Demand for total hip replacement (THR) increases in recent years as the average age of the population grows higher. The procedure of a THR surgery is shown in Fig.1. One of the key concerns in a THR surgery is the hip range of motion (ROM), including angles of flexion, extension, adduction, abduction, internal rotation and external rotation. THR with a prosthetic ROM larger than that for everyday activities will minimize the risk of dislocation and prosthetic impingement [1].