A total knee prosthesis comprising: a femoral component comprising a femoral intercondylar bearing surface positioned between a lateral femoral condylar surface and a medial femoral condylar surface, said intercondylar bearing surface extending from an approximately distal location to a posterior location and having a sagittal radius smaller than that of said lateral and medial femoral condylar bearing surfaces; a tibial component in articulating contact with said femoral component comprising a tibial intercondylar bearing surface positioned between a lateral tibial condylar surface and a medial tibial condylar surface, said tibial intercondylar surface being concave with minimum surface elevation points located posteriorly with respect to the middle of said tibial component; wherein, for flexion angles of approximately 0 (zero) degrees, portions of said femoral intercondylar bearing surface and said tibial intercondylar bearing surface are conformal and are configured to prevent posterior displacement of the femoral component with respect to the tibial component and portions of said femoral condylar surfaces and said tibial condylar surfaces are conformal and are configured to prevent anterior displacement of the femoral component; characterised in that the femoral intercondylar bearing surface has a center of curvature that substantially coincides with a center of curvature of the lateral and medial femoral condylar surfaces, wherein, for flexion angles of approximately 30 degrees, a portion of said femoral intercondylar bearing surface and said tibial intercondylar bearing surface are conformal and are configured to prevent posterior displacement of the femoral component and portions of said femoral condylar surfaces and said tibial condylar surfaces are partially conforming; and, for flexion angles of approximately 60 degrees, there is partial conformity between said femoral intercondylar bearing surface and said tibial intercondylar bearing surface; and, for flexion angles of approximately 90 degrees, said femoral intercondylar bearing surface and said tibial intercondylar bearing surface are configured so that there is no contact. a femoral component comprising a femoral intercondylar bearing surface positioned between a lateral femoral condylar surface and a medial femoral condylar surface, said intercondylar bearing surface extending from an approximately distal location to a posterior location and having a sagittal radius smaller than that of said lateral and medial femoral condylar bearing surfaces; a tibial component in articulating contact with said femoral component comprising a tibial intercondylar bearing surface positioned between a lateral tibial condylar surface and a medial tibial condylar surface, said tibial intercondylar surface being concave with minimum surface elevation points located posteriorly with respect to the middle of said tibial component; wherein, for flexion angles of approximately 0 (zero) degrees, portions of said femoral intercondylar bearing surface and said tibial intercondylar bearing surface are conformal and are configured to prevent posterior displacement of the femoral component with respect to the tibial component and portions of said femoral condylar surfaces and said tibial condylar surfaces are conformal and are configured to prevent anterior displacement of the femoral component; characterised in that the femoral intercondylar bearing surface has a center of curvature that substantially coincides with a center of curvature of the lateral and medial femoral condylar surfaces, wherein, for flexion angles of approximately 30 degrees, a portion of said femoral intercondylar bearing surface and said tibial intercondylar bearing surface are conformal and are configured to prevent posterior displacement of the femoral component and portions of said femoral condylar surfaces and said tibial condylar surfaces are partially conforming; and, for flexion angles of approximately 60 degrees, there is partial conformity between said femoral intercondylar bearing surface and said tibial intercondylar bearing surface; and, for flexion angles of approximately 90 degrees, said femoral intercondylar bearing surface and said tibial intercondylar bearing surface are configured so that there is no contact.