Time-dependent changes in dynamic mechanical properties of irradiated bone

Abstract

The increased use of allograft tissue for musculoskeletal repair has brought more focus to the safety of allogenic tissue and the efficacy of various sterilization techniques. The currently available literature contains few examples of studies on long-lasting strains of bones but no example for irradiated bones. In this study the bovine femurs from a 2-year-old animal were machine cut and irradiated with the doses of 10, 15, 25, 35, 45 and 50 kGy. The dynamic mechanical analysis was performed at 1 Hz at the room temperature in a 3-point bending configuration for 2880 minutes. The final values of E' and E″ were dose independent but they were reached at different periods. For this reason, so called "critical point" was introduced for the further analysis. All the examined sample groups were characterized by statistically significant lower values of the critical point in comparison with the control samples (p<0.05) but the biggest differences were observed between the control samples and the samples irradiated with the doses of 10, 15 and 25 kGy. Current results and literature review suggest that the dose of 35 kGy is the optimal dose for ionizing radiation sterilization.

Osteochondral Interface Stiffening in Mandibular Condylar Osteoarthritis

“…DMA at nanoscale was adopted in the current study because of the small size of rats' TMJ condyle, especially the osteochondral interface. The theoretical model and the data-processing methods of nano-DMA are similar to DMA, as previously reported (Tanaka et al 2006;Mardas et al 2012;Espino et al 2014;Mardas et al 2015). To diminish the influence of the fixation treatment on the mechanical property, we air-dried the samples, which was similar to other studies that explored the mechanical properties of bovine bones using the DMA technique (Mardas et al 2012(Mardas et al , 2015.…”

“…The DMA technique has been used to study the mechanical properties of biological tissue such as articular cartilage and bone (Tanaka et al 2006; Fulcher et al 2009; Mardas et al 2012; Espino et al 2014; Mardas et al 2015). The TMJ is under dynamic loading during chewing (Palla et al 2003), and the frequency of rat chewing is 4 to 5 Hz (Liu et al 1998).…”

Use of polyvinylpyrrolidone-iodine solution for sterilisation and preservation improves mechanical properties and osteogenesis of allografts

“…This finding also validates the concern regarding the use of irradiated tendon allografts with decreased mechanical properties. There is a significant amount of literature documenting a dose-dependent, deleterious effect of conventional GI on the biomechanical properties of tissues4243. Consequently, there is a general negative perception that high doses of GI adversely affect graft integrity and efficacy.…”

“…Consequently, there is a general negative perception that high doses of GI adversely affect graft integrity and efficacy. Bone loses a significant amount of strength during compression, bending, and torsion when exposed to >30 kGy doses of conventional irradiation424344. We used tendons for the test instead of bone grafts, because the strength of the former is more important in determining postoperative management.…”

Dynamic mechanical properties of gamma sterilized bovine cortical bone soaked in olive leaves extract

“…Tan δ, also known as damping, is the ratio between loss modulus and storage modulus [42]. DMA testing was performed by means of a Triton Technology dynamic mechanical analyzer (TT-DMA) at a frequency of 1 Hz, which is the closest to the strains present in physiological conditions [43]. The measurements were performed in the temperature range of 28-200°C at a scanning rate of 2°C/min.…”