There is limited knowledge regarding the relationship between the reason for revising a TKA and the clinical outcome in terms of satisfaction, pain, and function with time. In a cohort of patients receiving a fully revised TKA, we hypothesized (1) outcomes would differ according to reason for revision at 2 years, (2) outcomes would improve gradually during those 2 years, (3) rates of complications differ depending on the reason for revision, and (4) patients with complications have lower scores. We studied a prospective cohort of 150 patients receiving a fully revised TKA using a single implant system in two high-volume centers at 24 months of followup. VAS satisfaction, VAS pain, The Knee Society Scoring System^© (KSS) clinical and functional scores, and complication rate were correlated with their reasons for revision, including septic loosening, aseptic loosening, component malposition, instability, and stiffness. The aseptic loosening group showed better outcomes compared with the instability, malposition, and septic loosening groups, which showed intermediate results (p < 0.05). The stiffness group performed significantly worse on all outcome measures. The outcome for patients with a complication, after treatment of the complication, was less favorable. The reason for revision TKA predicts clinical outcomes. Satisfaction, pain reduction, and functional improvement are better and complication rates are lower after revision TKA for aseptic loosening than for other causes of failure. For component malposition, instability, and septic loosening groups, there may be more pain and a higher complication rate. For stiffness, the outcomes are less favorable in all scores. Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Background and purpose — The preferred treatment of an acute prosthetic joint infection (PJI) is debridement, antibiotics, irrigation and retention of the prosthesis (DAIR). The antibiotic treatment consists of an empirical and targeted phase. In the empirical phase, intravenous antibiotics are started after surgery before micro-organisms are determined in microbiological cultures. Which empirical antibiotic is used differs between hospitals, partly reflecting geographic differences in susceptibility spectrums. We investigated whether flucloxacillin should remain the antibiotic of choice in our hospital for empiric treatment of acute PJI with DAIR. Patients and methods — We retrospectively analyzed 91 patients treated for PJI with DAIR between 2012 and 2016. The susceptibility of micro-organisms was determined in multiple cultures of periprosthetic tissue and synovial fluid for 3 antibiotics: amoxicillin/clavulanic acid, cefazolin, and flucloxacillin. Results — Positive microbiological cultures from 68 patients were analyzed. Staphylococcus aureus was the predominant pathogen, cultured in half of the patients. In one-third of patients more than 1 micro-organism was found. On a patient level, the data showed that 65% were responsive to flucloxacillin, 76% to amoxicillin/clavulanic acid, and 79% to cefazolin. Interpretation — Flucloxacillin appeared to be a suboptimal choice in our patient population treated with DAIR. We therefore changed our practice to cefazolin as the preferred antibiotic in the empirical treatment of acute PJI with DAIR.

Introduction: Prosthetic joint infection (PJI) is a relatively uncommon (average incidence 0.5-2%) but devastating complication, with significant morbidity and leading to tremendously increased health care costs. In 2013, delegates from nine hospitals covering a large region in the South-East Netherlands composed one combined treatment protocol for acute PJI of total hip and knee arthroplasty (THA and TKA). This protocol was based on the definition of acute PJI according to Workgroup of the American Musculoskeletal Infection Society (MSIS) and the principles of debridement, antibiotics, irrigation and retention (DAIR).

Pseudomonas aeruginosa is considered as more difficult to treat than other Gram-negatives in patients with acute periprosthetic joint infections (PJIs). However, clinical data to support this hypothesis are lacking. This retrospective multicenter cohort study included 39 patients with acute PJIs caused by P. aeruginosa and 84 control patients with another Gram-negative bacillus (i.e., Enterobacterales). Both groups were managed by surgical debridement, antibiotics, and implant retention (DAIR). Treatment failure within one-year follow-up was defined as prosthesis extraction, a clinical need for suppressive antibiotic treatment and/or PJI-related death. Distribution of affected joints, and revision versus primary arthroplasties, did not differ between groups. Most PJIs were polymicrobial (87% in cases, 81% in control patients, p = 0.451). Surgical and antibiotic management was similar between groups. Treatment failure did not differ between groups: 5/39 cases (12.8%) and 14/84 control patients (16.7%, p = 0.610). An acceptable success rate of acute PJI caused by P. aeruginosa when treated with DAIR was observed. This success rate did not differ compared to PJIs caused by Enterobacterales. Therefore, P. aeruginosa should not be considered a more difficult to treat microorganism compared to other Gram-negatives. No additional surgical or antimicrobial interventions are needed when patients can be treated with a fluoroquinolone.