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Low Risk of Acute Iatrogenic Periprosthetic Joint Infection After Prosthetic Joint Aspiration
Timothy C Keating1, Jonathan Guntin1, William E Harkin1
1Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois.
Background:
Synovial fluid analysis is an essential tool in diagnosing periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). However, concern exists that aspiration may introduce infection into a noninfected joint. Therefore, the purpose of this study was to evaluate the incidence of iatrogenic PJI following diagnostic knee aspiration done within 6 months of the primary TKA.
Methods:
Between 2017 and 2021, the senior surgeon performed over 4,000 primary TKAs and aspirated 155 knees in 137 patients for whom there was a suspicion for PJI within 6 months of their primary TKA. There were 22 knees diagnosed as infected from the initial aspiration and therefore were excluded from the study. The remaining 133 aspirates in 115 patients who were negative for infection were followed for 6 months for signs and symptoms of PJI to elucidate whether aspiration introduced infection into an initially noninfected joint.
Results:
There were 70 of 133 knees (52.6%) aspirated between 0 and 6 weeks after index TKA, 40 of 133 (30.1%) between 6 weeks and 3 months, and 23 of 133 (17.3%) between 3 and 6 months. At final follow-up, none of the 133 initially noninfected knees exhibited evidence of subsequent iatrogenic PJI or had subsequent surgery for infection.
Conclusion:
While joint aspiration is a procedure with inherent risks, this study shows that the rate of iatrogenic PJI is extremely low (0%). Therefore, if infection is suspected, the surgeon should consider joint aspiration, even in the initial postoperative period, as the risk for introducing infection is far outweighed by the risk of missing an infection.
Insights
Diagnostic knee aspiration after total knee arthroplasty (TKA) is safe. This study found a 0% incidence of iatrogenic periprosthetic joint infection (PJI) in noninfected knees, supporting its use for suspected PJI.
Area of Science:
- Orthopedic Surgery
- Infectious Disease Diagnostics
Background:
- Synovial fluid analysis is crucial for diagnosing periprosthetic joint infection (PJI) after total knee arthroplasty (TKA).
- Aspiration carries a theoretical risk of introducing infection into a sterile joint.
Purpose of the Study:
- To evaluate the incidence of iatrogenic PJI following diagnostic knee aspiration within 6 months of primary TKA.
Main Methods:
- Retrospective review of 133 knee aspirations in patients with suspected PJI within 6 months of TKA.
- Exclusion of 22 knees with initial infection; follow-up of 115 patients (133 knees) for 6 months post-aspiration.
Main Results:
- Aspiration timing varied: 0-6 weeks (52.6%), 6 weeks-3 months (30.1%), 3-6 months (17.3%).
- None of the 133 initially noninfected knees developed iatrogenic PJI or required surgery for infection.
Conclusions:
- Diagnostic knee aspiration has an extremely low (0%) rate of causing iatrogenic PJI.
- The benefits of diagnosing suspected PJI via aspiration outweigh the minimal risk of infection introduction.
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