Background and purpose: For early detection of postoperative infections, the level of C-reactive protein (CRP) may be useful. We analyzed baseline and time-dependent reference values for the postoperative use of CRP as an indicator of infection.
Methods: We studied the kinetics of CRP levels after fracture surgery in 1,418 patients. In 787 cases the operative fracture treatment was uneventful; in 17 of the other cases a deep wound infection occurred.
Results: In the uneventful cases, a similar evolution in CRP concentrations was found: the peak level, which occurred on the second postoperative day, depended on the region (136 mg/L in femoral fractures and 45 mg/L in ankle fractures) and reflected the extent of surgical trauma. For deep wound infection, a cutoff level of 96 mg/L (sensitivity 92%, specificity 93%) after the fourth day of surgery was recorded.
Interpretation: CRP kinetics permit establishment of a time-dependent set of reference values of CRP after operative fracture treatment. Deviations of this course--especially CRP concentrations above 96 mg/L after the fourth day--may aid in early detection of surgical complications.