Open debridement and exchange of tibial insert in infected knee arthroplasty. A report from the Swedish knee arthroplasty register

Introduction: Total knee arthroplasty (TKA) is a common procedure with increasing demand. One of the most serious complications is infection. Open debridement and exchange of the tibial insert, followed by antibiotics, is a treatment option in early infections but the results presented vary. The aim of this study was to examine the success rate of open debridement and exchange of tibial insert after infected knee arthroplasty and to identify prognostic factors for outcome. Materials and methods: The study included 151 infected knees in 150 patients that underwent a primary TKA in Sweden during the years 2000 - 2008 and open debridement and exchange of tibial insert because of an infection. To evaluate the results information from medical records and culture reports was retrospectively collected. The outcome variables were re-revision because of infection, and failure to eradicate infection, which was defined as death within 60 days, re-revision due to infection, clinical signs of infection in the knee at latest follow-up, or persistent antibiotic treatment. Results: 27 (17.9%) of the cases were further revised due to infection. 37 (24.5%) cases were classified as failure. Patients operated with a revision type of implant had higher risk of failure (p = 0.007). In early infections (within 3 months) there was a tendency towards higher risk of failure in cases were the time from primary operation until debridement was > 4 weeks (p = 0.083). Bacteriology did not affect the results whereas staphylococcal infections treated without rifampicin had a higher failure rate than those treated with a combination including rifampicin, with a failure rate of 50% and 17.6%, respectively. Conclusions: Infection after a primary knee arthroplasty can be successfully treated by open debridement and exchange of tibial insert at least up to 4 weeks after primary operation. In staphylococcal infections rifampcin should be included in the antibiotic protocol