Laminar Airflow vs. Conventional High-Efficiency Particulate Air (HEPA)-Filtered Ventilation in Primary Total Hip and Knee Arthroplasty: A Retrospective Comparative Cohort Study of 1,425 Patients

Background and aimLaminar airflow (LAF) ventilation is used in orthopedic ORs with the aim of maintaining a controlled surgical environment and reducing the risk of surgical site infections (SSIs).Conventional high-efficiency particulate air (HEPA)-filtered ventilation is also widely used for maintaining air quality in operating theaters.However, the comparative effectiveness of these ventilation systems in primary total hip and knee arthroplasty remains an important clinical consideration.This retrospective cohort study aimed to compare SSI rates among patients undergoing primary total hip and knee arthroplasty in operating theaters equipped with LAF combined with HEPA filtration vs. conventional HEPA-filtered ventilation at a tertiary care hospital. Materials and methodsThis single-center, retrospective comparative cohort study included 1,425 consecutive patients who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) between January 2022 and December 2024 at a tertiary care hospital.Patients were allocated according to theater ventilation type: Group A, LAF combined with HEPA filtration (n = 695); and Group B, conventional HEPA-filtered ventilation (n = 730).Perioperative protocols, including antibiotic prophylaxis, skin antisepsis, draping, and wound closure, were standardized across groups.Outcomes were assessed using hospital records and a structured telephonic follow-up questionnaire, with SSI classification based on CDC criteria.Multivariable logistic regression was used to adjust for age, sex, BMI, operative duration, diabetes, inflammatory arthritis, renal disease, and procedure type. ResultsThe cohort comprised 1,031 TKAs (72.4%) and 394 THAs (27.6%).Baseline characteristics were comparable except for age (marginally higher in the HEPA-only group, p = 0.042) and BMI (higher in the LAF + HEPA group, p < 0.001).Superficial SSI occurred in 28 patients overall (1.96%): 2.16% (15/695) in the LAF + HEPA group vs. 1.78% (13/730) in the HEPA-only group (p = 0.704).No periprosthetic joint infections (PJIs) were identified in either group.On multivariable analysis, ventilation type was not an independent predictor of infection (adjusted OR 0.717; 95% CI 0.334-1.539;p = 0.393), nor were any other assessed covariates. ConclusionsIn this cohort of 1,425 primary hip and knee arthroplasties, no statistically significant association was demonstrated between theater ventilation type and postoperative SSI after adjustment for relevant patient and procedure-related factors.Given the retrospective design, the low number of infection events, and the absence of any PJI in either group, these findings should be interpreted as hypothesis-generating rather than as evidence that ventilation design is clinically unimportant or that perioperative infection-prevention measures are of greater causal importance than ventilation.Larger prospective multicenter studies with adequate power for deep infection outcomes are warranted.