Material selection and design of external fixator clamp for metacarpal fractures Philip Ajon M. Basat a , Emmanuel P. Estrella b,c , Eduardo R. Magdaluyo Jr. a,⇑ a Department of Mining, Metallurgical and Materials Engineering, University of the Philippines, Diliman, Quezon City 1101, Philippines b Institute of Clinical Epidemiology, National Institute of Health, University of the Philippines, Manila 1000, Philippines c Division of Hand and Reconstructive Microsurgery, College of Medicine, University of the Philippines, Manila 1000, Philippines article info Article history: Received 25 April 2020 Received in revised form 3 June 2020 Accepted 6 June 2020 Available online xxxx Keywords: Materials selection External fixator Metacarpal fracture TOPSIS Multi-criteria decision making abstract Metacarpal fractures are one of the most common types of fractures, comprising nearly 20% of emergency room visits. These types of fractures, however, are often neglected and left untreated. The lack of treat- ment, which usually due to high cost, may lead to deformities and disabilities for the affected patient. This study involved material selection and design of a miniature external fixator that may be easily man- ufactured, leading to improved accessibility and affordability. The study used Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria decision-making method to screen can- didate materials and determine which materials were the most suitable to the desired application. For a metallic fixator, Ti 6 Al 4 V was identified to be the best material and for a polymer-based fixator, the poly- ethylene terephthalate (PET) was found to be the most suitable. A design was also developed to serve as a basis for prototype. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 10th International Con- ference on Key Engineering Materials 2020. 1. Introduction One of the most common types of bone fractures are those found in the metacarpal bones, consisting of 14–28% of hospital emergency room visits. Despite being a common injury, this type of fracture is often classified as a minor injury and treated as less urgent unlike those of larger fractures. The lack of corrective action may result to further disabilities and deformities. One reason why such fractures are not treated immediately is due to limited com- mercially available treatment [1]. Available treatments for small fractures include braces which are purely external and involves application of constant pressure on the fractured area. However, the constant pressure that the area is exposed to may lead to bruises. There are also treatments that require intensive surgery such as percutaneous pin fixation, intraosseous and tension band wiring, interfragmentary screws, and plates and screws. These methods involve planting screws, pins, and plates directly into the bone around fractured area to hold the fragments in place dur- ing healing. After the fracture heals, these implants may be removed which will require further surgery [2]. An alternative solution to implants is the use of external fixa- tors. External fixators are devices used primarily for fracture heal- ing with applications in deformity correction, limb lengthening, and defect treatment. This medical apparatus is mostly used for fractures involving the humerus, forearm, pelvis, femur, tibia, and fibula [3]. Compared to implants, external fixators require less invasive surgery. These are applied by placing pins through the fractured bones and the pins are externally held by clamps which are also attached to a bar. External fixators may be adjusted once applied, allowing micro-movements which help in fracture heal- ing. Certain parts of such fixators may also be used multiple times such as the clamp and the bar, as these parts ideally do not directly interfere with the tissue. One downside to external fixators, how- ever, is that the area affected by the pins are prone to infections since it is exposed to the environment [4]. Current commercial external fixators are designed specifically for larger bone fractures. Miniature external fixators do exist but are rare and need to be customized to fit the application. In this study, a material selection on screened materials was performed to identify the best material for the external fixator. A design for a miniature external fixator was also developed that may be pro- duced easily through additive manufacturing or 3D printing to improve the availability and affordability of fracture treatments. https://doi.org/10.1016/j.matpr.2020.06.129 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 10th International Conference on Key Engineering Materials 2020. ⇑ Corresponding author. E-mail address: edmagdaluyo1@up.edu.ph (E.R. Magdaluyo Jr.). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: P. A. M. Basat, E. P. Estrella and E. R. Magdaluyo, Material selection and design of external fixator clamp for metacarpal fractures, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.06.129