|  Moyer JA, Metz CM, Callaghan JJ, et al. Durability of second-generation extensively porous-coated stems in patients age 50 and younger[J]. Clin Orthop Relat Res, 2010, 468(2): 448-453. Delaunay CP, Bonnomet F, Clavert P, et al. THA using Metal-on-Metal articulation in active patients younger than 50 years[J]. Clin Orthop Relat Res, 2008,466(2): 340-346. Almeida F, Pino L, Silvestre A, et al. Mid- to long-term outcome of cementless total hip arthroplasty in younger patients[J]. J Orthop Surg (Hong Kong), 2010, 18(2): 172-178. Girard J, Glorion C, Bonnomet F, et al. Risk factors for revision of hip arthroplasties in patients younger than 30 years[J]. Clin Orthop Relat Res , 2011, 469(4): 1141–1147. de Kam DC, Gardeniers JW, Veth RP, et al. Good results with cemented total hip arthroplasty in patients between 40 and 50 years of age[J]. . Acta Orthop, 2010, 81(2): 165-170. Girard J, Bocquet D, Autissier G, et al. Metal-on-metal hip arthroplasty in patients thirty years of age or younger. J Bone Joint Surg Am, 2010, 92(14): 2419-2426. Powers CC, Ho H, Beykirch SE, et al. A comparison of a secondand a third-generation modular cup design is new improved? [J]. J Arthroplasty, 2010, 25(4): 514-521.