Mechanical implications of interfacial defects between femoral hip implants and cement: a finite element analysis of interfacial gaps and interfacial porosity.
Proc Inst Mech Eng H
; 222(7): 1037-47, 2008 Oct.
Article
en En
| MEDLINE
| ID: mdl-19024152
Two types of defect between femoral hip implants and cement have been identified. Interfacial porosity arises from cement shrinkage during curing and presents as pores randomly located along the stem. Interfacial gaps are much larger stem-cement separations caused by air introduced during stem insertion. To investigate the mechanical consequences of both types of defect, a finite element analysis model was created on the basis of a computed tomography image of a Charnley-Kerboul stem, and alternating torsional and transverse loads were applied. The propagation of fatigue cracks within the cement and the rotational stability of the stem were assessed in models simulating increasing amounts of interfacial gaps and pores. Anterior gaps covering at least 30 per cent of the implant surface promoted cement cracks and destabilized the stem. Anterolateral gaps were less destabilizing, but had more potential to promote cracks. In both cases, cracks occurred mainly outside gap regions, in areas where the stem contacted the cement during cyclic loading. Although random interfacial pores did not destabilize the implant, they acted as crack initiators even at low fractions (10 per cent). In conclusion, random interfacial pores were more harmful for the cement mantle integrity than were larger regions of interfacial gaps, although gaps were more detrimental for the rotational stability of the stem.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cementos para Huesos
/
Ensayo de Materiales
/
Falla de Prótesis
/
Artroplastia de Reemplazo de Cadera
/
Prótesis de Cadera
/
Modelos Biológicos
Límite:
Humans
Idioma:
En
Revista:
Proc Inst Mech Eng H
Asunto de la revista:
ENGENHARIA BIOMEDICA
Año:
2008
Tipo del documento:
Article
País de afiliación:
Bélgica
Pais de publicación:
Reino Unido