Serial measurement of the C-reactive protein is a poor predictor of treatment outcome in prosthetic joint infection.

OBJECTIVES Prosthetic joint infection is usually treated using surgery and antibiotics. The response to the treatment regimen is often evaluated using serial monitoring of plasma C-reactive protein (CRP) concentrations. In order to examine how useful this monitoring is, we calculated the sensitivity and specificity of CRP concentrations for predicting treatment failure. PATIENTS AND METHODS We examined 3732 CRP measurements from 260 patients who were treated by either two-stage revision or debridement and retention. We tested the association between CRP concentration and outcome using logistic regression models, and assessed sensitivity and specificity by using receiver operator curves. RESULTS The areas under receiver operator curves for CRP concentrations predicting outcome ranged from 0.55 to 0.65. CONCLUSIONS CRP concentrations did not accurately predict treatment failure. Serial monitoring may not be of benefit.