Effect of pulsed electromagnetic fields on maturation of regenerate bone in a rabbit limb lengthening model

Abstract

To study the effect of applying pulsed electromagnetic fields (PEMF) during the consolidation phase of limb lengthening, a mid-tibial osteotomy was performed in 18 adult New Zealand White rabbits and an external fixator was applied anteromedially. Animals were randomly assigned to treatment and control groups. After a 7-day latency period, the tibiae were distracted 0.5 mm every 12 h for 10 days. The treatment group received a 20-day course of PEMF for 60 min daily, coinciding with initiation of the consolidation phase. The control group received sham PEMF. Radiographs were performed weekly after distraction. Animals were euthanized 3 weeks after the end of distraction. Radiographic analysis revealed no significant difference in regenerate callus area between treatment and control tibiae immediately after distraction, at 1 week, 2 weeks, or 3 weeks after distraction ( p = 0.71, 0.22, 0.44, and 0.50, respectively). There was also no significant difference in percent callus mineralization ( p = 0.96, 0.69, 0.99, and 0.99, respectively). There was no significant difference between groups with respect to structural stiffness ( p = 0.80) or maximal torque to failure ( p = 0.62). However, there was a significant positive difference in mineral apposition rate between groups during the interval 1-2 weeks post-distraction ( p < 0.05). This difference was no longer evident by the interval 2-3 weeks post-distraction. While PEMF applied during the consolidation phase of limb lengthening did not appear to have a positive effect on bone regenerate, it increased osteoblastic activity in the cortical bone adjacent to the distraction site. Since the same PEMF signal was reported to be beneficial in the rabbit distraction osteogenesis when applied during distraction phase and consolidation phase, application of PEMF in the early phase may be more effective. Further work is necessary to determine optimal timing of the PEMF stimulation during distraction osteogenesis.

Biophysical stimulation of bone fracture repair, regeneration and remodelling.

“…Another striking finding in this study was the effect of pulsed electromagnetic fields on the reduction of cortical porosity in the bone adjacent to the osteotomy when compared to the non-treated group (Fig 6) . However, in a rabbit tibial lengthening model, neither LIPU nor PEMF using the current signal type and dose had demonstrated any significant enhancement effect on bone regenerate maturation (Tis et al, 2002;Taylor et al, 2003).…”

Clinical significance of different effects of static and pulsed electromagnetic fields on human osteoclast cultures

“…PEMFs are now widely used also to promote healing of acute fractures, failed arthrodesis, and congenital pseudarthrosis and to decrease osteoporosis [23].…”

Magnetic responsive hydroxyapatite composite scaffolds construction for bone defect reparation

“…The specimen was immersed into 100 mL of fluid and shaken ceaselessly at 37°C. A 2 mL aliquot of leaching solution was taken away at each time point (2,4,8, and 12 hours, and 1, 2, 3, and 5 days), while the same volume of fresh medium was simultaneously added back into the solution. The samples were further diluted eightfold for atomic absorption spectroscopy analysis to evaluate the iron content and calculate the masses of released magnetite.…”

“…[1][2][3][4] Magnetic fields were also found to be beneficial in promoting the integration of bone and implants, increasing bone density and calcium content, and accelerating the healing of bone fractures. [5][6][7][8] Among the magnetic materials usually used in the biomedical field, magnetic nanoparticles (MNPs) have drawn great interest owing to their unique magnetic properties, including the fact that they become superparamagnetic at diameters of ,20 nm. 9 Coupled with their excellent biocompatibility, MNPs have been widely used in biomedical applications such as drug delivery, magnetic resonance imaging reagents, bio-separation, enzyme immobilization, and magnetic hyperthermia.…”