A two-dimensional model of cyclic strain accumulation in ultra-high molecular weight polyethylene knee replacements.
Proc Inst Mech Eng H
; 212(3): 189-98, 1998.
Article
em En
| MEDLINE
| ID: mdl-9695638
ABSTRACT
As new methods of sterilization of the ultra-high molecular weight polyethylene (UHMWPE) component in knee replacements are introduced, reported incidents of delamination will decrease. The prediction of plastic strain accumulation and associated failure mechanisms will then become more important in knee replacement design. The finite element analysis reported in this paper aims to advance the modelling of strain accumulation in UHMWPE over repeated gait cycles and seeks to determine the effects of the knee replacement design variables of geometry and kinematics. Material testing was performed under cyclic and creep conditions to generate the elastic, viscoplastic material model that has been used in this time-dependent analysis. Non-conforming geometries were found to accumulate plastic strains at higher rates than conforming geometries. The anatomical motion known as rollback initially produced lower strain rates, but predictions of the long-term response indicated that designs which allow rollback may produce higher strains than static designs after only about a week of loading for a knee replacement patient.
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Base de dados:
MEDLINE
Assunto principal:
Polietilenos
/
Materiais Biocompatíveis
/
Teste de Materiais
/
Prótese do Joelho
/
Modelos Biológicos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
1998
Tipo de documento:
Article