A Biomechanical Comparison of Superior and Anterior Positioning of Precontoured Plates for Midshaft Clavicle Fractures

With recent studies suggesting improved outcomes in displaced midshaft clavicle fractures treated with open reduction and internal fixation, debate has increased
over the preferred plate positioning. Biomechanical studies have yielded conflicting results and have been limited by the almost exclusive use of a simple transverse fracture model.

We conducted a study to biomechanically compare superior and anterior plate positioning for clinically relevant midshaft clavicle fracture patterns. Oblique, bending wedge, and complex comminuted fracture patterns were created sequentially in 12 synthetic clavicles. Half were plated with precontoured superior plates and half with precontoured anterior plates. Constructs were loaded in axial compression, torsion, and cantilever bending to determine construct stiffness for comparison of plate positioning.

Results showed that, for all fracture patterns, more construct stiffness was achieved in axial compression and torsion (except for the oblique fracture pattern in clockwise torsion) with a superior plate, whereas more construct stiffness was achieved in cantilever bending with an anterior plate. Oblique fractures were significantly stiffer than bending wedge and complex comminuted fractures.

Given the unknown relative importance of loading conditions, absolute recommendations for either superior or anterior plates cannot be made.