[Modified agar diffusion test for direct testing of the effectiveness of released antibiotics from bone cements]

A modified agar-diffusion method is used to test the bactericidal efficacy of antibacterial substances (model substance: Gentamicin) that have been mixed with Palacos osseous cement. Holes of a diameter slightly larger than the diameter of the cylindric Palacos test block are cut from the agar plate. The remaining space (inner wall of the hole--edge of the test body) is filled with various eluate media. The release of active antibacterial substances from polymethylmetacrylates can thereby be determined under nearly physiologic conditions at varying pHs by direct antibacterial testing.