[1] Changhua Christian Hosp, Dept Orthoped Surg, Changhua, Taiwan
[2] Changhua Christian Hosp, Res Educ & Epidemiol Ctr, Changhua, Taiwan
[3] Yuanlin Christian Hosp, Dept Orthoped Surg, Changhua, Taiwan
[4] Kaohsiung Med Univ, Orthoped Res Ctr, Kaohsiung, Taiwan
[5] Kaohsiung Med Univ, Kaohsiung Municipal Ta Tung Hosp, Dept Orthoped, Kaohsiung, Taiwan
[6] Tsinghua Univ, Inst Hosp Management, Beijing, Peoples R China
[7] Kaohsiung Med Univ, Dept Healthcare Adm & Med Informat, Kaohsiung, Taiwan
[8] Johns Hopkins Univ, Bloomberg Sch Publ Hlth, Dept Hlth Policy & Management, Baltimore, MD 21218 USA