A milling tool system for accurately preparing a portion of the tibia preparatory to making femoral resections. The milling tool system provides a minimally invasive procedure to provide an aperture within an exposed surface of the tibia, the aperture then being used as a referencing surface to accurately resect the femur. Once the femur resections have been made, the remaining uncut portions of the tibia are exposed and easily accessible for the tibial resections.