Incidence and Risk Factors for Fracture-Related Infection After Peri-Prosthetic Femoral Fractures: A Multicenter Retrospective Study (TRON Group Study)

Background: Fracture-related infection (FRI) sometimes occurs with peri-prosthetic femoral fracture (PPF) treatment. Fracture-related infection often leads to multiple re-operations, possible non-union, a decreased clinical function, and long-term antibiotic treatment. In this multicenter study, we aimed to clarify the incidence of FRI, the causative organisms of wound infection, and the risk factors associated with post-operative infection for PPF.Patients and Methods: Among 197 patients diagnosed with peri-prosthetic femoral fracture who received surgical treatment in 11 institutions (named the TRON group) from 2010 to 2019, 163 patients were included as subjects. Thirty-four patients were excluded because of insufficient follow-up (less than six months) or data loss. We extracted the following risk factors for FRI: gender, body mass index, smoking history, diabetes mellitus, chronic hepatitis, rheumatoid arthritis, dialysis, history of osteoporosis treatment, injury mechanism (high- or low-energy), Vancouver type, and operative information (waiting period for surgery, operation time, amount of blood loss, and surgical procedure). We conducted a logistic regression analysis to investigate the risk factors for FRI using these extracted items as explanatory variables and the presence or absence of FRI as the response variable.Results: Fracture-related infection occurred after surgery for PPF in 12 of 163 patients (7.3%). The most common causative organism was Staphylococcus aureus (n = 7). The univariable analysis showed differences for dialysis (p = 0.001), Vancouver type (p = 0.036), blood loss during surgery (p = 0.001), and operative time (p = 0.001). The multivariable logistic-regression analysis revealed that the patient background factor of dialysis (odds ratio [OR], 22.9; p = 0.0005), and the operative factor of Vancouver type A fracture (OR, 0.039-1.18; p = 0.018-0.19) were risk factors for FRI.Conclusions: The rate of post-operative wound infection in patients with a PPF was 7.3%. Staphylococcus was the most frequent causative organism. The surgeon should pay attention to infection after surgery for patients with Vancouver type A fractures and those undergoing dialysis.