Bicortical versus unicortical fixation of plated clavicular fractures: A biomechanical study

To compare the biomechanical properties of three plate stabilization techniques for midshaft clavicle fractures: anatomical bicortical locking construct, anatomical unicortical locking construct, and reconstruction bicortical locking construct.

We analyzed superior plating of the clavicle using an anatomical clavicle plate (Acumed) with both bicortical or unicortical screw fixation and a locking reconstruction plate (DePuy-Synthes). Twenty-one fourth generation composite clavicles were used for non-destructive stiffness testing in axial loading, bending, and torsion. Fifteen composite clavicles and 17 foam clavicles were used for cyclic failure testing using a combined loading method that included all three loading modes.

No significant differences were found between the three constructs in torsional stiffness nor in vertical bending loading. In axial loading, the anatomical bicortical locking construct was significantly stiffer than either anatomical unicortical locking construct or the reconstruction bicortical locking construct. The unicortical fixation was also significantly stiffer than the reconstruction bicortical locking construct. Regarding failure testing, there was not a significant difference between the bicortical and unicortical anatomical locking constructs; however, both were significantly stronger than bicortical screw fixation in the reconstruction plate.

Based on the biomechanical performance of these constructs, unicortical locked plate fixation may be a reasonable option in the treatment of displaced midshaft clavicle fracture fixation.