Monitoring antibiotic and immune activity in the knee after removal of an infected prosthesis and placement of an antibiotic spacer

Analysis of Immunological and Pharmacological Aspects Regarding Infection Free Survival After Surgical Treatment of a Periprosthetic Knee Infection During Hospitalization: a Microdialysis Study

Observational University Hospital, Bonn · NCT07299565

This project will use microdialysis to see if antibiotic levels and immune signals in the knee after spacer placement predict infection-free recovery for people having a two-stage revision for periprosthetic knee infection.

Quick facts

Study typeObservational
Enrollment30 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity Hospital, Bonn Academic / other
Locations1 site (Bonn, North Rhine-Westphalia)
Trial IDNCT07299565 on ClinicalTrials.gov

What this trial studies

This observational study places microdialysis probes in the knee joint after removal of an infected prosthesis and insertion of an antibiotic-impregnated cement spacer to continuously sample local antibiotic concentrations and immunologic markers during the initial hospitalization (typically about 14 days). Blood samples will be collected in parallel to compare systemic and intraarticular antibiotic levels. Clinical outcomes, including reinfection rates, infection-free survival, and functional recovery, will be tracked over a 12-month follow-up. The spacer materials contain gentamicin and vancomycin, and patients with known allergies to these antibiotics are excluded. Data will be analyzed to identify pharmacological and immunological profiles associated with better or worse outcomes after two-stage revision.

Who should consider this trial

Good fit: Adults (age >18) who are scheduled for two-stage revision for periprosthetic knee infection, cleared for surgery, and willing to provide informed consent (and without allergy to gentamicin or vancomycin) are ideal candidates.

Not a fit: People who are not undergoing a two-stage knee revision, or who have known allergies to the spacer antibiotics (gentamicin or vancomycin), are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, the results could help tailor local and systemic antibiotic strategies and spacer use to reduce reinfection and improve recovery after two-stage knee revision.

How similar studies have performed: A prior pilot by the same group used microdialysis for 72 hours, providing preliminary feasibility data, but prolonged in vivo monitoring during spacer implantation remains relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* clinical indication for two-stage revision of knee PJI
* approval for surgery by the orthopedic and anesthesiologic department
* being over 18 years of age
* written, informed consent after detailed patient information about the study protocol and possible study dependent risks

Exclusion Criteria:

* known allergies to antibiotics gentamicin and vancomycin used within the spacer

Where this trial is running

Bonn, North Rhine-Westphalia

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Periprosthetic Knee Infectiontwo-stage exchangeinfectionPJImicrodialysisinfection free survivaltreatment monitoringmuscle mass
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.