A new animal model of femoral head osteonecrosis: One that progresses to human-like mechanical failure

Michael G. Conzemius, Thomas D. Brown, Yongde Zhang, Robert A. Robinson

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83 Scopus citations


Existing animal models of femoral head osteonecrosis, while displaying varying levels of concordance with early histopathologic features of the human disorder, generally fail to progress to end-stage mechanical collapse. A new animal model of osteonecrosis is here introduced, utilizing the emu (Dromaius novaehollandie). These animals' bipedality and their high activity level represent a much more challenging biomechanical environment to the hip than seen in quadrupedal models of this disorder. Femoral head osteonecrosis was induced surgically, using a combination of ischemic (vessel ligation) and cryogenic (liquid nitrogen) insults. Of nineteen emus allowed free-roaming pen activity to study the natural history of such lesions, eighteen progressed to an osseous structural failure, sixteen of them developing incapacitating lameness at an average time point 11.75 weeks after the surgical insult. Histologically, the animals showed close concordance with both the early- and late-stage human pathology, in six cases even to the point of developing a crescent sign. Because of its large physical size and its consistent progression to mechanical collapse, the emu appears to offer a unique opportunity for the near-human-scale study of surgical interventions to forestall femoral head collapse. Toward this end, various directions for model refinement are outlined.

Original languageEnglish (US)
Pages (from-to)303-309
Number of pages7
JournalJournal of Orthopaedic Research
Issue number2
StatePublished - 2002
Externally publishedYes

Bibliographical note

Funding Information:
This work was funded by a University of Iowa/Iowa State University Interinstitutional Collaborative Grant Program, a University of Iowa Carver Trust Grant, and NIH Grant AR 44106.


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