2005 Abstract : BS 1

Authors: Alt V, Bitschnau A, Meissner SA, Sewing A, Cords SM, Wenisch S, Domann E, Schnettler R

Title: Gentamicin-Coating of Cementless Prostheses Leads to Improvement of Infection Prophylaxis for Revision Cases in Rabbits

Addresses: Department of Trauma Surgery, University Hospital Giessen, Germany

Purpose: For infection revision cases with cementless prostheses there is no local antibiotic prophylaxis at the time of reimplanatation compared to the use of antibiotic-loaded bone cement in cemented revision procedures. In this study, a gentamicin-coating which can be brought additionally onto standard hydroxyapatite (HA) coatings of cementless prostheses is presented. It was tested whether this gentamicin-coating can reduce infection rates in a rabbit infection model with Staphylococcus aureus compared to compared to standard-HA coating. Furthermore, the biocompatibility of this gentamicin coating was investigated.

Methods: Staphylococcus. aureus in a dose of 107 CFUs was inoculated intramedullary into the tibial shaft of 20 rabbits followed by the implantation of either gentamicin-HA-coated or of standard-HA-coated 2mm K-wire. The tibiae were removed after 4 weeks. X-rays, histological, and microbiological investigations by agar plating and DNA-fingerprinting were performed to detect infection. In a second trial without bacterial contamination of the tibial shaft, histological examination of the biocompatibility of the gentamicin-HA-coating was compared to standard HA-coatings

Discussion: There was a significant reduction in infection rates of gentamicin-coated implants compared to standard HA coating. For all animals that were found to be infected by microbiological methods, there were also clear pathohistological signs of infections as cortical osteolysis, sequester and abcess formation in histology showing an excellent correlation of microbiological and histological data. There were no major differences in the biocompatibility between the two different coatings

Significance: This gentamicin-coating showed an excellent infection prophylaxis and a good biocompatibility. This type of coating could help to improve infection prophylaxis in cementless arthroplasty, particularly in revision cases with elevated infection risk.