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Diagnostic Accuracy of Synovial Alpha-Defensin and Histopathology for Periprosthetic Joint Infection: A Validation
Sina Jamaria1, Sukhil Raina2, Malhar Choksi3
1Department of Pathology, Gujarat Adani Institute of Medical Sciences, Bhuj, Gujarat, India.
Introduction:
Periprosthetic joint infection (PJI) remains one of the most serious complications following total hip and knee arthroplasty, often leading to repeated surgeries, prolonged hospitalization, and poor functional outcomes. Accurate and timely diagnosis is challenging due to variable clinical presentation and the limitations of conventional diagnostic tests. Synovial alpha-defensin has emerged as a promising biomarker for PJI, while histopathological examination of periprosthetic tissue continues to be an important intraoperative diagnostic modality. This study aimed to validate and compare the diagnostic accuracy of synovial alpha-defensin and histopathology in detecting PJI.
Objectives:
The objective of the study was to evaluate the diagnostic performance of synovial alpha-defensin and histopathological examination of periprosthetic tissue individually and in combination for the diagnosis of PJI.
Methods:
This prospective diagnostic validation study included 50 patients undergoing revision total hip or knee arthroplasty at a tertiary care center. Preoperative synovial fluid samples were analyzed for alpha-defensin. Intraoperatively, multiple periprosthetic tissue samples were obtained for histopathological examination. The final diagnosis of PJI was established using standardized reference criteria incorporating clinical, laboratory, microbiological, and histological findings. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated for each modality.
Results:
Of the 50 patients, 22 (44%) were diagnosed with PJI. Synovial alpha-defensin demonstrated a sensitivity of 90.9% and specificity of 92.9%, with an overall diagnostic accuracy of 92%. Histopathology showed a sensitivity of 81.8% and specificity of 85.7%, with an accuracy of 84%. Combined interpretation of both tests improved sensitivity to 95.5% and specificity to 96.4%, yielding the highest diagnostic accuracy (96%).
Conclusion:
Synovial alpha-defensin is a highly reliable diagnostic marker for PJI and outperforms histopathology when used alone. However, the combined use of synovial alpha-defensin and histopathological examination provides superior diagnostic accuracy, supporting their complementary role in contemporary PJI diagnostic algorithms.
Insights
Synovial alpha-defensin is a reliable marker for diagnosing periprosthetic joint infection (PJI), outperforming histopathology alone. Combining both tests offers the highest diagnostic accuracy for PJI, improving patient outcomes.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Diagnostic Biomarkers
Background:
- Periprosthetic joint infection (PJI) is a severe complication of joint arthroplasty, leading to significant morbidity and healthcare costs.
- Accurate diagnosis of PJI is challenging due to nonspecific clinical signs and limitations of conventional tests.
Purpose of the Study:
- To validate and compare the diagnostic accuracy of synovial alpha-defensin and histopathology for PJI detection.
- To assess the combined diagnostic performance of these two modalities.
Main Methods:
- Prospective study of 50 patients undergoing revision hip or knee arthroplasty.
- Analysis of preoperative synovial fluid for alpha-defensin levels.
- Intraoperative periprosthetic tissue sampling for histopathological examination.
- Diagnosis confirmed using standardized criteria.
Main Results:
- Synovial alpha-defensin showed 90.9% sensitivity and 92.9% specificity (92% accuracy).
- Histopathology yielded 81.8% sensitivity and 85.7% specificity (84% accuracy).
- Combined testing achieved 95.5% sensitivity and 96.4% specificity (96% accuracy).
Conclusions:
- Synovial alpha-defensin is a highly accurate biomarker for PJI, superior to histopathology alone.
- The combination of synovial alpha-defensin and histopathology provides the highest diagnostic accuracy for PJI.
- These complementary tests should be integrated into PJI diagnostic algorithms.
