Periprosthetic joint infections (PJI) of the knee are difficult to treat and can require costly and prolonged hospital stays, weeks or months of antibiotic therapy, and multiple surgical procedures. Knee arthrodesis is considered a last resort for persistent knee joint infections and provides stability and pain relief by fusing the knee joint. The authors describe a case of a persistent and difficult to treat periprosthetic total knee arthroplasty (TKA) infection, subjected to multiple surgeries and revisions, where an arthrodesis was performed as a last resort. The arthrodesis was performed using a femoral-tibial endomedullary nail with interposed femoral condyle allograft. Complete graft integration and consolidation was achieved without complications. The patient performed well post-operatively and is currently ambulatory with walking aids and has no knee pain. The removal of well-fixed metaphyseal sleeves in TKA can be challenging and associated with complications such as damage to the surrounding bone and soft tissue during the removal process. Taking special care and not rushing this step can present an extremely meaningful difference in the final outcome. In cases with large bone defects, especially after sleeve removal, allograft usage can be extremely useful for managing dead space and limb-length discrepancies while promoting faster bone healing. When successful, as was the case described, arthrodesis using allografts can have beneficial outcomes with high patient satisfaction and deliver function to previously very unhealthy joints and limbs.