Patients presenting with prosthetic joint infections of a total knee replacement who are treated with an antibiotic spacer will be observed prospectively for their response to treatment and antibiotic elution profiles will be measured post-operatively utilizing mass spectrometry from synovial fluid acquired as part of standard of care in the management of prosthetic joint infection. Secondary outcomes including post-operative complications, re-operation rates, and re-admission rates will also be compared.
The current study aims to assess the surgical and patient-reported outcomes and in vivo antibiotic elution profile of the management of total knee arthroplasty (TKA) prosthetic joint infection (PJI). Within the standard of care, TKA PJI is treated via a resection arthroplasty and antibiotic cement spacer placement. Patients will be enrolled if they are undergoing surgical management for a chronic TKA PJI and will receive surgical treatment according to the standard of care. In the post-operative period, patients will be monitored for surgical and patient-reported outcomes including re-operation rate, pain scores, complication rates, and re-infection rates. Synovial fluid obtained from intra-articular postoperative drains and at postoperative knee aspirations during reimplantation evaluations will also be utilized for antibiotic concentration quantification via mass spectrometry, if sufficient specimen is available. Patient who undergo surgical management for their chronic TKA PJI will then have their measured antibiotic elution concentrations compared. The study hypothesizes that patients undergoing treatment of a PJI with antibiotic spacer + antibiotic cement spacer will have better surgical and patient-related outcomes with higher antibiotic elution concentrations. These improved outcomes would include lower re-operation rates, lower pain scores, lower wound healing complications, and higher rates of second stage re-implantation observed in patients with higher antibiotic elution concentrations. Specific aims: 1. To evaluate the antibiotic elution profile and post-operative intra-synovial concentrations in the treatment of chronic PJI after TKA. 2. To evaluate surgical and patient-related outcomes in chronic TKA PJI patients following implant resection and knee spacer placement, including amount of post-operative drain output, wound healing complications, 30- and 90-day risk of re-operation, pain scores, and rate of second stage re-implantation.
Study Type
OBSERVATIONAL
Patients will all undergo standard of care treatment for a chronic total knee arthroplasty prosthetic joint infection.
UPMC Shadyside
Pittsburgh, Pennsylvania, United States
Intra-articular Antibiotic Elution Profile
Antibiotic concentration will be quantified utilizing mass spectrometry from intra-articular synovial fluid obtained from post-operative drain and knee aspirations performed for re-implantation evaluation.
Time frame: Post-operative day 2 and during 2nd stage re-implantation evaluation (around 10 weeks according to standard of care)
Drain Output
Measured volume of output from post-operative drain will be quantified every 12 hours
Time frame: Each 12 hours period until removal of the drain up to 5 days postoperatively based on drain output less than 30cc in 12 hours.
Wound Healing Complications
Any issues with wound healing including closure, occurrence of infection, high drainage, or hematoma formation will be among wound healing complications which are measured.
Time frame: up to 6 months following surgery
Re-operation Rates
Rates of return to operating room will be quantified over course of 30 days and 90 days.
Time frame: 30 days and 90 days post-operatively.
Re-admission Rates
Rates of re-admission will be quantified over course of 30 days and 90 days.
Time frame: 30 days and 90 days post-operatively.
Pain Scores
Pain scores utilizing visual analog scale from 0 to 10 will be quantified during post-operative course.
Time frame: Daily on postop day 0 until postop day 5, 3 weeks, 6 weeks and 10 weeks, 6 months postoperatively.
Second Stage Re-implantation Rates
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Rates of successful second stage re-implantation will be quantified during the post-operative course.
Time frame: Through study completion up to 1 year
Knee aspiration cell count
Knee aspiration with number of white cells less than 1300
Time frame: 3 weeks, 6 weeks and 10 weeks - 6 months postoperatively.
Knee aspiration culture
Knee aspiration without evidence of bacteria on bacterial culture
Time frame: 3 weeks, 6 weeks and 10 weeks - 6 months postoperatively.
C-reactive protein assessment
C-reactive protein normalization (less than 1mg/dl)
Time frame: baseline, 10 weeks to 6 months posteroperatively
ESR assessment
Erythrocyte sedimentation rate normalization (less than 20 mm/hr)
Time frame: baseline, 10 weeks to 6 months posteroperatively