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 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 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 Femoral Periprosthetic Fracture Treatment Using the Ortho-Bridge System: A Biomechanical Study

2021 ◽  
Author(s):  
wen wang ◽  
Yuntao Long ◽  
Yubin Qi ◽  
Guilai Zuo ◽  
Qingjie Zhang ◽  
...  
Keyword(s):  
Axial Compression ◽  
Torsion Angle ◽  
Periprosthetic Fracture ◽  
Failure Modes ◽  
Fracture Site ◽  
Biomechanical Study ◽  
Compression Failure ◽  
System P ◽  
Significant Difference ◽  
Bridge System

Abstract Background: We undertook a comparative biomechanical study of type B1 fractures around the femoral prosthesis following cemented hip arthroplasty using the Ortho-Bridge System (OBS) and a locking compression plate/locking attachment plate structure (LCP+LAP), and aimed to determine the effectiveness and advantages of the OBS when treating this fracture type. Methods: An OBS fixation model was designed based on OBS and LCP+LAP fixation characteristics. The LCP+LAP combination (Group A) and three different OBS combinations (Groups B, C, and D) were used to fix a B1 fracture model with a femoral periprosthetic fracture. Axial compression and torsion experiments were then performed using simple and comminuted fracture models. We conducted axial compression failure, model stiffness, and torsion angle tests, and tested the vertical load of final failure. Results: When simulating simple oblique fractures, no significant difference was found in terms of stiffness between the four groups in the axial compression experiment (P = 0.257). The torsion angle of the LCP+LAP system was significantly higher than that of the OBS (P < 0.05); however, there was no significant difference in the torsion angle between the OBS combinations (P > 0.05). Axial compression experimental data showed that stiffness in the three OBS combinations was higher than that in the LCP+LAP system (P = 0.000). Torsion angles of the three OBS combinations were smaller than those of the LCP+LAP system (P < 0.05). In the axial compression failure test, the fixed failure mode in the LCP+LAP system involved destruction of the contact cortex at the fracture site, while the failure modes in the three OBS combinations involved destruction of the contact cortex at the fracture site and the fracture around the screws above the osteotomy. Conclusion: Compared with the LCP+LAP, the OBS showed superior biomechanical results. Furthermore, the OBS has the advantage of multiple choices and high flexibility of combinations. Stress dispersion was helpful in avoiding internal fixation failure during early postoperative functional exercise.

Effect of headless compression screw on construct stability for centre of rotation and angulation-based levelling osteotomy

2017 ◽  
Vol 30 (04) ◽  
pp. 1-5
Author(s):  
Mireya Perez ◽  
Mohammad Hossain ◽  
Edward Silverman ◽  
Randall Fitch ◽  
Ryan Wicker ◽  
...  
Keyword(s):  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Bone Plate ◽  
Compression Screw ◽  
Headless Compression Screw ◽  
Flexural Testing ◽  
Torsional Testing ◽  
The Difference ◽  
The Stability ◽  
Centre Of Rotation

Summary Objective: To compare the biomechanical properties of bone and implant constructs when used for the centre of rotation and angulation (CORA) based levelling osteotomy, with and without implantation of a trans-osteotomy headless compression screw tested under three-point flexural and torsional forces; thereby determining the contribution of a trans-osteotomy headless compression screw with regards to stability of the construct. Methods: Experimental biomechanical study utilizing 12 pairs of cadaveric canine tibias. Using the CORA based levelling osteotomy (CBLO) procedure, the osteotomy was stabilized with either a standard non-locking CBLO bone plate augmented with a headless compression screw (HCS) or a CBLO bone plate alone. Tibial constructs were mechanically tested in three-point craniocaudal flexural testing or in torsion. Results: In three-point flexural testing, the difference between the two constructs was not significant. In torsion, the difference in the angle of failure between constructs with a HCS (48.46°) and constructs without a HCS (81.65°) was significant (p = 0.036). Maximum torque achieved by constructs with a HCS (21.7 Nm) was greater than those without (18.7 Nm) (p = 0.056). Stiffness differences between both groups in torsion and bending were not significant. Use of a HCS did increase the stability of the CBLO construct in torsional testing, but not in flexural testing.

Influence of the connecting rod on the biomechanical properties of five external skeletal fixation configurations

2003 ◽  
Vol 16 (02) ◽  
pp. 82-87 ◽  
Author(s):  
J. D. Ross ◽  
J. P. Toombs ◽  
R. D. Welch ◽  
D. G. Bronson
Keyword(s):  
Axial Compression ◽  
External Fixator ◽  
Biomechanical Properties ◽  
Type Ii ◽  
Connecting Rod ◽  
Size Number ◽  
Frame Stiffness ◽  
Fixation System

SummaryA recently developed external skeletal fixation system (SK™, IMEX Veterinary, Inc.) utilizes larger diameter connecting rods, therefore overcoming one of the weaknesses of the original Kirschner-Ehmer (KE) system. The purpose of the current study was to compare five typical external fixator constructs in axial compression, torsion, Cranial-Caudal (C-C) and Medial-Lateral (M-L) bending to determine the effect of the larger connecting rods on frame stiffness. The results demonstrate that the larger connecting rod has a significant effect on overall frame stiffness. The use of two or more full-pins, as in the type II and III techniques nullified the contribution of the connecting rod diameter and frame stiffness was more a factor of pin size, number and orientation.

MECHANICAL PROPERTIES OF THE HUMAN METATARSAL BONES

2012 ◽  
Vol 12 (04) ◽  
pp. 1250062 ◽  
Author(s):  
VALENTINA DANESI ◽  
LUCA CRISTOFOLINI ◽  
MATEUSZ MARIA JUSZCZYK ◽  
PAOLO ERANI ◽  
MARCO VICECONTI
Keyword(s):  
Axial Compression ◽  
Biomechanical Properties ◽  
Metatarsal Bone ◽  
Elastic Behavior ◽  
Destructive Testing ◽  
First Metatarsal ◽  
Four Point Bending ◽  
Metatarsal Bones ◽  
Significant Difference ◽  
Metatarsal Fractures

Despite the incidence of metatarsal fractures and the associated risk of significant disability, little is known about the biomechanical properties (strength and stiffness) of metatarsal bones. In most cases a single metatarsal bone (first, second and fifth) has been investigated. An extensive investigation of the biomechanical properties of the metatarsal bones is essential in the understanding and prevention of metatarsal injuries. Entire sets of metatarsal bones from four feet were tested. The first foot was used to fine-tune the testing set-ups. To measure the stiffness, each metatarsal bone was subjected to non-destructive four-point-bending in the sagittal and transverse planes, axial compression and torsion. Strain was measured at two locations. To measure the strength, each metatarsal bone was tested to failure in torsion. Significant differences (p < 0.0001) existed among the stiffness of the five metatarsal bones: (i) in torsion the first metatarsal bone was 2–3 times stiffer than the others; (ii) in four-point-bending and axial compression this difference was less pronounced than in torsion; (iii) differences were smaller among the other metatarsal bones; (iv) the second metatarsal bone was less stiff than the third and fourth in bending. The second, third and fourth metatarsal bones were stiffer in the sagittal than in the transverse plane (p < 0.0001). Conversely, there was no significant difference between the two planes of bending for the first and fifth bones. During destructive testing, all metatarsal bones exhibited a linear elastic behavior and brittle failure. The torsional strength at failure ranged between 1.9 Nm and 6.9 Nm. The first metatarsal bone was stronger than all the others. Stiffness in different loading conditions and failure were measured and compared for all metatarsal bones. These data corroborate previous biomechanical studies concerning the role and load sharing of the different metatarsal bones.

Role of the anconeus in the stability of a lateral ligament and common extensor origin–deficient elbow: an in vitro biomechanical study

2019 ◽  
Vol 28 (5) ◽  
pp. 974-981 ◽  
Author(s):  
Armin Badre ◽  
David T. Axford ◽  
Sara Banayan ◽  
James A. Johnson ◽  
Graham J.W. King
Keyword(s):  
Biomechanical Study ◽  
Lateral Ligament ◽  
The Stability

Buckling of Circular Cylindrical Shells Using a Displacement Function

1974 ◽  
Vol 96 (4) ◽  
pp. 1322-1327
Author(s):  
Shun Cheng ◽  
C. K. Chang
Keyword(s):  
Boundary Conditions ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
External Pressure ◽  
Displacement Function ◽  
Combined Loading ◽  
Trial Solution ◽  
Governing Differential Equation ◽  
Circular Cylindrical Shells ◽  
The Stability

The buckling problem of circular cylindrical shells under axial compression, external pressure, and torsion is investigated using a displacement function φ. A governing differential equation for the stability of thin cylindrical shells under combined loading of axial compression, external pressure, and torsion is derived. A method for the solutions of this equation is also presented. The advantage in using the present equation over the customary three differential equations for displacements is that only one trial solution is needed in solving the buckling problems as shown in the paper. Four possible combinations of boundary conditions for a simply supported edge are treated. The case of a cylinder under axial compression is carried out in detail. For two types of simple supported boundary conditions, SS1 and SS2, the minimum critical axial buckling stress is found to be 43.5 percent of the well-known classical value Eh/R3(1−ν2) against the 50 percent of the classical value presently known.

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