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.