The instrumentation set of this invention assists the surgeon in selecting the proper implant components, in determining the amount of distal bone to resect, and in aligning instrumentation designed to resect the bone. The instrumentation set provides numerous systems for verifying to the surgeon that he has correctly aligned the instruments prior to removing any bone.The set includes a rotational alignment guide, which aids the surgeon in establishing the appropriate rotational alignment for the knee as determined by reference to standard femoral landmarks such as the posterior condyles and epicondyles. The rotational alignment guide includes a slot for guiding a saw blade for removal of the posterior condyles of the femur.The set further includes a tensor designed to tense the knee joint in flexion and extension. The tensor is activated by a torque wrench so that a measured amount of tension force can be applied to the joint. The tensor is configured to slidably carry sizing rods, which contact the femur and include a plurality of markings, which relate to the size of the femur as well as the spacing between the femur and tibia. This information is used by the surgeon to select the proper size of femoral and tibial articulate surface components. The sizing rods are connected to the tensor when the tibial is in flexion and in extension, which will indicate to the surgeon any variation required in the amount of bone to be resected.