title: Effect of friction and clearance on kinematics and contact mechanics of dual mobility hip implant.
abstract: The dual mobility hip implant has been introduced recently and increasingly used in total hip replacement to maintain the stability and reduce the risk of post-surgery dislocation. However, the kinematics and contact mechanisms of dual mobility hip implants have not been investigated in detail in the literature. Therefore, finite element method was adopted in this study to investigate dynamics and contact mechanics of a typical metal-on-polymer dual mobility hip implant under different friction coefficient ratios between the inner and the outer articulations and clearances/interferences between the ultra-high-molecular-weight polyethylene liner and the metal back shell. A critical ratio of friction coefficients between the two pairs of contact interfaces was found to mainly determine the rotating surfaces. Furthermore, an initial clearance between the liner and the back shell facilitated the rotation of the liner while an initial interference prevented such a motion at the outer articulating interface. In addition, the contact area and the sliding distance at the outer articulating surface were markedly greater than those at the inner cup-head interface, potentially leading to extensive wear at the outer surface of the liner.
authors.affiliation: State Key Laboratory for Manufacturing System Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Orthopaedics, General Hospital of Chinese People's Liberation Army, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chai
authors.affiliation: State Key Laboratory for Manufacturing System Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China menlwang@mail.xjtu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Manufacturing System Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Manyi
authors.initials: M
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Manufacturing System Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Jin
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D001696:Biomechanical Phenomena / Q000502:physiology*; D017276:Friction / Q000502:physiology*; D005684:Gait / Q000502:physiology; D006622:Hip Prosthesis; D006801:Humans; D020959:Polyethylene; D011312:Pressure; D011474:Prosthesis Design
chemical_list: D020959:Polyethylene
keywords: Dual mobility hip implant; clearance/interference; contact mechanics; dynamics; friction coefficient