The purpose of this study is to develop a computer aided surgical planning system of acetabular cup with haptic device for total hip arthroplasty. In the preprocessing process, this system determines 3-dimensional safety-zone and critical-zone for cup placement with various criteria, and generates the reaction force at an each vertex of the grid map. In the planning phase, the system enables surgeons to feel the reaction force for guiding to the safety-zone. In the experiments, we used primary and secondary osteoarthritis cases and confirmed that this system could display the reaction force real time and manipulation cursor was guided properly.
