Stability of mid-shaft clavicle fractures after plate fixation versus intramedullary repair and after hardware removal

Operative treatment for middle-third clavicle fractures has been increasing as recent data has demonstrated growing patient dissatisfaction and functional deficits after non-operative management. A controlled biomechanical comparison of the characteristics of locked intramedullary (IM) fixation versus superior pre-contoured plating for fracture repair and hardware removal is warranted. Therefore, the purpose of the present study was to investigate potential differences between these devices in a biomechanical model. Thirty fourth-generation composite clavicles were randomized to one of five groups with 6 specimens each and tested in a random order. The groups tested were intact, repair with plate, repair with IM device, plate removal, and IM device removal. The lateral end of the clavicles was loaded to failure at a rate of 60 mm/min in a cantilever bending setup. Failure mechanism, energy (J), and torque (Nm) at the site of failure were recorded. Failure torque of the intact clavicle (mean +/- A standard deviation) was 36.5 +/- A 7.3 Nm. Failure torques of the IM repair (21.5 +/- A 9.0 Nm) and plate repair (18.2 +/- A 1.6 Nm) were not significantly different (n.s.) but were significantly less than the intact group (P < 0.05). Failure torque following IM device removal (30.2 +/- A 6.5 Nm) was significantly greater than plate removal (12.9 +/- A 2.0 Nm) (P < 0.05). No significant differences were observed between the intact and IM device removal groups (n.s.). The results of the current study demonstrate that IM and plate devices provide similar repair strength for middle-third clavicle fractures. However, testing of the hardware removal groups found the IM device removal group to be significantly stronger than the plate removal group.