The influence of wire positioning upon the initial stability of scaphoid fractures fixed using Kirschner wires: A finite element study

Ezquerro, F.; Jiménez, S.; Pérez, A.; Prado, M.; de Diego, G.; Simón, A.

doi:10.1016/j.medengphy.2006.08.005

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Volume 29, Issue 6 , Pages 652-660, July 2007

The influence of wire positioning upon the initial stability of scaphoid fractures fixed using Kirschner wires:

A finite element study

F. Ezquerro
- Department of Mechanical Engineering, Universidad de Málaga, ETSII, Pza. El Ejido s/n, 29013 Málaga, Spain
- Corresponding author. Tel.: +34 952 131314; fax: +34 952 132691.
S. Jiménez
- Department of Mechanical Engineering, Universidad de Málaga, ETSII, Pza. El Ejido s/n, 29013 Málaga, Spain
A. Pérez
- Department of Mechanical Engineering, Universidad de Málaga, ETSII, Pza. El Ejido s/n, 29013 Málaga, Spain
M. Prado
- Department of Mechanical Engineering, Universidad de Málaga, ETSII, Pza. El Ejido s/n, 29013 Málaga, Spain
G. de Diego
- Servicio de Traumatología, Hospital Virgen de la Vitoria, Colonia Sta. Inés s/n, 29010 Málaga, Spain
A. Simón
- Department of Mechanical Engineering, Universidad de Málaga, ETSII, Pza. El Ejido s/n, 29013 Málaga, Spain

Received 15 June 2006; received in revised form 4 August 2006; accepted 7 August 2006. published online 30 October 2006.

Abstract

A finite element model of the carpal scaphoid and its joints was developed to study how wire positioning affects the initial stability of the fixation of scaphoid waist fractures using Kirschner wires. A transverse fracture of the scaphoid waist was simulated along with its fixation using five different two-wire configurations. The resulting models were subjected to a load simulating a 200N force passing through the wrist. Friction between bony fragments was taken into account; as the friction coefficient of cancellous bone is unknown, three different values were analysed. For each of these friction coefficient values, the smallest transverse interfragmentary displacements, and consequently maximum initial stability, were obtained for the model that simulated the maximum gap between wires in the plane of fracture. Results also show that for a similar gap in the plane of fracture, more stable fixation can be achieved when wires cross each other not only in the frontal plane of the hand, but also perpendicularly to it.