Faculty Advisor

Billiar, Kristen


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

Date Accepted

April 2012


Biomedical Engineering

Project Type

Major Qualifying Project



Advisor Department

Biomedical Engineering