Diagnostic accuracy of C-reactive protein to rule out infectious complications following hip fracture surgery

Background and Objective: Knowledge of the C-reactive protein trend and deviation from the expected value may give an early indication of a possible postoperative infection. According to previous studies, CRP appears to be a more sensitive and specific marker of postoperative infections than ESR and white cell count. This study was conducted to determine the diagnostic accuracy of C-reactive protein to rule out surgical site infection in patients undergoing hip fracture surgery.

Methods: This cross-sectional study was conducted at The Indus Hospital and Health Network, Karachi from July 1, 2018 to February 24, 2020. All operative hip fracture patients aged 11-90 years were included. CRP was done on admission, days 3, 14 and 28. Wound assessment was done using the criteria of the Center of Disease Control and prevention on postoperative days 3, 14 and 28. Data was analyzed using STATA version 16.

Results: Out of 152 patients, 11(7.2%) developed infection. One patient (0.7%) presented with the infection on day three post-surgery, eight (5.3%) and two (1.3%) patients on days 14 and 28 respectively. CRP levels at admission had poor diagnostic accuracy for diagnosing infection at 14th and 28th day post-surgery respectively (AUC=0.490 and 0.447). CRP levels measured on post-op Day-3 (cutoff value 230mg/dl) had good diagnostic accuracy for diagnosing infection at 14th and 28th day post-surgery respectively (AUC=0.819 and 0.818).

Conclusion: CRP level at post-operative day three is a sensitive indicator of infection after hip fracture surgery.