Biomechanical Evaluation Method to Optimize External Fixator Configuration in Long Bone Fractures—Conceptual Model and Experimental Validation Using Pilot Study

Abstract

External fixation is a commonly used method in stabilizing fracture sites. The performance of the fixator depends on how it affects the mechanical properties of the fracture site and is governed by parameters like the fixator type and fixator configuration. Identifying ideal configurations prior to surgery will help surgeons in planning the procedure, limiting the possibility of complications such as non-union. In this study, a framework has been proposed as a surgical pre-planning tool, to assist surgeons compare mechanical properties of a fracture site under different fixator configurations, and thereby identify the optimum solution. A computational tool was identified as the best method for this purpose. Cost and time of computation were given special consideration to reduce complexity in clinical settings. A pilot study was conducted on a section of the proposed framework, where the aim was to understand the feasibility of implementation. In the pilot study, a unilateral uni-planar fixator on a simple diaphyseal transverse fracture was analyzed. During the pilot study the selected fixator was tested and a few models were developed to assess system stability. The models were then compared to identify the optimum model that could be used with the proposed framework. The proposed framework provided a suitable solution for the use case and out of the models developed the simplified finite element model was identified as the best option for the use case.

Low-cost locally manufacturable unilateral imperial external fixator for low- and middle-income countries

“…There have been many studies on low-cost external fixators, but most of them have reported the clinical outcomes ( 2 , 26 – 28 ) often without performing thorough biomechanical investigations ( 10 , 19 , 29 ). This could be associated with the circumstances that the devices have been developed under, i.e., poor economical condition or conflict.…”

“…During the project, several versions of the device were developed and modified according to the feedback received from the local partners and surgeons. The final design only is discussed in this paper and other designs were investigated by our partners in Sri Lanka ( 19 ).…”

Limb Salvage after Lower-Leg Fracture and Popliteal Artery Transection—The Role of Vessel-First Strategy and Bone Fixation Using the Ilizarov External Fixator Device: A Case Report

“…Whether this is attributable to the treatment itself, the thin-wire circular device, or the severity of the injury was unclear, a prolonged healing time for tibial fractures treated with external fixators has been reported in the literature, which may lead to an increased risk of loss of wire pre-tension, potentially affecting the process of fracture healing [22,23]. It has been shown that changes in the mechanical properties of a fracture site affect the time taken for a fracture to heal, thus modifying the type and proportion of tissues formed [24]. In addition, poor new bone formation and premature removal can lead to axial deformity and re-fracture of the new bone [25,26].…”

An engineering review of external fixators

“…Furthermore, such studies will be able to identify the most cost-effective material and manufacturing technique for each component of the EF, which when incorporated into conceptual models such as the one developed by Sellahewa et al. [129] ,can lead to better optimization and customization of EFs in the future.…”