scholarly journals Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices

2018 ◽  
Vol 7 (1) ◽  
pp. 111-120 ◽  
Author(s):  
A. MacLeod ◽  
A. H. R. W. Simpson ◽  
P. Pankaj
Keyword(s):  
Numerical Investigation ◽  
Fracture Fixation ◽  
Computational Models ◽  
Locking Plate ◽  
Biomechanical Testing ◽  
Loading Conditions ◽  
Secondary Fracture ◽  
Plate Fracture ◽  
Fixation Devices ◽  
Working Length

ObjectivesSecondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs.MethodsSynthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests.ResultsThe method of loading was found to affect the gap stiffness strongly (by up to six times) but also the magnitude of the plate stress and the location and magnitude of strains at the bone-screw interface.ConclusionsThis study demonstrates that the method of loading is responsible for much of the difference in reported stiffness values in the literature. It also shows that previous contradictory findings, such as the influence of working length and very large differences in failure loads, can be readily explained by the choice of loading condition. Cite this article: A. MacLeod, A. H. R. W. Simpson, P. Pankaj. Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices. Bone Joint Res 2018;7:111–120. DOI: 10.1302/2046-3758.71.BJR-2017-0074.R2.

Numerical investigation of fracture impaction in proximal humeral fracture fixation with locking plate and intramedullary nail

2017 ◽  
Vol 41 (7) ◽  
pp. 1471-1480 ◽  
Author(s):  
Yen-Nien Chen ◽  
Chih-Wei Chang ◽  
Chia-Wei Lin ◽  
Chih-Wei Wang ◽  
Yao-Te Peng ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Intramedullary Nail ◽  
Fracture Fixation ◽  
Proximal Humeral Fracture ◽  
Locking Plate ◽  
Humeral Fracture

scholarly journals Biomechanical stability of complex coronal plane fracture fixation of the capitellum

2021 ◽  
Author(s):  
Paul Borbas ◽  
Rafael Loucas ◽  
Marios Loucas ◽  
Maximilian Vetter ◽  
Simon Hofstede ◽  
...  
Keyword(s):  
Fracture Fixation ◽  
Ultimate Load ◽  
Locking Plate ◽  
Distal Humerus ◽  
Coronal Plane ◽  
Fixation Strength ◽  
Biomechanical Stability ◽  
Significant Difference ◽  
Load To Failure ◽  
Headless Compression Screws

Abstract Introduction Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat due to their complexity and intra-articular nature. There is no gold standard for surgical management of these complex fractures. The purpose of this study was to compare the biomechanical stability and strength of two different internal fixation techniques for complex coronal plane fractures of the capitellum with posterior comminution. Materials and methods Fourteen fresh frozen, age- and gender-matched cadaveric elbows were 3D-navigated osteotomized simulating a Dubberley type IIB fracture. Specimens were randomized into one of two treatment groups and stabilized with an anterior antiglide plate with additional anteroposterior cannulated headless compression screws (group antiGP + HCS) or a posterolateral distal humerus locking plate with lateral extension (group PLP). Cyclic testing was performed with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, construct stiffness, and ultimate load to failure. Results There was no significant difference in displacement during 2000 cycles (p = 0.291), stiffness (310 vs. 347 N/mm; p = 0.612) or ultimate load to failure (649 ± 351 vs. 887 ± 187 N; p = 0.140) between the two groups. Conclusions Posterolateral distal humerus locking plate achieves equal biomechanical fixation strength as an anterior antiglide plate with additional anteroposterior cannulated headless compression screws for fracture fixation of complex coronal plane fractures of the capitellum. These results support the use of a posterolateral distal humerus locking plate considering the clinical advantages of less invasive surgery and extraarticular metalware. Level of evidence Biomechanical study.

Characterization of short-fibre reinforced thermoplastics for fracture fixation devices

Biomaterials ◽  
1990 ◽  
Vol 11 (8) ◽  
pp. 541-547 ◽  
Author(s):  
Stanley A. Brown ◽  
Robert S. Hastings ◽  
Jeffrey J. Mason ◽  
Abdelsamie Moet
Keyword(s):  
Fracture Fixation ◽  
Short Fibre ◽  
Fixation Devices ◽  
Reinforced Thermoplastics

Short-Term In Vivo Response to Anodized Magnesium Alloy as a Biodegradable Material for Bone Fracture Fixation Devices

2021 ◽  
Author(s):  
Julieta L. Merlo ◽  
María R. Katunar ◽  
María Florencia Tano de la Hoz ◽  
Sabrina Carrizo ◽  
Leandro Salemme Alonso ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Bone Fracture ◽  
Fracture Fixation ◽  
Biodegradable Material ◽  
Short Term ◽  
Fixation Devices

An Adaptable Ct-Derived 3D-Printed Alignment Fixture Minimizes Errors in Whole-Bone Biomechanical Testing

2021 ◽  
Author(s):  
Jordan V. Inacio ◽  
DanielleM Cristino ◽  
Michael W. Hast ◽  
Hannah Dailey
Keyword(s):  
Computational Models ◽  
Biomechanical Testing ◽  
Ct Scanning ◽  
Industrial Applications ◽  
Long Bone ◽  
Implant Design ◽  
Orthopaedic Implant ◽  
Test Frame ◽  
3D Printed ◽  
The Impact

Abstract Biomechanical testing of long bones can be subject to undesirable errors and uncertainty due to malalignment of specimens with respect to the mechanical axis of the test frame. To solve this problem, we designed a novel, customizable alignment and potting fixture for long bone testing. The fixture consisted of 3D-printed components modeled from specimen-specific CT scans to achieve a predetermined specimen alignment. We demonstrated the functionality of this fixture by comparing benchtop torsional test results to specimen-matched finite element models and found a strong and statistically significant correlation (R2 = 0.9536, p < 0.001). Additional computational models estimated the impact of malalignment on mechanical behavior in both torsion and axial compression. Results confirmed that torsion testing is relatively robust to alignment artifacts, with absolute percent errors less than 8% in all malalignment scenarios. In contrast, axial testing was highly sensitive to setup errors, experiencing absolute percent errors up to 40% with off-center malalignment and up to 130% with angular malalignment. This suggests that whenever appropriate, torsion tests should be used preferentially as a summary mechanical measure. When more challenging modes of loading are required, pre-test clinical-resolution CT scanning can be effectively used to create potting fixtures that allow for precise pre-planned specimen alignment. This may be particularly important for more sensitive biomechanical tests (e.g. axial compressive tests) that may be needed for industrial applications, such as orthopaedic implant design.

DEM Simulations in Geotechnical Earthquake Engineering Education

2012 ◽  
pp. 100-109
Author(s):  
J. S. Vinod
Keyword(s):  
Engineering Education ◽  
Granular Materials ◽  
Earthquake Engineering ◽  
Laboratory Experiments ◽  
Computational Models ◽  
Cyclic Behavior ◽  
Advanced Mathematics ◽  
Loading Conditions ◽  
Geotechnical Earthquake Engineering ◽  
Element Method

Behaviour of geotechnical material is very complex. Most of the theoretical frame work to understand the behaviour of geotechnical materials under different loading conditions depends on the strong background of the basic civil engineering subjects and advanced mathematics. However, it is fact that the complete behaviour of geotechnical material cannot be traced within theoretical framework. Recently, computational models based on Finite Element Method (FEM) are used to understand the behaviour of geotechnical problems. FEM models are quite complex and is of little interest to undergraduate students. A simple computational tool developed using Discrete Element Method (DEM) to simulate the laboratory experiments will be cutting edge research for geotechnical earthquake engineering education. This article summarizes the potential of DEM to simulate the cyclic triaxial behaviour of granular materials under complex loading conditions. It is shown that DEM is capable of simulating the cyclic behavior of granular materials (e.g. undrained, liquefaction and post liquefaction) similar to the laboratory experiments.

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