The apparent critical isotherm for cryoinsult-induced osteonecrotic lesions in emu femoral heads

Jessica E. Goetz, Douglas R. Pedersen, Duane A. Robinson, Michael G. Conzemius, Thomas E. Baer, Thomas D. Brown

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Cryoinsult-induced osteonecrosis (ON) in the emu femoral head provides a unique opportunity to systematically explore the pathogenesis of ON in an animal model that progresses to human-like femoral head collapse. Among the various characteristics of cryoinsult, the maximally cold temperature attained is one plausible determinant of tissue necrosis. To identify the critical isotherm required to induce development of ON in the cancellous bone of the emu femoral head, a thermal finite element (FE) model of intraoperative cryoinsults was developed. Thermal material property values of emu cancellous bone were estimated from FE simulations of cryoinsult to emu cadaver femora, by varying model properties until the FE-generated temperatures matched corresponding thermocouple measurements. The resulting FE model, with emu bone-specific thermal properties augmented to include blood flow effects, was then used to study intraoperatively performed in vivo cryoinsults. Comparisons of minimum temperatures attained at FE nodes corresponding to the three-dimensional histologically apparent boundary of the region of ON were made for six experimental cryoinsults. Series-wide, a critical isotherm of 3.5°C best corresponded to the boundary of the osteonecrotic lesions.

Original languageEnglish (US)
Pages (from-to)2197-2205
Number of pages9
JournalJournal of Biomechanics
Issue number10
StatePublished - Jul 19 2008
Externally publishedYes


  • Cryoinsult
  • Emu
  • Finite element model
  • Histology
  • Osteonecrosis

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Rehabilitation
  • Biophysics
  • Biomedical Engineering


Dive into the research topics of 'The apparent critical isotherm for cryoinsult-induced osteonecrotic lesions in emu femoral heads'. Together they form a unique fingerprint.

Cite this