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.

Biomechanical comparison of 3.0 mm headless compression screw and 3.5 mm cortical bone screw in a canine humeral condylar fracture model

2016 ◽  
Vol 29 (05) ◽  
pp. 353-360
Author(s):  
Daniel Jankovits ◽  
Michael Huber ◽  
Adam Strom ◽  
Tanya Garcia ◽  
Susan Stover ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Biomechanical Properties ◽  
Compression Screw ◽  
Condylar Fracture ◽  
Bone Screw ◽  
Headless Compression Screw ◽  
Failure Loads ◽  
Condylar Fractures ◽  
Biomechanical Comparison

Summary Objective: To compare the biomechanical properties of simulated humeral condylar fractures reduced with one of two screw fixation methods: 3.0 mm headless compression screw (HCS) or 3.5 mm cortical bone screw (CBS) placed in lag fashion. Methods: Bilateral humeri were collected from nine canine cadavers. Standardized osteotomies were stabilized with 3.0 mm HCS in one limb and 3.5 mm CBS in the contralateral limb. Condylar fragments were loaded to walk, trot, and failure loads while measuring construct properties and condylar fragment motion. Results: The 3.5 mm CBS-stabilized constructs were 36% stiffer than 3.0 mm HCS-stabilized constructs, but differences were not apparent in quality of fracture reduction nor in yield loads, which exceeded expected physiological loads during rehabilitation. Small residual fragment displacements were not different between CBS and HCS screws. Small fragment rotation was not significantly different between screws, but was weakly correlated with moment arm length (R2 = 0.25). Clinical significance: A CBS screw placed in lag fashion provides stiffer fixation than an HCS screw, although both screws provide similar anatomical reduction and yield strength to condylar fracture fixation in adult canine humeri.

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.

Headless Compression Screw Fixation for Proximal Phalanx Fractures: A Biomechanical Study

Hand ◽  
2020 ◽  
pp. 155894472092664
Author(s):  
Lauren Fader ◽  
Luke Robinson ◽  
Michael Voor
Keyword(s):  
Screw Fixation ◽  
Proximal Phalanx ◽  
Biomechanical Study ◽  
Materials Testing ◽  
Compression Screw ◽  
Headless Compression Screw ◽  
Screw Length ◽  
Significant Difference ◽  
Flexion Extension ◽  
Bending Load

Background: Proximal phalanx fractures are common injuries of the hand with multiple treatment options. Intramedullary (IM) screw fixation has become more widely used, and early outcomes are promising. However, biomechanical data regarding this type of fixation are sparse. Methods: Two methods of IM screw fixation of proximal phalanx fractures were tested in cadaver specimens. All specimens were treated with a single antegrade headless compression screw, with half getting the addition of a blocking screw. To test the most common deforming force of flexion-extension, each phalanx was subjected to apex volar 3-point bending using the Materials Testing System test frame. Results: There was no significant difference in the stiffness of 3-point bending with single antegrade screws alone and with a blocking screw (mean, 63.1 vs 52.2 N/mm; P = .27). When comparing smaller with larger specimens, stiffness of the small group was significantly greater than that of the large group when both fixation methods were included (85.3 vs 30.1 N/mm; P < .0002). When comparing stiffness with percent fill of the screw within bone, there was a moderately positive correlation (0.51). Conclusions: Addition of a blocking screw did not increase the stability of the IM screw fixation construct for proximal phalanx fractures. When comparing specimen size, the smaller bones were stiffer under 3-point bending load, regardless of the type of fixation. In addition, those specimens that had a larger longitudinal screw length to bone length ratio were stiffer. These findings provide valuable information as techniques for IM screw fixation of proximal phalanx fractures continue to evolve.

Headless Compression Screw Versus Kirschner Wire Fixation for Metacarpal Neck Fractures: A Biomechanical Study

2017 ◽  
Vol 42 (5) ◽  
pp. 392.e1-392.e6 ◽  
Author(s):  
Daniel M. Avery ◽  
Stephen Klinge ◽  
Felix Dyrna ◽  
Leo Pauzenberger ◽  
David Lam ◽  
...  
Keyword(s):  
Kirschner Wire ◽  
Biomechanical Study ◽  
Compression Screw ◽  
Headless Compression Screw ◽  
Kirschner Wire Fixation ◽  
Wire Fixation

Biomechanical evaluation of an intramedullary clavicle screw in simple oblique and butterfly wedge fractures

2021 ◽  
pp. 095441192110310
Author(s):  
Bryce F Kunkle ◽  
John D DesJardins ◽  
Joel R Campbell ◽  
Josef K Eichinger ◽  
Michael J Kissenberth ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Bending Moment ◽  
Biomechanical Properties ◽  
Fracture Pattern ◽  
Biomechanical Study ◽  
Torsional Stiffness ◽  
Oblique Fracture ◽  
Torsional Testing ◽  
Fresh Frozen ◽  
Wedge Fracture

This biomechanical study evaluates the performance of a solid titanium-alloy intra-medullary ( IM) clavicular screw in torsion and cantilever bending in cadaveric clavicle specimens with simulated simple oblique and butterfly wedge midshaft fractures. Thirty-two fresh-frozen male clavicles were sorted into six experimental groups: Torsion Control, Torsion Simple Oblique Fracture, Torsion Butterfly Wedge Fracture, Bending Control, Bending Simple Oblique Fracture, and Bending Butterfly Wedge Fracture. The experimental groups were controlled for density, length, diameter, and laterality. All other samples were osteotomy-induced and implanted with a single 90 mm × 3 mm clavicle screw. All groups were tested to physiologically relevant cutoff points in torsion or bending. There were no statistically significant differences in the performance of the oblique and butterfly wedge fracture models for any torsion or bend testing measures, including maximum torsional resistance ( p = 0.66), torsional stiffness ( p = 0.51), maximum bending moment ( p = 0.43), or bending stiffness ( p = 0.73). Torsional testing of samples in the direction of thread tightening tended to be stronger than samples tested in loosening, with all groups either approaching or achieving statistical significance. There were no significant differences between the simple oblique or the butterfly-wedge fracture groups for any of the tested parameters, suggesting that there is no difference in the gross biomechanical properties of the bone-implant construct when the IM clavicle screw is used in either a simple midshaft fracture pattern or a more complex butterfly wedge fracture pattern.

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.

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

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