Enhancement of bone consolidation using high-frequency pulsed electromagnetic fields (HF-PEMFs): An experimental study on rats

Abstract

In vitro studies showed that high-frequency pulsed electromagnetic fields (HF-PEMFs) increase the activity/expression of early and late osteogenic markers and enhance bone mineralization. The main aim of this study was to investigate the in vivo effects of HF-PEMFs on fracture healing using a rat model. A femur fracture was established by surgery in 20 male Wistar rats. Titanium nails were implanted to reduce and stabilize the fracture. After surgery, 20 rats were equally divided into untreated control and treated group (from the first postoperative day HF-PEMFs at 400 pulses/sec [pps] were applied for 10 minutes/day, for two weeks). Quantitative and qualitative assessment of bone formation was made at two and eight weeks following surgery and included morphological and histological analysis, serological analysis by ELISA, micro-computed tomography (micro-CT), and three-point bending test. At two weeks in HF-PEMF group, soft callus was at a more advanced fibrocartilaginous stage and the bone volume/total tissue volume (BV/TV) ratio in the callus area was significantly higher compared to control group (p = 0.047). Serum concentration of alkaline phosphatase (ALP) and osteocalcin (OC) was significantly higher in HF-PEMF group (ALP p = 0.026, OC p = 0.006) as well as the mechanical strength of femurs (p = 0.03). At eight weeks, femurs from HF-PEMF group had a completely formed woven bone with dense trabeculae, active bone marrow, and had a significantly higher BV/TV ratio compared to control (p = 0.01). HF-PEMFs applied from the first postoperative day, 10 minutes/day for two weeks, enhance bone consolidation in rats, especially in the early phase of fracture healing.

The Efficacy of Pulsed Electromagnetic Fields on Pain, Stiffness, and Physical Function in Osteoarthritis: A Systematic Review and Meta-Analysis

“…In addition, PEMF also prevents degenerative changes in pig knee cartilage [ 33 ]. Other studies have shown that high-frequency pulsed electromagnetic fields (HF-PEMFs) could accelerate mineralization and consolidation of bone, upregulate osteogenesis markers [ 34 ], and augment osteopontin and osteocalcin expression [ 35 ]. In addition, Huegel considered that different frequencies of PEMF treatment will play a positive role in rat rotator cuff rehabilitation [ 36 ].…”

Gathering Evidence to Leverage Musculoskeletal Magnetic Stimulation Towards Clinical Applicability

“…Additionally, Figure 1E portrays a photograph of an actual IC stimulation device used in a pre-clinical study here reviewed. [102] The tested pulse frequencies ranged from 1 Hz [73] -400 Hz, [66] with the most tested frequency being 15 Hz (in 36.5% of the tested frequencies, Figure 2A). Unless stated otherwise, all frequencies here indicated refer to pulses (that comprise sets of bursts), and not to individual bursts (see Figure S1, Supporting Information, for the distinction between pulses and bursts).…”

“…Managing Bone Defects in Small-Sized Animals Through IC Stimulation PEMF of rather different parameters were applied to heal rat bone defects (fractures and osteotomies) and consolidate bone fusions, with promising effects such as faster osseous bridging, assessed by osteogenic markers and other readouts. [60,63,66,69,77,78,80,81,106] PEMF of 15 Hz quasi-rectangular pulses and 0.15-0.18 mT MF strength, applied for 12 h day À1 over 5 weeks to bone defects of rats' premaxilla, were able to increase by 2-fold the alkaline phosphatase (ALP) activity from day 7 (D7) to D14, and Ca 2þ incorporation at D14 by 3-fold. [60] PEMF of the same frequency and higher MF strengths also ameliorated other rats' bone defects.…”

“…[78] Rats' femur fractures stimulated with PEMF of 400 Hz pulses (bursts of 27 MHz) for 10 min day À1 over 2 weeks, had increased circulating ALP (þ21.7%) and OC (þ21.5%) levels, more bone volume in the callus (1.14-fold) with better microarchitecture (þ18.4% Tb.Th; À16.5% Tb.S), which led to mechanically stronger bones (þ60.8% strength; À32.0% elastic deformation). [66] An FDA-approved PEMF device, Physio-Stim, delivering pulses at the most commonly used frequency (15 Hz pulse), of triangular or sawtooth bursts at 3.85 kHz, and 2.0 mT with a daily exposure of 3 h day À1 , has improved healing of rat fibular osteotomies. [63,69] One study applied such stimulation parameters over 3 and 5 weeks, and reported higher osteotomy gap filling and a 2-fold increase in hard callus formation rate and volume, and in bending strength.…”

“…For example, tibial bone conditions seem to overall respond less to PEMF than femoral ones, in intermediate-and medium-sized animal models. [65,66,77] For comparison purposes, efficacy analyses separated per small-sized, intermediate-sized, and medium-sized animal models are presented in Figure S2-S4, Supporting Information. These analyses reveal that IC stimulation induced much higher improvement rates (in 64-72% of the assays) in small and intermediate-sized animals like rats and rabbits.…”