Finite Element Analysis of External Fixation Systems for Open Bone Fractures: A Comprehensive Review

Abstract

External fixation is important for treating open fractures. It helps keep bones stable and protects soft tissues. Finite element analysis (FEA) is used to study how external fixators work. It looks at how they handle weight, how materials behave, and how fractures heal without surgery. FEA examines modeling methods, material properties, loading conditions, fixator setups, stress distribution, and patient-specific CT models. Research shows that the closeness of the fixator, pin setup, and frame shape affect how strong and stable it is. Titanium alloys handle stress better than stainless steel under the same load. Recent studies confirm FEA predictions with real-world and lab results, increasing trust in these models. New trends include using CT scans for patient-specific designs, real-time stress monitoring, and making custom fixators with 3D printing. This review points out research gaps and suggests future studies in both computer models and clinical settings.

Introduction

Open fractures, especially of the tibia, are severe injuries that can lead to infection, poor healing, and disability. External fixators are commonly used to stabilize these fractures using pins and frames while preserving blood supply. Their effectiveness depends on design factors such as pin placement, frame distance from bone, and material properties.

Since real-life testing is difficult, FEA is widely used to simulate bone–implant systems and analyze stress distribution, stability, and failure risk. These models use CT-based 3D geometries, realistic material properties (bone and metal implants), fine meshing, and physiological loading conditions (compression, bending, twisting).

Key findings from reviewed studies show that:

• Fixator stability improves when design parameters are optimized (e.g., closer frame placement increases stability).
• Hybrid and cross-locking configurations often provide better stiffness than simple unilateral frames.
• Titanium implants generally perform better than stainless steel due to improved load distribution and lower stress concentration.
• Accurate anatomical modeling significantly improves prediction of stress patterns and implant behavior.

Overall, the review highlights that FEA is a powerful tool for improving external fixator design, helping reduce complications and improve healing outcomes in open fracture treatment.

Conclusion

Finite element analysis (FEA) plays a crucial role in biomechanical investigations of external fixation in open fractures, facilitating the prediction of stress distribution, fracture stability, and construct rigidity in the bone. The critical factors influencing these outcomes include the proximity of the fixator to the bone, pin configuration, frame geometry, and material selection. Titanium alloys are favoured over stainless steel because of their ability to minimise peak stresses and reduce modulus mismatch. Cross-locking frames demonstrate superior performance for specific fracture types. The use of patient-specific CT models enhances clinical relevance, whereas iterative FEA monitoring assists in evaluating fracture healing. However, limitations persist, such as the linear elastic approximation of bone, exclusion of soft tissue, and absence of dynamic loading conditions. Future research should prioritise the clinical validation of FEA predictions, standardisation of modelling protocols, and development of efficient patient-specific pipelines. The integration of FEA with additive manufacturing and digital health technologies positions computational biomechanics at the forefront of personalised fracture-management research.

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Copyright

Copyright © 2026 Uma Jayagonar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.