The chemical interaction of femoral heads with polyethylene liners is an important new area of research in total hip arthroplasty (THA) as a consequence of an unabating quest for elongated artificial joint lifetimes. It is a topic that goes beyond simple mechanical behavior or wear. It seeks to describe the prosthetic device as a whole by adding chemical considerations to mechanics and abrasion. One of the poorly understood chemical interactions is oxygen affinity of the femoral heads. While oxygen unavoidably diffuses into the non-crystalline enclaves of the polyethylene liner as a result of its contact with the tribolayer, a ceramic femoral head can either attract or release oxygen due to its tribochemical interactions. In this study, changes in liner crystallinity and oxidation were observed during simple static contact with different femoral heads within a hydrothermal environment. Examinations were made using Raman microprobe spectroscopy coupled with nanometer-scale spectroscopic analyses (x-ray photoelectron spectroscopy (XPS) and cathodoluminescence (CL) spectroscopy) on different sets of ceramic and polyethylene couples exposed for increasing periods to a hydrothermal environment. Even in the absence of frictional loading, structural modifications were clearly detected, statistically validated, and correlated with the oxygen affinity of various femoral head materials. It was found that oxide (Al2O3, Al2O3/ZrO2, and m-ZrO2) and non-oxide (Si3N4) ceramic heads release or attract nascent oxygen species, respectively. This research unequivocally identified a new gap in our knowledge of THA biomaterial interactions, with future studies and material improvements undoubtedly leading to an increase in longevity for prosthetic joints.

On the molecular interaction between femoral heads and polyethylene liners in artificial hip joints: Phenomenology and molecular scale phenomena

CASAGRANDE, ELISA;PUPPULIN, LEONARDO
2017

Abstract

The chemical interaction of femoral heads with polyethylene liners is an important new area of research in total hip arthroplasty (THA) as a consequence of an unabating quest for elongated artificial joint lifetimes. It is a topic that goes beyond simple mechanical behavior or wear. It seeks to describe the prosthetic device as a whole by adding chemical considerations to mechanics and abrasion. One of the poorly understood chemical interactions is oxygen affinity of the femoral heads. While oxygen unavoidably diffuses into the non-crystalline enclaves of the polyethylene liner as a result of its contact with the tribolayer, a ceramic femoral head can either attract or release oxygen due to its tribochemical interactions. In this study, changes in liner crystallinity and oxidation were observed during simple static contact with different femoral heads within a hydrothermal environment. Examinations were made using Raman microprobe spectroscopy coupled with nanometer-scale spectroscopic analyses (x-ray photoelectron spectroscopy (XPS) and cathodoluminescence (CL) spectroscopy) on different sets of ceramic and polyethylene couples exposed for increasing periods to a hydrothermal environment. Even in the absence of frictional loading, structural modifications were clearly detected, statistically validated, and correlated with the oxygen affinity of various femoral head materials. It was found that oxide (Al2O3, Al2O3/ZrO2, and m-ZrO2) and non-oxide (Si3N4) ceramic heads release or attract nascent oxygen species, respectively. This research unequivocally identified a new gap in our knowledge of THA biomaterial interactions, with future studies and material improvements undoubtedly leading to an increase in longevity for prosthetic joints.
Pubblicato
http://iopscience.iop.org/article/10.1088/1748-605X/12/1/015005/pdf
File in questo prodotto:
File Dimensione Formato  
pezzotti2017.pdf

non disponibili

Tipologia: Documento in Versione Editoriale
Licenza: Digital Rights Management non definito
Dimensione 3.81 MB
Formato Adobe PDF
3.81 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2897034
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 8
  • ???jsp.display-item.citation.isi??? 7
social impact