Stiffness of simulated radial neck fractures fixed with 4 different devices

We performed a structural investigation of several fixation devices for radial head and neck fixation. Fourteen pairs of fresh-frozen human elbows were used to simulate unstable radial neck fractures fixed with each of the following plates: 2.0-mm T-plate, 2.0-mm blade plate, 2.7-mm T-plate, and 2.7-mm T-plate modified with a fixed-angle blade. The plate constructs were axially loaded in compression with a materials testing machine, and stiffness was calculated from a load-deformation curve. Through use of paired comparisons, the average stiffness of the modified 2.7-mm plate was found to be significantly greater than that of either 2.0-mm plate, whereas a trend was observed for increased stiffness of the modified 2.7-mm T-plate in comparison with the standard 2.7-mm T-plate. The results indicate that two important variables affecting construct stiffness are plate thickness and incorporation of a fixed-angle blade. Given these findings, the addition of a fixed blade to the 2.7-mm plate may improve the stability of fixation of comminuted radial neck fractures. (J Shoulder Elbow Surg 2001;10:57-61.)