The value of white blood cell counts before revision total knee arthroplasty

J Arthroplasty. 2003 Dec;18(8):1038-43. doi: 10.1016/s0883-5403(03)00448-0.

Abstract

A white blood cell count (WBC) of >50000 cell/mm(3) from a knee aspirate with >or=80% polymorphonuclear cells (PMNCs) is suggestive of infection. This study sought to determine if these same criteria were applicable when interpreting aspirates from a total knee. Of 440 revision total knee arthroplasties, 86 patients had preoperative aspirations of the knee before revision. Fifty-five aspirates were from aseptic failures; 31 aspirates were from patients determined to have septic failure. The mean white blood cell (WBC) count in aspirates from the aseptic group was 645 cells/mm(3) (SD = 878). The mean WBC count in the septic group was 25951 cells/mm(3) (SD = 34994; P=<.001). The mean percentage of PMNCs was statistically higher in the septic group compared with the aseptic group (72.8% vs 27.3%; P=<.001). The synovial fluid WBC count differential analysis is a statistically relevant indicator of the presence or absence of infection in revision knee arthroplasty. Aspirates with a WBC count of 2500 per milliliter and 60% PMNCs are highly suggestive of infection.

MeSH terms

  • Arthroplasty, Replacement, Knee*
  • Humans
  • Leukocyte Count*
  • Preoperative Care
  • Prosthesis-Related Infections / diagnosis
  • Prosthesis-Related Infections / surgery*
  • Reoperation
  • Retrospective Studies
  • Sensitivity and Specificity
  • Synovial Fluid / cytology*