Biomechanical Measurements of Torsion-Tension Coupling in Human Cadaveric Femurs

Zdero, Rad; McConnell, Alison J; Peskun, Christopher; Syed, Khalid; Schemitsch, Emil H.

doi:10.1115/1.4002937

Cited by 15 publications

(12 citation statements)

References 23 publications

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“…43 A previous study also demonstrated no left-versus-right difference in human cadaveric femurs concerning the simultaneous mechanical coupling of torsion and tension. 16 Twelve of the 16 human femurs had normal bone quality. Although the data can help researchers better understand the nature of femoral bone injury in those with healthy bone, a deeper understanding of the behaviour of osteoporotic or osteopenic bone has not been gained.…”

Section: Limitationsmentioning

confidence: 99%

Biomechanical measurements of axial crush injury to the distal condyles of human and synthetic femurs

Crookshank

Coquim

Olsen

et al. 2012

Proc Inst Mech Eng H

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Few studies have evaluated the 'bulk' mechanical properties of human longbones and even fewer have compared human tissue to the synthetic longbones increasingly being used by researchers. Distal femur fractures, for example, comprise about 6% of all femur fractures, but the mechanical properties of the distal condyles of intact human and synthetic femurs have not been well quantified in the literature. To this end, the distal portions of a series of 16 human fresh-frozen femurs and six synthetic femurs were prepared identically for mechanical testing. Using a flat metal plate, an axial 'crush' force was applied in-line with the long axis of the femurs. The two femur groups were statistically compared and values correlated to age, size, and bone quality. Results yielded the following: crush stiffness (human, 1545 +/- 728 N/mm; synthetic, 3063 +/- 1243 N/mm; p = 0.002); crush strength (human, 10.3 +/- 3.1 kN; synthetic, 12.9 < or = 1.7 kN; p = 0.074); crush displacement (human, 6.1 +/- 1.8 mm; synthetic, 2.8 +/- 0.3 mm; p = 0.000); and crush energy (human, 34.8 +/- 15.9J; synthetic, 18.1 +/- 5.7J; p = 0.023). For the human femurs, there were poor correlations between mechanical properties versus age, size, and bone quality (R2 < or = 0.18), with the exception of crush strength versus bone mineral density (R2 = 0.33) and T-score (R2 = 0.25). Human femurs failed mostly by condyle 'roll back' buckling (15 of 16 cases) and/or unicondylar or bicondylar fracture (7 of 16 cases), while synthetic femurs all failed by wedging apart of the condyles resulting in either fully or partially displaced condylar fractures (6 of 6 cases). These findings have practical implications on the use of a flat plate load applicator to reproduce real-life clinical failure modes of human femurs and the appropriate use of synthetic femurs. To the authors' knowledge, this is the first study to have done such an assessment on human and synthetic femurs.

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Section: Limitationsmentioning

confidence: 99%

Biomechanical measurements of axial crush injury to the distal condyles of human and synthetic femurs

Crookshank

Coquim

Olsen

et al. 2012

Proc Inst Mech Eng H

Self Cite

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“…A population group or individual may show nominally different geometry from side-to-side for the lower limbs, 50 but there are no statistical differences between the mechanical properties of left versus right femurs. 51–53…”

Section: Discussionmentioning

confidence: 99%

Biomechanical measurements of cortical screw stripping torque in human versus artificial femurs

Nicayenzi

Crookshank

Olsen

et al. 2012

Proc Inst Mech Eng H

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Femur fracture plates are applied using cortical bone screws. Surgeons do this manually by subjective ‘feel’ without monitoring torque. Few studies have quantified stripping torque in human bone. No studies have measured stripping torque in the artificial bones from Sawbones (Vashon, WA, USA) that are frequently used in biomechanical studies. The present aim was to measure stripping torque of cortical screws in human versus artificial femurs. Sixteen fresh-frozen human femurs and eight artificial femurs were used. Using a digital torque screwdriver, each femur had a 3.5-mm diameter unicortical screw manually inserted into the anterior midshaft until failure of the screw–bone interface. Results were normalized by cortical thickness and the screw–bone interfacial area. There were no statistical differences in human versus artificial data, respectively, for stripping torque (1741 ± 442 N.mm, 2012 ± 176 N.mm, p = 0.11), stripping torque/thickness (313 ± 59 N, 305 ± 30 N, p = 0.74), and stripping torque/area (28.5 ± 5.3 N/mm, 27.8 ± 2.8 N/mm, p = 0.74). Artificial unicortical thickness (6.6 ± 0.3 mm) was greater than human thickness (5.6 ± 1.1 mm) (p = 0.02). For human specimens, there was a moderate linear correlation of absolute and normalized stripping torque versus standardized bone mineral density (R ≥ 0.32) and clinical T-score (R = 0.29), but not with age (R ≤ 0.29). Surgeons should be aware of the stripping torque limits for human femurs and potentially take steps to monitor these values during surgery. The artificial femurs being increasingly used in research accurately replicate human cortical properties during screw insertion. To date, this is the first series of human femurs evaluated for cortical screw stripping.

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“…Synthetic longbones are gaining more widespread use due to advantages they provide over cadaveric specimens. The use of artificial or synthetic femurs has a sufficiently established history in biomechanics studies [45,81,[122][123][124][125][126][127] because of their similar axial vs. torsional stiffness ratio [128], cancellous and cortical screw pullout shear stress [129,130], and identical failure mechanism under axial compression compared to human femurs [131].…”

Section: Testing Methods In Biomechanical Analysismentioning

confidence: 99%

Biomechanical development and analysis of a new carbon-fiber/flax/epoxy plate for repairing femur fractures

Bagheri¹

2022

Preprint

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Femur fracture at the tip of a total hip replacement (THR), commonly known as Vancouver B1 fracture, is mainly treated using rigid metallic bone plates, which may result in "stress shielding" leading to bone resorption and implant loosening. To minimize "stress shielding", a novel carbon fiber (CF)/Flax/Epoxy composite plate with a “sandwich structure” has been developed and characterized mechanically, biologically and biomechanically compared to a standard clinical metal plate. The CF/Flax/Epoxy composite material showed no cytotoxicity with no negative influence on the expression level of bone formation genes at all incubation time. The results of mechanical tests revealed a considerably high ultimate strength in tension (399.8 MPa), flexion (510.6 MPa) and fatigue loading (200-220 MPa). The composite plate showed higher elastic modulus in bending tests (57.4 GPa) compared to tension tests (41.7 GPa). The dynamic modulus (E*) was found to stay almost constant versus the number of cycles, which can be related to the contribution of both flax/epoxy and CF/epoxy laminae to the stiffness of the composite. The results of biomechanical assessment of the plate showed that the bone beneath the CF/Flax/Epoxy plate was the only area that had a significantly higher average surface stress (fractured = 2.10 ± 0.66 MPa; healed = 1.89±0.39 MPa) compared to bone beneath the metal plate (fractured = 1.shielding” effect. The CF/Flax/Epoxy plated femur had comparable axial stiffness (fractured = 645 ± 67 N/mm; healed = 1731 ± 109 N/mm) to the metal plated femur (fractured = 658 ± 69 N/mm; healed = 1751 ± 39 N/mm) (p=1.00). These results confirm that the new CF/Flax/Epoxy material could be a potential candidate for bone fracture plate applications as it shows good biocompatibility and considerably higher strength in tension, flexion and fatigue than actual clinical load level experienced by femur during daily normal activities. Moreover, it can simultaneously provide similar mechanical stiffness and lower “stress shielding” (i.e. higher bone stress) compared to commercially-used metal bone plates.18 ± 0.93 MPa; healed = 0.71 ± 0.24 MPa) (p<0.05), cause less “stress

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Biomechanical Measurements of Torsion-Tension Coupling in Human Cadaveric Femurs

Cited by 15 publications

References 23 publications

Biomechanical measurements of axial crush injury to the distal condyles of human and synthetic femurs

Biomechanical measurements of axial crush injury to the distal condyles of human and synthetic femurs

Biomechanical measurements of cortical screw stripping torque in human versus artificial femurs

Biomechanical development and analysis of a new carbon-fiber/flax/epoxy plate for repairing femur fractures

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