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Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
Optimization of sampling protocol, specimen types, and sampling sites in periprosthetic joint infections: a
Chenghan Chu1,2,3, Xiaoyu Wu1,2,3, Zilong Wang1,2,3
1Department of Joint Surgery, The First Affiliated Hospital of Sun Yat-sen University, No. 58 Zhongshan Er Road, Guangzhou, 510080, Guangdong, People's Republic of China.
Background:
Intraoperative culture is critical for diagnosing periprosthetic joint infection (PJI) and antibiotic guidance, yet its value is limited by high culture-negative rates. To improve microbial yield, we developed a multi-site intraoperative sampling protocol (MSP) with following objectives: (1) to evaluate whether MSP could improve the yield of cultures; (2) to identify the optimal specimen types and anatomical sites for culture.
Methods:
A retrospective study was conducted on 163 PJIs from 2015 to 2025. Among these cases, 69 underwent traditional intraoperative sampling protocol (TSP), while 94 underwent MSP. Pathogen detection rates and contamination rates were compared between the two groups. Additionally, culture positivity rates were compared across various specimen types and anatomical sites within MSP group.
Results:
The MSP showed significantly higher pathogen detection rates than TSP (P = 0.003), consistent across knee (P = 0.038) and hip PJIs (P = 0.034). The adoption of MSP (OR = 2.430, P = 0.030) was independent predictor of pathogen detection. Regarding specimen type, synovial fluid (unadjusted P < 0.001, adjusted P = 0.001), pseudocapsule (unadjusted P < 0.001, adjusted P = 0.001), and interface membrane (unadjusted P = 0.001, adjusted P = 0.004) had higher culture positivity rates than synovium. Besides, synovial fluid had higher culture positivity rates than sinus tract (unadjusted P = 0.012, FDR-adjusted P = 0.046). Regarding sampling site, for hip, femoral neck specimens demonstrated higher culture positivity rates than medullary cavity (unadjusted P = 0.008, adjusted P = 0.040) and superficial layer specimens (unadjusted P = 0.008, adjusted P = 0.040). For knee, femoral intercondylar area specimens showed higher culture positivity rates than tibial medullary cavity (unadjusted P = 0.003, adjusted P = 0.037), infrapatellar fat pad (unadjusted P = 0.002, adjusted P = 0.037).
Conclusions:
The MSP enhanced the yield of cultures without increasing the contamination rate. The optimal specimen types for culture included synovial fluid, interface membrane, and pseudocapsule. For hip, the optimal anatomical site for culture was femoral neck. For knee, the optimal anatomical site for culture was intercondylar area.
Insights
A new multi-site intraoperative sampling protocol (MSP) significantly improves pathogen detection rates for diagnosing periprosthetic joint infection (PJI) without increasing contamination. Optimal sites include synovial fluid, interface membrane, and pseudocapsule for improved PJI diagnosis.
Area of Science:
- Orthopedics
- Infectious Disease
- Microbiology
Background:
- Intraoperative cultures are crucial for diagnosing periprosthetic joint infection (PJI) and guiding antibiotic therapy.
- High culture-negative rates limit the diagnostic value of traditional intraoperative sampling protocols (TSP).
- A multi-site intraoperative sampling protocol (MSP) was developed to enhance microbial yield.
Purpose of the Study:
- To evaluate the efficacy of MSP in improving culture yield for PJI diagnosis.
- To identify optimal specimen types and anatomical sampling sites for enhanced microbial detection in PJI cases.
Main Methods:
- A retrospective study compared 69 patients with traditional intraoperative sampling protocol (TSP) against 94 patients with multi-site intraoperative sampling protocol (MSP) for PJI from 2015-2025.
- Pathogen detection and contamination rates were compared between TSP and MSP groups.
- Culture positivity rates were analyzed across different specimen types and anatomical sites within the MSP group.
Main Results:
- MSP demonstrated significantly higher pathogen detection rates than TSP (P=0.003), applicable to both knee and hip PJIs.
- MSP adoption was an independent predictor of pathogen detection (OR=2.430, P=0.030).
- Optimal specimen types for culture positivity included synovial fluid, pseudocapsule, and interface membrane. For hip PJI, the femoral neck was optimal; for knee PJI, the intercondylar area was optimal.
Conclusions:
- The MSP effectively enhances microbial yield for PJI diagnosis without increasing contamination rates.
- Synovial fluid, interface membrane, and pseudocapsule are identified as optimal specimen types for intraoperative cultures.
- Specific anatomical sites, the femoral neck for hip and the intercondylar area for knee, yield superior culture positivity in PJI cases.
