Festigkeitsuntersuchungen an Pins aus humaner Femurkortikalis

Abstract

For biomechanical evaluation of cortical bone as a potential source for internal fixation devices, pins of 2 and 3 mm in diameter were made from fresh human femora and subjected to bending loads. Some of the pins were tested without further treatment; others were defatted and dried in acetone solution. Of the acetone-treated pins, some were autoclaved either at 121 degrees C for 20 min or at 134 degrees C for 8 min. Acetone treatment of the pins caused a 5.5% increase in bending strength (p < or = 0.05) and a 6.6% increase in the elastic modulus (p < or = 0.05). The mean bending strength of the acetone-treated pins was 257 +/- 52 N/mm2 and the mean elastic modulus was 18,346 +/- 1292 N/mm2. Autoclaving of the pins at the lower temperature for a longer time led to a decrease in the bending strength of up to 16% and at the higher temperature for a shorter time to a decrease of up to 41%. To compare the strengths of the cortical and synthetic pins, 2-mm Biofix pins were also tested. The Biofix pins showed a 25% higher bending strength than the acetone-treated pins but a 12.5% lower elastic modulus. It should be noted that in animal studies the synthetic Biofix pins showed a 20% loss of strength within 2 days after implantation in situ.

Effect of specimen conditioning on the microarchitectural parameters of trabecular bone assessed by micro-computed tomography

“…Defatting induced deleterious effects on the biomechanical properties of bone. Indeed, defatting of cortical bone specimens increased bone strength and elastic modulus in bending (Berns et al 2001). In compression for trabecular bone, Linde and Sorensen (1993) showed that defatting caused a 30% increase in stiffness.…”

“…The effects of different preservation methods on bone biomechanical parameters have been investigated (Laforest et al 1991, Linde andSorensen 1993). For example, defatting specimens of cortical bone increased bone strength and elastic modulus in bending (Berns et al 2001). Likewise, stiffness of trabecular bone under compression was increased by 30% (Linde and Sorensen 1993).…”

Bovine Bone Screws: Metrology and Effects of Chemical Processing and Ethylene Oxide Sterilization on Bone Surface and Mechanical Properties

“…Mechanical performance of the samples in the present investigation showed that the ultimate strength of the processed bone was higher in relation to the control samples. Berns et al [20] and Hofmann et al [5] prepared bone with acetone and used ethylene oxide for bone sterilization, but the method showed that the ultimate strength remained unchanged. Actis et al [4] employed another option, using pepsin and collagenase.…”