John Wixted, M.D.
Screw loosening in ankle syndesmosis fixation is a major problem causing permanent arthritis. Loosening is caused by axial and transverse loading, resulting in joint malreduction. Our goal was to develop a fixation method to minimize screw loosening by optimizing screw insertion angles. Finite element analysis, pullout, load-to-failure, and cyclic shear testing were used to find the optimal screw insertion angles. Results indicate 0 deg(*) screws have significantly greater pullout strength than 23* or 45*, 23* screws create a stiffer fixation than 0*, and a two-screw system with 0* and 23* screws is able to withstand greater transverse loads than the current gold standard of two 0* screws. Findings indicate a screw system of 0* and 23* angled screws will provide better fixation.
Worcester Polytechnic Institute
Major Qualifying Project
All authors have granted to WPI a nonexclusive royalty-free license to distribute copies of the work, subject to other agreements. Copyright is held by the author or authors, with all rights reserved, unless otherwise noted.