Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty

Sang Gyun Kim, Jae Gyoon Kim, Ki-Mo Jang, Seung Bum Han, Hong Chul Lim, Ji Hoon Bae

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Background The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. Methods We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. Results There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/μL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/μL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). Conclusion Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

Original languageEnglish
Pages (from-to)3724-3728
Number of pages5
JournalJournal of Arthroplasty
Volume32
Issue number12
DOIs
Publication statusPublished - 2017 Dec 1

Fingerprint

Knee Replacement Arthroplasties
Leukocyte Count
C-Reactive Protein
Blood Proteins
Joints
Infection
Serum
Blood Sedimentation
Sensitivity and Specificity
Knee Joint
ROC Curve
Knee
Leukocytes

Keywords

  • C-reactive protein
  • erythrocyte sedimentation rate
  • periprosthetic joint infection
  • synovial fluid analysis
  • total knee arthroplasty
  • unicompartmental knee arthroplasty

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

Cite this

Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty. / Kim, Sang Gyun; Kim, Jae Gyoon; Jang, Ki-Mo; Han, Seung Bum; Lim, Hong Chul; Bae, Ji Hoon.

In: Journal of Arthroplasty, Vol. 32, No. 12, 01.12.2017, p. 3724-3728.

Research output: Contribution to journalArticle

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title = "Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty",
abstract = "Background The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. Methods We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. Results There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/μL, acute PJI could be diagnosed with the highest sensitivity (100{\%}) and specificity (98.9{\%}); with the cutoff value set at 16,000 cells/μL, the best PPV and NPV were found (100{\%} and 99.5{\%}, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100{\%}) and specificity (90.3{\%}), whereas the CRP level >74.5 mg/L had the best PPV (100{\%}) and NPV (99.2{\%}). Conclusion Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.",
keywords = "C-reactive protein, erythrocyte sedimentation rate, periprosthetic joint infection, synovial fluid analysis, total knee arthroplasty, unicompartmental knee arthroplasty",
author = "Kim, {Sang Gyun} and Kim, {Jae Gyoon} and Ki-Mo Jang and Han, {Seung Bum} and Lim, {Hong Chul} and Bae, {Ji Hoon}",
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T1 - Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty

AU - Kim, Sang Gyun

AU - Kim, Jae Gyoon

AU - Jang, Ki-Mo

AU - Han, Seung Bum

AU - Lim, Hong Chul

AU - Bae, Ji Hoon

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N2 - Background The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. Methods We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. Results There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/μL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/μL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). Conclusion Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

AB - Background The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. Methods We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. Results There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/μL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/μL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). Conclusion Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

KW - C-reactive protein

KW - erythrocyte sedimentation rate

KW - periprosthetic joint infection

KW - synovial fluid analysis

KW - total knee arthroplasty

KW - unicompartmental knee arthroplasty

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