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Regional and temporal changes in the acoustic properties of fracture callus in secondary bone healing
Author(s) -
Harten Robert D.,
Lee Francis Y.,
Zimmerman Mark C.,
Hurowitz Eli,
Arakal Rajesh,
Behrens Fred F.
Publication year - 1997
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100150413
Subject(s) - callus , endochondral ossification , electrical impedance , bone healing , fracture (geology) , materials science , biomedical engineering , acoustic impedance , intramembranous ossification , composite material , anatomy , biology , medicine , cartilage , horticulture , engineering , electrical engineering
Controlled fractures were created in the right femora of 17 male Sprague‐Dawley rats. The fractured limbs were harvested at 2, 4, 6, and 8 weeks after fracture, fixed, and embedded in polymethylmethacrylate. Midsagittal sections from each animal were evaluated with a scanning acoustic microscope, a device that generates an acoustic impedance map of the scanned material. The impedance of the fracture callus was measured in six regions on each specimen. These regions were chosen in an effort to distinguish between the impedance of the callus formed through intramembranous or endochondral ossification, and we found that the time course of increasing impedance differed for the fracture callus formed through the two pathways. Additionally, we found a significant difference in the mean impedance of the callus at each time period (p ≤ 0.0013 for all comparisons), which resulted in an extremely linear relationship (r 2 = 0.999) between mean callus impedance and healing time. This experimental model has become a popular choice for the investigation of fracture healing. As such, an accurate determination of the mechanical properties of the fracture callus is often sought. We propose that the implementation of scanning acoustic microscopy in the study of fracture healing may determine the changes in the material properties more accurately than conventional testing methods.