Neutrophil to lymphocyte ratio as a predictor for diagnosis of early Periprosthetic joint infection

Abstract

Background Periprosthetic joint infection (PJI) is a catastrophic complication after total knee or hip arthroplasty. The diagnosis of PJI is very difficult, especially in the early postoperative period. The value of the neutrophil to lymphocyte ratio (NLR) is useful for diagnosing infectious diseases. The objective of this study was to investigate the accuracy of the NLR for the diagnosis of early PJI after total knee or hip arthroplasty. Methods We retrospectively evaluated consecutive primary total knee or hip arthroplasty and identified the patients who readmitted within the first 90 days postoperatively between January 2011 and October 2018.There were 20 cases diagnosed early PJI and 101 uninfected cases on the basis of the modified Musculoskeletal Infection Society (MSIS) criteria. The serum parameters including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood-cell (WBC) count, NLR and interleukin-6 (IL-6) were compared between the two groups. Receiver operating characteristic curves were generated to estimate the optimal cutoff values for each parameter. The sensitivity, specificity, positive predictive value and negative predictive value for each parameter were calculated. Results The CRP, ESR, WBC, NLR and IL-6 values were all significally higher in the infected group than the uninfected group. The median of CRP was 66.6 mg/l in the infected group and 8.6 mg/l in the uninfected group (p < 0.001). The median of ESR was 34.8 mm/hr. in the infected group and 17.4 mm/hr. in the uninfected group (p < 0.001). In the infected group and uninfected group, the median of WBC was 8.2X109 /L and 6.1 X109 /L (p = 0.002), respectively; while the median of NLR was 5.2 and 2.1 (p < 0.001). The median of IL-6 was 46 pg/ml and 6.4 pg/ml (p < 0.001),respectively. The best parameter for the diagnosis of early PJI was IL-6 (AUC = 0.814) followed by the NLR (AUC =0.802), CRP (AUC =0.793), ESR (AUC =0.744) and WBC (AUC = 0.632). Conclusions This study is the first to show that NLR values are more accurate than CRP and may be considered as useful parameters for the diagnosis of early PJI because it is a cheap and convenient parameter to be calculated in daily practice without extra costs.

Neutrophil-to-Lymphocyte Ratio (NLR) and Platelet-to-Lymphocyte Ratio (PLR) Are Potentially Valuable Tests for Diagnosing Periprosthetic Joint Infection

“…However, Zhao et al [23] and Yu et al [14] demonstrated that NLR and PLR had greater predictive value for diagnosis of PJI than ESR and CRP, in stark contrast to our results. Our further analysis indicated that this was most likely due to differences in the characteristics of the enrolled patients; in our study, examined patients were diagnosed as chronic PJI, but the other two studies [14,23] examined patients who had acute PJI .…”

“…They used an NLR cutoff of 2.77, similar to our cutoff (2.71). Similarly, Yu et al [14] found that the NLR was effective in diagnosing PJI (AUC: 0.802, 85% sensitivity, 68.3% speci city, 34.7% PPV, 95.8% NPV) with a cut-off value of 2.13. However, Zhao et al [23] and Yu et al [14] demonstrated that NLR and PLR had greater predictive value for diagnosis of PJI than ESR and CRP, in stark contrast to our results.…”

“…For example, Paziuk et al found that the PVR was associated with PJI (optimal cutoff: 31.70), and that PVR with C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) signi cantly improved the diagnostic accuracy of PJI compared with traditional biomarkers [13]. A recent study by Yu et al showed that the NLR had a higher accuracy for early diagnosis of PJI than CRP and ESR, and their receiver operating characteristic (ROC) analysis indicated the area under curve (AUC) for NLR was 0.802 [14]. Tirumala et al found that the PLR and PVR signi cantly improved the accuracy of PJI diagnosis when combined with traditional serum biomarkers and joint aspirate results, with sensitivity and speci city above 97% [15].…”

Serum Inflammatory Biomarkers in the Diagnosis of Periprosthetic Joint Infections

“…Lower cut-off values were described by Glehr et al [13] (cut-off: 5.48 G/L) and Klim et al [20] (cut-off 5.68), leading to a higher sensitivity (91% and 90%, respectively) but at the expense of specificity (34% and 39%, respectively). Table 3 shows the recent literature of WBC depending on the used infection definition [2,10,11,13,[15][16][17]20,23,25,29,35].…”

“…However, the available data reveals controversial results regarding the performance of IL-6. A proper comparison cannot be made due to the different infection definitions and cut-offs (Table 6) [11,13,15,16,18,23,25,80]; hence, no recommendation can be given. Further studies are needed to elucidate the diagnostic value of IL-6 in diagnosing PJI.…”