1. Department of Orthopedics, Kaohsiung Municipal Gangshan Hospital, Kaohsiung 820002, Taiwan
2. Department of Orthopedics, Show Chwan Memorial Hospital, Changhua 500009, Taiwan
3. Department of Orthopedics, Asia University Hospital, Taichung 413505, Taiwan
4. Department of Anesthesiology, Taichung Veterans General Hospital, Taichung 407204, Taiwan