The biomechanical study and clinical application of internal fixation with Kirschner wire placed in the nerval fossa of ulna for GartlandⅢsupracondylar fractures of humerus in children / 中华创伤杂志

ABSTRACT

Objective To perform a biomechanical study on and compare the stability of internal fixation with closed Kirschner wire in different spots from the epicondylus medialis to sulcus nervi ulnaris and epicondylus lateralis of humerus in the treatment of GartlandⅢsupracondylar fractures of humerus in children in order to provide basis for avoiding cubitus varus in clinic.Methods Twenty models of su- pracondylar fractures were made from ten humerus samples,then divided into two groups(group A and group B).They were fixed with closed Kirschner'wires.Ulnar Kirschner wire varied.In group A five spots were selected averagely from the epicondylus medialis to the sulcus nervi ulnaris.Kirschner wires entered from one of the five spots into another spot of humerus.In group B Kirschner wires entered defferent spots of humerus from the central spot of sulcus nervi ulnaris.Biomechanical tests were carried out,such as axial load,axial displacement,stress intensity,axial rigidity and anti-twisty ability.Forty-six children with Gart- landⅢsupracondylar fracture of humerus were treated and followed up for more than one year.Results In beth groups,with the angle of Kirschner wires and fracture side increasing,the strain and the vertical displacement decreased,the stress intensity and the axial rigidity increased,and the anti-twists ability was enhanced.There was statistic difference(P＜0.05).The follow-up of the 46 patients showed the elbow joint function recovered well with no cubitus varus malformation.Conclusion Internal fixation with closed Kirschner wires in sulcus nervi ulnaris from the epicondylus medialis and the epicondylns lateralis of humerus for GartlandⅢsupracondylar fracture of humerus in children has the advantages of enhancing bio- mechanical stability,effective prevention of secondary replacement of outlying black of the fracture and a- voidance of cubitus varus.It can be widely used clinically.