Aminoglycoside-impregnated polymethylmethacrylate beads, which are used
to deliver antibiotic directly to infected sites in the musculoskeletal
system, are available as a manufactured product or they can be mold-made by
a pharmacy or hand-rolled by the orthopaedist in the operating suite. We
investigated the leaching of antibiotic from each of these types of beads.
Our hypothesis was that the elutions of antibiotic from the three types of
beads are similar. Three study groups (hand-made, mold-made, and
manufactured beads), each composed of four five-bead subsets, were formed
so that twenty beads of each type were tested. Each bead was leached daily
in a two-milliliter aliquot of normal saline solution throughout a
sixty-day period, and the aminoglycoside concentration in twenty of these
aliquots was determined. Analysis of variance showed no statistically
significant differences when the antibiotic elutions within each subset,
between the different subsets, and between the three groups were compared.
The clinically important finding of this investigation is that the leaching
characteristics of the three types of aminoglycoside-impregnated beads are
equivalent when the beads have been fabricated out of comparable
materials.