A new model of implant-related osteomyelitis in the metaphysis of rat tibiae

Norbert Harrasser, Johannes Gorkotte, Andreas Obermeier, Susanne Feihl, Melanie Straub, Julia Slotta-Huspenina, Ruediger Von Eisenhart-Rothe, Walter Moser, Philipp Gruner, Michael De Wild, Hans Gollwitzer, Rainer Burgkart

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Background: Animal models serve as an important tool to understand peri-implant infection. Most of the models use high bacterial loads (>104 colony forming units, CFU) to provide high infection rates. Therefore these animals evolve rather similarly, making comparison between groups and statistical analysis possible. On the other hand, to mimic clinical constellation of surgery-related infections the use of low amounts of bacteria would be more advantageous. Methods: We developed a metaphyseal rat model of peri-implant bone infection with low amount of bacterial loads (102 and 103 CFU of Staphylococcus aureus) and investigated osseointegration of the implants coated with hydroxyapatite (HA) and low-dosed HA-silver (HA-Ag). Non-infected implants served as controls. After 6 weeks rats were sacrificed and implants evaluated for osseointegration and infection. Results: Infection of implanted devices was reliably induced, independently whether 102 or 103 CFU of S. aureus were inoculated and HA or HA-Ag coated implants were used. No systemic infection was present in any of the animals at the time of sacrifice, and no animal developed acute infection requiring premature sacrifice. All CFU counts of the implant and the bone at sacrifice were significantly higher than the inoculated load (p <.05). All sterilely inserted implants showed excellent osseointegration and no infection. Conclusions: Our present study of a rat tibia model reliably induced osteomyelitis in the metaphysis with low-doses of bacteria. The addition of low-dosed Ag to the implant coating was not able to reduce the infection rates. The results demonstrate that it is possible to develop a model of implant-related osteomyelitis in rats with low amounts of bacteria to better mimic clinical constellations. No other promoters of infection besides insertion of the screw implant were used in this model.

Original languageEnglish
Article number152
JournalBMC Musculoskeletal Disorders
Volume17
Issue number1
DOIs
StatePublished - 8 Apr 2016
Externally publishedYes

Keywords

  • Implant-associated infections
  • Metaphysis
  • Rat
  • Screw
  • Staphylococcus aureus

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