Biomechanical Aspects of Locking Reconstruction Plate Positioning in Osteosynthesis of Transverse Clavicle Fracture

The aim of this study was to evaluate and compare the biomechanical effects of locking reconstruction plate positioning on the osteosynthesis of clavicle midshaft simulated transverse fractures.
Material and Methods. Twelve synthetic clavicles with simulated midshaft transverse fractures were repaired with a 3.5-mm locking reconstruction plate in the anteroinferior or the superior position. The clavicles were randomly assigned to 2 groups (6 per group). Each repaired clavicle was tested in cantilever bending by using the universal testing machine. The maximal load and the displacement of the specimens at a load of 40 N were recorded for each group.
Results. The anteroinferior plating osteosynthesis with a 3.5-mm locking reconstruction plate could bear an average maximal load of 183.3 N (SD, 11.3); the corresponding load for the superior plating osteosynthesis with the identical implants was 444.8 N (SD, 102.3), and the mean displacement was 1.5 mm (SD, 0.5) and 0.7 mm (SD, 0.2), respectively.
Conclusions. The superior plating osteosynthesis of simulated midshaft transverse clavicle fractures with the 7-hole 3.5-mm locking reconstruction plate had a significantly higher bending (from top to bottom) load to failure in comparison with the anteroinferior plating osteosynthesis of the clavicle with the identical implants. Clavicles plated with the 7-hole 3.5-mm locking reconstruction plate at the superior aspect exhibited a significantly greater biomechanical stability at a load of 40 N than those plated at the anteroinferior aspect.