The goal of this observational study is to monitor the eluted antibiotic concentrations of gentamicin and vancomycin by a static knee cement spacer in patients being treated for periprosthetic infections of the knee. The main question aims to answer if eluted antibiotics are in a therapeutic range for treatment at sight of infection. Secondarily, local antibiotic concentrations are compared with systemic blood levels, as are systemically applied antibiotics compared to intra-articular concentrations. Intra-articular samples are collected over a 72 hour postoperative period.
The present study moinitors antibiotic concentrations eluted by a static cement knee spacer as two-stage revision treatment of a knee PJI. The static cement spacer consists of COPAL G+V cement containing 2g of vancomycin and 0.5g of gentamicin. Microdialysis is used as a technique for continuous extra cellular sample collection directly from the knee joint cavity. It is implemented guided by a drainage tube during the surgery to remove the infected prosthesis and implement the spacer. Over a 72 hour period samples directly from the knee joint are generated continiously. These are analyzed for the eluded antibiotic concentrations of gentamicin and vancomycin from the knee spacer. Once every 24 hours venous blood samples were collected as well and analyzed for gentamicin and vancomycin and also systemically applied antibiotics (a.e. cefuroxim, clindamycin).
Study Type
OBSERVATIONAL
Enrollment
10
The intervention decive is placed during the routine surgery to remove the infected knee prosthesis and implantation of the static cement spacer. A microdialysis catheter is implemented to generate continious intra-articular samples of the knee joint. To ensure complete removal and no damage of the membrane it is inserted via a regular drainage tube. The catheter membrane is placed intra-articularly next to the spacer and continious to an outlet tube for sample collection.
University Hospital Bonn
Bonn, North Rhine-Westphalia, Germany
antibiotic concentrations in intra-articular samples
Both locally through the spacer eluted antibiotics (gentamicin and vancomycin) and systemically administered antibiotics (e.g. cefuroxim, clindamycin) are measured in intra-articular knee samples.
Time frame: Concentrations are measured for 72 hours after spacer implantation.
Antibiotic concentrations in blood samples
Antibiotic concentrations eluted by the spacer (gentamicin, vancomycin) and systemically administered antibiotics (e.g. cefuroxim, clindamycin) are measured in venous blood samples.
Time frame: Antibiotic concentrations are measured once every 24 hours after spacer implantation. In total at three time points during the 72 hour observation period.
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