1. Department of Orthopaedic Surgery, Asan Medical CenterUniversity of Ulsan College of Medicine86 Asanbyeongwongil, Songpa‐gu Seoul 138‐736 South Korea
2. Department of Mechanical EngineeringKorea Advanced Institute of Science and TechnologyDaehak‐ro 291, Yuseong‐gu Daejeon 305‐701 South Korea