Faculty Advisor

Billiar, Kristen

Project Center

University of Massachusetts Medical Center


Current screw/plate sternal closure for patients after open-heart surgery requires bicortical fixation which is disadvantageous due to the proximity of the heart. The goal of this project was to design, model and test a single-unit unicortical screw and plate system which provides both lag and locking functionality. The final design utilizes a novel reverse splaying of the head to provide a locking mechanism following initial tightening. The design also allows the surgeon to properly locate and secure the bone to the plate prior to engagement of a locking mechanism. Cyclic shear loading will be used to compare the effectiveness of this screw design with standard non-locking unicortical and bicortical screws.


Worcester Polytechnic Institute

Date Accepted

April 2012


Biomedical Engineering

Project Type

Major Qualifying Project



Advisor Department

Biomedical Engineering