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

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.

J Orthop Res. 2002 Mar;20(2):303-9.

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Founded in 1989, The American Emu Association is a non-profit trade association representing breeders, producers and marketers of emu meat, oil and other emu co-products. The emu industry is an alternative agricultural industry, dominated by the small farmer, who is devoted to humane and environmentally positive practices that will produce beneficial products for society. For more information about the American Emu Association (AEA) or the emu industry visit https://aea-emu.org