As the numbers of arthroplasties performed worldwide increase, so do complications such as prosthetic joint infection. Cases that require a two-stage revision of a total femur replacement in the femur pose an ongoing challenge to the modern orthopedic surgeon. Unlike antibiotic spacers in hip and knee arthroplasty, there lacks a commercially available cement spacer for use in total femur replacements. We describe a novel technique for the intraoperative fabrication of a total femur spacer which uses modular components. As such, our technique is unique as it is modular and, therefore, highly customisable to each individual patient. Individual components can be made by different members of the team simultaneously and then assembled to make the final construct, thereby minimizing operative time. Furthermore, the inherent stability of the spacer allows immediate partial weightbearing and functional rehabilitation while patients are waiting for their second-stage procedure.