Perioperative decision-making for primary total hip arthroplasty in osteonecrosis of the femoral head using an IL-6-centered composite pathway: a retrospective cohort study

Elevated CRP/ESR in osteonecrosis of the femoral head (ONFH) without overt infection complicates the choice between one-stage total hip arthroplasty (THA) and staged management. We evaluated an IL-6-centered perioperative composite assessment to guide decision-making. In this single-center retrospective study (2019–2024), 40 ONFH patients with elevated inflammatory markers and concern for occult infection were analyzed: a one-stage THA group (n = 20) and a suspected-infection comparison group treated with staged management due to suspected infection (n = 20). All underwent preoperative IL-6/CRP/ESR testing and hip MRI; intraoperative gross assessment and frozen section informed the strategy. Cultures (≥ 14 days) and selective metagenomic next-generation sequencing (mNGS) were used for verification. IL-6 discrimination was assessed by ROC analysis; performance was summarized at 5.4 pg/mL and a pragmatic cutoff of 8 pg/mL. Cultures were positive in 13/20 (65%) patients in the comparator group and negative in 20/20 (100%) patients in the one-stage THA group; mNGS was performed in 9/20 comparator cases and detected pathogens in all 9, whereas it was negative in all 12 tested one-stage cases. One-stage THA follow-up was 22–76 months (median 42), with no prosthetic joint infection, reoperation, or radiographic failure. IL-6 was higher in the comparator group than the one-stage group (median 13.8 vs 2.5 pg/mL; p < 0.001) and showed high discrimination (AUC 0.993, 95% CI 0.977–1.000). At 8 pg/mL, sensitivity was 90% (95% CI 68.3–98.8) and specificity 95% (95% CI 75.1–99.9). In this retrospective cohort, an IL-6-centered composite perioperative assessment may help inform selection of one-stage THA versus staged management in ONFH patients with elevated CRP/ESR and suspected occult infection, showing good discriminatory performance and favorable mid-term outcomes after one-stage THA. External validation in larger, multicenter prospective studies is warranted.