In vitro and in vivo experiments were performed to study the
antibacterial and mechanical properties of Simplex and Palacos acrylic bone
cements utilized for the production of acrylic cement-antibiotic
composites. Acrylic cement without antibiotic had no bacteriostatic effect
on Staphylococcus aureus, Escherichia coli, and Pseudomonas. Oxacillin,
cefazolin, and gentamicin are stable in acrylic cement and are released in
a microbiologically active form. The three antibiotics diffused from the
Palacos in larger amounts daily and for a significantly longer time than
from the Simplex. Mechanical tests demonstrated that admixture of
antibiotics and acrylic cement had no influence on the compressive and
diametral tension strengths of the cement. Bacteriostatic concentrations of
oxacillin in wound hematomas were measured for fourteen days after
implantation of an oxacillin-Simplex composite in dogs. High bactericidal
concentrations of the antibiotic were measured in the surrounding bone for
twenty-one days after implantation.