A posterior-stabilized femoral component adapted to articulate with a tibial bearing component in a knee prosthesis, the tibial bearing component including a proximally extending spine, the femoral component comprising: medial and lateral condyles (226, 224) shaped to articulate with the tibial bearing component through a range of motion, in which full extension corresponds to zero degrees flexion of the knee prosthesis and positive flexion corresponds to greater than zero degrees flexion of the knee prosthesis, said medial and lateral condyles comprising inwardly facing condylar walls (238, 239) forming an intercondylar space therebetween, said intercondylar space having a medial/lateral width (ML T); and a femoral cam sized and positioned to engage the spine of the tibial bearing component in positive flexion through a portion of the range of motion, said femoral cam comprising a medial/lateral cam length spanning said intercondylar space such that said femoral cam joins said medial and lateral condyles to one another, said femoral cam having an articular surface comprising: a central articular surface that is one of cylindrical and convex across a medial/lateral extent of said central articular surface; a convex medial transition surface flanking said central articular surface and disposed between said central articular surface and said medial condyle; and a convex lateral transition surface flanking said central articular surface and disposed between said central articular surface and said lateral condyle, said convex medial transition surface and said convex lateral transition surface each defining an arc extending in a medial/lateral direction, characterised in that said arc defines a radius (R 4) equal to between 40% and 56% of said medial/lateral width (ML T), whereby said femoral cam defines widely rounded, convex surfaces. medial and lateral condyles (226, 224) shaped to articulate with the tibial bearing component through a range of motion, in which full extension corresponds to zero degrees flexion of the knee prosthesis and positive flexion corresponds to greater than zero degrees flexion of the knee prosthesis, said medial and lateral condyles comprising inwardly facing condylar walls (238, 239) forming an intercondylar space therebetween, said intercondylar space having a medial/lateral width (ML T); and a femoral cam sized and positioned to engage the spine of the tibial bearing component in positive flexion through a portion of the range of motion, said femoral cam comprising a medial/lateral cam length spanning said intercondylar space such that said femoral cam joins said medial and lateral condyles to one another, said femoral cam having an articular surface comprising: a central articular surface that is one of cylindrical and convex across a medial/lateral extent of said central articular surface; a convex medial transition surface flanking said central articular surface and disposed between said central articular surface and said medial condyle; and a convex lateral transition surface flanking said central articular surface and disposed between said central articular surface and said lateral condyle, said convex medial transition surface and said convex lateral transition surface each defining an arc extending in a medial/lateral direction, characterised in that said arc defines a radius (R 4) equal to between 40% and 56% of said medial/lateral width (ML T), whereby said femoral cam defines widely rounded, convex surfaces. a central articular surface that is one of cylindrical and convex across a medial/lateral extent of said central articular surface; a convex medial transition surface flanking said central articular surface and disposed between said central articular surface and said medial condyle; and a convex lateral transition surface flanking said central articular surface and disposed between said central articular surface and said lateral condyle, said convex medial transition surface and said convex lateral transition surface each defining an arc extending in a medial/lateral direction, characterised in that said arc defines a radius (R 4) equal to between 40% and 56% of said medial/lateral width (ML T), whereby said femoral cam defines widely rounded, convex surfaces.