Our material property tables list values for “parallel to rise”. If load direction is perpendicular to rise, the foams’ properties are about 25% lower in modulus and 5% lower strength. However, this only applies to foams with a density of 20pcf and less. Densities higher than 20pcf may be considered isotropic in their material properties. We maintain direction of rise parallel to block thickness when possible.

Healthy cancellous bone: 12-20pcf
Healthy vertebral cancellous bone: 10-15pcf
Osteoporotic/weak bone: 10pcf or less

Yes; however, solid and cellular foam image with similar intensity to lung tissue. Open-cell foams image better because of its higher material density

Our absolute™ bones do not show up in magnetic resonance imaging (MRI) as there are no water/fat molecules in the materials. absolute™ bones need to be submerged in a water based media in order to see a definitive contrast.

In short, material, shape and structural characteristics are similar to cadaver bone for the purposes of load testing with implants. They exhibit much lower variation in these characteristics allowing your study to produce reliable results. They are readily available, do not degrade and do not require any special handling. References to peer reviewed scientific articles verifying the performance of these models may be found here.

Cellular foam contains larger pores than solid foam; however, both are made of the same base material.See tables on website

Porosity is the ratio of void volume/total volume. It is the inverse of volume fraction or in bone morphology “BV/TV” where it is a ratio of solid material volume vs. total volume. See tables on website

Foam density may vary ± 10% from its nominal value for a standard size block
Short fiber filled epoxy may vary ± 2.5%

We do not have lot tracking for our foam blocks because variation of ± 10% may occur within a single “batch”. If density is the major contributor to variation in your results use an ANCOVA (analysis of co-variance). This analysis requires you to measure and record the density of each block tested (weight and dimensions). This method is similar to the t-test but instead of comparing means it compares the slope of two test groups, which is much more accurate when accounting for a co-variant such as density.

17pcf solid polyurethane foam
0.078 Thermal Conductivity (W/mK)
0.251 Thermal Diffusivity (mm^2/s)
0.31 Specific Heat (MJ/m^3K)

50pcf solid polyurethane foam
0.106 Thermal Conductivity (W/mK)
1.477 Specific Heat (J/gC)

40pcf solid polyurethane foam
0.087 Thermal Conductivity (W/mK)
1.477 Specific Heat (J/gC)

60mm.

Trabecular Thickness (Tb.Th)(mm) was measured on average at 0.38mm for the 7.5pcf open cell foam

Short-fiber filled epoxy
0.452 Thermal Conductivity (W/mK)
0.276 Thermal Diffusivity (mm^2/s)
1.64 Specific Heat (MJ/m^3K)

Fiberglass is long and skinny and aligns itself with the direction of flow when molding. Fiber orientation is longitudinal within the shaft of a long bone making it transverse isotropic and then becomes random at proximal and distal extents of bone making it isotropic.

There is no minimum on the standard block sizes, 120mm x 170mm x thickness. However, blocks smaller than this will have a multiple requested for ordering.

Yes, we can laminate open-cell foam. We use the same laminating resin 40pcf.

Solid foam: 1, 2, 3mm
absolute™ sheets: 0.5, 1, 2, 3, 4, 6, 8, 10mm

Other sizes require a custom quote for machining

0.5mm for 30# – 50# and 1mm for 20# or less

Manual Cut Tolerance is ± 2mm, upon request ± 1mm
CNC Machine Cut tolerance is ± 0.3mm, upon request ± -0.1mm, custom quote required.

Please note that open-cell blocks are harder to cut and may produce damage struts on and near surface.

0.26 is Poisson’s ratio for our short fiber-filled epoxy.

17 pcf Solid foam, representative of healthy adult cancellous bone

10 pcf, some bones may be available with 8pcf

12.5 pcf is the lowest but prefer 20 pcf because manufacturing issues can arise where larger cell sizes may fill with cortical material.

Yes, we use a robotic arm to make a 1.6mm (1/16”) wide by 2-3mm deep cut, followed by manual load application to complete the fracture. This requires a one-time development fee. Less complex (planar) can be done with a bandsaw.

No plan yet for canine; however, absolute™ cylinders are an alternative.

Rowe-Guthrie, Kathleen M et al. “Mechanical Evaluation of Locking, Nonlocking, and Hybrid Plating Constructs Using a Locking Compression Plate in a Canine Synthetic Bone Model.” Veterinary surgery : VS vol. 44,7 (2015): 838-42. doi:10.1111/vsu.12368

Yes, we can fill the canal with the same cancellous foam as a secondary operation.

No.

No specific age; they are meant to simulate healthy adult bone

Large, male, adult, 6’0”, 200lbs (183cm, 91kg)
85th percentile 20 and over, all race

Medium, male, adult, 5’9”, 185lbs (175cm, 84kg)
50th percentile 20 and over, all race

Asian, male, adult, 5’3”, weight unknown (160cm)
Small, no data avail, but size aligns 50th percentile data for: 10yrs, 4’7”, 75lbs (140cm, 34kg)

Source based on Height tables: https://www.cdc.gov/nchs/data/series/sr_03/sr03-046-508.pdf

Yes, 3503 is a medium sized femur with a thin cortical wall and a newly formulated lower density fiber filled epoxy to mimic natural femurs with osteoporosis. The cancellous foam in this femur is also lower in density than the standard 3403.

Gluek, Cooper et al. “Evaluating the mechanical response of novel synthetic femurs for representing osteoporotic bone.” Journal of biomechanics vol. 111 (2020) : 110018. doi:10.1016/j.jbiomech.2020.110018

Large femur, 3406 anteversion 8deg, neck angle 120deg, canal 16mm, anterior bow greater then 153mm radius

Medium femur, 3403 anteversion 11 deg, neck angle 135deg, canal 13mm, anterior bow greater than 153mm radius

Asian femur, 3447 anteversion 20deg, neck angle 129deg, canal 12mm

Small femur, 3414 anteversion 10deg, neck angle 130deg, canal 9.5mm, anterior bow greater than 111mm radius

Upon request, we can add cancellous foam, including solid, cellular or open cell foams to absolute™ cylinders. When solid foam is added it is a continuous layer whereas cellular and open-cell foams will be stacked in 40mm length sections and glued to the walls of the cylinder. Additional fee applies for filling the cylinders with foam.

Cylinders are available in various wall thicknesses with an outer diameter of 10, 20, 27, 30, 35, 40mm. 10mm diameter cylinders have a maximum length of 150mm and all others are 500mm