Abstract
Aim
C-reactive protein(CRP) and erythrocyte sedimentation rate(ESR) are non-specific markers with variable reported accuracy in the diagnosis of prosthetic joint infection(PJI). They are often used as a part of the initial diagnostics as they are widely available and inexpensive. Given its high false-negative rate, CRP is an insufficient screening tool for PJI especially in low virulence microorganisms. Nevertheless, many advocate ESR offers no added advantage and is useless in this setting. Our goal is to determine if the combined measurement of ESR and CRP offers increased sensitivity for the preliminary screening of PJI over isolated CRP measurement.
Method
We retrospectively evaluated every single- or first-stage for presumed aseptic or known infected revision total hip/knee arthroplasty procedures between 2013–2018. Cases without preoperative CRP and ESR measurement as well those without synovial fluid for differential leukocyte count and/or no multiple cultures including sonication of removed implant obtained during surgery were excluded. Diagnostic accuracy was compared against two different PJI definitions: 2013 International Consensus Meeting and ProImplant Foundation definitions.
Results
A total of 398 revision were performed during the study period. After excluding 293 cases with insufficient information, a total of 105 patients were studied. Naturally, CRP and ESR mean values were significantly higher among PJI cases compared to aseptic cases. When compared against 2013 International Consensus Meeting definition, CPR has a sensibility 86.5% (45/52) that increases to 94.2% (49/52) with the combined measurement (ESR and CRP). The sensitivity also increased when compared against the ProImplant Foundation definition (72.6% (45/62) vs 85.5% (53/62)).
Conclusions
After the inciting insult, CRP raises and drops rapidly and ESR response is slower but also much more enduring. One can only hypothesize that chronic PJI runs perhaps a fluctuating inflammatory course that can sometimes be more accurately picked up by ESR and not CRP measurement. Our results seem to corroborate that ESR measurement is a valid adjunct to isolated CRP measurement in the initial screening of PJI in painful total joint arthroplasties.
