scholarly journals Comparison of Fixation Stability of the Novel Lisfranc Plate to Transarticular Screws

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0003
Author(s):  
Stephen Shymon ◽  
Thomas Harris ◽  
Spenser Cassinelli ◽  
Edward Ebramzadeh ◽  
John Fleming ◽  
...  
Keyword(s):  
Motion Tracking ◽  
Three Dimensional ◽  
Axial Loading ◽  
Fixation Method ◽  
Implant Fixation ◽  
Lisfranc Joint ◽  
Second Metatarsal ◽  
Fixation Stability ◽  
The Stability ◽  
Lisfranc Injuries

Category: Midfoot/Forefoot, Trauma Introduction/Purpose: The objective of this study was to compare the stability of fixation of ligamentous Lisfranc injuries stabilized using two devices: a novel Lisfranc plate and conventional transarticular screws. Methods: A biomechanical cadaver model was developed to compare the fixation stability of a novel Lisfranc plate to that of traditional fixation, using transarticular screws. Thirteen pairs of cadaveric specimens were tested intact, after a simulated injury, and after implant fixation. Optical motion tracking was used to measure the three dimensional (3D) motion between each of the following four bones: first metatarsal, second metatarsal, first cuneiform, and second cuneiform. Testing included both cyclic abduction loading and cyclic axial loading. Results: Both the Lisfranc plate and screw fixation method provided stability such that the average 3D motions across the Lisfranc joint (between the second metatarsal and the first cuneiform), were between 0.2 and 0.4 mm under cyclic abduction loading and between 0.4 and 0.5 mm under cyclic axial loading. Comparing the stability of fixation between the Lisfranc plate and the screws, the differences in motion were all 0.3 mm or lower, with no significant differences (p > 0.16). Conclusion: Average 3D motions of the Lisfranc joint were 0.5 mm or below, whether fixed with the Lisfranc plate or the screws. Therefore, the Lisfranc plate provided comparable stability to the transarticular screws, which have been established as the gold standard for arthrodesis in Lisfranc injuries. Due to its anatomical placement, the Lisfranc plate may provide adequate support without risk of iatrogenic injury to the articular cartilage.

scholarly journals Early Outcomes of Patient-Specific Modular Cones for Substitution of Methaphysial and Diaphysial Bone Defects in Revision Knee Arthroplasty

2019 ◽  
Vol 25 (2) ◽  
pp. 9-18 ◽  
Author(s):  
A. A. Cherny ◽  
A. N. Kovalenko ◽  
S. S. Bilyk ◽  
A. O. Denisov ◽  
A. V. Kazemirskiy ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Scoring Systems ◽  
Bone Defects ◽  
Patient Specific ◽  
Implant Fixation ◽  
Diaphyseal Bone ◽  
Custom Made ◽  
The Stability ◽  
Valid Solution

The aim of this study was the assessment of early outcomes of patient-specific three-dimensional titanium cones with specified porosity parameters to compensate for extensive metaphysical-diaphyseal bone defects in RTKA.Materials and Methods. Since 2017 till 2019 30 patient-specific titanium cones (12 femoral and 18 tibial) implanted during 26 RTKAS. Clinical outcomes evaluated using KSS, WOMAC and fjS-12 scoring systems on average 10 (2–18) months after surgery. At the same time the stability of implant fixation analyzed using frontal, lateral and axial knee roentgenograms.Results. During all procedures there were no technical difficulties in positioning and implantation of custom-made titanium cones. At the time of preparation of the publication, none of the patients had indications for further surgical intervention, as well as intra- and postoperative complications. Six months after surgery all scores improved significantly: KSS from 23 (2–42, SD 19.96) to 66.5 (62–78, SD 7.68), WOMAC from 59 (56–96, SD 28.31) to 32.25 (19–46, SD 11.76), the index FJS-12 was 29.16 points (0–68.75, SD 30.19). The average scores continued to improve up to 18 months: KSS — 97.5 (88–108, SD 9.14), WOMAC — 16.5 (9–24, SD 6.45), FJS-12 — 45.85 (25–75, SD 22.03). No radiolucent lines were noticed during this period of observation.Conclusion. The original additive technology of designing and producing patient-specific titanium cones for compensation of extensive metaphyseal-diaphyseal bone defects in RTKA is a valid solution at least in the short term. A longer follow-up period is required to assess its medium-and long-term reliability compared to existing alternative surgical solutions.

scholarly journals Lisfranc fracture-dislocations: current management

2019 ◽  
Vol 4 (7) ◽  
pp. 430-444 ◽  
Author(s):  
Inmaculada Moracia-Ochagavía ◽  
E. Carlos Rodríguez-Merchán
Keyword(s):  
Surgical Treatment ◽  
Weight Bearing ◽  
Correct Diagnosis ◽  
Foot Deformities ◽  
Current Management ◽  
Lisfranc Joint ◽  
Fracture Dislocations ◽  
Post Traumatic ◽  
The Stability ◽  
Lisfranc Injuries

It is essential to know and understand the anatomy of the tarsometatarsal (TMT) joint (Lisfranc joint) to achieve a correct diagnosis and proper treatment of the injuries that occur at that level. Up to 20% of Lisfranc fracture-dislocations go unnoticed or are diagnosed late, especially low-energy injuries or purely ligamentous injuries. Severe sequelae such as post-traumatic osteoarthritis and foot deformities can create serious disability. We must be attentive to the clinical and radiological signs of an injury to the Lisfranc joint and expand the study with weight-bearing radiographs or computed tomography (CT) scans. Only in stable lesions and in those without displacement is conservative treatment indicated, along with immobilisation and initial avoidance of weight-bearing. Through surgical treatment we seek to achieve two objectives: optimal anatomical reduction, a factor that directly influences the results; and the stability of the first, second and third cuneiform-metatarsal joints. There are three main controversies regarding the surgical treatment of Lisfranc injuries: osteosynthesis versus primary arthrodesis; transarticular screws versus dorsal plates; and the most appropriate surgical approach. The surgical treatment we prefer is open reduction and internal fixation (ORIF) with transarticular screws or with dorsal plates in cases of comminution of metatarsals or cuneiform bones. Cite this article: EFORT Open Rev 2019;4:430-444. DOI: 10.1302/2058-5241.4.180076

scholarly journals On Measuring Implant Fixation Stability in ACL Reconstruction

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6632
Author(s):  
Emir Benca ◽  
Ivan Zderic ◽  
Jan Caspar ◽  
Kenneth van Knegsel ◽  
Lena Hirtler ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Motion Tracking ◽  
Ultimate Load ◽  
Structural Characteristics ◽  
Tracking System ◽  
Cruciate Ligament ◽  
Implant Fixation ◽  
Fixation Stability ◽  
Anterior Cruciate ◽  
Motion Tracking System

Numerous methods and devices are available for implant fixation in anterior cruciate ligament (ACL) reconstruction. Biomechanical data indicate high variability in fixation stability across different devices. This study aims to provide a better insight into measuring the structural characteristics and mechanical behavior of ACL implant fixations. Fourteen human tibial specimens with reconstructed ACLs were subjected to progressively increasing dynamic loading until failure. The motions of the tibia, the proximal and distal graft ends, as well as the testing frame and actuator, were continuously recorded via a motion tracking system. Significantly higher displacements of the machine actuator (1.0 mm at graft slippage onset, and 12.2 mm at ultimate load) were measured compared to the displacements of the proximal (0.8 and 4.3 mm, respectively) and distal graft (0.1 and 3.4 mm, respectively) ends. The displacements measured at different sites showed significant correlations. The provided data suggest significant and systematic inaccuracies in the stiffness and slippage of the fixation when using machine displacement, as commonly reported in the literature. The assessment of the distal graft displacement excludes the artifactual graft elongation, and most accurately reflects the graft slippage onset indicating clinical failure. Considering the high displacement at the ultimate load, the ultimate load could be used as a standardized variable to compare different fixation methods. However, the ultimate load alone is not sufficient to qualitatively describe fixation stability.

Three-Dimensional Finite Element Analysis of Several Internal and External Pelvis Fixations

2000 ◽  
Vol 122 (5) ◽  
pp. 516-522 ◽  
Author(s):  
J. M. Garcı´a ◽  
M. Doblare´ ◽  
B. Seral ◽  
F. Seral ◽  
D. Palanca ◽  
...  
Keyword(s):  
Finite Element ◽  
Pelvic Ring ◽  
Three Dimensional ◽  
Fixation Method ◽  
Individual Treatment ◽  
Element Analysis ◽  
Sacroiliac Screws ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

The Finite Element Method (FEM) can be used to analyze very complex geometries, such as the pelvis, and complicated constitutive behaviors, such as the heterogeneous, nonlinear, and anisotropic behavior of bone tissue or the noncompression, nonbending character of ligaments. Here, FEM was used to simulate the mechanical ability of several external and internal fixations that stabilize pelvic ring disruptions. A customized pelvic fracture analysis was performed by computer simulation to determine the best fixation method for each individual treatment. The stability of open-book fractures with external fixations at either the iliac crests or the pelvic equator was similar, and increased greatly when they were used in combination. However, external fixations did not effectively stabilize rotationally and vertically unstable fractures. Adequate stabilization was only achieved using an internal pubis fixation with two sacroiliac screws. [S0148-0731(00)00905-5]

scholarly journals Anatomical Pathology of Subtle Lisfranc Injury

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Naoki Haraguchi ◽  
Koki Ota ◽  
Takuma Ozeki ◽  
Shingo Nishizaka
Keyword(s):  
Computed Tomography ◽  
Injury Patterns ◽  
Lisfranc Joint ◽  
Joint Injury ◽  
Lisfranc Injury ◽  
Orthopedic Surgeons ◽  
Computed Tomography Images ◽  
Second Metatarsal ◽  
Lisfranc Injuries ◽  
Anatomical Pathology

Abstract The extent and patterns of Lisfranc joint complex disruption in subtle Lisfranc injuries have not been well clarified. We reviewed the direct intraoperative findings for 87 patients, examined computed tomography images that had been obtained preoperatively for 73 of the patients, and classified the injuries according to the Kaar  et al. criteria as the transverse type (instability between the first cuneiform [C1] and the second metatarsal [M2] and between the second cuneiform [C2] and M2) or longitudinal type (instability between C1 and M2 and between C1 and C2). Our patients’ injuries were classified as follows: longitudinal type (38%), transverse type (30%), transverse type and first tarsometatarsal (TMT) joint injury (20%), longitudinal type plus transverse type (7%), longitudinal type and first TMT joint injury (3%), and longitudinal type, transverse type, and first TMT joint injury (2%). In 11 patients, the longitudinal injury extended into the naviculo-first cuneiform joint. In 41 (56%) of the 73 patients for whom CT images were obtained, 1 or more fractures (not counting small avulsion fragments between C1 and M2) were found. Orthopedic surgeons should be aware of the various injury patterns possible in cases of subtle Lisfranc injury.

A Liquid Metal Flow Between Two Coaxial Cylinders System

2019 ◽  
Vol 11 (1) ◽  
pp. 79-86
Author(s):  
Abdelkrim Merah ◽  
Ridha Kelaiaia ◽  
Faiza Mokhtari
Keyword(s):  
Couette Flow ◽  
Metal Flow ◽  
Three Dimensional ◽  
Liquid Sodium ◽  
Taylor Vortex ◽  
Turbulent Regime ◽  
Coaxial Cylinders ◽  
Concentric Cylinders ◽  
Ideal Tool ◽  
The Stability

Abstract The Taylor-Couette flow between two rotating coaxial cylinders remains an ideal tool for understanding the mechanism of the transition from laminar to turbulent regime in rotating flow for the scientific community. We present for different Taylor numbers a set of three-dimensional numerical investigations of the stability and transition from Couette flow to Taylor vortex regime of a viscous incompressible fluid (liquid sodium) between two concentric cylinders with the inner one rotating and the outer one at rest. We seek the onset of the first instability and we compare the obtained results for different velocity rates. We calculate the corresponding Taylor number in order to show its effect on flow patterns and pressure field.

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

scholarly journals Gum Tragacanth (GT): A Versatile Biocompatible Material beyond Borders

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1510 ◽  
Author(s):  
Mohammad Ehsan Taghavizadeh Yazdi ◽  
Simin Nazarnezhad ◽  
Seyed Hadi Mousavi ◽  
Mohammad Sadegh Amiri ◽  
Majid Darroudi ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Food Packaging ◽  
Three Dimensional ◽  
Great Promise ◽  
Anionic Polymer ◽  
Gum Tragacanth ◽  
New Horizons ◽  
Tissue Healing ◽  
The Stability ◽  
Therapeutic Substance

The use of naturally occurring materials in biomedicine has been increasingly attracting the researchers’ interest and, in this regard, gum tragacanth (GT) is recently showing great promise as a therapeutic substance in tissue engineering and regenerative medicine. As a polysaccharide, GT can be easily extracted from the stems and branches of various species of Astragalus. This anionic polymer is known to be a biodegradable, non-allergenic, non-toxic, and non-carcinogenic material. The stability against microbial, heat and acid degradation has made GT an attractive material not only in industrial settings (e.g., food packaging) but also in biomedical approaches (e.g., drug delivery). Over time, GT has been shown to be a useful reagent in the formation and stabilization of metal nanoparticles in the context of green chemistry. With the advent of tissue engineering, GT has also been utilized for the fabrication of three-dimensional (3D) scaffolds applied for both hard and soft tissue healing strategies. However, more research is needed for defining GT applicability in the future of biomedical engineering. On this object, the present review aims to provide a state-of-the-art overview of GT in biomedicine and tries to open new horizons in the field based on its inherent characteristics.

scholarly journals Emergent chiral symmetry in a three-dimensional interacting Dirac liquid

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
András L. Szabó ◽  
Bitan Roy
Keyword(s):  
Fixed Points ◽  
Chiral Symmetry ◽  
Rotational Symmetry ◽  
Three Dimensional ◽  
Spatial Dimension ◽  
Dirac Fermions ◽  
Electronic Interactions ◽  
Emergent Phenomena ◽  
Ordered Phases ◽  
The Stability

Abstract We compute the effects of strong Hubbardlike local electronic interactions on three-dimensional four-component massless Dirac fermions, which in a noninteracting system possess a microscopic global U(1) ⊗ SU(2) chiral symmetry. A concrete lattice realization of such chiral Dirac excitations is presented, and the role of electron-electron interactions is studied by performing a field theoretic renormalization group (RG) analysis, controlled by a small parameter ϵ with ϵ = d−1, about the lower-critical one spatial dimension. Besides the noninteracting Gaussian fixed point, the system supports four quantum critical and four bicritical points at nonvanishing interaction couplings ∼ ϵ. Even though the chiral symmetry is absent in the interacting model, it gets restored (either partially or fully) at various RG fixed points as emergent phenomena. A representative cut of the global phase diagram displays a confluence of scalar and pseudoscalar excitonic and superconducting (such as the s-wave and p-wave) mass ordered phases, manifesting restoration of (a) chiral U(1) symmetry between two excitonic masses for repulsive interactions and (b) pseudospin SU(2) symmetry between scalar or pseudoscalar excitonic and superconducting masses for attractive interactions. Finally, we perturbatively study the effects of weak rotational symmetry breaking on the stability of various RG fixed points.

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