Risk factors for surgical site infection following treatment of proximal femoral fracture: a matched-pair analysis.

Background: Surgical site infection (SSI) is a major postoperative complication following internal fixation or arthroplasty for proximal femoral fracture (PFF). Few studies have examined the potential risk factors for SSI; therefore, we conducted this matched-pair analysis.

Materials and methods: This single-centre study was based on a retrospective database of patients treated for PFF with internal fixation or arthroplasty between 2006 and 2024. Patients with revision for SSI were enrolled and matched with an uneventfully treated group at a 1:3 ratio. Matching was performed on the basis of sex, age, body mass index, diagnosis and treatment. The primary outcomes were risk factors for SSI. The secondary outcomes were risk factors for mortality, as determined by multivariate Cox regression analysis.

Results: Initially, a total of 5000 patients were enrolled. The mean follow-up was 11.7 years. The total SSI rate was 2.8% (140/5,000). Ultimately, 130 patients with confirmed SSI and 390 matched patients were enrolled in this study. Most of the SSIs were Staphylococcus aureus, followed by Staphylococcus epidermidis. The factors that significantly influenced SSI were female sex, American Society of Anaesthesiologists (ASA) score of 4, dementia, atrial fibrillation, and the number of red blood transfusions (≥ 3 units). The mean survival duration of the total cohort was 4.2 years (SD ± 3.38). The 30-day, 3-month and 1-year all-cause mortality rates of patients with SSIs were 5.4%, 25.4%, and 40%, respectively. Multivariate Cox regression revealed that SSI was an independent risk factor for mortality (hazard ratio 1.59; 95% confidence interval 1.28-1.98; p < 0.001), Further risk factors for mortality were living in a retirement home, reduced mobility, anaemia at admission, elevated C-reactive protein, ASA score 3 or 4, intraoperative blood loss greater than 400 ml, Charlson comorbidity index score above ≥ 1, dementia and renal insufficiency.

Conclusions: In this study, patients with SSI following surgery of PFF had a significantly shorter survival time than patients in the uneventfully treated matched-pair group. Most risk factors associated with SSI are unaffected. Fortunately, the rate of SSI was low and decreased significantly within the study period.

Lever of evidence: III; clinical case series with matched pair controls.