A knee arthroplasty assembly for use in a patient's knee joint including a tibia and a femur is disclosed. The assembly can include a tool, a first accessory, and a second accessory. The tool can include a tibial component configured for placement against the tibia and a femoral component configured for placement against the femur. The femoral component can be moveably coupled to the tibial component to place the patient's knee joint in tension by separating the tibia and the femur. The first accessory can be removeably coupled to the tibial component of the tool. The second accessory can be referenced to the first accessory and can have a reference indicator that references the femur for determining a size of the femur.