Fixation of Regan-Morrey Type II Coronoid Fractures: A Comparison of Screws and Suture Lasso Technique for Resistance to Displacement.

Abstract

The aim of this study was to compare the load to failure and stiffness achieved in coronoid fractures treated with a posterior-to-anterior screw versus a suture lasso technique. We performed a biomechanical study using 10 pairs of fresh-frozen cadaveric elbows. A transverse osteotomy at the midpoint of the coronoid height was created to simulate a Regan-Morrey type II coronoid fracture. The specimens were randomized to screw fixation or suture lasso fixation. The load to failure and stiffness were then measured using a materials testing machine. Screw fixation provided greater strength and stiffness than suture lasso fixation. Mean load to failure was 405 N in the screw fixation group compared with a load to failure of 207 N for suture fixation. Screw fixation resulted in a mean stiffness of 284 kPa/mm compared with 119 kPa/mm after suture fixation. Screw fixation was biomechanically superior to fixation using a suture lasso technique. For coronoid fractures in which screw or suture fixation is feasible, screw fixation may provide greater resistance to displacement of the coronoid compared with a suture lasso technique. Clinical studies have reported a higher rate of failure after screw fixation compared with suture lasso fixation; however, this study demonstrated a greater stiffness and load to failure after screw fixation of type II coronoid fractures. Screw fixation may provide a stronger fixation construct for fractures of adequate size to support a screw. Further studies may be warranted to assess the importance of securing the anterior capsule to the coronoid tip when using a suture lasso construct because this may affect the stability of the elbow after fixation.