJI. Disclosures All Authors: No reported disclosures