Single versus dual orthogonal plating for comminuted midshaft clavicle fractures: a biomechanics study

BACKGROUND: Dual orthogonal plating of clavicle fractures may provide greater stiffness and strength than unilateral plate constructs and allow the use of lower-profile plates. We aim to biomechanically compare three clavicle plating constructs in a comminuted clavicle fracture model. METHOD: Fifteen clavicle sawbones were osteotomised, simulating a comminuted midshaft fracture and allocated to either: group 1, single superior plate (3.5 mm superior plate); group 2, combination plating (3.5 mm superior plate, 2.8 mm anterior plate) and group 3, dual mini-plates (two 2.8-mm orthogonal mini-plates). Specimens were biomechanically tested under torsion and cantilever bending. Construct stiffness (Nm/degree) and load to failure (Nm) were measured. RESULTS: Group 2 had higher torsional (0.70 vs. 0.60 Nm/deg, p = 0.017) and cantilever bending stiffness (0.61 vs. 0.51 Nm/deg, p = 0.025) than group 1. Group 3 had lower cantilever bending stiffness (0.39 vs. 0.51 Nm/deg, p < 0.004) and load to failure (40.87 vs. 54.84 Nm, p < 0.01) than group 1. All dual plate constructs that catastrophically failed did so from fracture at the lateral ends of the plates. Single plate constructs failed due to plate bending. CONCLUSION: Dual orthogonal fixation with mini-plates demonstrated lower stiffness and strength than traditional superior plating. The addition of an anterior mini-plate to a traditional superior plating improved construct stiffness and may have a role in patients seeking early return to activity. LEVEL OF EVIDENCE: Basic science biomechanical study