2021 Undergraduate Research Showcase


A Repeatable Method for Joint Alignment of Disarticulated Human Knees

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Student Presentation


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Trevor J. Lujan


Misalignment of human knee joints can significantly increase joint forces, kinematic errors, and cause specimen damage. While previous studies have developed methods to accurately align whole human knees prior to testing, no such study has developed a method to re-establish natural alignment for disarticulated knees. A surrogate knee bone model was used to address this problem. Embedded and reference coordinate systems were created by digitizing kinematic markers on each bone. The initial position was digitized prior to disarticulation. A custom MATLAB code was used to quantify clinical translations and rotations using Grood-Suntay convention. This provided adjustments to guide the disarticulated joint to within ±0.5° and 1.0 mm of the initial position. Final positions were digitized three times and compared to the initial position to determine the repeatability of the method. After three trials, errors were found to be insignificant with p < 0.05. Average differences in rotation and translation were 0.33° and 0.50 mm, respectively. For the first time, this study provides a method to re-establish natural joint alignment accurately and repeatedly for disarticulated human knees. By improving joint alignment, this study can help to advance clinically impactful research in knee biomechanics and TKA technology.

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