Bacterial contamination of endoprostheses especially in revision surgery is an upcoming problem according to increasing number of joint replacements. Early adherence of bacteria producing a biofilm is difficult to treat. Silver coating of implants offers the opportunity to avoid bacterial adhesions acting against all relevant bacteria causing infections on the implant. We developed a new technique of nano-silver coating using elemental silver covered with SiOxCy whose thickness can be varied determing duration of the coating on the implant. The SiOxCy and silver is completely soluble at least at 3 months. The silver coatings used so far are measuring at least 10um and they are not soluble making a cementless implantation of the endoprostheses impossible. The aim of this study was to test the compatibility of the new combined coating with human osteoblastic cells.

The test was carried out with fHOB 1.19 (ATCCR CRL-11372TM). The cells were cultivated in 1:1 mixture of DMEM/Ham's F12 with usual supplements. The protein content was measured colourimetrically using BCA reagents and staining of the cells was done with XTT-reagent (Roche). The cells were incubated on Titanium and PEEK with and without coating for 2,6,16 and 48 hours.

No adverse effects of the silver coating on the early cell adhesion at 2 and 6 hours and the further proliferation at 16 and 48 hours were observed. The adhesion on Titanium showed no significant difference against coated Titanium but an improvement of cell adhesion was seen on coated PEEK.

This soluble silver coating did not negatively influence human osteoblastic cells. As the complete surfacing is soluble it might be possible to combine early protection against bacteria and osseous integration. An animal study is in progress verifying the in vitro results. It should investigate the maximum duration of the coating on the implant not disturbing osseous integration.