title: Infection rates in patients undergoing primary knee arthroplasty with pre-existing orthopaedic fixation-devices.
abstract: BACKGROUND
  Prior knee surgery in the setting of knee arthroplasty (KA) can influence the overall outcome of the procedure and render the operation more technically challenging. The effects of residual fixation devices on subsequent procedures about the knee are ill-defined. Some authors claim an increase in periprosthetic infection in this cohort of patients. The objective of this study was to evaluate the overall incidence of periprosthetic infections in patients undergoing primary KA with pre-existing osteosynthetic hardware in situ.
  
  
  METHODS
  The current investigators retrospectively reviewed 124 patients undergoing knee arthroplasty and removal of orthopaedic fixation devices, due to prior high tibial osteotomies, fracture fixation or cruciate ligament reconstruction. The exclusion criterion was a prior history of infection of the fixation device. The mean follow-up time was 5.4 years (range 15 months to 9 years). Nine patients were lost to follow-up.
  
  
  RESULTS
  Joint aspiration was performed two weeks prior to surgery in 53 patients (42.4%) and intra-operative samples were obtained in 106 patients (84.8%), which did not show any bacterial growth. A subacute periprosthetic infection occurred after seven months in only one patient.
  
  
  CONCLUSIONS
  The results of the current study demonstrate that previously implanted osteosynthetic fixation devices do not significantly increase the risk of developing periprosthetic knee infections. A two-stage procedure with implant retrieval prior to total knee arthroplasty is not clinically indicated in the cohort described, amongst whom an infection rate of 0.9% was revealed.
authors.affiliation: Orthopaedic Surgery, HELIOS ENDO-Klinik Hamburg, Holstenstr. 2, 22767 Hamburg, Germany. o.klatte@gmx.de
authors.forename: T O
authors.initials: TO
authors.lastname: Klatte
authors.forename: M M
authors.initials: MM
authors.lastname: Schneider
authors.forename: M
authors.initials: M
authors.lastname: Citak
authors.forename: P
authors.initials: P
authors.lastname: Oloughlin
authors.forename: M
authors.initials: M
authors.lastname: Gebauer
authors.forename: M
authors.initials: M
authors.lastname: Rueger
authors.forename: T
authors.initials: T
authors.lastname: Gehrke
authors.forename: D
authors.initials: D
authors.lastname: Kendoff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D001424:Bacterial Infections / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D016268:Internal Fixators / Q000009:adverse effects*; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors