Pulsed Electromagnetic Fields (PEMFs) promote joint tissue anabolic activities, particularly in cartilage and bone. Here we investigated the effect of selected PEMFs (75Hz, 1.5mT, 1.3msec) in a differentiating model of murine myoblasts (C2C12) in vitro. C2C12 were seeded at 5×10³ cells/cm² in 4 well plates and left to adhere for 24h. Subsequently, cells were either maintained in growth medium (GM) or induced towards myogenic differentiation in low-serum conditions, with and without PEMF exposure, for 4 days. Morphological analysis, myotube formation and fusion index (FI) were assessed with fluorescence microscopy techniques. Metabolic activity was determined by MTT; moreover, a multiplex cytokine array (RayBiotech) allowed cell supernatant molecule quantification. Cells exposed to PEMFs in GM acquired a distinctive elongated morphology, with increased bi-nuclear figures (3.2-fold FI increase over PEMF-unexposed cells) and displayed a significantly higher metabolic activity (+31%, p<0.05 over PEMF-unexposed cells). PEMF exposure increased metabolic activity also under myogenic differentiation (+15% over PEMF-unexposed differentiating cells, p<0.05), with the formation of long, thick polynuclear myotubes, suggesting a role of PEMFs in enhancing myogenesis (7.7-fold FI increase over PEMF-unexposed cells). 4-day culture supernatants revealed the presence of several myokines (KC/CXCL1, LIX, MCP-1, TIMP-1). Preliminary analysis showed a 1.16-fold increase (n=2) of LIX and, notably, a 1.91-fold increase (n=2) of TNF-RI, in cell supernatants of PEMF-exposed over PEMF-unexposed cells. Collectively, these results suggest that PEMF may successfully be applied in models of muscle cell trauma to optimise muscle fibre repair, by fine-tuning the release of myokines, promoting myoblast proliferation and myotube formation.

Several studies explored the biological effects of low frequency low energy pulsed electromagnetic fields (PEMFs, Igea Biophysics Laboratory, Carpi, Italy) on human body reporting different functional changes. In the orthopedic field, PEMFs have been shown to be effective in enhancing endogenous bone and osteochondral repair, incrementing bone mineral density, accelerating the process of osteogenic differentiation and limiting cartilage damage. Much research activity has focused on the mechanisms of interaction between PEMFs and membrane receptors such as adenosine receptors (ARs). In particular, PEMF exposure mediates a significant upregulation of A_2A and A₃ARs expressed in various cells or tissues involving a reduction of most of the pro-inflammatory cytokines. In tissue engineering for cartilage repair a double role for PEMFs could be hypothesized: in vitro by stimulating cell proliferation, colonization of the scaffold and production of tissue matrix; in vivo after surgical implantation of the construct by favoring the anabolic activities of the implanted cells and surrounding tissues and protecting the construct from the catabolic effects of inflammation. Of particular interest is the observation that PEMFs, through the increase of ARs, enhance the working efficiency of the endogenous modulator adenosine, producing a more physiological effect than the use of exogenous drugs. This observation suggests the hypothesis that PEMFs could be considered a non-invasive treatment with a low impact on daily life. In conclusion, PEMFs represent an important approach in the pharmacological field providing excellent therapeutic results in various inflammatory diseases and in particular in the functional recovery of the damaged joint tissues.

The purine nucleoside, adenosine regulates functions in every tissue and organ in the body acting via four G-protein-coupled receptors, A₁, A_2A, A_2B, and A₃ adenosine receptors (ARs). Electromagnetic field (EMF) stimulation is an innovative therapeutic technique able to increase cellular anabolic activity and limit the catabolic effects of inflammatory cytokines. The mechanisms of cell reception of EMFs are not well known and much research activity has focused on the interactions between EMFs and membrane receptors. Interestingly, links have been found between ARs and their modulation by such physical agents as pulsed EMFs. EMF exposure mediates a significant upregulation of A_2A and A₃ARs in chondrocytes, synoviocytes and osteoblasts, leading to the reduction of synthesis and release of pro-inflammatory cytokines. In cultured full-thickness cartilage explants, pulsed EMFs preserve the integrity of the extracellular matrix and antagonize the effect of catabolic cytokines, such as IL-1. Pulsed EMFs, through the increase of ARs, enhance the working efficiency of adenosine without the side effects, desensitization, and receptor down-regulation often related to the use of agonist drugs. Modulation of adenosine receptors by pulsed EMFs could be a mechanism of cell reception of EMFs and an innovative physiologic alternative to the use of adenosine agonists.

A multicenter retrospective analysis of patients treated for tibial fracture was conducted to develop a score that correlates with fracture healing time and, ultimately, to identify the risk gradient of delayed healing.

The clinical records of 93 patients treated for tibial fracture at three orthopaedic centers were evaluated. Patients were considered healed when full weight bearing was allowed and no further controls were scheduled. For the purpose of our analysis, we separated patients healed within or after 180 days.

Patient's risk factors known to be associated to delay healing, as well as fracture morphology and orthopaedic treatment were recorded in an electronic Case Report Form (e-CRF). Information available in the literature was used to weight the relative risk (RR) associated to each risk factor; values were combined to calculate a score to be correlated to the fracture healing time: L-ARRCO (Literature-Algoritmo Rischio Ritardo Consolidazione Ossea). Among all information collected in e-CRFs, we identified other risk factors, associated to delayed healing, that were used to calculate a new score: ARRCO. Univariate logistic analysis was used to determine a correlation between the score and healing time. Analysis by receiver operating characteristic (ROC) and calculation of the area under the curve (AUC) were used for sensitivity and specificity.

Complete information was available for 53 patients. The mean value of the L-ARRCO score among patients healed within 180 days was 5.78 ± 1.59 and 7.05 ± 2.46 among those healed afterwards, p=0.044. The mean value of the ARRCO score of patients healed within 180 days was 5.92 ± 1.78 and 9.03 ± 2.79 among those healed afterwards, p<0.0001. The ROC curve shows an AUC of 0.62±0.09 for L-ARRCO and an AUC of 0.82±0.07 for ARRCO, (p<0.0001).

We have shown that the ARRCO score value is significantly correlated to fracture healing time. The score may be used to identify fractures at risk of delayed healing, thus allowing surgeon's early intervention to stimulate osteogenesis.

Short intense electrical pulses transiently increase the permeability of the cell membrane, an effect known as electroporation. This can be combined with antiblastic drugs for ablation of tumours of the skin and subcutaneous tissue. The aim of this study was to test the efficacy of electroporation when applied to bone and to understand whether the presence of mineralised trabeculae would affect the capability of the electric field to porate the membrane of bone cells.

Different levels of electrical field were applied to the femoral bone of rabbits. The field distribution and modelling were simulated by computer. Specimens of bone from treated and control rabbits were obtained for histology, histomorphometry and biomechanical testing.

After seven days, the area of ablation had increased in line with the number of pulses and/or with the amplitude of the electrical field applied. The osteogenic activity in the ablated area had recovered by 30 days. Biomechanical testing showed structural integrity of the bone at both times.

Electroporation using the appropriate combination of voltage and pulses induced ablation of bone cells without affecting the recovery of osteogenic activity. It can be an effective treatment in bone and when used in combination with drugs, an option for the treatment of metastases.

We investigated the effect of stimulation with a pulsed electromagnetic field on the osseointegration of hydroxyapatite in cortical bone in rabbits. Implants were inserted into femoral cortical bone and were stimulated for six hours per day for three weeks.

Electromagnetic stimulation improved osseointegration of hydroxyapatite compared with animals which did not receive this treatment in terms of direct contact with the bone, the maturity of the bone and mechanical fixation. The highest values of maximum push-out force (F_max) and ultimate shear strength (σ_u) were observed in the treated group and differed significantly from those of the control group at three weeks (F_max; p < 0.0001; σ_u, p < 0.0005).