A posterior stabilized knee orthopaedic prosthesis (10) includes a tibial bearing (12) and a femoral component (14) configured to articulate with the tibial bearing. The tibial bearing includes a spine (30) having a concavely curved inferior cam surface and a convexly curved superior cam surface. The femoral component includes a posterior cam (50) having a concave cam surface (56) and a convex cam surface (58). During flexion, the concave cam surface of the posterior cam having an anterior cam surface which is concavely curved and contacts the superior cam surface of the spine at a first degree of flexion, and a posterior cam surface which is convexly curved and contacts the inferior cam surface of the spine at a second degree of flexion which is greater than the first degree of flexion.
