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.