134 patients with open fractures of lower limbs type II, IIIA, IIIB and IIIC were prospectively studied between February 1998 and May 2000 at the Orthopedics and Traumatology Institute ofthe São Paulo University Medical School, to determine predictable risk factors of infection. All patients were enrolled to a protocol where they had initial bone fragment samples collected for bacterial cultures, clinical conditions evaluation and early introduction of antibiotics. During the initial approach, causes of fractures, time of bone exposure and place of first medical care were observed.During the initial debridement, volume of blood transfusion, clinical ASA classification, surgical time, surgical wound and type of skeletal stabilization were observed. Univariate analysis was performed to identify predictable statistically significant risks to develop infection, with the following results : time of bone exposure (p=0.0201), place of first medical care (p=0.400), type of fracture (p=0.0130), ASA classification (p=0.0005), volume of blood transfusion (p=0.0002), fractured bone (p=0.0052), type of accident (p=0.0450), surgical wound (p=0.0024), skeketal stabilization (p=0.0446), positive bacterial culture in admission (p=0.5290) and concomitant surgeries (p=0.1867). The variables with significant association with infection were introduced into a multivariate regression equation (logistic model) to identify those with independent effect from other factors. The final logistic model was obtained and demonstrated the probabilities of infection in the open fractures studied. The relative risks revealed in the final logistic model were : volume of blood transfusion (more than 1 unit) - 6.4; ASA classification level III - 5.2; Internal fixation of the bone (immediate) - 3.9; fractured bone (femur) - 3.5 and open wound - 3.0.
Fractures; Open; Infection; Lower extremity
