The present disclosure provides knee prostheses that replicate at least a portion of the function of an individual patient's anterior cruciate ligament (ACL). An exemplary knee prosthesis includes a femoral component configured to be implanted on the distal end of the patient's femur and a tibial component configured to be implanted on the proximal end of the patient's tibia. In extension, the femoral component and the tibial component may cooperate to limit anterior movement of the tibial component relative to the femoral component. In flexion, the femoral component may be free to rotate relative to the tibial component.