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    Literature Discrepancies in Biomechanical Loading of Orthopedic Trauma Devices Intended for Lower Extremities

    Published: 2013

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    No standards presently exist for loading magnitudes employed in biomechanical studies of fracture fixation. Thus, the purpose of this investigation was to analyze the loading magnitudes utilized in published technical papers on biomechanical fracture fixation investigations. The hypothesis was that loading magnitudes used in biomechanical testing are not standardized, are inconsistent, and are poorly documented. English-language medical literature was searched for references to lower extremity biomechanical testing related to fracture fixation that utilized body weight as the loading scenario. Included articles were categorized based upon weight bearing (WB) protocol, implant type, and anatomic region and were compared to reported body weights published by the U.S. Department of Health and Human Services Centers for Disease Control (CDC). There were 5289 publications identified as potentially applicable; 54 articles met all included conditions. The majority of articles attempted to mimic full WB conditions. Others utilized half body weight, partial WB protocols, crutch-assisted WB protocols, and toe-touch only. A range of biomechanical testing forces from 31 to 980 N was reported, depending upon the desired percentage of WB that corresponded to a mass range of 3 to 100 kg. The CDC reported mean body masses for U.S. females and males, across all races and ethnicities, of 75 kg (736 N) and 88 kg (863 N), respectively, for an averaged total of 82 kg (804 N). In comparison to the report from the CDC, the literature underestimated mean body weight. Consistent loading parameters among biomechanical tests are not well documented. Biomechanical testing results should support clinical experience, and in this study a discrepancy was observed between biomechanical test parameters that might ultimately influence the orthopedic standard of care. Based on the literature search and reported CDC findings, a force of 804 N or greater might be most appropriate for simulations of full WB protocol.


    body weight, orthopedics, trauma, biomechanics, lower extremity

    Author Information:

    Whitten, Andy
    Smith & Nephew, Inc., Memphis, TN

    Cartner, Jacob
    Smith & Nephew, Inc., Memphis, TN

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP155920120206