A drug-eluting spacer for temporary implantation in a knee joint includes a femoral component configured to interface with a femur, a tibial tray component having an upper surface, a lower surface, and a shaft extending from the lower surface, the shaft configured to be positioned axially within a tibia, the lower surface configured configured to interface with the tibia, and a tibial insert component having an upper surface and a lower surface, the lower surface of the tibial insert component configured to engage the upper surface of the tibial tray component, the upper surface of the tibial insert component configured to receive the femoral component in an articulating manner. The femoral component, the tibial tray component, and the tibial insert component carry joint loads when implanted. The drug-eluting spacer is configured to elute a biologically active agent in an amount effective to treat an infection of the knee joint.