A very important consideration with antibiotic release from spacers is how is the antibiotic going to move from the spacer into the surrounding tissue. And if it is a diffusion limited situation, maybe the antibiotic will only get a certain distance at the concentrations needed to kill the biofilm. Weâ€ve set up some experiments in my lab where weâ€re using agar to grow biofilms on the agar. We put in PMMA, and what we find is we get a about a 1 centimetre zone away from that surface where we can kill the bacteria â€“ kill the biofilm. However, we have tested spacers from infected patients and found that antibiotics are still being delivered but presumably the infecting biofilm was â€œout of reachâ€ of the antibiotic.