Three-dimensional Finite Element Analysis Of Residual Lateral Displacement After Manual Reduction Of Distal Radius AO C3.1 Fracture Corrected By Dynamic Airbag Pad Of Small Splint

Objective:To quantitatively study the pressure of residual lateral displacement,angular displacement and rotation displacement of the distal radius AO C3.1 fracture after manual reduction corrected by dynamic airbag pad through using three-dimensional finite element analysis.To verify the effectiveness of correcting the residual displacement of fractures and biomechanical stability wrist of after reduction.Methods:AO C3.1 fracture was taken as research objects.IMAGEWARE 13,MIMICS and AN SYS WORKBENCH were used to simulate straight position injury mechanism of distal radius and 1cm dorsal and radial lateral displacement,volar angulation of 30 degrees’displacement and rotation angulation of 30 degrees’ displacement.Residual displacement of distal radius AO C3.1 fracture after manual reduction corrected by dynamic airbag pad was simulated.The correlation between corrective distance as well as angular dimension of residual displacement and the adjustment of splint pad pressure were quantitatively studied.Meanwhile,the biomechanical stability of carpal bone and soft tissue after correction were analyzed.Results:By FE analysis,in the case of constant load of airbag ribbon and the process of pressure adjustment,the stress nephogram was mainly distributed in dorsal and radialis part in which the fracture end where the airbag pad located was the most significant.The maximum value of stress on wrist’s local soft tissue of C3.1 type fracture calculated by the FE analysis software was 0.080592MPa.The stress on fracture aperture was 2.1259MPa.About 2.4Kpa of the pressure was needed to correct 1mm shift.About 1.3Kpa was needed for 1mm dorsal displacement.4.7KPa was needed to correct volar angulation of 30 degrees’ displacement.3.3KPa was needed to correct rotation angulation of 30 degrees’ displacement.The dynamic airbag pad was depressurized after the restoration of residual shift.At this time,it could be effectively prevented from being displaced by friction among fracture fragments and constraining force of airbag.Conclusion:The intelligent airbag of small splint can fix the C3.1 fracture of the distal radius stably.During the correction of residual displacement,the dynamic airbag pad can effectively correct 1mm dorsal shift,volar angulation of 30 degrees’ displacement,rotation angulation of 30 degrees’ displacement by adjusting the pressure of the pad.Constant load of airbag ribbon and friction among fracture fragments can maintain the fixed effect after depressurizing the airbag pad and prevent from being displaced.