EFFECT OF LAMINAR FLOW ON DEEP INFECTION RATES FOLLOWING CEMENTED HIP HEMIARTHROPLASTY FOR INTRACAPSULAR HIP FRACTURES: A RETROSPECTIVE COHORT STUDY

Laminar flow (LF) ventilation is widely used in orthopaedic theatres to reduce surgical site infection, yet evidence for its benefit in hip hemiarthroplasty remains limited. This study aimed to determine whether LF theatre use is associated with a reduced rate of deep infection within one year following cemented hip hemiarthroplasty for intracapsular hip fracture. A retrospective cohort study was performed of all patients undergoing cemented hip hemiarthroplasty for intracapsular hip fracture at Aberdeen Royal Infirmary between June 2020 and June 2024. Patients were stratified by theatre type: LF (Theatre 11, n=941) versus non-LF (n=778). The primary outcome was deep infection within one year. Secondary outcomes included one-year mortality. Chi-square analysis was used for group comparisons. Groups were well-matched for age (82.2 vs 81.5 years), BMI (24.1 vs 24.3), sex, diabetes, blood transfusion rate, and urinary tract infection (UTI) during admission (all p>0.05). Non-LF patients had significantly longer operative times (82.1 +/− 24.1 vs 73.7 +/− 20.5 minutes). Deep infection within one year occurred in 7 patients (0.7%) in the LF group and 4 (0.5%) in the non-LF group, with no significant difference between groups (chi-square 0.084, p=0.77). One-year mortality was 29.8% versus 28.0% respectively, with no significant difference (chi-square 0.62, p=0.43). Laminar flow theatre use was not associated with a significant reduction in deep infection or one-year mortality following cemented hip hemiarthroplasty in this cohort of 1,719 patients. The low event rate limits definitive conclusions; multivariable logistic regression adjusting for operative time and other confounders is planned.