Contact mechanics studies of an ellipsoidal contact bearing surface of metal-on-metal hip prostheses under micro-lateralization.
The morphology of the contact bearing surfaces plays an important role in the contact mechanics and potential wear of metal-on-metal (MOM) hip prostheses. An ellipsoidal bearing surface was proposed for MOM hip implants and the corresponding contact mechanics were studied by using the finite element method (FEM) under both standard and micro-lateralization conditions. When under micro-lateralization, the maximum contact pressure decreased from 927.3MPa to 203.0MPa, with increased ellipticity ratio medial-laterally. And the contact region was found to shift from the rim of the cup to the inner region compared to the spherical design. Under standard conditions, an increasing trend of the maximum contact pressure for the acetabular component was predicted as the major radius of the ellipsoidal bearing surface was increased. Nevertheless, the maximum contact pressure reached an asymptotic value when the ellipticity ratio was increased to 1.04. Therefore it is critical to optimize the ellipticity ratio in order to reduce the contact pressure under micro-lateralization condition and yet not to cause a markedly increased contact pressure under normal condition. Additionally, the maximum contact pressure in the ellipsoidal bearing surface remained relatively constant with the increased micro-lateralization. It is concluded that an ellipsoidal bearing surface morphology may be a promising alternative by offering better contact mechanisms when micro-lateralization should occur and attributing to minimized wear.
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, 710054, China.
Ling
L
Wang
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, 710054, China.
Xiaohua
X
Liu
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, 710054, China.
Dichen
D
Li
School of Mechanical Engineering, University of Leeds, LS2 9JT, UK.
Feng
F
Liu
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, 710054, China; School of Mechanical Engineering, University of Leeds, LS2 9JT, UK. Electronic address: zmjin@mail.xjtu.edu.cn.
Zhongmin
Z
Jin
D002858:Chromium Alloys; D003198:Computer Simulation; D020342:Finite Element Analysis; D006622:Hip Prosthesis; D006801:Humans; D055595:Mechanical Phenomena; D011312:Pressure; D011474:Prosthesis Design
D002858:Chromium Alloys
Contact mechanics; Ellipsoidal bearing surfaces; Hip implants; Micro-lateralization