[1] Natl Univ Singapore, Saw Swee Hock Sch Publ Hlth, 12 Sci Dr 2,11-01D, Singapore 117549, Singapore
[2] Khoo Teck Puat Hosp, Yishun Hlth, Natl Healthcare Grp, Singapore, Singapore
[3] Natl Univ Singapore Hosp, Univ Spine Ctr, Dept Orthopaed Surg, Singapore, Singapore
[4] Natl Univ Singapore, Yong Loo Lin Sch Med, Dept Orthopaed Surg, Singapore, Singapore
[5] Natl Univ Singapore, Alice Lee Ctr Nursing Studies, Yong Loo Lin Sch Med, Singapore, Singapore