Several antibiotics can be added to the bone cement and should be selected based on the pathogen sensitivity. Synergistic elution activity has been seen with vancomycin and tobramycin [50]. These antibiotics also have thermal stability and come in powder form, which are important factors for successful spacer construction. Contrary to antibiotic cement used for prosthesis fixation, antibiotic-loaded cement spacers combine 2–4 g of vancomycin and 2.4–4.8 g of gentamicin per 40 g bag of cement [51]. Adding more antibiotics to the cement decreases the strength of the cement, but since this is a temporary spacer, increased antibiotic elution is desirable [52–54]. Different antibiotics at different concentrations have been proposed, as stated in Table 18.1.

Prior to reimplantation, a course of 6 weeks of antibiotics is often prescribed, followed by an antibiotic-free holiday to verify if the infection has been controlled. The total duration between the two stages is a matter of ongoing controversy [59]. There is no consensus for the optimal time period between stages, as reports vary between days and up to several months [8], and Insall (1983) described a 6-week interval as appropriate [36]. There are no definitive markers for reimplantation, but serological erythrocyte sedimentation rate (ESR), serological C-reactive protein (CRP), and synovial fluid leukocyte count [60, 61] should decline or reach normal values prior to reimplantation. Synovial fluid cultures can also be of value, although they can be falsely negative and misleading [62]. Lastly, other markers such as leukocyte esterase and alpha-defensin may also aid with the timing of the second surgical stage [63, 64]. The second stage consists of a final reimplantation and prosthetic reconstruction.