Diagnosis of infection in hip and knee revision surgery: intraoperative frozen section analysis.
In this study we validated intraoperatively the analysis of polymorphonuclear leucocyte frozen sections for diagnosis of infection in hip and knee revisions. Between 1996 and 2002 we examined sections and cultured periprosthetic tissues in prosthetic revision in 170 cases, including 146 cases (83 hips and 63 knees). We assessed sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), Youden index, positive likelihood ratio (PLR) and negative likelihood ratio (NLR). We compared intraoperative findings and paraffin-embedded samples. The results in the knee group were SE=66.7%, SP=89.7% [95% confidence interval (CI)], PPV=81% (95% CI), NPV=81.4% (95% CI), Youden index=0.56, PLR=6.5 (95% CI) and NLR=0.4 (95% CI). In the paraffin-embedded samples the results were SE=91%, SP=87% (95% CI), PPV=81% (95% CI), NPV=94% (95% CI), PLR=7 (95% CI) and NLR=8.7 (95% CI). We found a significant difference. The results in the hip group were SE=50%, SP=100% (95% CI), PPV=100% (95% CI), NPV=94.9% (95% CI), Youden index=0.5 and PLR=0.5 (95% CI). In hip and knee prosthetic revision surgery the presence of polymorphonuclear cells correlates with infection, but their absence does not exclude it. It is a quick and inexpensive test that should be included in the diagnostic protocol in revision surgery.


METHODS
diagnostic Study (investigating a diagnostic test), level I. See instructions to authors for a complete description of levels of evidence.
Servicio de Cirugía Ortopédica y Traumatología, Hospital Clínico San Carlos de Madrid, Madrid, Spain. albertofrances@hotmail.com
Alberto
A
Francés Borrego
Fernando Marco
FM
Martínez
Juan Luis
JL
Cebrian Parra
David Serfaty
DS
Grañeda
Rodrigo García
RG
Crespo
Luis
L
López-Durán Stern
D000368:Aged; D000369:Aged, 80 and over; D019072:Antibiotic Prophylaxis; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D001431:Bacteriological Techniques; D003430:Cross-Sectional Studies; D005260:Female; D005629:Frozen Sections / Q000379:methods*; D006621:Hip Joint / Q000382:microbiology / Q000473:pathology; D006801:Humans; D007432:Intraoperative Period; D007719:Knee Joint / Q000382:microbiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D012086:Reoperation; D013030:Spain / Q000453:epidemiology; D013530:Surgical Wound Infection / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology