gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie
72. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 94. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie und 49. Tagung des Berufsverbandes der Fachärzte für Orthopädie und Unfallchirurgie

22. - 25.10.2008, Berlin

Polymeric implant coatings with incorporated antibiotics inhibit bacterial growth and are scratch resistant

Meeting Abstract

  • R. Steck - Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia
  • D. McMillan - Queensland Institute of Medical Research, Bacterial Pathogenesis Laboratory, Brisbane, Australia
  • B. Goss - Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia
  • N. Rosenzweig - Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia
  • M. Schütz - Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia

Deutscher Kongress für Orthopädie und Unfallchirurgie. 72. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 94. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 49. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 22.-25.10.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocPO13-1075

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dkou2008/08dkou657.shtml

Veröffentlicht: 16. Oktober 2008

© 2008 Steck et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

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Introduction: Implant-related bone infections remain one of the most feared complications in orthopaedics. Incorporated foreign bodies, such as implants, are known to promote onset and maintenance of infections significantly, with devastating complications for the patient. These infections are typically caused by organisms growing in biofilms, which are difficult to treat by systemic antibiotic therapy. Therefore, prevention of infections is a priority in clinical practice. Recently, biodegradable surface coatings for orthopaedic implants have been developed that act as local drug delivery devices. The goal of this study was to determine the antibacterial properties of new combinations of antibiotics incorporated into biodegradable poly(D,L)-lactic acid (PDLLA) coatings, and to demonstrate the mechanical stability of the PDLLA implant coatings.

Methods: We used stainless steel Kirschner (K-) wires (Ø1.8 mm, Synthes Australia) as model implants. The K-wires were coated by a solvent casting technique with/without incorporated antibiotics for in vitro studies. The following groups were tested: uncoated, coated with PDLLA only, coated with PDLLA and incorporated Gentamycin sulfate (GS), Gentamycin Palmitate (GP), Vancomycin (V) and combinations of these antibiotics (GS+V, GP+V). The K-wires (n=10 for each group) were incubated in a Staph. aureus suspension for 2 hours. After rinsing, treatment with trypsin and sonication of the K-wires, the number of colony forming units (cfu) was counted.

A new method for testing the scratch resistance of the coatings against abrasion at implant-bone contact during implantation was developed, where the coated Kirschner wires (n=16) were inserted into 1.8 mm diameter drill holes in bovine cortical bone specimens, and the loss of coating mass (LCM) was determined gravimetrically after removal.

Results: Our data demonstrate that the number of cfu on implants coated with PDLLA with incorporated antibiotics was significantly reduced for all tested combinations of antibiotics, compared to uncoated or PDLLA-only coated implants (Wilcoxon-test). Among the different antibiotics, GS and GS+V resulted in the smallest number of cfu’s, while the numbers were slightly higher for GP and V and were highest for GP+V. After insertion and removal of PDLLA-coated K-wires into drill holes in bovine cortical bone, LCM averaged 37.5% ± 34% SD.

Conclusions: Our experiments confirmed that PDLLA has excellent properties as an implant coating material for drug delivery, with high mechanical stability and (with incorporated antibiotics) good antimicrobial properties in vitro. Importantly, we could show the antibacterial efficacy of incorporated antibiotic formulations and combinations (V, GP, GS+V, GP+V) which previously have not been reported. Furthermore, we have established a test for abrasion resistance, which we consider more reproducible, albeit more rigorous than previously described methods.