Open debridement of acute gram-positive infections after total knee arthroplasty.

Open debridement and retention of components is an attractive, but often ineffective strategy for the treatment of a total knee arthroplasty (TKA) with acute infection. Few studies have stratified the outcomes of debridement specifically according to bacterial species. Thirty-one TKAs with acute gram-positive infections, seen at our institution during the past 10 years, were treated with open debridement, component retention, and antibiotics. The average duration of symptoms before debridement was 9 days (range, 1-40 days), and 78% of debridements were done within 10 days of the onset of symptoms. Eleven (35%) of the 31 patients successfully retained their components at most recent followup, without ongoing infection (mean, 4 years; range, 2-10 years). Only one (8%) of the 13 who had an infection with Staphylococcus aureus was treated successfully, compared with 10 (56%) of 18 patients who had infections, with either Staphylococcus epidermidis or a streptococcal species. The difference between these groups is statistically significant. The success rate of debridement of acute infections in TKA varies significantly depending on the involved pathogen. A high failure rate suggests that immediate component removal should be considered in the presence of acute Staphylococcus aureus infection in TKA. Debridement for acute streptococcal or Staphylococcus epidermidis species has better success, but likely should be done within 2 to 3 days from the onset of symptoms.