Comparison of antibiotic release from polymethylmethacrylate beads and sponge collagen.

The rates of elution of tobramycin in vitro were compared for polymethylmethacrylate beads impregnated with the powder form and an alternative biodegradable substance, sponge collagen. The impregnated polymethylmethacrylate beads initially had a lower zone of inhibition, but the rate of release was slow in comparison with that of the impregnated sponge collagen. The sponge collagen delivered a higher dose faster and with a shorter duration than the polymethylmethacrylate beads with the same antibiotic concentration in vitro, but the beads delivered a therapeutic concentration for longer periods. Because it deteriorates rapidly, sponge collagen may be unsatisfactory as an agent of antibiotic delivery in patients who have chronic osteomyelitis; however, it may be useful for patients who have acute trauma with highly contaminated bone or soft tissue, or during hemiarthroplasty revision, to deliver a high local concentration of antibiotic for a short period of time.