Spacer device (1) for the knee joint comprising a tibial component (2), adapted to be fixed to one end of the tibia) bone in proximity to the knee joint, and a femoral component (3), adapted to be fixed to one end of the femoral bone in proximity to the knee joint, wherein the tibial component (2) is adapted to come into contact and be articulated with the femoral component (3), wherein the tibial component (2) comprises a protrusion (25) adapted to be inserted in an opening present in the femoral component (3)； method for the assembly of the spacer device (1).
