scholarly journals Low cost 3D printed clamps for external fixator for developing countries: a biomechanical study

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Felix J. Landaeta ◽  
Jose Nauaki Shiozawa ◽  
Arthur Erdman ◽  
Cara Piazza
Keyword(s):  
Developing Countries ◽  
External Fixation ◽  
Axial Compression ◽  
External Fixator ◽  
Low Cost ◽  
Biomechanical Properties ◽  
External Fixators ◽  
The Novel ◽  
Astm Standard ◽  
3D Printed

Abstract Background External fixation is a mainstream limb reconstruction technique, most often used after a traumatic injury. Due to the high rates of trauma in developing countries, external fixation devices are often utilized for immediate fracture stabilization and soft tissue repair. Proper external fixation treatment too often still fails to be adopted in these regions due to the high cost and trauma complexity. A novel, inexpensive, unilateral fixator was constructed using 3D printed clamps and other readily available supporting components. ASTM standard F1541 tests were used to assess the biomechanical properties of this novel external fixator. Methods Applicable sections of ASTM standard F1541 were used to determine the biomechanical properties of the novel external fixator. 3D printed clamps modeled using SolidWorks and printed with chopped carbon fibers using a fuse deposition modeling (FDM) based 3D printer by Markforged (Boston, MA) were used. This study included 3 different testing configurations: axial compression, anterior-posterior (AP) bending, and medial-lateral (ML) bending. Using the novel unilateral fixator with 3D printed clamps previously sterilized by autoclave, an input load was applied at a rate of 20 N/s, starting at 0 N via a hydraulic MTS tester Model 359. Force and deformation data were collected at a sampling rate of 30 Hz. There was a load limit of 750 N, or until there was a maximum vertical deformation of 6 mm. Also, 4 key dimensions of the 3D printed clamps were measured pre and post autoclave: diameter, width, height and length. Results The novel external fixator had axial compression, AP and ML bending rigidities of 246.12 N/mm (σ = 8.87 N/mm), 35.98 N/mm (σ = 2.11 N/mm) and 39.60 N/mm (σ =2.60 N/mm), respectively. The 3D printed clamps shrunk unproportionally due to the autoclaving process, with the diameter, width, height and length dimensions shrinking by 2.6%, 0.2%, 1.7% and 0.3%, respectively. Conclusion Overall, the biomechanical properties of the novel fixator with 3D printed clamps assessed in this study were comparable to external fixators that are currently being used in clinical settings. While the biomechanics were comparable, the low cost and readily available components of this design meets the need for low cost external fixators in developing countries that current clinical options could not satisfy. However, further verification and validation routines to determine efficacy and safety must be conducted before this novel fixator can be clinically deployed. Also, the material composition allowed for the clamps to maintain the appropriate shape with minimal dimensional shrinkage that can be accounted for in clamp design.

scholarly journals Results of application of external fixation with different types of fixators

2012 ◽  
Vol 140 (5-6) ◽  
pp. 332-338 ◽  
Author(s):  
Predrag Grubor ◽  
Milan Grubor
Keyword(s):  
External Fixation ◽  
External Fixator ◽  
Bone Fractures ◽  
Biomechanical Properties ◽  
Long Bone ◽  
External Fixators ◽  
Vertical Force ◽  
Computer Simulator ◽  
Lateral Plane ◽  
Healthy Part

Introduction. Extra-focal or external fixation is the method of fracture fixation through the healthy part of the bone using pins or wires. Objective. The aim was to determine which external splints (Ortofix, Mitkovic, Charnley and Ilizarov) had the best biomechanical properties in primary stabilization of spiral, transverse and commutative bone fractures. Methods. To determine the investigation methodology of biomechanical characteristics of the external fixator we used mathematical and computer simulator (software), juvidur physical model and clinical examination. Results. Values of advancing fragments in millimetres obtained by the study of mathematical and computer simulator (software): Charnley - 0.080 mm, Mitkovic M 20 - 0.785 mm, Ilizarov - 2.245 mm and Ortofix - 1.400 mm. In testing the juvidur model the following values were obtained: the external fixator Mitkovic M20 - 1.380 mm, Ortofix - 1.470 mm, Ilizarov - 2.410 mm, and Charnley - 2.510 mm. Clinical research of biomechanical characteristics of the effect of vertical force yielded the following results: Mitkovic M20 - 0.89 mm, Ortofix - 0.14 mm, Charnley - 0.80 mm and Ilizarov - 1.23 mm. Conclusion. When determining the total number of the stability test splints under the effect of vertical force (compression) and force effect in antero-posterior, later-lateral plane of cross, spiral and comminuted long bone fractures, the best unified biomechanical stability was shown by the following external fixators: firstly, Mitkovic M20 (0.93mm), secondly, Charnley fixator (1.14 mm), thirdly, Ortofix (1.22 mm), and fourthly, Ilizarov (1.60 mm).

Methyl methacrylate in external fixation of supracondylar humerus fractures: An experimental study

2018 ◽  
Vol 232 (10) ◽  
pp. 1025-1029
Author(s):  
Ali Güleç ◽  
Mehmet Ali Acar ◽  
Bahattin Kerem Aydin ◽  
Teyfik Demir ◽  
Mustafa Özkaya
Keyword(s):  
Methyl Methacrylate ◽  
External Fixation ◽  
External Fixator ◽  
External Fixators ◽  
Three Point Bending ◽  
Fixation Methods ◽  
Supracondylar Humerus Fractures ◽  
Methacrylate Group ◽  
Humerus Fractures ◽  
K Wires

Supracondylar humerus fractures are common fractures around the elbow. Open fractures, comminuted metaphyseal fractures and also fractures with bone loss may need to be treated with external fixators. The aim of this study is to compare two different external fixators, tubular external fixators and polymethyl methacrylate with K wires external fixators, with regard to stiffness and stability for metaphyseal-diaphyseal osteotomies of distal humerus close to the joint. Six matched pairs (24 specimens) of second-generation sawbone humerus were prepared in a standard fashion to create a metaphyseal fracture, 5 cm proximal to the distal joint line of humerus and were randomly divided into two groups of 12 specimens each. Each sawbone humerus was osteotomized transversely at the mid-olecranon fossa with a 2-mm oscillating saw to simulate a Gartland type III fracture. The osteotomy was then reduced and stabilized using two different external fixation methods: carbon tubular external fixator with Schanz screws and methyl methacrylate with multiple K wires. Three-point bending and torsion tests were performed on the specimens. Bending and torsional stiffness of specimens were obtained for the fixation methods. According to the results of the study, the methyl methacrylate group has provided higher stiffness than classical tubular fixator with Schanz screws in three-point bending test (7.79 ± 2.33 N/mm vs 3.78 ± 1.18 N/mm, p = 0.006). The methyl methacrylate group also showed better stiffness in torsion test (0.12 ± 0.042 N m/° vs 0.067 ± 0.013 N m/°, p = 0.02). We determined for the first time in literature that external fixation with methyl methacrylate was significantly superior to the classical tubular external fixator with Schanz screws with regard to stiffness and stability under three-point bending and torsional loads. Moreover, methyl methacrylate is inexpensive and easily applied.

Evaluation of Stiffness and Stress of External Fixators with Curved Acrylic Connecting Bars

2000 ◽  
Vol 13 (02) ◽  
pp. 65-72 ◽  
Author(s):  
R. Shahar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Axial Compression ◽  
External Fixator ◽  
External Fixators ◽  
Analysis Method ◽  
Lateral Bending ◽  
Element Analysis ◽  
The Finite Element Analysis

SummaryThe use of acrylic connecting bars in external fixators has become widespread in veterinary orthopaedics. One of the main advantages of an acrylic connecting bar is the ability to contour it into a curved shape. This allows the surgeon to place the transcortical pins according to safety and convenience considerations, without being bound by the requirement of the standard stainless steel connecting bar, that all transcortical pins be in the same plane.The purpose of this study was to evaluate the stiffness of unilateral and bilateral medium-sized external fixator frames with different curvatures of acrylic connecting bars. Finite element analysis was used to model the various frames and obtain their stiffness under four types of load: Axial compression, four-point medio-lateral bending, fourpoint antero-posterior bending and torsion. The analysis also provided the maximal pin stresses occurring in each frame for each loading condition.Based on the results of this study, curvatures of acrylic connecting bars of up to a maximal angular difference between pins of 25° will result in very similar stiffness and maximal pin stresses to those of the equivalent, uniplanar stainless steel system. In both unilateral and bilateral systems the stiffness decreases slightly as angulation increases for axial compression and medio-lateral bending, increases slightly for torsion and increases substantially for antero-posterior bending.External fixator systems with curved acrylic connecting bars are commonly used in veterinary orthopaedics. This paper evaluates the biomechanical performance of such systems by applying the finite element analysis method. It shows that external fixators with curved acrylic connecting bars exhibit stiffness and maximal pin stresses which are similar to those of the standard stainless steel system.

scholarly journals Investigating the biomechanics function of the plate-type external fixator in the treatment of tibial fractures: a biomechanical study

2019 ◽  
Author(s):  
Di Shi ◽  
Kaiyuan Liu ◽  
Haomeng Zhang ◽  
Xinli Wang ◽  
Guochen Li ◽  
...  
Keyword(s):  
Axial Compression ◽  
External Fixator ◽  
Failure Modes ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Four Point Bending ◽  
Low Profile ◽  
Load Mode ◽  
The Stability ◽  
Plate Type

Abstract Background People have been pursuing to design an external fixator with the optimal biomechanics function and the lowest profile, since the fracture healing is dependent on the stability and durability of fixation and a low profile is more acceptable to patients. The plate-type external fixator, a novel prototype of an external tibial fixation device, is a low profile construct. However, the biomechanical properties remained unclear. The objective of the study was to investigate stiffness and strength of the plate-type external fixator and the unilateral external fixator. We hypothesized that the plate-type external fixator could provide higher stiffness, while retaining sufficient strength. Methods Fifty-four cadaver tibias underwent a standardized midshaft osteotomy to create a fracture gap model to simulate a comminuted diaphyseal fracture. All specimens were randomly divided into three groups of eighteen specimens each and stabilized with either the unilateral external fixator or the two configurations of the plate-type external fixator. Six specimens of each configuration were tested to determine fixation stiffness in axial compression, four-point bending, and torsion, respectively. Afterwards, dynamically loading until failure was performed in each load mode to determine construct strength and failure modes. Results The plate-type external fixator provided higher stiffness and strength compared with the traditional unilateral external fixator. The highest biomechanics was observed for the classical plate-type external fixator, with the extended plate-type external fixator close behind. Conclusions The plate-type external fixator is stiffer and stronger than the traditional unilateral external fixator under axial compression, four-point bending and torsion loading conditions.

scholarly journals Optimization of a Patient-Specific External Fixation Device for Lower Limb Injuries

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2661
Author(s):  
Mohammed S. Alqahtani ◽  
Abdulsalam Abdulaziz Al-Tamimi ◽  
Mohamed H. Hassan ◽  
Fengyuan Liu ◽  
Paulo Bartolo
Keyword(s):  
Topology Optimization ◽  
External Fixation ◽  
Polylactic Acid ◽  
External Fixator ◽  
Bone Fractures ◽  
Healing Process ◽  
Patient Specific ◽  
External Fixators ◽  
Fixation Devices ◽  
Limb Injuries

The use of external fixation devices is considered a valuable approach for the treatment of bone fractures, providing proper alignment to fractured fragments and maintaining fracture stability during the healing process. The need for external fixation devices has increased due to an aging population and increased trauma incidents. The design and fabrication of external fixations are major challenges since the shape and size of the defect vary, as well as the geometry of the human limb. This requires fully personalized external fixators to improve its fit and functionality. This paper presents a methodology to design personalized lightweight external fixator devices for additive manufacturing. This methodology comprises data acquisition, Computer tomography (CT) imaging analysis and processing, Computer Aided Design (CAD) modelling and two methods (imposed predefined patterns and topology optimization) to reduce the weight of the device. Finite element analysis with full factorial design of experiments were used to determine the optimal combination of designs (topology optimization and predefined patterns), materials (polylactic acid, acrylonitrile butadiene styrene, and polyamide) and thickness (3, 4, 5 and 6 mm) to maximize the strength and stiffness of the fixator, while minimizing its weight. The optimal parameters were found to correspond to an external fixator device optimized by topology optimization, made in polylactic acid with 4 mm thickness.

scholarly journals Surgical treatment of tibial nonunion after wounding by high velocity missile and external fixators: A case report

2012 ◽  
Vol 140 (7-8) ◽  
pp. 515-520
Author(s):  
Ivan Golubovic ◽  
Zoran Vukasinovic ◽  
Predrag Stojiljkovic ◽  
Zoran Golubovic ◽  
Danilo Stojiljkovic ◽  
...  
Keyword(s):  
External Fixation ◽  
External Fixator ◽  
High Velocity ◽  
Primary Treatment ◽  
External Fixators ◽  
Risk Of Infection ◽  
Tissue Destruction ◽  
Reconstructive Operations ◽  
Delayed Healing ◽  
Tibial Nonunion

Introduction. The missiles of modern firearms can cause severe fractures of the extremity. High velocity missile fractures of the tibia are characterized by massive tissue destruction and primary contamination with polymorphic bacteria. Treatment of these fractures is often complicated by delayed healing, poor position healing, nonhealing and bone tissue infection. Case Outline. We present the management of tibial nonunion after wounding by high velocity missile and primary treatment by external fixation in a 25-year-old patient. The patient was primarily treated with external fixation and reconstructive operations of the soft tissue without union of the fracture. Seven months after injury we placed a compression-distraction external fixator type Mitkovic and started with compression and distraction in the fracture focus after osteotomy of the fibula and autospongioplasty. We recorded satisfactory fracture healing and good functional outcome. Conclusion. Contamination and devitalization of the softtissue envelope increase the risk of infection and nonunion in fractures after wounding by high velocity missile. The use of the compression-distraction external fixator type Mitkovic may be an effective method in nonunions of the tibia after this kind of injury.

scholarly journals Investigating the biomechanical function of the plate-type external fixator in the treatment of tibial fractures : a biomechanical study

2020 ◽  
Author(s):  
Di Shi ◽  
Kaiyuan Liu ◽  
Haomeng Zhang ◽  
Xinli Wang ◽  
Guochen Li ◽  
...  
Keyword(s):  
Axial Compression ◽  
External Fixator ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Loading Mode ◽  
Four Point Bending ◽  
Low Profile ◽  
The Stability ◽  
Sufficient Strength ◽  
Plate Type

Abstract Background The design of an external fixator with the optimal biomechanical function and the lowest profile has been highly pursued, as fracture healing is dependent on the stability and durability of fixation, and a low profile is more desired by patients. The plate-type external fixator, a novel prototype of an external tibial fixation device, is a low profile construct. However, its biomechanical properties remain unclear. The objective of this study was to investigate the stiffness and strength of the plate-type external fixator and the unilateral external fixator. We hypothesized that the plate-type external fixator could provide higher stiffness while retaining sufficient strength. Methods Fifty-four cadaver tibias underwent a standardized midshaft osteotomy to create a fracture gap model to simulate a comminuted diaphyseal fracture. All specimens were randomly divided into three groups of eighteen specimens each and stabilized with either a unilateral external fixator or two configurations of the plate-type external fixator. Six specimens of each configuration were tested to determine fixation stiffness in axial compression, four-point bending, and torsion, respectively. Afterwards, dynamic loading until failure was performed in each loading mode to determine the construct strength and failure mode. Results The plate-type external fixator provided higher stiffness and strength than the traditional unilateral external fixator. The highest biomechanics were observed for the classical plate-type external fixator, closely followed by the extended plate-type external fixator. Conclusions The plate-type external fixator is stiffer and stronger than the traditional unilateral external fixator under axial compression, four-point bending and torsion loading conditions.

scholarly journals Investigating the biomechanical function of the plate-type external fixator in the treatment of tibial fractures : a biomechanical study

2020 ◽  
Author(s):  
Di Shi ◽  
Kaiyuan Liu ◽  
Haomeng Zhang ◽  
Xinli Wang ◽  
Guochen Li ◽  
...  
Keyword(s):  
Axial Compression ◽  
External Fixator ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Loading Mode ◽  
Four Point Bending ◽  
Low Profile ◽  
The Stability ◽  
Sufficient Strength ◽  
Plate Type

Abstract Background The design of an external fixator with the optimal biomechanical function and the lowest profile has been highly pursued, as fracture healing is dependent on the stability and durability of fixation, and a low profile is more desired by patients. The plate-type external fixator, a novel prototype of an external tibial fixation device, is a low profile construct. However, its biomechanical properties remain unclear. The objective of this study was to investigate the stiffness and strength of the plate-type external fixator and the unilateral external fixator. We hypothesized that the plate-type external fixator could provide higher stiffness while retaining sufficient strength. Methods Fifty-four cadaver tibias underwent a standardized midshaft osteotomy to create a fracture gap model to simulate a comminuted diaphyseal fracture. All specimens were randomly divided into three groups of eighteen specimens each and stabilized with either a unilateral external fixator or two configurations of the plate-type external fixator. Six specimens of each configuration were tested to determine fixation stiffness in axial compression, four-point bending, and torsion, respectively. Afterwards, dynamic loading until failure was performed in each loading mode to determine the construct strength and failure mode. Results The plate-type external fixator provided higher stiffness and strength than the traditional unilateral external fixator. The highest biomechanics were observed for the classical plate-type external fixator, closely followed by the extended plate-type external fixator. Conclusions The plate-type external fixator is stiffer and stronger than the traditional unilateral external fixator under axial compression, four-point bending and torsion loading conditions.

scholarly journals Evaluation Of The Trochantertc Fracture Of The Femur Treated By Uniaxial External Fixator In Risk Elderly Patient.

1970 ◽  
Vol 39 (3) ◽  
Author(s):  
AKM Zahiruddin ◽  
SK Paul ◽  
MLR Khan ◽  
SN Alam
Keyword(s):  
External Fixation ◽  
External Fixator ◽  
Low Cost ◽  
Operation Time ◽  
Attractive Alternative ◽  
Surgical Trauma ◽  
Trochanteric Fractures ◽  
Fracture Union ◽  
Medical Disorders ◽  
Fractures Of The Femur

Trochanteric fractures occur in elderly osteoporotic patients with concomitant medical disorders, who are unable to tolerate lengthy periods of anaesthesia or any appreciable blood loss. For this reason, external fixation represents an attractive alternative. External fixation can be easily applied by modern equipments like c-arm. It is simple, quick, low cost with minimal surgical trauma, lower rate of morbidity, less operation time, shorter duration of hospital stay and early mobilization.This clinical study is the result of trochanteric fractures of the femur in high risk elderly patients treated with an external fixator on 11 patients over a period of 2 years from July 2005 to June 2007 at NITOR.The object of the study was to evaluate the outcome of operation. All the patients were in a poor general condition and with severe associated medical diseases and also more than one condition were present. The external fixator was removed after adequate clinical radiological sign of fracture union (averaged 16.54 weeks) as an out patient procedure. The overall radiological improvement was observed in 11 cases in 6 months followup. The overall satisfactory result was observed in 9 (81.8%) and unsatisflictory in 2(18.2%).DOI: http://dx.doi.org/10.3329/bmj.v39i3.9951 BMJ 2010; 39(3)

scholarly journals Hughes External Fixator in Treatment of Tibial Fractures

1985 ◽  
Vol 78 (10) ◽  
pp. 830-837 ◽  
Author(s):  
C M Court-Brown ◽  
S P F Hughes
Keyword(s):  
External Fixation ◽  
External Fixator ◽  
Prospective Trial ◽  
Tibial Fractures ◽  
External Fixators ◽  
Complication Rates ◽  
Initial Reduction ◽  
Diaphyseal Fractures ◽  
Grade Ii

The results of a prospective trial of the use of the Hughes unilateral external fixator in the management of 48 tibial diaphyseal fractures are presented. Good results were obtained in grade II and III fractures but not in closed and grade I fractures. The results and complication rates were comparable with those of other more complex external fixators. Good results were found to be dependent on the adequacy of the initial reduction and the duration of external fixation, but independent of alterations in pin angle, length and location as well as fixator location.

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