Anterolateral and Medial Locking Plate Stiffness in Distal Tibial Fracture Model

Abstract

The purpose of this study was to compare the axial and torsional stiffness between anterolateral and medial distal tibial locking plates in a pilon fracture model. The biomechanical stiffness of anterolateral or medial plated pilon fracture models was evaluated. Six Sawbones Composite Tibiae with a simulated pilon fracture representing varus or valgus comminution (OTA 43-A2.2) were plated with a Synthes 3.5-mm contoured LCP anterolateral or medial locking distal tibia plate. Load as a function of axial displacement and torque as a function of angular displacement were recorded. Each tibia was tested with a fracture wedge in place and removed with a medial and then anterolateral plate. Loading the tibial plateau medial to the central axis, no significant difference in mean stiffness between the anterolateral and medial plates was demonstrated with the fracture wedge in place. A significant difference was demonstrated with the wedge removed. Loading the plateau posterior to the central axis, no significant difference in mean stiffness between plates was demonstrated with the wedge in place or removed. With the wedge in place, there was a significant difference in mean torsional stiffness for clockwise rotation, but not counterclockwise rotation. With the wedge removed, no significant difference appeared in mean stiffness for clockwise and counterclockwise rotation. Distal tibia extra-articular fractures stabilized with anterolateral or medial locking plate constructs demonstrated no statistically significant difference in biomechanical stiffness in compression and torsion testing. We believe this study indicates the primary concern when treating a pilon fracture may be soft-tissue considerations. Further clinical studies are required before definitive changes can be recommended regarding pilon fracture fixation.