Abstract: Systems and methods for providing deeper knee flexion capabilities, more physiologic load bearing, and improved patellar tracking for knee prosthesis patients. In some instances, such systems and methods include a knee prosthesis that includes a femoral component for replacing at least a portion of a distal end of a femur. While the femoral component can include any feature, in some cases, it includes a condylar surface configured to articulate with an articular surface of a tibia. In some cases, the femoral component also includes a proximal extension that extends from a proximal, posterior portion of the condylar surface. In such cases, the proximal extension provides the femoral component with a concave articulation surface that is configured to articulate against a portion of the tibia. Other implementations are also described.