title: Sufficient release of antibiotic by a spacer 6 weeks after implantation in two-stage revision of infected hip prostheses.
abstract: BACKGROUND
  Although antibiotic-loaded spacers are commonly used to treat periprosthetic infections, it is unclear whether spacers continue to release bactericidal levels of antibiotic 6 weeks after implantation.
  
  
  OBJECTIVE
  We asked whether an antibiotic can be detected in the tissue surrounding the spacer 6 weeks after implantation and whether the concentration is higher than the minimal inhibition concentration (MIC) previously determined for pathogens that are responsible for most periprosthetic infections.
  
  
  METHODS
  We removed 14 spacers used in two-stage septic revisions of infected hip prostheses 6 weeks after the primary implantations and determined the concentration of the antibiotics in the membrane formed between the spacer and the neighboring bone on the acetabular and the femoral sides. In seven cases Copal cement with gentamicin and clindamycin were used, and in seven other cases vancomycin was added to the Copal cement. Concentrations of the spacer antibiotics in the neighboring tissue were determined by tandem mass spectroscopy.
  
  
  RESULTS
  All three antibiotics were detected in concentrations higher than their MIC. There were no differences between the groups regardless whether vancomycin was added to the cement, or whether the cement was applied with the acetabular cup spacer or with the stem spacer.
  
  
  CONCLUSIONS
  We concluded that, using the spacer technique described in this study, 6 weeks after spacer implantation, the concentrations of antibiotic are sufficient to treat a periprosthetic infection.
authors.affiliation: Clinic of Joint Replacement, General and Rheumatic Orthopaedics, Orthopaedic Clinic Markgröningen gGmbH, Kurt-Lindemann-Weg 10, 71706 Markgröningen, Germany. b.fink@okm.de
authors.forename: Bernd
authors.initials: B
authors.lastname: Fink
authors.forename: Sebastian
authors.initials: S
authors.lastname: Vogt
authors.forename: Martin
authors.initials: M
authors.lastname: Reinsch
authors.forename: Hubert
authors.initials: H
authors.lastname: Büchner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019644:Arthroplasty, Replacement, Hip; D001682:Biological Availability; D001843:Bone Cements / Q000737:chemistry / Q000627:therapeutic use; D005260:Female; D006621:Hip Joint / Q000737:chemistry / Q000382:microbiology / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000517:prevention & control / Q000601:surgery*; D012086:Reoperation; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D001843:Bone Cements