An orthopaedic prosthesis , comprising: a femoral component configured to be attached to a distal end of a patient's femur, a tibial tray configured to be attached to a proximal end of a patient's tibia, the tibial tray including (i) a base having an outer surface, (ii) a post extending distally from the base , and (iii) an aperture extending defined in the post and the base , a tibial insert configured to rotate relative to the tibial tray , the tibial insert including (i) a platform shaped to engage the base of the tibial tray , (ii) a stem extending distally from the platform and received in the aperture of the tibial tray , and (iii) a cavity extending longitudinally through the platform , and a modular insert configured to be received in the cavity defined in the tibial insert , the modular insert including an elongated stem , wherein the femoral component is configured to rotate about a first axis relative to the tibial insert over a first range of motion, the first axis extending in a medial-lateral direction, characterised in that the modular insert further includes a body rotatably coupled to the elongated stem , wherein the femoral component is rotatably coupled to the body of the modular insert , wherein the body of the modular insert is configured to rotate relative to the tibial insert about a second axis extending parallel to the first axis over a second range of motion, the second range of motion being less than the first range of motion, and wherein the tibial insert includes a tab coupled to the platform , the tab being configured to engage the outer surface of the base to limit rotation of the tibial insert relative to the tibial tray . a femoral component configured to be attached to a distal end of a patient's femur, a tibial tray configured to be attached to a proximal end of a patient's tibia, the tibial tray including (i) a base having an outer surface, (ii) a post extending distally from the base , and (iii) an aperture extending defined in the post and the base , a tibial insert configured to rotate relative to the tibial tray , the tibial insert including (i) a platform shaped to engage the base of the tibial tray , (ii) a stem extending distally from the platform and received in the aperture of the tibial tray , and (iii) a cavity extending longitudinally through the platform , and a modular insert configured to be received in the cavity defined in the tibial insert , the modular insert including an elongated stem , wherein the femoral component is configured to rotate about a first axis relative to the tibial insert over a first range of motion, the first axis extending in a medial-lateral direction, characterised in that the modular insert further includes a body rotatably coupled to the elongated stem , wherein the femoral component is rotatably coupled to the body of the modular insert , wherein the body of the modular insert is configured to rotate relative to the tibial insert about a second axis extending parallel to the first axis over a second range of motion, the second range of motion being less than the first range of motion, and wherein the tibial insert includes a tab coupled to the platform , the tab being configured to engage the outer surface of the base to limit rotation of the tibial insert relative to the tibial tray . <EOS>