The Effect of Screw Design on Union Rates in Scaphoid Nonunions

Abstract

Background: The purpose of this study is to compare the outcome of the conical fully threaded headless screw to that of a smooth shaft headless screw in a series of scaphoid nonunions requiring screw fixation to determine if screw design had an influence on union rates. Methods: We retrospectively reviewed 104 cases of surgically treated scaphoid nonunions. After eliminating cases with our exclusion criteria, the study cohort had 40 cases for analysis. A comparison and analysis of union rates was undertaken between the fully threaded Acutrak 2 mini screw and the smooth shaft Herbert screw. Results: Overall union rate for screw fixation was 88%. The fully threaded conical screw fixation had a significantly lower union rate of 50% compared to 97% for the smooth shaft screws. Conclusions: Our data revealed that the fully threaded conical screws were associated with significantly lower union rate compared to the smooth shaft Herbert type screws.