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In vivo assessment of regenerate axial stiffness in distraction osteogenesis
Author(s) -
Aarnes Gudrun Trøite,
Steen Harald,
Ludvigsen Per,
Waanders Nicholas A.,
Huiskes Rik,
Goldstein Steven A.
Publication year - 2005
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 - 10.1016/j.orthres.2004.08.024
Subject(s) - external fixator , distraction , stiffness , orthodontics , medicine , distraction osteogenesis , biomechanics , bone healing , materials science , biomedical engineering , surgery , anatomy , composite material , neuroscience , biology
This paper presents an in vivo test for assessment of regenerate axial stiffness after the distraction phase of lengthening therapy. The test result supplements radiography in evaluating bone healing and assists in determining when the regenerate stiffness is sufficient for removal of the external fixator. The test is non‐invasive and does not require fixator removal. The theoretical basis for the method is that an externally applied load is shared between the fixator and the regenerating bone. The amount of load carried by the regenerate depends on its axial stiffness, which increases with advanced mineralization. By measuring the force in the fixator while applying a known external load to the limb, the load‐share ratio between fixator and limb can be assessed. A load‐share ratio of 100% indicates that the entire load is carried by the fixator. The ratio decreases as the regenerate structure gradually stiffens. In a clinical trial of 22 individuals with tibial lengthening, the fixator was removed when the load‐share ratio dropped below 10%. None of the patients experienced fracture after removal of the fixator. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.