Abstract:Objective To analyze the stress distribution and peak stress on midshaft clavicular fractures fixed by titanium elastic nail (TEN) or reconstruction plate, respectively. Methods CT data of the clavicle was adopted to reconstruct the intact clavicle model and the midshaft clavicular fracture models with the TEN and reconstruction plate fixation by using Mimics software. All the threedimensional finite element models were analyzed using Abaqus 6.9 software. The distal displacement, the peak stress and stress distribution on the distal clavicle under the axial load (250 N) and vertical load (250 N) were calculated for the three models. Results The axial displacement of the distal clavicle under the axial load showed TEN (0.23 mm)>intact clavicle (0.14 mm)>reconstruction plate (0.11 mm), respectively. While the vertical displacement of the distal clavicle under the vertical load was 5.12 mm for TEN, 3.71 mm for intact clavicle and 2.25 mm for reconstruction plate, respectively. But the peak stress of the clavicle under the axial load was 33.1 MPa for TEN, 18.7 MPa for reconstruction plate, and 15.5 MPa for intact clavicle model, respectively. And the peak stress under the vertical load was 146.3, 64.1, 56.1 MPa in the TEN, intact clavicle model, and reconstruction plate model, respectively. The stress distribution in TEN model under both kinds of loads was similar to that in intact clavicle model, while under the vertical load, the stress distribution in reconstruction plate model was clearly different with that in intact clavicle model. For the implants under the axial load, the peak stresses were 191.5, 52.3 MPa in the TEN model and reconstruction plate model, respectively, and the peak stress on implants under the vertical load was 1 248.0, 421.7 MPa in the TEN model and reconstruction plate model, respectively. Conclusions The TEN for treating midshaft clavicular fractures showed a stress distribution similar to the intact clavicle, with a higher peak stress and a higher peak implant stress at the fracture site. The reconstruction plate fixation for midshaft clavicular fractures was shown to be more stable, but with obvious stress shielding. Therefore, TEN is generally preferable for treating the simple displaced fractures of midshaft clavicle. However, the ipsilateral shoulder should avoid excessive exercise and weight bearing in the early postoperative period.