In Vitro Strain Patterns of the Intact Equine Metacarpus and Metatarsus Following Plate Luting

1990 ◽  
Vol 3 (03) ◽  
pp. 84-89 ◽  
Author(s):  
J. R. Cordey ◽  
D. M. Nunamaker ◽  
M. L. Tate ◽  
T. McIff ◽  
S. M. Perren ◽  
...  
Keyword(s):  
Internal Fixation ◽  
Bone Cement ◽  
Mechanical Behaviour ◽  
Plate Fixation ◽  
Bone Surface ◽  
Physiological Conditions ◽  
Cement Layer ◽  
Metatarsal Bones ◽  
The Stability

SummaryWith internal fixation of fractures using a plate and screws, the stability of the fixation is achieved mainly by the force generated by either lag screws or plate screws. The plate protects the bone from overload. The important mechanism in the function of plate fixation is the friction between the undersurface of the plate and the bone surface. It has become evident that plate luting, i. e. interposition of a bone cement layer between the plate and the bone, will alter the transmission of expected forces due to improved contact between the plate and the bone. The purpose of this project was to evaluate the load/strain relationships that occurred following plate luting and to understand why this procedure improved the mechanical behaviour of plate fixation in equine bone. We measured the strain patterns that occurred in unplated, plated and luted equine third metacarpal and metatarsal bones under simulated physiological conditions. Plate application resulted in reduced strain under the plate and increased strain at the opposite cortex. Following plate luting, this effect was more pronounced. Hysteresis between the loading-unloading cycle was less pronounced in the luted plates. This indicated that plate luting increased the effect of strain protection.Plate luting was shown to reduce the strain under the plate and to increase it in the transcortex, effectively increasing the effect of strain protection.

A Biomechanical Evaluation of Three Forms of Internal Fixation Used in Ankle Arthrodesis

1994 ◽  
Vol 15 (6) ◽  
pp. 297-300 ◽  
Author(s):  
Michael P. Dohm ◽  
James B. Benjamin ◽  
Jeffrey Harrison ◽  
John A. Szivek
Keyword(s):  
Internal Fixation ◽  
Plate Fixation ◽  
Ankle Arthrodesis ◽  
Biomechanical Study ◽  
The Other ◽  
Fixation Failure ◽  
Plate Group ◽  
Biomechanical Evaluation ◽  
The Stability ◽  
Fibular Strut

A biomechanical study was undertaken to evaluate the relative stability of three types of internal fixation used for ankle arthrodesis. Crossed screw fixation, RAF fibular strut fixation, and T-plate fixation were tested in 30 cadaver ankles using an MTS machine. T-plate fixation consistantly provided the stiffest construct when compared with the other types of fixation. Failure occurred by distraction of bony surfaces, posterior to the plane of fixation, in the crossed screw and RAF groups. In contrast, failure in the T-plate group occurred through compression of bone anterior to the midcoronal plane of the tibia. Although the stability of fixation is only one factor in determining the success or failure of ankle arthrodesis, the results of this study would support T-plate fixation over the other forms tested.

Acute Failure Characteristics of Six Methods for Internal Fixation of Canine Femoral Oblique Fractures

1996 ◽  
Vol 09 (03) ◽  
pp. 106-10 ◽  
Author(s):  
E. Egger ◽  
J. Huhta ◽  
M. Histand ◽  
C. Mallinckrodt ◽  
R. Nye
Keyword(s):  
Internal Fixation ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Testing Machine ◽  
Maximum Load ◽  
Dynamic Compression Plate ◽  
Fixation Methods ◽  
Compression Plate

SummaryA long oblique osteotomy model of canine femoral fractures was created to compare six methods of internal fixation. The following methods were tested: three cerclage wires, three lag screws, eight-hole dynamic compression plate attached with six cerclage wires, eight-hole dynamic compression plate attached with six cortical screws, eight-hole dynamic compression plate attached with six cortical screws superimposed over three cerclage wires, and an eight-hole dynamic compression plate attached with six cortical screws superimposed over three lag screws. The repaired femurs were mounted in a mechanical testing machine in an orientation designed to mimic physiological loading. Axial compression was applied which resulted in the test specimens experiencing simultaneous compressive and bending forces. The effects of the method of osteotomy repair, bone temperature, and bone diameter were analyzed. The maximum load and the stiffness of the composite fixation and bones were determined. There were not any statistically significant differences in stiffness among the groups. All fixation methods, in which plates were attached with screws, resulted in significantly greater maximum load values than treatment techniques where plates were not used. None of the fixation methods attained a mean maximum load greater than 58% of the mean maximum load of the control femurs.Six methods of commonly used internal fixation methods are compared. A method of in vitro positioning of test femurs to mimic in vivo orientation is presented. Maximum load capabilities of fixation do not significantly increase with the addition of interfragmentary compression to plate fixation.

Evaluation of the stability of a novel lateral plate internal fixation: an in vitro biomechanical study

2021 ◽  
Author(s):  
Zecheng Cai ◽  
Rong Ma ◽  
Jianqun Zhang ◽  
Xiaoyin Liu ◽  
Wei Yang ◽  
...  
Keyword(s):  
Internal Fixation ◽  
Biomechanical Study ◽  
Lateral Plate ◽  
The Stability

scholarly journals A Biomechanical Comparison of Three 1.5-mm Plate and Screw Configurations and a Single 2.0-mm Plate for Internal Fixation of a Mandibular Condylar Fracture

2014 ◽  
Vol 7 (3) ◽  
pp. 218-223 ◽  
Author(s):  
Peter Aquilina ◽  
William C.H. Parr ◽  
Uphar Chamoli ◽  
Stephen Wroe ◽  
Philip Clausen
Keyword(s):  
Internal Fixation ◽  
Material Properties ◽  
Plate Fixation ◽  
Pure Titanium ◽  
Mandibular Condyle ◽  
Titanium Implants ◽  
Condylar Fracture ◽  
Square Plate ◽  
The Stability ◽  
Condyle Fracture

The most stable pattern of internal fixation for mandibular condyle fractures is an area of ongoing discussion. This study investigates the stability of three patterns of plate fixation using readily available, commercially pure titanium implants. Finite element models of a simulated mandibular condyle fracture were constructed. The completed models were heterogeneous in bone material properties, contained approximately 1.2 million elements and incorporated simulated jaw adducting musculature. Models were run assuming linear elasticity and isotropic material properties for bone. No human subjects were involved in this investigation. The stability of the simulated condylar fracture reduced with the different implant configurations, and the von Mises stresses of a 1.5-mm X-shaped plate, a 1.5-mm rectangular plate, and a 1.5-mm square plate (all Synthes (Synthes GmbH, Zuchwil, Switzerland) were compared. The 1.5-mm X plate was the most stable of the three 1.5-mm profile plate configurations examined and had comparable mechanical performance to a single 2.0-mm straight four-hole plate. This study does not support the use of rectangular or square plate patterns in the open reduction and internal fixation of mandibular condyle fractures. It does provide some support for the use of a 1.5-mm X plate to reduce condylar fractures in selected clinical cases.

scholarly journals SALMO and S3M: A Saliva Model and a Single Saliva Salt Model for Equilibrium Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Francesco Crea ◽  
Concetta De Stefano ◽  
Demetrio Milea ◽  
Alberto Pettignano ◽  
Silvio Sammartano
Keyword(s):  
Literature Analysis ◽  
Formation Model ◽  
Standard Medium ◽  
Equilibrium Studies ◽  
Temperature Changes ◽  
Physiological Conditions ◽  
The Stability ◽  
Equilibrium Calculations ◽  
Inorganic Components

A model of synthetic saliva (SALMO, SALiva MOdel) is proposed for its use as standard medium inin vitroequilibrium and speciation studies of real saliva. The concentrations come out from the literature analysis of the composition of both real saliva and synthetic saliva. The chief interactions of main inorganic components of saliva, as well as urea and amino acids, are taken into account on the basis of a complex formation model, which also considers the dependence of the stability constants of these species on ionic strength and temperature. These last features allow the modelling of the speciation of saliva in different physiological conditions deriving from processes like dilution, pH, and temperature changes. To simplify equilibrium calculations, a plain approach is also proposed, in order to take into account all the interactions among the major components of saliva, by considering the inorganic components of saliva as a single 1 : 1 salt (MX), whose concentration iscMX=(1/2)∑ci(ci= analytical concentration of all the ions) andzion charge calculated asz=±(I/cMX)1/2= ±1.163. The use of the Single Saliva Salt Model (S3M) considerably reduces the complexity of the systems to be investigated. In fact, only four species deriving from internal ionic medium interactions must be considered.

scholarly journals The Effect of Cement Aging on the Stability of a Cement-in-Cement Revision Construct

2021 ◽  
Vol 11 (6) ◽  
pp. 2814
Author(s):  
Mareike Schonhoff ◽  
Therese Bormann ◽  
Kevin Knappe ◽  
Tobias Reiner ◽  
Linda Stange ◽  
...  
Keyword(s):  
Bone Cement ◽  
Revision Surgery ◽  
Bending Strength ◽  
Intraoperative Complications ◽  
In Vitro Study ◽  
Cement Mantle ◽  
Significant Difference ◽  
Different Types ◽  
The Stability

A revision surgery can be a complicated procedure. The prevention of the removal of a well-integrated cement mantle can minimize intraoperative complications. With the cement-in-cement technique, the implant will be fixated with a layer of bone cement onto the remaining cement mantle. In our experimental in vitro study, we investigated the effect of cement aging of a cement-in-cement revision construct and regular cement mantle on the bending strength. Two different types of bone cement were tested at four different stages of aging. The Palacos cement showed no significant difference in bending strength at any aging point, regardless of whether it was used primarily or as a cement-in-cement revision. In contrast, the SmartSet MV cement showed a significant difference between the primary and cement-in-cement applications depending on cement aging time. The comparison of the two cement-in-cement structures investigated showed significant differences between the manufacturers depending on the cement aging.

scholarly journals Open Rigid Internal Fixation of Low-Neck Condylar Fractures of the Mandible: Mechanical Comparison of 16 Plate Designs

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1953 ◽  
Author(s):  
Marcin Kozakiewicz ◽  
Rafał Zieliński ◽  
Bartłomiej Konieczny ◽  
Michał Krasowski ◽  
Jakub Okulski
Keyword(s):  
Internal Fixation ◽  
Gold Standard ◽  
Plate Fixation ◽  
Fracture Line ◽  
Screw Loosening ◽  
Condylar Fracture ◽  
Rigid Internal Fixation ◽  
Fracture Osteosynthesis ◽  
The Stability ◽  
Condylar Fractures

Background: In the literature, no information on plates for low-neck mandibular condylar osteosynthesis can be found, despite the fact that 30 plate designs have already been published. The aim of this study was to compare any dedicated plates for possible use in low-neck condylar fracture osteosynthesis. Methods: The force required for 1-mm displacement of the fixed fracture fragments and incidents of screw loosening were recorded on polyurethane mandibles among 16 designs of titanium plates fixed by 6-mm screws in a 2.0 system. Results: Double-straight plate fixation was the mechanical gold standard (15.2 ± 3.5 N), followed by A-shape Condylar Plates (14.9 ± 2.1 N), X-shape Condylar Plates (14.2 ± 1.3 N) and Auto Repositioning Plates (11.8 ± 2.4 N). Screw loosening was uncommon, as a minimum of three screws were placed into the condylar part. Fewer screws were lost from the ramus part of the fixation if the plate was attached to the condylar part by three screws. Often, the stability of the ramus screws was lost when there were only two fixing screws in the condyle (p < 0.001). Conclusions: It is advisable to consider the mechanical advantages as one decides which plate to choose for open rigid internal fixation in low-neck condylar fractures, or to only be aware of the significant differences in mobility within the fracture line after fixation with different dedicated plates.

scholarly journals A Dynamic Hanging-Drop System for Mesenchymal Stem Cell Culture

2020 ◽  
Vol 21 (12) ◽  
pp. 4298
Author(s):  
Shu-Wei Huang ◽  
Shian-Chiuan Tzeng ◽  
Jem-Kun Chen ◽  
Jui-Sheng Sun ◽  
Feng-Huei Lin
Keyword(s):  
Cell Culture ◽  
Spheroid Formation ◽  
Hanging Drop ◽  
Mesenchymal Stem Cell Culture ◽  
Physiological Conditions ◽  
The Past ◽  
Hanging Drop Culture ◽  
The Stability

There have been many microfluid technologies combined with hanging-drop for cell culture gotten developed in the past decade. A common problem within these devices is that the cell suspension introduced at the central inlet could cause a number of cells in each microwell to not regularize. Also, the instability of droplets during the spheroid formation remains an unsolved ordeal. In this study, we designed a microfluidic-based hanging-drop culture system with the design of taper-tube that can increase the stability of droplets while enhancing the rate of liquid exchange. A ring is surrounding the taper-tube. The ring can hold the cells to enable us to seed an adequate amount of cells before perfusion. Moreover, during the period of cell culture, the mechanical force around the cell is relatively low to prevent stem cells from differentiate and maintain the phenotype. As a result of our hanging system design, cells are designed to accumulate at the bottom of the droplet. This method enhances convenience for observation activities and analysis of experiments. Thus, this microfluid chip can be used as an in vitro platform representing in vivo physiological conditions, and can be useful in regenerative therapy.

In Vitro Testing of Posterior Cervical Lateral Mass Plating Systems: Comparison of Constrained Versus Semi-Constrained Screw-Slot Connections

2000 ◽  
Author(s):  
Denis J. DiAngelo ◽  
Bobby J. McVay ◽  
Kristine M. Olney ◽  
Kevin T. Foley
Keyword(s):  
Cervical Spine ◽  
Standard Treatment ◽  
Plate Fixation ◽  
Alternative Methods ◽  
Lateral Mass ◽  
Biomechanical Stability ◽  
Cervical Spine Instability ◽  
The Stability ◽  
With Screws

Abstract Interspinous or facet wiring has been the standard treatment for posterior cervical spine instability secondary to trauma or decompression (Wellmann et al., 1998). However, wire techniques may be limited when posterior elements are deficient or fractured. Alternative methods, such as posterior lateral mass plate fixation, may restore the stability of the affected region and promote fusion (Wellmann et al., 1998). The objective of the study was to determine if lateral mass plate fixation restored the stability of a reconstructed posterior destabilized cervical spine and to compare the biomechanical stability of two lateral mass plate designs: plates with screws constrained in slots (SCS) versus plates with screws unconstrained and free to translate in slots (SUS). Two posterior destabilized conditions were studied: a one-level (C4-C5) model and a two-level (C4-C6) model in which all posterior ligaments were sectioned.

Sign in / Sign up

Export Citation Format

Share Document