Failure mechanism of the all-polyethylene glenoid implant

JOURNAL OF BIOMECHANICS

卷:43

Article

Junaid, Sarah¹  Gupta, Sanjay¹  Sanghavi, Sanjay¹  Anglin, Carolyn^2,3  Emery, Roger^4,5  Amis, Andrew^1,4  Hansen, Ulrich¹ 

[1] Univ London Imperial Coll Sci Technol & Med, Dept Mech Engn, London SW7 2AZ, England

[2] Univ Calgary, Ctr Bioengn Res & Educ, Calgary, AB T2N 1N4, Canada

[3] Univ Calgary, Dept Civil Engn, Calgary, AB T2N 1N4, Canada

[4] Univ London Imperial Coll Sci Technol & Med, London W6 8RF, England

[5] St Marys Hosp, Dept Orthopaed Surg, London, England

关键词: Glenoid;    Loosening;    Fixation failure;   

DOI  :  10.1016/j.jbiomech.2009.10.019

来源: Elsevier

【 摘 要 】

Fixation failure of glenoid components is the main cause of unsuccessful total shoulder arthroplasties. The characteristics of these failures are still not well understood, hence, attempts at improving the implant fixation are somewhat blind and the failure rate remains high. This lack of understanding is largely due to the fundamental problem that direct observations of failure are impossible as the fixation is inherently embedded within the bone. Twenty custom made implants, reflecting various common fixation designs, and a specimen set-up was prepared to enable direct observation of failure when the specimens were exposed to cyclic superior loads during laboratory experiments. Finite element analyses of the laboratory tests were also carried out to explain the observed failure scenarios. All implants, irrespective of the particular fixation design, failed at the implant-cement interface and failure initiated at the inferior part of the component fixation. Finite element analyses indicated that this failure scenario was caused by a weak and brittle implant-cement interface and tensile stresses in the inferior region possibly worsened by a stress raiser effect at the inferior rim. The results of this study indicate that glenoid failure can be delayed or prevented by improving the implant/cement interface strength. Also any design features that reduce the geometrical stress raiser and the inferior tensile stresses in general should delay implant loosening. (C) 2009 Elsevier Ltd. All rights reserved.

【 授权许可】

Free