Biomechanical Measurements of Stiffness and Strength for Five Types of Whole Human and Artificial Humeri

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Mina S. R. Aziz ◽  
Bruce Nicayenzi ◽  
Meghan C. Crookshank ◽  
Habiba Bougherara ◽  
Emil H. Schemitsch ◽  
...  
Keyword(s):  
Bending Strength ◽  
Shear Stiffness ◽  
Shaft Fracture ◽  
Biomechanical Properties ◽  
Torsional Stiffness ◽  
Mineral Density ◽  
Statistical Equivalence ◽  
Fresh Frozen ◽  
Cantilever Bending ◽  
Loading Modes

The human humerus is the third largest longbone and experiences 2–3% of all fractures. Yet, almost no data exist on its intact biomechanical properties, thus preventing researchers from obtaining a full understanding of humerus behavior during injury and after being repaired with fracture plates and nails. The aim of this experimental study was to compare the biomechanical stiffness and strength of “gold standard” fresh-frozen humeri to a variety of humerus models. A series of five types of intact whole humeri were obtained: human fresh-frozen (n = 19); human embalmed (n = 18); human dried (n = 15); artificial “normal” (n = 12); and artificial “osteoporotic” (n = 12). Humeri were tested under “real world” clinical loading modes for shear stiffness, torsional stiffness, cantilever bending stiffness, and cantilever bending strength. After removing geometric effects, fresh-frozen results were 585.8 ± 181.5 N/mm2 (normalized shear stiffness); 3.1 ± 1.1 N/(mm2 deg) (normalized torsional stiffness); 850.8 ± 347.9 N/mm2 (normalized cantilever stiffness); and 8.3 ± 2.7 N/mm2 (normalized cantilever strength). Compared to fresh-frozen values, statistical equivalence (p ≥ 0.05) was obtained for all four test modes (embalmed humeri), 1 of 4 test modes (dried humeri), 1 of 4 test modes (artificial “normal” humeri), and 1 of 4 test modes (artificial “osteoporotic” humeri). Age and bone mineral density versus experimental results had Pearson linear correlations ranging from R = −0.57 to 0.80. About 77% of human humeri failed via a transverse or oblique distal shaft fracture, whilst 88% of artificial humeri failed with a mixed transverse + oblique fracture. To date, this is the most comprehensive study on the biomechanics of intact human and artificial humeri and can assist researchers to choose an alternate humerus model that can substitute for fresh-frozen humeri.

Comparison of double locking plate constructs with single non-locking plate constructs in single cycle to failure in bending and torsion

2015 ◽  
Vol 28 (04) ◽  
pp. 234-239 ◽  
Author(s):  
K. D. Hutcheson ◽  
S. E. Elder ◽  
J. R. Butler
Keyword(s):  
Locking Plate ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Dynamic Compression ◽  
Biomechanical Properties ◽  
Torsional Stiffness ◽  
Single Cycle ◽  
Torsional Testing ◽  
Bending Loads

SummaryObjective: To evaluate the biomechanical properties of single 3.5 mm broad dynamic compression plate (DCP) and double 3.5 mm String-of-Pearls (SOP) plate constructs in single-cycle bending and torsion. We hypothesized that the double SOP construct would outperform the broad DCP in both bending and torsional testing.Methods: Broad DCP plates and double 3.5 mm SOP plates were secured to a previously validated bone model in an effort to simulate bridging osteosynthesis. Constructs were tested in both four-point bending and torsional testing.Results: The double SOP constructs had significantly greater bending stiffness, bending strength, bending structural stiffness, and torsional stiffness when compared to the broad DCP constructs. The single broad DCP constructs had significantly higher yield torque and yield angles during torsional testing.Clinical relevance: Although the in vitro mechanical performance of the double SOP construct was significantly greater than the single broad DCP constructs under bending loads, the actual differences were small. Various patient, fracture, and implant factors must be considered when choosing an appropriate implant for fracture 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.

A realistic model for transverse shear stiffness prediction of composite corrugated-core sandwich structure with bonding effect

2021 ◽  
pp. 109963622199386
Author(s):  
Tianshu Wang ◽  
Licheng Guo
Keyword(s):  
Present Model ◽  
Shear Stiffness ◽  
Realistic Model ◽  
Torsional Stiffness ◽  
Fem Model ◽  
The Core ◽  
Bonding Effect ◽  
Stiffness Model ◽  
Bonding Area ◽  
The Relationship

In this paper, a shear stiffness model for corrugated-core sandwich structures is proposed. The bonding area is discussed independently. The core is thought to be hinged on the skins with torsional stiffness. The analytical model was verified by FEM solution. Compared with the previous studies, the new model can predict the valley point of the shear stiffness at which the relationship between the shear stiffness and the angle of the core changes from negative correlation to positive correlation. The valley point increases when the core becomes stronger. For the structure with a angle of the core smaller than counterpart for the valley point, the existing analytical formulations may significantly underestimate the shear stiffness of the structure with strong skins. The results obtained by some previous models may be only 10 persent of that of the present model, which is supported by the FEM model.

scholarly journals Influence of peracetic acid-ethanol sterilisation on the biomechanical properties of human meniscus transplants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Volker Eras ◽  
Josefine Graffunder ◽  
Norus Ahmed ◽  
Jan C. Brune
Keyword(s):  
Peracetic Acid ◽  
Biomechanical Properties ◽  
Bone Block ◽  
Test Device ◽  
Level Of Evidence ◽  
Load To Failure ◽  
Graft Extrusion ◽  
Fresh Frozen ◽  
Failure Loads ◽  
N Loading

Abstract Purpose Meniscus allograft transplantation (MAT) is a possible treatment for patients suffering with pain after meniscectomy. Here, peracetic acid (PAA) sterilised meniscus transplants were investigated on whether they would provide an adequate alternative to fresh-frozen transplants in their viscoelastic and mechanical properties. Methods In this analysis, 31 menisci donors (26 male and 5 female) were included. The average donor age was 49.87 years, ranging from 32 to 65 years. Menisci of matched pairs of knees underwent chemical sterilisation while counterparts were left fresh-frozen. Stiffness and load to failure were determined via suture retention. Further menisci were analysed while attached to the tibial bone block using a novel test device to mimic physiological load distribution. Meniscus relaxation, stiffness and failure loads were determined. Histology and biphasic properties of the menisci were examined and results were analysed using paired t-tests. Results A novel custom built test device allowed the application of physiological loads for suture retention testing and revealed no significant differences between PAA sterilised (14.85 ± 4.46 N/mm, 50.49 ± 17.01 N) and fresh-frozen (18.26 ± 4.46 N/mm, 59.49 ± 21.07 N) regarding stiffness and failure load, respectively. Furthermore, initial 200 N loading showed significantly higher strain in sterilised menisci (18.87 ± 1.56) compared to fresh frozen (13.81 ± 1.04). Load relaxation experiments demonstrated significantly lower relaxation for sterilised menisci (77.71 ± 1.62) compared to fresh-frozen (89.11 ± 1.00, p-value < 0.0001). Conclusion Peracetic acid sterilised human menisci performed equally to fresh-frozen counterparts in a suture retention test and in physiological failure testing providing an adequate alternative. However, meniscus relaxation, biphasic properties and strain were shown to be significantly different between the groups. A common problem of MAT is graft extrusion or shrinkage, therefore the parameters measured here should be considered and may influence meniscus extrusion after transplantation. Level of evidence n/a (experimental study)

Free fall landing and interval running have different effects on trabecular bone mass and microarchitecture, serum osteocalcin, biomechanical properties, SOST expression and on osteocyte related characteristics

2021 ◽  
Author(s):  
Arnaud Boudenot ◽  
stephane PALLU ◽  
Rustem UZBEKOV ◽  
Eric DOLLEANS ◽  
Hechmi Toumi ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Mrna Expression ◽  
Interval Training ◽  
Free Fall ◽  
Biomechanical Properties ◽  
Bending Test ◽  
Blue Staining ◽  
Control Group ◽  
Mineral Density ◽  
Osteocyte Lacunae

The effects of treadmill interval training (IT) and free fall exercise were evaluated on bone parameters including osteocyte related characteristics. Thirty-eight 4-month-old male Wistar rats were randomly divided into a control group (C) and exercise groups: IT, 10 free fall impacts/day with a 10s (FF10) or 20s interval between drops (FF20), 5 days/week, for 9 weeks. We assessed: BMD, microarchitecture by µCT, mechanical strength by a three-point bending test, density and occupancy of the osteocyte lacunae by toluidine blue staining, osteocalcin and NTx systemic levels by ELISA, and bone tissue Sost mRNA expression by RT-PCR. NTx levels were significantly lower in exercise groups as compared to C. In exercise groups Sost mRNA expression was significantly lower than in C. Tb.N was significantly higher for IT and FF20 compared to C; Tb.Sp was significantly lower in FF10 compared to C. Both IT and FF20 were associated with higher tibial lacunar density as compared to FF10. Compared to FF10, IT fat mass was lower, while tibial osteocyte lacunae occupancy and systemic osteocalcin level were higher. All exercise modes were efficient in reducing bone resorption. Both IT and FF impact with appropriate recovery periods might be beneficial for bone health and osteocyte related characteristics. Novelty bullets: • Interval training is beneficial for bone mineral density • Exercises decreased both bone resorption and inhibition of bone formation (sost mRNA) • Longer interval recovery time favors osteocyte lacunae density

scholarly journals Dietary n-3 PUFA content as a modulator of the femur properties in growing pigs

2019 ◽  
Vol 121 (5) ◽  
pp. 508-518
Author(s):  
Monika Sobol ◽  
Grzegorz Skiba ◽  
Stanisława Raj
Keyword(s):  
Linolenic Acid ◽  
Bone Mineral ◽  
Linseed Oil ◽  
Control Diet ◽  
Biomechanical Properties ◽  
Growing Pigs ◽  
Mineral Density ◽  
Pufa Content ◽  
Left Femur ◽  
Pufa Ratio

AbstractThe relationships between both dietary and empty body fatty acid composition and the morphometry, densitometry, geometry and biomechanical properties of the femur of growing pigs were analysed. A total of thirty-two pigs aged 115 d were divided into four groups (n 8 per group). The pigs were fed either a control diet (group C) or a diet supplemented with linseed oil (rich in α-linolenic acid (C18 : 3n-3), group L), fish oil (rich in EPA (C20 : 5n-3) and DHA (C22 : 6n-3), group F) and beef tallow (rich in SFA, group T). The diets differed in n-3 PUFA contents (0·63–18·52 g/kg) and n-6:n-3 PUFA ratios (0·91–14·51). At 165 d of age, the pigs were slaughtered and the fatty acids in the empty body were determined. Moreover, the left femur was dissected. The cortical wall thickness, cross-sectional area, cortical index, bone mineral content, bone mineral density, maximum elastic strength and maximum strength were lower (P<0·05) in the femurs of pigs from groups C and T than in those from groups F and L. Significant positive correlations were found between the densitometry, geometry and biomechanical properties of the femur and both dietary and empty body n-3 PUFA content, whereas significant negative correlations were observed between the same properties and both dietary and empty body n-6:n-3 PUFA ratio. The results of the present study suggest that in growing pigs α-linolenic acid has a similar positive effect on bone health to that of EPA and DHA.

The effects of ovariectomy on bone mineral density, geometrical, and biomechanical characteristics in the rabbit femur

2010 ◽  
Vol 23 (01) ◽  
pp. 31-36 ◽  
Author(s):  
M. E. Kara ◽  
F. Sevil
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Animal Studies ◽  
Biomechanical Properties ◽  
Mineral Density ◽  
Cross Sectional ◽  
Tomographic Images ◽  
Three Point Bending ◽  
Rabbit Femur

SummaryThe aim of the study was to evaluate the bone mineral density, as well as the biomechanic and morphometric changes in the femur of ovariectomised rabbits.Twenty-four six-month-old New Zealand rabbits were randomly divided into an ovariectomy (n = 12) and a sham (n = 12) group. Six rabbits in each group were euthanatized at eight and 16 weeks after surgery, and the femora were resected. The morphometric data were obtained from tomographic images. Periosteal and endosteal diameters and cortical thickness were measured. Total cross-sectional, cortical and medullary areas were also measured. The bone mineral content, the bone area and the bone mineral density were measured from the proximal, distal and mid-shaft of the femur as well as the total femur by dual energy X-ray absorptiometry. Employing the three-point bending method, the ultimate force, stiffness and work-to-failure were measured. The mechanical data were normalised to obtain intrinsic biomechanical properties such as ultimate stress, elastic modulus, and toughness, all of which are independent of size and shape.The results indicated that the femur was both larger and weaker 16 weeks after surgery in the ovariectomised group. Results also suggest that the rabbit might be a useful animal model for investigation of diseases related to oestrogen loss such as human postmenopausal osteoporosis. However, additional studies with advanced techniques at several time points via in vivo animal studies, and precision and predictability analyses should be designed to standardise the rabbit as a model for osteoporosis.

The Dynamic Characteristics of Rigid Frame Single-Rib Arch Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1426-1430
Author(s):  
Li Xiong Gu ◽  
Rong Hui Wang
Keyword(s):  
Dynamic Characteristics ◽  
Bending Strength ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Lateral Stiffness ◽  
Arch Bridge ◽  
Vertical Stiffness ◽  
Rigid Frame

In this paper, by establishing the finite element model to study the dynamic characteristics of rigid frame single-rib arch bridge. By respectively changing structural parameters of the span ratios, and the compressive stiffness of arch, and the bending stiffness of arch, and the bending stiffness of bridge girder, and the layout of boom to find out the regularity of the structure on lateral stiffness, and vertical stiffness, and torsional stiffness as well as dynamic properties, it come out the results of that lateral stiffness of the structure is weaker, and increasing the span ratios and the compressive strength of arch are conducive to the improvement of the overall stiffness, and improving the bending strength of arch and layout of boom are less effect on the overall stiffness and mode shape.

CORRELATION STUDY BETWEEN BONE MINERAL DENSITY DETERMINED BY RADIOGRAPHIC ABSORPTIOMETRY AND BONE RESISTANCE OF EQUINE THIRD METACARPAL BONE SUBMITTED TO BIOMECHANICAL TESTING

2012 ◽  
Vol 15 (01) ◽  
pp. 1250007
Author(s):  
Paulo J R Frazao ◽  
Rodrigo Crispim ◽  
Cesar A M Pereira ◽  
Mariana B Selim ◽  
Lara L Facó ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Correlation Study ◽  
Metacarpal Bone ◽  
Mineral Density ◽  
Radiographic Absorptiometry ◽  
Study Bone Mineral Density ◽  
Significant Linear Correlation

Knowledge about non-invasive methods for early diagnostics in equine orthopedic disorders is economically important and has been widely studied. In this study, bone mineral density determined by radiographic absorptiometry was correlated to bone resistance of the equine third metacarpal bone submitted to biomechanical testing. Thirty pairs of third metacarpal bone of adult horses were collected, dissected, radiographed, analyzed by the radiographic absorptiometry technique, and submitted to tomographic study and biomechanical testing. No significant linear correlation between radiographic bone density values and measured biomechanical properties was observed. Therefore, bone mineral density of the third metacarpal bone determined by radiographic absorptiometry does not predict bone capacity to resist compression and flexion loads. Further studies should be developed to establish which techniques are reliably capable of giving such predictive information.

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