Influence of Screw-Hole Defect Size on the Biomechanical Properties of Feline Femora in an Ex Vivo Model

2021 ◽  
Author(s):  
QiCai Jason Hoon ◽  
Tian Wang ◽  
Evelyn Hall ◽  
William R. Walsh ◽  
Kenneth A. Johnson
Keyword(s):  
Ex Vivo ◽  
Drill Hole ◽  
Biomechanical Properties ◽  
Defect Size ◽  
Ex Vivo Model ◽  
Load Torque ◽  
Screw Hole ◽  
Loading Rates ◽  
Defect Groups ◽  
Hole Defects

Abstract Objective The study aims to evaluate the biomechanical properties of feline femora with craniocaudal screw-hole defects of increasing diameter, subjected to three-point bending and torsion to failure at two different loading rates. Study Design Eighty femoral pairs were harvested from adult cat cadavers. For each bending and torsional experiment, there were five groups (n = 8 pairs) of increasing craniocaudal screw-hole defects (intact, 1.5 mm, 2.0 mm, 2.4 mm, 2.7mm). Mid-diaphyseal bicortical defects were created with an appropriate pilot drill-hole and tapped accordingly. Left and right femora of each pair were randomly assigned to a destructive loading protocol at low (10 mm/min; 0.5 degrees/s) or high rates (3,000 mm/min; 90 degrees/s) respectively. Stiffness, load/torque-to-failure, energy-to-failure and fracture morphology were recorded. Results Defect size to bone diameter ratio was significantly different between defect groups within bending and torsional experiments respectively (intact [0%; 0%], 1.5 mm [17.8%; 17.1%], 2.0 mm [22.8%; 23.5%], 2.4 mm [27.8%; 27.6%], 2.7 mm [31.1%; 32.4%]) (p < 0.001). No significant differences in stiffness and load/torque-to-failure were noted with increasing deficit sizes in all loading conditions. Screw-hole (2.7 mm) defects up to 33% bone diameter had a maximum of 20% reduction in bending and torsional strength compared with intact bone at both loading rates. Stiffness and load/torque-to-failure in both bending and torsion were increased in bones subjected to higher loading rates (p < 0.001). Conclusion Screw-hole defects up to 2.7 mm did not significantly reduce feline bone failure properties in this ex vivo femoral study. These findings support current screw-size selection guidelines of up to 33% bone diameter as appropriate for use in feline fracture osteosynthesis.

Investigation of the effects of two-, four-, six- and eight-strand suture repairs on the biomechanical properties of canine gastrocnemius tenorrhaphy constructs

2021 ◽  
pp. 1-7
Author(s):  
Yi-Jen Chang ◽  
Daniel J. Duffy ◽  
George E. Moore
Keyword(s):  
Failure Modes ◽  
Clinical Decision Making ◽  
Ex Vivo ◽  
Biomechanical Testing ◽  
Tendon Repair ◽  
Clinical Decision ◽  
Biomechanical Properties ◽  
Suture Technique ◽  
Gap Formation ◽  
Ex Vivo Model

Abstract OBJECTIVE To determine the effects of 2-, 4-, 6- and 8-strand suture repairs on the biomechanical properties of canine gastrocnemius tenorrhaphy constructs in an ex vivo model. SAMPLE 56 cadaveric gastrocnemius musculotendinous units from 28 adult large-breed dogs. PROCEDURES Tendons were randomly assigned to 4 repair groups (2-, 4-, 6- or 8-strand suture technique; n = 14/group). Following tenotomy, repairs were performed with the assigned number of strands of 2-0 polypropylene suture in a simple interrupted pattern. Biomechanical testing was performed. Yield, peak, and failure loads, the incidence of 1- and 3-mm gap formation, forces associated with gap formation, and failure modes were compared among groups. RESULTS Yield, peak, and failure forces differed significantly among groups, with significantly greater force required as the number of suture strands used for tendon repair increased. The force required to create a 1- or 3-mm gap between tendon ends also differed among groups and increased significantly with number of strands used. All constructs failed by mode of suture pull-through. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that increasing the number of suture strands crossing the repair site significantly increases the tensile strength of canine gastrocnemius tendon repair constructs and their resistance to gap formation. Future studies are needed to assess the effects of multistrand suture patterns on tendon glide function, blood supply, healing, and long-term clinical function in dogs to inform clinical decision-making.

Development and characterization of a novel meniscal extracellular matrix-derived scaffold

2017 ◽  
Author(s):  
◽  
Farrah Ann Monibi
Keyword(s):  
Extracellular Matrix ◽  
Tissue Repair ◽  
Cellular Proliferation ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Critical Role ◽  
Meniscal Repair ◽  
Biomechanical Properties ◽  
Ex Vivo Model

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Musculoskeletal injuries are a common and significant problem in orthopaedic practice. Despite advances in orthopaedic surgery, effective treatments for injuries to the knee meniscus remain a common and significant clinical challenge. Tissue engineering is a developing field that aims to regenerate injured tissues with a combination of cells, scaffolds, and signals. Many natural and synthetic scaffold materials have been developed and tested for the repair and restoration of a number of musculoskeletal tissues. Among these, biological scaffolds derived from extracellular matrix (ECM) have been developed and tested given the critical role of the ECM for maintaining the biological and biomechanical properties, structure, and function of native tissues. Decellularized scaffolds composed of ECM hold promise for repair and regeneration of the meniscus given the potential for ECM-based biomaterials to aid in cell recruitment, infiltration, and differentiation. The objectives of this research were to decellularize canine menisci in order to fabricate a micronized, ECM-derived scaffold, and to determine the cytocompatibility and repair potential of the scaffold ex vivo by developing an in vitro model for meniscal repair. In the first series of experiments, menisci were decellularized with a combination of physical agitation and chemical treatments. For scaffold fabrication, decellularized menisci were cryoground into a powder and the size and morphology of the ECM particles were evaluated using scanning electron microscopy. Histologic and biochemical analyses of the scaffold confirmed effective decellularization with loss of proteoglycan from the tissue but no significant reduction in collagen content. When washed effectively, the decellularized scaffold was cytocompatible to meniscal fibrochondrocytes, synoviocytes, and whole meniscal tissue based on the resazurin reduction assay, fluorescent live/dead staining, and histologic evaluation. Further, the scaffold supported cellular attachment and proliferation when combined with platelet rich plasma, and promoted an upregulation of genes associated with meniscal ECM synthesis and tissue repair. In an ex vivo model for meniscal repair, radial tears repaired and augmented with the scaffold demonstrated increased cellular proliferation and tissue repair compared to non-augmented repairs. Therefore, a micronized scaffold derived from decellularized meniscus may be a viable biomaterial for promoting avascular meniscal healing. However, further studies are necessary to determine an optimal carrier for delivery of the scaffold, and to examine the potential for the scaffold to induce cellular differentiation and functional meniscal fibrochondrogenesis.

The effect of external coaptation on plate deformation in an ex vivo model of canine pancarpal arthrodesis

2012 ◽  
Vol 25 (06) ◽  
pp. 439-444 ◽  
Author(s):  
R. J. Wallace ◽  
J. R. Mosley ◽  
S. Woods
Keyword(s):  
Ex Vivo ◽  
Distal Portion ◽  
External Support ◽  
Carpal Bone ◽  
Ex Vivo Model ◽  
Screw Hole ◽  
Plate Deformation ◽  
Measured Strain ◽  
Mean Strain ◽  
Plate Failure

SummaryObjectives: Since external coaptation is applied clinically to prevent plate failure during healing in canine pancarpal arthrodesis (PCA), we tested the hypothesis that external coaptation does not significantly reduce plate strain in an experimental ex vivo model of canine PCA.Methods: Ten thoracic limbs from healthy Greyhounds euthanatized for reasons un- related to the study were harvested and the carpus was stabilised with a dorsally applied 2.7/3.5 mm hybrid PCA plate. The strain in the plate adjacent to the most distal radial screw hole (R4) and the radial carpal bone (RCB) screw hole was measured as the limbs were loaded axially to a load that approximated that of controlled walking. Each limb was tested with and without external coaptation in place.Results: Mean strain amplitude at the RCB was –177.2 με (± 20.78) without external coaptation. Following cast application, strain reduced significantly to –34.7 με (± 9.84) (p <0.002). Mean strain at R4 was –89.4 με (± 22.10) without external support and –66.9 με (± 10.74) following application of a cast. This reduction in recorded strain was not statistically significant.Clinical significance: The application of a cast to the distal portion of the limb significantly reduced strain in the 2.7/3.5 mm hybrid PCA plate, but the magnitude of the measured strain was low, suggesting that fatigue damage is unlikely to accumulate as a result of this type of loading and that external coaptation may not be necessary to prevent fatigue failure of the plate.

1849: Systematic Evaluation of 21μm Thulium Laser Device for Treatment of Benign Prostatic Enlargement in an Ex-VIVO Model

2007 ◽  
Vol 177 (4S) ◽  
pp. 614-614 ◽  
Author(s):  
Gunnar Wendt-Nordahl ◽  
Stefanie Huckele ◽  
Patrick Honeck ◽  
Peter Aiken ◽  
Thomas Knoll ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Systematic Evaluation ◽  
Thulium Laser ◽  
Laser Device ◽  
Benign Prostatic Enlargement ◽  
Ex Vivo Model ◽  
Prostatic Enlargement

Porcine small intestine, a good ex vivo model to investigate absorption and metabolism of natural products

2017 ◽  
Author(s):  
J Houriet ◽  
YE Arnold ◽  
C Petit ◽  
YN Kalia ◽  
JL Wolfender
Keyword(s):  
Natural Products ◽  
Small Intestine ◽  
Ex Vivo ◽  
Ex Vivo Model

Effects of Two Different Doses of Hirudin on APTT, Determined with Eight Different Reagents

1995 ◽  
Vol 73 (02) ◽  
pp. 219-222 ◽  
Author(s):  
Manuel Monreal ◽  
Luis Monreal ◽  
Rafael Ruiz de Gopegui ◽  
Yvonne Espada ◽  
Ana Maria Angles ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Anticoagulant Activity ◽  
Subcutaneous Administration ◽  
In Vitro Study ◽  
Ex Vivo Model ◽  
Suitable Candidate ◽  
Significant Prolongation ◽  
High Doses ◽  
Different Doses

SummaryThe APTT has been considered the most suitable candidate to monitor the anticoagulant activity of hirudin. However, its use is hampered by problems of standardization, which make the results heavily dependent on the responsiveness of the reagent used. Our aim was to investigate if this different responsiveness of different reagents when added in vitro is to be confirmed in an ex vivo study.Two different doses of r-hirudin (CGP 39393), 0.3 mg/kg and 1 mg/kg, were administered subcutaneously to 20 New Zealand male rabbits, and the differences in prolongation of APTT 2 and 12 h later were compared, using 8 widely used commercial reagents. All groups exhibited a significant prolongation of APTT 2 h after sc administration of hirudin, both at low and high doses. But this prolongation persisted 12 h later only when the PTTa reagent (Boehringer Mannheim) was used. In general, hirudin prolonged the APTT most with the silica- based reagents.In a further study, we compared the same APTT reagents in an in vitro study in which normal pooled plasma was mixed with increasing amount of hirudin. We failed to confirm a higher sensitivity for silica- containing reagents. Thus, we conclude that subcutaneous administration of hirudin prolongs the APTT most with the silica-based reagents, but this effect is exclusive for the ex vivo model.

EMR+: Vorstellung einer neuen endoskopischen Resektionsmethode im ex-vivo Model

2019 ◽  
Author(s):  
RF Knoop ◽  
E Wedi ◽  
V Ellenrieder ◽  
A Neesse ◽  
S Kunsch
Keyword(s):  
Ex Vivo ◽  
Ex Vivo Model
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