Table 4.
False-negative rates based on the threshold defined by the modified definition of PJI
| Parameter | False-negative rate on antibiotics | False-negative rate off antibiotics | Risk ratio (95% CI) | p value |
|---|---|---|---|---|
| ESR | 19.2% (9/47) | 6.1% (6/99) | 3.1 (1.2–8.3) | 0.020 |
| CRP | 14.9% (7/47) | 2.0% (2/100) | 7.4 (1.6–34.4) | 0.005 |
| SF WBC | 9.4% (5/53) | 6.5% (7/108) | 1.4 (0.5–4.3) | 0.532 |
| SF PMN% | 23.1% (12/52) | 9.4% (10/106) | 2.4 (1.1–5.2) | 0.027 |
| Culture | 26.4% (14/53) | 12.9% (14/108) | 2.0 (1.05–3.9) | 0.046 |
PJI = periprosthetic joint infection; ESR = erythrocyte sedimentation rate; CRP = C-reactive protein; SF WBC = synovial fluid white blood cell; SF PMN = synovial fluid polymorphonuclear neutrophil; CI = confidence interval.