Treatment of knee prosthesis infections: evaluation of 15 patients over a 5-year period

Our objective was to evaluate different treatment alternatives for total knee arthroplasty (TKA) infection and to compare outcomes depending on adherence to a current treatment algorithm. All patients treated for a first episode of TKA infection between January 2000 and July 2005 were included. Patient records were reviewed and data were extracted retrospectively. Fifteen patients were followed up for a median of 25 months. The cure rate in patients with two-stage exchange of knee prosthesis was higher than in patients who had débridement without implant removal (100 vs 37%, p = 0.03). Cure rates were not different between these two surgical approaches in ten patients who were treated according to a current treatment algorithm. Success rates for treatment of TKA infections varied considerably with the treatment strategy chosen. Our results support the use of existing algorithms to select patients who are eligible for débridement with retention of the prosthesis or need two-stage exchange of knee implants

Diagnosis and Management of Infected Total Knee Arthroplasty§

Infection following total knee arthroplasty can be difficult to diagnose and treat. Diagnosis is multifactorial and relies on the clinical picture, radiographs, bone scans, serologic tests, synovial fluid examination, intra-operative culture and histology. Newer techniques including ultrasonication and molecular diagnostic studies are playing an expanded role. Two-stage exchange arthroplasty with antibiotic cement and 4-6 weeks of intravenous antibiotic treatment remains the most successful intervention for infection eradication. There is no consensus on the optimum type of interval antibiotic cement spacer. There is a limited role for irrigation and debridement, direct one-stage exchange, chronic antibiotic suppression and salvage procedures like arthrodesis and amputation. We examine the literature on each of the diagnostic modalities and treatment options in brief and explain their current significance

Synovial fluid biomarkers for periprosthetic infection. Clin Orthop Relat Res.

Abstract Background We have previously described a unique gene expression signature exhibited by synovial fluid leukocytes in response to bacterial infection, identifying a number of potential biomarkers for infection. However, the diagnostic performance of these potential biomarkers in an immunoassay format is unknown. Questions/purposes We therefore evaluated the sensitivity, specificity, and accuracy of several potential synovial fluid biomarkers for infection, and compared them to current standards of testing for periprosthetic infection. Methods We prospectively collected synovial fluid from 14 patients classified as having a periprosthetic infection and 37 patients classified as having an aseptic failure. The synovial fluid samples were tested for 23 potential biomarkers for periprosthetic infection. We then determined differences in biomarker levels between infected and aseptic groups, then computed the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for select biomarkers, and finally compared those to current standard tests for infection. Results Twelve synovial fluid biomarkers had substantially higher average levels in the synovial fluid of infected versus aseptic patients. Synovial fluid levels of IL-1 were a mean of 258 times higher in patients with a periprosthetic infection compared to patients having revision for aseptic diagnoses. Synovial fluid IL-1 and IL-6 levels correctly classified all patients in this study with a sensitivity, specificity, positive predictive value, negative predictive value and accuracy equal to 1. Several markers tested in this study outperformed the ESR and CRP tests. Conclusions Patients with a periprosthetic infection have elevated levels of numerous synovial fluid biomarkers, when compared to patients with aseptic diagnoses. Several of these biomarkers exhibited nearly ideal sensitivity, specificity, and accuracy in this study, suggesting that synovial fluid biomarkers could be a valuable tool for diagnosing periprosthetic infection