An orthopaedic prosthesis, comprising: a femoral component configured to be coupled to a surgically-prepared distal end of a patient's femur, the femoral component including a pair of condyles spaced apart to define an intercondylar notch, each condyle including a convex curved condylar surface (30, 32), a tibial component including a tray configured to be coupled to a surgically-prepared proximal end of a patient's tibia and a platform pivotally coupled to the tray, the platform including a pair of concave curved surfaces (60, 62) corresponding to the convex curved condylar surfaces (30, 32) of the femoral component and a proximal opening positioned between the concave curved surfaces (60, 62), and a modular insert configured to be selectively coupled to the femoral component, the modular insert including a bracket sized to be positioned in the intercondylar notch of the femoral component, an elongated stem sized to be received in the proximal opening defined in the platform of the tibial component; characterized in that: a hinge pin pivotally couples the elongated stem to the bracket, and a fastener configured to secure the femoral component to the bracket of the modular insert, and in which the platform is configured to pivot about a first axis extending in an inferior-superior direction and the elongated stem is configured to pivot about a second axis relative to the bracket and the femoral component, the second axis extending in a medial-lateral direction orthogonal to the first axis, and in which the bracket of the modular insert includes a bore that is offset from the elongated stem, the fastener is configured to extend through the bore to couple the modular insert to the femoral component. a femoral component configured to be coupled to a surgically-prepared distal end of a patient's femur, the femoral component including a pair of condyles spaced apart to define an intercondylar notch, each condyle including a convex curved condylar surface (30, 32), a tibial component including a tray configured to be coupled to a surgically-prepared proximal end of a patient's tibia and a platform pivotally coupled to the tray, the platform including a pair of concave curved surfaces (60, 62) corresponding to the convex curved condylar surfaces (30, 32) of the femoral component and a proximal opening positioned between the concave curved surfaces (60, 62), and a modular insert configured to be selectively coupled to the femoral component, the modular insert including a bracket sized to be positioned in the intercondylar notch of the femoral component, an elongated stem sized to be received in the proximal opening defined in the platform of the tibial component; characterized in that: a hinge pin pivotally couples the elongated stem to the bracket, and a fastener configured to secure the femoral component to the bracket of the modular insert, and in which the platform is configured to pivot about a first axis extending in an inferior-superior direction and the elongated stem is configured to pivot about a second axis relative to the bracket and the femoral component, the second axis extending in a medial-lateral direction orthogonal to the first axis, and in which the bracket of the modular insert includes a bore that is offset from the elongated stem, the fastener is configured to extend through the bore to couple the modular insert to the femoral component. a hinge pin pivotally couples the elongated stem to the bracket, and a fastener configured to secure the femoral component to the bracket of the modular insert, and in which the platform is configured to pivot about a first axis extending in an inferior-superior direction and the elongated stem is configured to pivot about a second axis relative to the bracket and the femoral component, the second axis extending in a medial-lateral direction orthogonal to the first axis, and in which the bracket of the modular insert includes a bore that is offset from the elongated stem, the fastener is configured to extend through the bore to couple the modular insert to the femoral component.