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Characterization of the torsional structural properties of feline femurs and surrogate bone models for mechanical testing of orthopedic implants
Author(s) -
Marturello Danielle M.,
Wei Feng,
Déjardin Loïc M.
Publication year - 2019
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/vsu.13136
Subject(s) - medicine , femur , cadaveric spasm , orthopedic surgery , biomedical engineering , torsion (gastropod) , orthodontics , surgery
Objective To characterize the torsional structural properties of the feline femur and design a bone model surrogate for mechanical testing of feline orthopedic implants. Study design Experimental. Sample population Paired feline femurs (n = 30) and bone models (8 materials, n = 4/group). Methods Femurs were cyclically tested nondestructively in torsion and then loaded to failure. A generic femoral model was then designed from native femur dimensions and tested similarly by using 1 of 8 materials that were 3‐dimensionally printed or machined. Outcome measures consisting of torsional compliance, angular deformation (AD), and torque to failure were compared by using Student's t test ( P < .05). Failure modes are reported as descriptive statistics. Results Torsional compliance (1.6 ± 0.3°/Nm, 2.0 ± 0.1°/Nm), AD (3.1 ± 0.6°, 3.8 ± 0.2°) and torque to failure (7.8 ±1.2 Nm, 8.1 ± 1.3 Nm) did not differ between feline femurs and short‐fiber epoxy (SFE) models. Conversely, most printed materials displayed excessive TC and failed by plastic deformation (AD > 15‐fold that of native femurs) rather than by fracture. Feline bone and SFE both failed by spiral fractures. Conclusion None of the outcome measures differed between the 4th generation SFE model and cadaveric femurs, but differences were identified between feline bone and printed materials. Clinical impact Machined SFE can be used to create a surrogate bone model with torsional structural properties similar to those of feline femurs. In contrast, common printable materials appear unsuitable to produce a realistic feline bone surrogate.