Impact of Intraoperative Povidone–Iodine Lavage on 90-Day Periprosthetic Joint Infection Rates Following Primary Total Hip and Knee Arthroplasty: A Retrospective Cohort Study of 1,084 Patients

PURPOSE: Periprosthetic joint infection (PJI) is a rare but serious complication after total hip (THA) and total knee (TKA) arthroplasties. A dilute povidone-iodine (PI) lavage has been proposed as a simple intraoperative measure to reduce infection risk, but evidence is conflicting. We evaluated the association between intraoperative PI lavage and 90-day PJI after THA and TKA and explored whether this association differed by joint type and sex. METHODS: We conducted a retrospective cohort study of all consecutive THAs and TKAs performed within a standard infection-prevention protocol from 2017 to 2021. Intraoperative wound irrigation before closure was performed with either normal saline (Saline Group) or dilute PI (PI Group), according to the institutional protocol at the time of surgery. The primary outcome was 90-day PJI, defined by Musculoskeletal Infection Society criteria and identified from hospital records. Associations between lavage type and PJI were analysed using Firth's logistic regression, adjusting for patient and surgical factors, with a sex-by-group interaction tested. RESULTS: Overall, 1,084 arthroplasties were analysed, with 28 PJIs (2.6%). PJI occurred more frequently in the Saline than in the PI Group (3.87% vs. 1.16%). In multivariable analysis without interaction terms, saline irrigation was associated with higher odds of PJI than PI lavage (odds ratio OR: 2.64). After including a sex-by-group interaction, the increased risk with saline persisted only in male patients (OR 8.67), with no difference between groups in females. TKA was associated with lower odds of PJI than THA (OR 0.25). CONCLUSIONS: In this cohort of THAs and TKAs, intraoperative PI lavage was associated with lower 90-day PJI than saline irrigation, particularly in male patients. These findings support PI lavage as a valuable component of PJI prevention. Still, the retrospective design and imbalances between groups and event numbers warrant cautious interpretation and confirmation in prospective studies with sex-stratified analyses.