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Updated: Aug 14, 2026
Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
Intraoperative frozen section for detecting active infection in failed hip and knee arthroplasties
Yiu-Chung Wong1, Qun-Jid Lee, Yuk-Leung Wai
1Department of Orthopaedics and Traumatology, Yan Chai Hospital, Tsuen Wan, New Territories, Hong Kong.
Abstract:
The authors reported the result of 40 sessions of intraoperative frozen section on polymorph count in 33 patients undergoing exploration or revision hip and knee surgery to detect active infection. The correlation rate between frozen section and permanent section was 0.95 to 1.00. If the polymorph count more than 5 per high-power field (40 X) was chosen as positive, the sensitivity, specificity, positive predictive value, and negative predictive value would be 0.93, 0.77, 0.68, and 0.95, respectively. Taking polymorph count of more than 10 as positive, the sensitivity, specificity, positive predictive value, and negative predictive value would then be 0.86, 0.85, 0.75, and 0.92, respectively. The authors concluded that intraoperative frozen section is an inexpensive, rapid, and helpful adjunct to detect active infection. A polymorph count of lower than 5 highly suggests the absence of active infection.
Insights
Intraoperative frozen section analysis of polymorph counts aids in detecting active joint infections during hip and knee surgery. A low polymorph count reliably indicates the absence of infection, assisting surgeons in diagnosis.
Area of Science:
- Orthopedic Surgery
- Surgical Pathology
- Infectious Disease Diagnosis
Background:
- Accurate detection of active infection is critical in hip and knee revision or exploration surgery.
- Intraoperative assessment is valuable for guiding surgical decisions.
- Polymorph count in frozen sections is a potential biomarker for infection.
Purpose of the Study:
- To evaluate the efficacy of intraoperative frozen section analysis of polymorph counts for detecting active infection in hip and knee surgery.
- To determine optimal polymorph count thresholds for diagnosing infection.
Main Methods:
- 40 intraoperative frozen section sessions were performed on 33 patients undergoing hip or knee surgery.
- Polymorph counts per high-power field (40X) were assessed.
- Correlation with permanent section results was analyzed.
- Sensitivity, specificity, and predictive values were calculated for different polymorph count thresholds.
Main Results:
- High correlation (0.95-1.00) between frozen and permanent sections.
- A polymorph count >5/HPF yielded sensitivity of 0.93 and specificity of 0.77.
- A polymorph count >10/HPF yielded sensitivity of 0.86 and specificity of 0.85.
- A polymorph count <5/HPF strongly suggested the absence of active infection.
Conclusions:
- Intraoperative frozen section is a rapid, inexpensive, and helpful tool for detecting active joint infection.
- Polymorph count serves as a valuable indicator in frozen section analysis for surgical site infections.
- A low polymorph count (<5/HPF) is a reliable negative predictor of active infection.
