Does The Novel PJI-TNM Classification Have Predictive Value for The Failure of One- Stage Revision Hip Arthroplasty?

Background One-stage revision has emerged as an effective treatment option for periprosthetic joint infection (PJI) of the hip. However, reliable tools to predict failure remain limited. The PJI-TNM classification is a novel, standardized system incorporating implant status (T), pathogen characteristics (N), and host comorbidities (M). This study evaluated whether preoperative PJI-TNM classification predicts failure following one-stage revision hip arthroplasty. Methods A retrospective matched cohort study was performed of patients undergoing one-stage revision for hip PJI between 2009 and 2017. Thirty patients who required subsequent re-revision surgery (failure group) were matched 1:1 by age and sex to 30 patients with successful outcomes and minimum 6-year follow-up. All patients met International Consensus Meeting criteria for PJI. Preoperative PJI-TNM scores were assigned. Group comparisons were performed using t-tests, chi-square tests, and Mann-Whitney U tests as appropriate. Results T and N components did not differ significantly between groups (T: χ²=0.31, p = 0.989; N: χ²=2.97, p = 0.396). The M component differed significantly, with higher comorbidity burden in the failure group (χ²=9.59, p = 0.008). Polymicrobial and gram-negative infections were more common among failures (χ²=6.28, p = 0.043). Time from index arthroplasty to revision was significantly shorter in the failure group (p = 0.0047). Conclusion Host comorbidity (M component) is the strongest predictor of failure following one-stage revision. While T and N components remain clinically relevant, patient systemic health appears paramount. PJI-TNM provides a structured framework for preoperative risk stratification and may guide patient selection and perioperative optimization. Level of Evidence: III (retrospective cohort)