Embalmed and fresh frozen human bones in orthopedic cadaveric studies: which bone is authentic and feasible?

Abstract

Background and purpose The most frequently used bones for mechanical testing of orthopedic and trauma devices are fresh frozen cadaveric bones, embalmed cadaveric bones, and artificial composite bones. Even today, the comparability of these different bone types has not been established.Methods We tested fresh frozen and embalmed cadaveric femora that were similar concerning age, sex, bone mineral density, and stiffness. Artificial composite femora were used as a reference group. Testing parameters were pullout forces of cortex and cancellous screws, maximum load until failure, and type of fracture generated.Results Stiffness and type of fracture generated (Pauwels III) were similar for all 3 bone types (fresh frozen: 969 N/mm, 95% confidence interval (CI): 897–1,039; embalmed: 999 N/mm, CI: 875–1,121; composite: 946 N/mm, CI: 852–1,040). Furthermore, no significant differences were found between fresh frozen and embalmed femora concerning pullout forces of cancellous screws (fresh frozen: 654 N, CI: 471–836; embalmed: 595 N, CI: 365–823) and cortex screws (fresh frozen: 1,152 N, CI: 894–1,408; embalmed: 1,461 N, CI: 880–2,042), and axial load until failure (fresh frozen: 3,427 N, CI: 2,564–4290; embalmed: 3,603 N, CI: 2,898–4,306). The reference group showed statistically significantly different results for pullout forces of cancellous screws (2,344 N, CI: 2,068–2,620) and cortex screws (5,536 N, CI: 5,203–5,867) and for the axial load until failure (> 7,952 N).Interpretation Embalmed femur bones and fresh frozen bones had similar characteristics by mechanical testing. Thus, we suggest that embalmed human cadaveric bone is a good and safe option for mechanical testing of orthopedic and trauma devices.

Internal fixation of fragility fracturesof the femoral neck

“…Composite femurs were also found to be good analogs to human bones regarding pull-out force of screws (Zdero et al 2007 and. On the contrary, a later study found that the pull-out force was significantly higher in composite femurs than in cadaver femurs (Topp et al 2012). …”

“…Our laboratory has traditionally used fresh frozen femurs for biomechanical experiments (Aamodt et al 2001, Wik et al 2010) and fresh frozen femurs were chosen accordingly. During the course of our study embalmed femurs were shown to provide similar mechanical properties to fresh frozen ones and could have been an alternative (Topp et al 2012). Our aim was to evaluate the implants for use in old patients with femoral neck fractures that constitute the major bulk of the patients.…”

Mechanical and corrosion properties of partially degradable bone screws made of pure iron and stainless steel 316L by friction welding

“…As shown in Fig. 2a, the pull-out test was performed using a section of a commonly fresh frozen two years old cow tibia, which was selected to mimic the mechanical strength of the human bone [21,22]. The cortical bone screw prototype was inserted manually with a screwdriver then extracted by a universal testing machine (Instron Fast Track 8874, USA) with displacement control at a fixed rate of 0.4 mm min −1…”

Regional Variations in Shear Strength and Density of the Human Thoracic Vertebral Endplate and Trabecular Bone

“…20,21 However, other studies like the one by Topp et al (2012) have described similar stiffness and fracture patterns between both types of samples. Additionally, they described differences, which were not significant in screw pullout forces and axial maximum load to failure for cancellous and cortical screws.…”

“…Additionally, they described differences, which were not significant in screw pullout forces and axial maximum load to failure for cancellous and cortical screws. 22 Moreover, we evaluated differences between regions of the same embalmed samples, which diminish potential limitations caused by not utilizing fresh cadavers.…”