Corrigendum to 'A mathematical method for precisely calculating the radiographic angles of the cup after total hip arthroplasty' Medical Engineering & Physics 38 (2016) 1376–1381. (August 2017) - Zhao, Jing-Xin; Su, Xiu-Yun; Xiao, Ruo-Xiu; Zhao, Zhe; Zhang, Li-Hai; Zhang, Li-Cheng; Tang, Pei-Fu