UFix - Emergency External Fixator Surgical Bone-Stabiliser

The UFix System

External fixation is a common technique for treating bone fractures, however commercially available systems remain prohibitively expensive and reliant on complex supply chains, which causes significant challenges in conflict environments.

UFix is a novel low-cost uniplanar external fixator system designed for manufacture using entry-level 3D printers. The design prioritises mechanical performance, ease of manufacture, and configurability.

Features

• CAD Design: Developed in SolidWorks.

• Testing: Subjected to preliminary Finite Element Analysis (FEA) and mechanical testing at Imperial College London.

• Adaptability: Initially designed for lower limb applications but can be adapted for upper limb use via parametric modelling of rod and pin sizes.

• Assembly: Simple and inspired by commercial external fixators, modelled after the metal Imperial External Fixator.

• Sizes: Currently only imperial 0.5" rod supported, with bone pin 5mm.

Due to the rapid development of this device, please look at our GitHub repository for the latest files and information.

Print Instructions

• Infill MUST be 100%

• PLA material (see below)

• Layer height: 0.2mm

• No support or Brim

Choice of 3D printing material depends on local material availability and printer compatibility, however note this may affect performance/strength and has not been tested! Recommended materials and printer models may change as testing progresses.

Bill of Materials

A detailed Bill of Materials is available as a PDF in the files.

Printed Parts:

• 4x UFix Rod-to-Pin Clamp

Other Hardware:

• 4x Schanz Bone Pins

• 1/2 inch diameter SS316 Rod

• 4x M8 bolt, 55mm length (ISO 4017, SS316)

• 4x M8 nut (ISO 4032, SS316)

• 4x M8 washer, 16mm OD (DIN 125)

Total cost is ~£65.

Assembly Instructions

A step-by-step guide for assembling the fixator is available as a PDF in the files.

Note that a washer must be used with the bolt.

Status and Disclaimer

Development Stage

This medical device project is in the prototype phase, and is subject to further design and testing.

Clinical use is strictly prohibited in it's current state. This device is not certified or tested for human or animal clinical procedures. The device is for research, academic, and educational purposes only.

Licensing

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). It is not permitted to build derivative models based on UFix or its features and make them publicly available. This is to ensure safety of the device is guaranteed before its worldwide use.

Contact & Acknowledgement

If any issues occur, please share with the team via the comments here or on the GitHub,

Developed by the research team in the Department of Bioengineering at Imperial College London.

Many thanks to the many researchers who have been involved in this project:
Dr Mehdi Saeidi, Dr Angus Clark, Prof Anthony Bull, Jenny Shang, Hannah Tollemache, and Kyung-Hoon Moon.