A method of implanting a knee replacement system in a leg with a femur and a tibia of a patient can include, implanting a femoral component onto a condyle of the femur and placing a trial tibial component on a tibial plateau of the tibia. The tension of a posterior cruciate ligament can be adjusted. The tension of an anterior cruciate ligament can be adjusted. The posterior position of the trial tibial component can be adjusted. The knee condition at toe off onset can be simulated during walking.