STABILITY COMPARISON OF THE SCREWED AND UNSCREWED KIRSCHNER WIRE USED IN SUPRACONDYLAR HUMERUS FRACTURES IN CHILDREN: ANSYS 16.0 FINITE ELEMENT ANALYSIS

Abstract Background : This study aimed at finding out the effect of exit height of pins, pin trajectory and pin number on the stability of crossed and lateral pinning configurations used in the fixation of extension-type supracondylar humerus fracture (SHF) in children, through finite element analysis of a novel pediatric humerus bone model. Method : Distal humerus model consisting of the ossific nucleus of the capitellum (ONC) and distal cartilage of a 6-year-old boy was developed computationally. Various crossed and lateral pinning fixation models with either two or three pins were simulated on an extension-type, transverse SHF and tested in six loading directions. Results : Two-crossed pins and 2-lateral pins were respectively more stable in rotation and compression loadings, while 3-crossed pins were the most stable in all loading directions. The crossed pins exiting at the upper border of the distal metaphyseal-diaphyseal junction (MDJ) had the best stiffness among the 2-crossed pins, while the lateral pins with a mid-ONC distal pin provided the best stiffness among the 2-lateral pins. A third pin however, going through the olecranon fossa led to improved stability of the 2-lateral pins in flexion, extension, internal and external rotations. Conclusion : In the fixation of extension-type, transverse supracondylar humerus fractures, 2-crossed pins are only superior to 2-divergent lateral pins in rotational loadings. Two-crossed pins exiting at the upper border of the MDJ provides the best stability, whereas 2-lateral pins with a distal pin going through the middle third of the ONC provides the best stability against compression forces for these fractures. Three-crossed pins however offer the best stability against both compression and rotation forces.This study offers important clues in the preoperative evaluation and management of extension-type supracondylar fractures in children.

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The most stable pinning configurations in transverse supracondylar humerus fracture fixation in children: A novel three-dimensional finite element analysis of a pediatric bone model

10.21203/rs.3.rs-15966/v2 ◽

2020 ◽

Author(s):

Allieu Kamara ◽

Xianglu Ji ◽

Chuang Liu ◽

Tianjing Liu ◽

Enbo Wang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Three Dimensional ◽

Humerus Fracture ◽

Supracondylar Humerus Fracture ◽

Element Analysis ◽

Bone Model ◽

Fractures In Children ◽

Supracondylar Humerus Fractures ◽

Flexion Extension

Abstract Background: This study aimed at finding out the effect of exit height of pins, pin trajectory and pin number on the stability of cross and lateral pinning configurations used in the fixation of extension-type supracondylar humerus fracture (SHF) in children, through finite element analysis of a novel pediatric humerus bone model. Methods: Distal humerus model consisting of the ossific nucleus of the capitellum (ONC) and distal cartilage of a 6-year-old boy was developed via three-dimensional finite modeling. Various cross and lateral pinning fixation models with either two or three pins were simulated on an extension-type, transverse SHF and tested in six loading directions. Results: Two-cross pins and 2-lateral pins were respectively more stable in rotation and compression loadings, while 3-cross pins were the most stable in all loading directions. The cross pins exiting at the upper border of the distal metaphyseal-diaphyseal junction (MDJ) had the best stiffness among the 2-cross pins, while the lateral pins with a mid-ONC distal pin provided the best stiffness among the 2-lateral pins. A third pin however, going through the olecranon fossa led to improved stability of the 2-lateral pins in flexion, extension, internal and external rotations. Conclusion: In the fixation of extension-type, transverse supracondylar humerus fractures, 2-cross pins are only superior to 2-divergent lateral pins in rotational loadings. Two-cross pins exiting at the upper border of the MDJ provides the best stability, whereas 2-lateral pins with a distal pin going through the middle third of the ONC provides the best stability against compression forces for these fractures. Three-cross pins however offer the best stability against both compression and rotation forces. This study offers important clues in the preoperative evaluation and management of extension-type supracondylar fractures in children.

Download Full-text