Spacer device (1) for the knee joint comprising a femoral component (2) a tibial component (3) and an intermediate component (30) wherein the femoral component (2) is adapted to be constrained to an end of the femoral bone in proximity to the knee joint wherein the tibial component (3) is adapted to be constrained to an end of the tibial bone in proximity to the knee joint the femoral component (2) being adapted to come into contact and to articulate with the tibial component (3) wherein the intermediate component (30) is placed in use between the femoral component (2) and the tibial component (3) and wherein the constrained spacer device (1) comprises a first hinge (32a) and a second hinge (32b) adapted to rotatably constrain the femoral component (2) to the tibial component (3).
