A system and process for performing orthopedic surgery is provided that uses a tibial trial system in total knee arthroplasty for assessing optimal internal-external rotation and posterior tibial slope, and for measuring the rotation of a tibial trial throughout flexion-extension to determine and mark the best position for the final tibial component. The tibial trial system determines the internal-external location on a patient specific basis with improved component placement well within the present manual methods. One particular advantage to the tibial trial system is to assess the natural internal-external rotation that the tibial component will experience relative to the femoral component during flexion-extension as opposed to simply recording and balancing forces on a static tibial trial. The invention disclosed herein may also be adapted to be used with a computer assisted surgical device. Such surgical devices include active, semi-active, and haptic devices as well as articulating drill and saw systems.
