Pull-out strength of 0°/30° Kirschner wire syringe external fixators with and without polymer augmentation: A biomechanical study

• Main Authors: Atthakomol,P., Wangjiraphan,N., Krudtong,S., Panya,J., Leuvitoonvejchakij,S., Kraisarin,J., Sananpanich,K.
• Format: Article
• Published: Medical Association of Thailand 2015
• Subjects: Medicine (all)
• Online Access: http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84924326252&origin=inward; http://cmuir.cmu.ac.th/handle/6653943832/38431
• Institution: Chiang Mai University

© 2015, Medical Association of Thailand. All rights reserved. Background: Hand external fixators are in use worldwide and insulin syringes can generally be found in an operating room. Objective: To compare the pull-out strength between degrees of Kirschner wire fixation (0° and 30°) and the effect of filling an insulin syringe with polymer. Material and Method: Pull-out strength was compared between a syringe external fixator and a bone or plastic tube model. Fifty-two plastic tube models and 20 dry phalangeal bones were included. The syringe external fixator was attached via two Kirschner wires. Four variations were studied: 0° non-polymer, 0° with polymer augmentation, 30° non-polymer, and 30° with polymer augmentation. The pull-out strength was measured in each group. Results: The strength of polymer augmentation was higher than non-polymer augmentation at 0° (p = 0.0003) and 30° (p = 0.0002). The Kirschner wire at 30° provided more pull-out strength than at 0° (p = 0.0003) using the syringe with no polymer. However, using the syringe with polymer augmentation, there was no significant difference (p = 0.5136). Conclusion: Polymer augmentation significantly increases the pull-out strength at both degrees of fixation. The degree of fixation significantly increases the pull-out strength only in the non-polymer group, where pinning at 30° was superior to 0°.