Prospective Study on the Incidence and Risk Factors for the Occurrence of Surgical Site Infection After Intramedullary Nailing of Diaphyseal Femoral and Tibial Fractures
Conditions: Fracture Fixation, Intramedullary, Surgical Wound Infection
Sponsor: University of Sao Paulo

Title: Incidence and Risk Factors Associated with Infection after Intramedullary 
Nailing of Femoral and Tibial Diaphyseal Fractures: Prospective Study 
Document date: 05/31/2018 
NCT 03148067 
BACKGROUND: Diaphyseal fractures of femur and tibia are prominent due to its 
high incidence and high economic and social impact. Intramedullary nailing (IN) is 
the surgical procedure of choice. Surgical site infection (SSI) related to this procedure 
is considered a difficult to treat complication. AIMS: Determine the incidence of SSI 
after IN of femoral and tibial diaphyseal fractures and evaluate possible risk factors. 
METHODS: Prospective observational cohort study. SSI was defined according to 
CDC-NHSN criteria and surveillance period for the occurrence of infection was 12
months. Incidence of SSI was calculated as the ratio between the number of patients 
with SSI and total number of patients. Analysis of potential risk factors included 
patients-related factors (age, gender, body mass index, active foci of infection, 
immunosuppressive conditions, ASA score, alcohol or illicit drug abuse, smoking, 
polytrauma, etiology of fracture, type of fracture if closed or open, classification of 
fracture according to Müller AO, Tcherne classification for closed fractures, Gustilo-
Anderson classification for open fractures, previous surgical manipulation, use of 
blood products); environmental and surgical-related factors (surgical wound 
classification, duration of surgery, hair removal, intraoperative contamination, 
antimicrobial use, presence of drains, hypothermia or hypoxia in the perioperative 
period, type of IN used, reaming, need for soft tissue reconstruction, use of negative 
pressure therapy) and microbiota-related factors (cultures of nasopharyngeal swabs 

for Staphylococcus aureus and axillary/inguinal/perineal swab for Acinetobacter 
baumannii).  
STATISTICAL ANALYSIS: The studied factors were described and compared 
according to the occurrence of infection using Mann-Whitney or Student’s t-tests for 
the quantitative variables and using chi-squared or exact tests (Fisher’s exact test or 
likelihood ratio test), for the qualitative variables. The odds ratio of each variable was 
studied for the occurrence of infection, and the respective 95% confidence intervals 
were estimated by unadjusted logistic regression. Multiple logistic regression model 
was estimated to simultaneously assess the characteristics that affected the occurrence 
of infection, selecting the variables with significance levels lower than 0.10 (p < 0.10) 
in the bivariate tests, maintaining only the variables with a significance level equal to 
or lower than 0.05 (p ≤ 0.05) in the final model. Software IBM-SPSS for Windows 
version 20.0 was used to perform the analyses, and the data were tabulated using 
software Microsoft Excel 2003. Tests were performed with a 5% significance level. 
RESULTS: 221 patients were included and completed the 12-month follow-up period. 
Incidence of SSI was 11.8%. In the initial analysis by unadjusted logistic regression, 
following factors were associated SSI: Müller AO classification of the fracture 
morphology groups 2 or 3, previous use of external fixator, presence of drains, use of 
negative pressure therapy and need for muscle or skin flap repair. In the multiple 
logistic regression-adjusted analysis, previous use of external fixator and need for 
muscle or skin flap repair remained associated with SSI. CONCLUSIONS: Incidence 
of SSI associated with IN for femoral and tibial diaphyseal fractures was 11.8%. 
Previous use of external fixators and need for muscle or skin flap repair were factors 
associated with occurrence of infection.