Biomechanical evaluation of pin placement of external fixator in treating tranverse tibia fracture: Analysis on first and second cortex of cortical bone

Abstract

Biomechanical perspective of external fixator is one of the greatest factor to consider in successfully treating bone fracture. This is due to the fact that mechanical behavior of the structure can be analyzed and optimized in order to avoid mechanical failure, increase bone fracture healing rate and prevent pre-term screw loosening. There are three significant factors that affect the stability of external fixator which are the placement of pin at the bone, configuration and components of external fixator. These factors lead to one question: what is the optimum pin placement in which exerts optimum stability? To date, literature on above mentioned factors is limited. Therefore, we conducted a study to evaluate the uniplanar-unilateral external fixator for two different pin placement techniques in treating transverse tibia fracture via finite element method. The study was started off with the development of transverse tibia fracture using Mimics software. Computed tomography (CT) data image was utilized to develop three dimensional tibia bone followed by crafting fracture on the bone. Meanwhile, the external fixator was developed using SolidWork software. Both tibia bone and external fixator were meshed in 3-matic software with triangular mesh element. Simulation of this configuration was took place in a finite element software, Marc.Mentat software. A load of 400 N was applied to the proximal tibia bone in order to simulate stance phase of a gait cycle. From the findings, the pin placement at the second cortex of bone provided optimum stability in terms of stress distribution and displacement, which should be considered for better treatment for transverse tibia fracture. On the other hand, the pin placement at first cortex should be avoided to prevent many complications.

Finite Element Analysis of External Fixator for Treating Femur Fracture: Analysis on Stainless Steel and Titanium as Material of External Fixator

“…After 3D model of both fixator and femur were completed, the next step was to assemble both 3D model before proceed to simulation stage. 3-Matics Medical software was used in positioning and align the external fixator with the femur (Ramlee et al, 2019). Both external fixation techniques were consisted of four pins, four clamps and one connecting rod.…”

Influence of parameter deviation on the closeness of the tibial limb and external fixator based on a novel collision detection algorithm

“…Similarly, if m 2 ¼ n 12 Â p 2 p 0 , the position vector of foot point n 2 can be found with Equation (11).…”

“…Currently, the widely used types of external fixator include unilateral, bilateral, delta, hybrid, Ilizarov, hexapod, etc 3,6–8 . The unilateral frame can not only provide flexible and stable fixation but also leave a larger space for movement of the limb joints 9–11 . However, it has such disadvantages that weaker lateral rigidity and poor ability to withstand lateral shearing forces 12,13 .…”

“…3,[6][7][8] The unilateral frame can not only provide flexible and stable fixation but also leave a larger space for movement of the limb joints. [9][10][11] However, it has such disadvantages that weaker lateral rigidity and poor ability to withstand lateral shearing forces. 12,13 The Ilizarov frame, widely used in various disorders of the long bone, has strong lateral rigidity and can provide high stability, 14 but it requires clinicians to have a long learning curve due to a large number of parts and the complex configuration assembly.…”