Clinical Treatment And A Finite Element Analysis Of The Neer Type ⅡB Distal Clavicle Fracture

[Objective]1.To explore the clinical effect of rigid internal fixation(double-plate)and flexible internal fixation(double-plate double Endobutton belt loops plate)on the treatment of Neer type ⅡB distal clavicle fracture.2.To explore the finite element biomechanical characteristics of Neer type ⅡB distal clavicle fractures fixed by double plate and double Endobutton belt loops plate respectively so tha we can provide theoretical support for clinical application.[Methods]1.We retrospectively analyzed 35 cases of Neer type ⅡB distal clavicle fracture treated with open clavicle distal double-plate internal fixation(19 cases)and coracoclavicular ligament reconstruction(16 cases)from January 2012 to December 2016 in our hospital.It was compared the difference of operative time,intraoperative blood loss,postoperative shoulder function and fracture healing time between the two groups.2.In the finite element software,there was established a three-dimensional finite element model of the clavicle by using the normal human shoulder computed tomography(CT)to simulate the distal fracture of the Neer type ⅡB,and install the double-plate and the double Endobutton belt loops plate implant respectively,and perform axial compression,Three-point bending,clockwise torsion test.[Results]1.The average follow-up time of all cases was 18.2 months(range 15~22 months).There is no significant difference in the amount of bleeding between the two groups and the operation time.The fracture healing time of the double-plate group and the double Endobutton belt loops plate were(15.2±6.3)weeks and(17.2±8.4)weeks,respectively,and there is statistically significant difference(P<0.05).There is no significant difference in shoulder function scores after surgery of the 1,3,6 and 12 months(P>0.05).2.In the clockwise torsion and axial compression tests,the double plate is significantly less than the double Endobutton belt loops plate in the maximum equivalent stress(P<0.05),but there is no significant differences in the maximum stress displacement between the two groups(P>0.05).[Conclusion]1.Both of the double plate and the double Endobutton belt loops plate can achieve satisfactory clinical results for the distal fracture of the Neer ⅡB type,but the healing time of the double plate fixation is shorter than that of thedouble Endobutton belt loops plate.2.Within a certain range,under the same loading conditions,the double-plate fixed Neer ⅡB distal clavicle fracture is more biomechanically stable than the double Endobutton belt loops plate.3.Under certain conditions,the superior biomechanical stability of the double plate may be beneficial to shorten the healing time of the distal fracture of the Neer type ⅡB compared with the double Endobutton belt loops plate.