Effective mechanical properties of diaphyseal cortical bone in the canine femur

Abstract

The effective elastic modulus, yield strength, yield strain, ultimate strength, ultimate strain, strain energy density at yield and strain energy density at ultimate failure of femoral diaphyseal cortical bone were investigated on canine femurs. Four femurs representative of the canine population were selected from four statistically-determined clusters based on increasing size and weight comprising the Toy poodle (5 kg), Poodle (12 kg), German shorthaired pointer (25 kg) and Doberman (50 kg). The zones of interest were the lateral, medial, cranial, and caudal quadrants of the mid-diaphysis. Effective mechanical properties were measured using quasi-static three-point bending tests on strips. The averages ± SD were 15.6 ± 2.6 GPa for effective elastic modulus, 174.3 ± 32.1 MPa for yield strength, 0.012 ± 0.003 for yield strain, 251.0 ± 49.1 MPa for ultimate strength, 0.021 ± 0.005 for ultimate strain, 10.7 ± 4.0J m(-3) × 10(5) for strain energy density at Yield and 33.0 ± 14.1 Jm(-3)× 10(5) for strain energy density at ultimate failure. Significant differences were found between dogs and the effective elastic modulus increased with breed weight and size (13.9 GPa for the Toy poodle to 17.2 GPa for the Doberman). The ultimate strength σ(u) and strain energy density at ultimate failure U(u) were significantly lower in the Toy poodle than in the Poodle and German shorthaired pointer indicating that the cortical bone material in the Toy poodle differed from that of the other dogs. Examination of the zones of interest revealed that the cranial quadrant showed the greatest stiffness, whereas strength was highest at the medial site. The caudal cortex was less stiff and strong than the cranial cortex.

Pullout strength of 2.0 mm cancellous and cortical screws in synthetic bone

“…A second set of polyurethane foam blocks of identical size laminated on both sides with 1 mm thick short‐fiber‐filled epoxy sheets (Sawbones) (total dimensions 25 mm × 25 mm × 17 mm) were used to mimic bicortical canine bone. The short‐fiber‐filled epoxy sheets were selected because their mechanical properties (compressive strength, compressive modulus, and density), when tested according to ASTM D‐638 and D‐695, are similar to that of canine cortical bone . The 1 mm thick epoxy sheets were chosen based on a previous study reporting an average canine femoral cortical thickness of 1.08 ± 0.29 mm .…”

“…The short‐fiber‐filled epoxy sheets were selected because their mechanical properties (compressive strength, compressive modulus, and density), when tested according to ASTM D‐638 and D‐695, are similar to that of canine cortical bone . The 1 mm thick epoxy sheets were chosen based on a previous study reporting an average canine femoral cortical thickness of 1.08 ± 0.29 mm . A total of 30 cancellous blocks were randomly assigned to 2.0 mm cortical screws or 2.0 mm cancellous screws (Veterinary Orthopedic Implants, St. Augustine, Florida), creating 15 blocks per group.…”

“…30,31 The 1 mm thick epoxy sheets were chosen based on a previous study reporting an average canine femoral cortical thickness of 1.08 6 0.29 mm. 30 A total of 30 cancellous blocks were randomly assigned to 2.0 mm cortical screws or 2.0 mm cancellous screws (Veterinary Orthopedic Implants, St. Augustine, Florida), creating 15 blocks per group. The number of blocks per group was based on a previous study achieving statistical significance with that group size.…”

Preclinical testing of drug delivery systems to bone

“…It varies in the range of 20% by region (epiphysis, metaphysis, diaphysis) in the long bone [33]. Interestingly, minor interspecies differences exist concerning the elastic modulus [32,34,35]. In addition, differences between the cortical and trabecular bone within the femur exists.…”

An EMG-driven biomechanical model of the canine cervical spine

“…In vivo studies on canines can be easily conducted and used to validate overall subject-specific model outputs. Moreover, this model will provide a suitable platform to explore the validity of canine cervical spine models that have been employed extensively for investigating effects of spinal instruments developed for human spine (Autefage et al, 2012;Lim et al, 1994;Sharir et al, 2006;Sheng et al, 2010). Several human cervical spine models have been developed and validated to better understand the mechanical loads on the human spine (Horst et al, 1997;Hyeonki Choi, 2010;Jager et al, 1996;Lopik and Acar, 2007;Snijders et al, 1991;Stemper et al, 2004;Vasavada et al, 1998).…”