Article: Microfracture and changes in energy absorption to fracture of young vertebral cancellous bone following physiological fatigue loading

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TitleMicrofracture and changes in energy absorption to fracture of young vertebral cancellous bone following physiological fatigue loading
AuthorsLu, WW2
Luk, KDK2
Cheung, KCM2
GuiXing, Q3
Shen, JX3
Yuen, L1
Ouyang, J1
Leong, JCY2
KeywordsEnergy absorption
Fatigue loading
Microfracture
Issue Date2004
PublisherLippincott, Williams & Wilkins. The Journal's web site is located at http://www.spinejournal.com
CitationSpine, 2004, v. 29 n. 11, p. 1196-1201 [How to Cite?]
DOI: http://dx.doi.org/10.1097/00007632-200406010-00007
AbstractStudy Design. Fifty-five human thoracolumbar vertebrae were randomly fatigue loaded and analyzed. Objectives. The purpose of this study was to explore the relationship between fatigue loading, trabecular microfracture, and energy absorption to fracture in human cadaveric thoracolumbar vertebrae. Background. Although trabecular microfractures are found in vivo and have been produced by fatigue loading in vitro, the effect of the level of physiologic fatigue loading on microfracture and energy absorption has not been investigated. Methods. Fifty-five human thoracolumbar vertebrae (T11-L4) were randomly divided into 5 groups: 1) control (no loading, n = 6); 2) axial compression to yield (n = 7); and 3-5) 20,000 cycles of fatigue loading at 2 Hz (each n = 14). The level of fatigue loading was determined as a proportion of the yield load of Group 2 as follows: 10% (Group 3), 20% (Group 4), and 30% (Group 5). Half of the specimens in groups 3 to 5 were used for radiographic and histomorphometric analysis to determine microfracture density and distribution, whereas the other half were tested to determine the energy absorption to yield failure. Results. No radiographic evidence of gross fracture was found in any of the groups following fatigue loading. A mean 7.5% increase in stiffness was found in specimens subject to cyclic loading at 10% of yield stress (Group 3). Fatigue at 20% (Group 4) and 30% of yield stress (Group 5) caused significantly higher (P < 0.05) increases in mean stiffness of 23.6% and 24.2%, respectively. Microfracture density increased from 0.46/mm2 in Group 3 to 0.66/mm2 in Group 4 and 0.94/mm2 in Group 5 (P < 0.05). The energy absorbed to failure decreased from 21.9 J in Group 3 to 18.1 J and 19.6 J in Groups 4 and 5, respectively (P < 0.05). Conclusions. Fatigue loading at physiologic levels produced microfractures that are not detectable by radiography. Increased fatigue load results in an increase in microfracture density and decrease energy absorbed to fracture, indicating a reduced resistance to further fatigue loading.
ISSN0362-2436
2011 Impact Factor: 2.078
2011 SCImago Journal Rankings: 0.137
DOIhttp://dx.doi.org/10.1097/00007632-200406010-00007
ReferencesReferences in Scopus
DC Field
Value
dc.contributor.authorLu, WW
dc.contributor.authorLuk, KDK
dc.contributor.authorCheung, KCM
dc.contributor.authorGuiXing, Q
dc.contributor.authorShen, JX
dc.contributor.authorYuen, L
dc.contributor.authorOuyang, J
dc.contributor.authorLeong, JCY
dc.date.accessioned2010-09-06T07:54:10Z
dc.date.available2010-09-06T07:54:10Z
dc.date.issued2004
dc.description.abstractStudy Design. Fifty-five human thoracolumbar vertebrae were randomly fatigue loaded and analyzed. Objectives. The purpose of this study was to explore the relationship between fatigue loading, trabecular microfracture, and energy absorption to fracture in human cadaveric thoracolumbar vertebrae. Background. Although trabecular microfractures are found in vivo and have been produced by fatigue loading in vitro, the effect of the level of physiologic fatigue loading on microfracture and energy absorption has not been investigated. Methods. Fifty-five human thoracolumbar vertebrae (T11-L4) were randomly divided into 5 groups: 1) control (no loading, n = 6); 2) axial compression to yield (n = 7); and 3-5) 20,000 cycles of fatigue loading at 2 Hz (each n = 14). The level of fatigue loading was determined as a proportion of the yield load of Group 2 as follows: 10% (Group 3), 20% (Group 4), and 30% (Group 5). Half of the specimens in groups 3 to 5 were used for radiographic and histomorphometric analysis to determine microfracture density and distribution, whereas the other half were tested to determine the energy absorption to yield failure. Results. No radiographic evidence of gross fracture was found in any of the groups following fatigue loading. A mean 7.5% increase in stiffness was found in specimens subject to cyclic loading at 10% of yield stress (Group 3). Fatigue at 20% (Group 4) and 30% of yield stress (Group 5) caused significantly higher (P < 0.05) increases in mean stiffness of 23.6% and 24.2%, respectively. Microfracture density increased from 0.46/mm2 in Group 3 to 0.66/mm2 in Group 4 and 0.94/mm2 in Group 5 (P < 0.05). The energy absorbed to failure decreased from 21.9 J in Group 3 to 18.1 J and 19.6 J in Groups 4 and 5, respectively (P < 0.05). Conclusions. Fatigue loading at physiologic levels produced microfractures that are not detectable by radiography. Increased fatigue load results in an increase in microfracture density and decrease energy absorbed to fracture, indicating a reduced resistance to further fatigue loading.
dc.description.natureLink_to_subscribed_fulltext
dc.identifier.citationSpine, 2004, v. 29 n. 11, p. 1196-1201 [How to Cite?]
DOI: http://dx.doi.org/10.1097/00007632-200406010-00007
dc.identifier.doihttp://dx.doi.org/10.1097/00007632-200406010-00007
dc.identifier.epage1201
dc.identifier.hkuros94019
dc.identifier.isiWOS:000221812800006
dc.identifier.issn0362-2436
2011 Impact Factor: 2.078
2011 SCImago Journal Rankings: 0.137
dc.identifier.issue11
dc.identifier.openurl
dc.identifier.pmid15167657
dc.identifier.scopuseid_2-s2.0-2542469596
dc.identifier.spage1196
dc.identifier.urihttp://hdl.handle.net/10722/79391
dc.identifier.volume29
dc.languageeng
dc.publisherLippincott, Williams & Wilkins. The Journal's web site is located at http://www.spinejournal.com
dc.publisher.placeUnited States
dc.relation.ispartofSpine
dc.relation.referencesReferences in Scopus
dc.subjectEnergy absorption
dc.subjectFatigue loading
dc.subjectMicrofracture
dc.titleMicrofracture and changes in energy absorption to fracture of young vertebral cancellous bone following physiological fatigue loading
dc.typeArticle
Author Affiliations
  1. Southern Medical University
  2. The University of Hong Kong
  3. Peking Union Medical College