This invention relates to a floating bearing knee joint prosthesis having a fixed tibial post used for replacing the articulating knee portion of a femur and a tibia. The floating bearing knee joint prosthesis includes a femoral component, a tibial component, a guide post and a bearing member. The femoral component includes an engagement member, a first femoral bearing surface and a second femoral bearing surface. The tibial component includes a tibial bearing surface. The guide post extends from the tibial component and is operable to be engaged by the engagement member of the femoral component. The bearing member includes a first bearing surface that articulates with the first femoral bearing surface, a second bearing surface that articulates with the second femoral bearing surface and a third bearing surface that articulates with the tibial bearing surface. The bearing member further includes a posterior lip extension that substantially inhibits the bearing member from dislocating upon flexion of the knee joint prosthesis. The bearing member also defines an opening that receives the guide post where the opening is configured to substantially inhibit rotational movement of the bearing member relative to the tibial component in extension.L'invention concerne une prothèse d'articulation de genou à support flottant, comprenant une tige tibiale fixe, utilisée afin de remplacer la partie d'articulation de genou d'un fémur et d'un tibia. Cette prothèse d'articulation de genou à support flottant comprend un composant fémoral, un composant tibial, une tige de guidage, et un élément de support. Ledit composant fémoral comprend un élément d'engagement, une première surface d'appui fémorale, et une seconde surface d'appui fémorale. Ledit composant tibial comprend une surface d'appui tibiale. Ladite tige de guidage s'étend à partir du composant tibial, et est conçue pour être engagée à l'aide de l'élément d'engagement du composant fémoral. Ledit élément de support comprend un
