Pulsed electromagnetic fields for the treatment of tibial delayed unions and nonunions. A prospective clinical study and review of the literature

A coaxial electrospun mat coupled with piezoelectric stimulation and atorvastatin for rapid vascularized bone regeneration

The repair of critical bone defects caused by various clinical conditions needs to be addressed urgently, and the regeneration of large bone defects depends on early vascularization. Therefore, enhanced vascularization of artificial bone grafts may be a promising strategy for the regeneration of critical-sized bone defects. Taking into account the importance of rapid angiogenesis during bone repair and the potential of piezoelectric stimulation in promoting bone regeneration, novel coaxial electrospun mats coupled with piezoelectric materials and angiogenic drugs were fabricated in this study using coaxial electrospinning technology, with a shell layer loaded with atorvastatin (AVT) and a core layer loaded with zinc oxide (ZnO). AVT was used as an angiogenesis inducer, and piezoelectric stimulation generated by the zinc oxide was used as an osteogenesis enhancer. The multifunctional mats were characterized in terms of morphology, core-shell structure, piezoelectric properties, drug release, and mechanical properties, and their osteogenic and angiogenic capabilities were validated in vivo and ex vivo. The results revealed that the coaxial electrospun mats exhibit a porous surface morphology and nanofibers with a core-shell structure, and the piezoelectricity of the mats improved with increasing ZnO content. Excellent biocompatibility, hydrophilicity and cell adhesion were observed in the multifunctional mats. Early and rapid release of AVT in the fibrous shell layer of the mat promoted angiogenesis in human umbilical vascular endothelial cells (HUVECs), whereas ZnO in the fibrous core layer harvested bioenergy and converted it into electrical energy to enhance osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs), and both modalities synergistically promoted osteogenesis and angiogenesis. Furthermore, optimal bone regeneration was achieved in a model of critical bone defects in the rat mandible. This osteogenesis-promoting effect was induced by electrical stimulation via activation of the calcium signaling pathway. This multifunctional mat coupling piezoelectric stimulation and atorvastatin promotes angiogenesis and bone regeneration, and shows great potential in the treatment of large bone defects.

Role of Pulsed Electromagnetic Field on Alveolar Bone Remodeling during Orthodontic Retention Phase in Rat Models

Alveolar bone remodeling during the retention phase is essential for successful orthodontic treatment. Pulsed electromagnetic field (PEMF) therapy is an adjunctive therapy for bone-related diseases that induces osteogenesis and prevents bone loss. This study aimed to examine the role of PEMF exposure during the retention phase of orthodontic treatment in alveolar bone remodeling. A total of 36 male Wistar rats were divided into control, PEMF 7, and PEMF 14 groups; a 50 g force nickel-titanium closed-coil spring was inserted to create mesial movement in the first molar for 21 d. Furthermore, the spring was removed, and the interdental space was filled with glass ionomer cement. Concurrently, rats were exposed to a PEMF at 15 Hz with a maximum intensity of 2.0 mT 2 h daily, for 7 and 14 days. Afterwards, the cements were removed and the rats were euthanized on days 1, 3, 7, and 14 to evaluate the expression of Wnt5a mRNA and the levels of RANKL, OPG, ALP, and Runx2 on the tension side. The data were analyzed with ANOVA and post hoc tests, with p < 0.05 declared statistically significant. PEMF exposure significantly upregulated Wnt5a mRNA expression, OPG and ALP levels, and Runx2 expression, and decreased RANKL levels in the PEMF 7 and 14 groups compared to the control group (p < 0.05). This study showed that PEMF exposure promotes alveolar bone remodeling during the orthodontic retention phase on the tension side by increasing alveolar bone formation and inhibiting resorption.

Regenerative Medicine in Orthopedic Surgery: Expanding Our Toolbox

Regenerative medicine leverages the body's inherent regenerative capabilities to repair damaged tissues and address organ dysfunction. In orthopedics, this approach includes a variety of treatments collectively known as orthoregeneration, encompassing modalities such as prolotherapy, extracorporeal shockwave therapy, pulsed electromagnetic field therapy, therapeutic ultrasound, and photobiomodulation therapy, and orthobiologics like platelet-rich plasma and cell-based therapies. These minimally invasive techniques are becoming prominent due to their potential for fewer complications in orthopedic surgery. As regenerative medicine continues to advance, surgeons must stay informed about these developments. This paper highlights the current state of regenerative medicine in orthopedics and advocates for further clinical research to validate and expand these treatments to enhance patient outcomes.

Investigation of the effectiveness of intermittent electromagnetic field stimulation for early internal cartilaginous ossification in prechondrocytic ATDC5 cells

Pulsed electromagnetic field (PEMF) stimulation has been widely applied clinically to promote bone healing; however, its detailed mechanism of action, particularly in endochondral ossification, remains elusive, and long-term stimulation is required for its satisfactory effect. The aim of this study was to investigate the involvement of the mammalian target of rapamycin (mTOR) pathway in chondrocyte differentiation and proliferation using a mouse prechondroblast cell line (ATDC5), and establish an efficient PEMF stimulation strategy for endochondral ossification. The changes in cell differentiation (gene expression levels of aggrecan, type II collagen, and type X collagen) and proliferation (cellular uptake of bromodeoxyuridine [BrdU]) in ATDC5 cells in the presence or absence of rapamycin, an mTOR inhibitor, was measured. The effects of continuous and intermittent PEMF stimulation on changes in cell differentiation and proliferation were compared. Rapamycin significantly suppressed the induction of cell differentiation markers and the cell proliferation activity. Furthermore, only intermittent PEMF stimulation continuously activated the mTOR pathway in ATDC5 cells, significantly promoting cell proliferation. These results demonstrate the involvement of the mTOR pathway in chondrocyte differentiation and proliferation and suggest that intermittent PEMF stimulation could be effective as a stimulus for endochondral ossification during fracture healing process, thereby reducing stimulation time.

Towards Stem Cell Therapy for Critical-Sized Segmental Bone Defects: Current Trends and Challenges on the Path to Clinical Translation

The management and reconstruction of critical-sized segmental bone defects remain a major clinical challenge for orthopaedic clinicians and surgeons. In particular, regenerative medicine approaches that involve incorporating stem cells within tissue engineering scaffolds have great promise for fracture management. This narrative review focuses on the primary components of bone tissue engineering-stem cells, scaffolds, the microenvironment, and vascularisation-addressing current advances and translational and regulatory challenges in the current landscape of stem cell therapy for critical-sized bone defects. To comprehensively explore this research area and offer insights for future treatment options in orthopaedic surgery, we have examined the latest developments and advancements in bone tissue engineering, focusing on those of clinical relevance in recent years. Finally, we present a forward-looking perspective on using stem cells in bone tissue engineering for critical-sized segmental bone defects.

Non-cannulated versus cannulated cancellous screws for the internal fixation of femoral neck fractures in osteoporotic patients: A single-blind randomized clinical trial

Background

The incidence of femoral neck fractures in osteoporotic patients is rising worldwide and is associated with significant increases in healthcare and social costs, as well as dependency. Improving minimally invasive treatment strategies, including internal fixation with screws, can result in favorable clinical outcomes and lesser incidence of complications, while preserving the hip. This study compared the outcomes of using non-cannulated cancellous screws (NCS) and cannulated cancellous screws (CS) in the internal fixation of undisplaced intracapsular femoral neck fractures (UIFNF) of osteoporotic patients of Iranian descent.

Methods

This randomized clinical trial was conducted on the patients referring to an institutional tertiary hospital in northwestern Iran between March 2020 and June 2021. The patients' preoperative, perioperative, and postoperative characteristics were evaluated for at least two years. Primary endpoints were defined as the incidence of hip-related complications, while secondary endpoints were assessed based on the patients' hip function using Harris Hip Score (HHS).

Results

Fifty-seven patients with osteoporosis and UIFNF were included in the final analysis, with 27 patients in the NCS group and 30 patients in the CS group. The surgical duration, the amount of intraoperative blood loss, and the frequency of C-arm were considerably lower in the CS group (p < 0.05). The incidence of implant failure was higher in the NCS group (p = 0.04). Screw migration occurred more frequently in the CS group (p = 0.03). The HHS values were significantly higher for the NCS group than those of the CS group at both the 1-year and 2-years of follow-up assessments (1 year, p = 0.007; 2 years, p = 0.001).

Conclusion

Fixation using CS was accompanied by enhanced perioperative outcomes and lower implant failure rates compared to the NCS group. However, patients in the NCS group posed a reduced risk of complications, including screw migration, and experienced a long-term improvement in HHS scores.

Extremely low-frequency electromagnetic fields facilitate both osteoblast and osteoclast activity through Wnt/β-catenin signaling in the zebrafish scale

Electromagnetic fields (EMFs) have received widespread attention as effective, noninvasive, and safe therapies across a range of clinical applications for bone disorders. However, due to the various frequencies of devices, their effects on tissues/cells are vary, which has been a bottleneck in understanding the effects of EMFs on bone tissue. Here, we developed an in vivo model system using zebrafish scales to investigate the effects of extremely low-frequency EMFs (ELF-EMFs) on fracture healing. Exposure to 10 millitesla (mT) of ELF-EMFs at 60 Hz increased the number of both osteoblasts and osteoclasts in the fractured scale, whereas 3 or 30 mT did not. Gene expression analysis revealed that exposure to 10 mT ELF-EMFs upregulated wnt10b and Wnt target genes in the fractured scale. Moreover, β-catenin expression was enhanced by ELF-EMFs predominantly at the fracture site of the zebrafish scale. Inhibition of Wnt/β-catenin signaling by IWR-1-endo treatment reduced both osteoblasts and osteoclasts in the fractured scale exposed to ELF-EMFs. These results suggest that ELF-EMFs promote both osteoblast and osteoclast activity through activation of Wnt/β-catenin signaling in fracture healing. Our data provide in vivo evidence that ELF-EMFs generated with a widely used commercial AC power supply have a facilitative effect on fracture healing.

Osteogenesis Stimulator Devices Reduce Surgical Intervention, Opioid Utilization, and Overall Costs in Patients with Fracture Nonunions

Background

Approximately 10% of fractures result in delayed union or nonunion. These cases result in pain and disability as well as increased utilization of healthcare resources such as pain medication, physical therapy, and subsequent surgery. Osteogenesis stimulator devices are a safe and low-cost, non-invasive option to aid healing in nonunion cases.

Objective

Study objectives aimed to evaluate real-world data of osteogenesis stimulator device usage in a variety of healthcare utilization endpoints including surgical intervention for nonunion, pain medication use, and overall healthcare costs. Data were stratified into three groups: the Stim Device group and the No Stim and Surgical control groups.

Methods

A retrospective analysis of a large claims-based database was conducted. The database was queried for adult patients having a diagnosis of nonunion, with evidence of a prior fracture in the previous 180 days (n = 11,010). The osteogenesis stimulator group (Stim Device group, n = 1,628) was defined as those patients having at least one claim for an osteogenesis stimulator in the period 90 to 180 days following fracture and up to 60 days following the nonunion diagnosis. The control group (No Stim group, n = 9,382) had a nonunion diagnosis with evidence of a fracture in the prior 180 days but did not receive a device. A total of 1,751 patients from the No Stim group were sub-grouped into surgical/operative controls (No Stim - Surgical group).

Results

Stim Device patients showed lower rates of surgical intervention for their bone nonunion compared to the No Stim patients (214/1,628, 13.1% vs. 1,751/9,382, 18.7%, p < 0.001). Stim Device patients had lower rates of opioid utilization post-index compared to No Stim patients (948/1,628, 58.2% vs. 6,359/9,382, 67.8%, p < 0.001). Overall healthcare costs were significantly reduced in the Stim Device group ($21,654) compared with No Stim ($29,101; p < 0.001) and Surgical ($35,914; p < 0.001) control groups.

Conclusion

The results show that bone growth stimulator devices have a positive individual and societal impact on treating patients with fracture nonunions.

Early protection against bone stress injuries by mobilization of endogenous targeted bone remodeling

Bone stress injuries are common overuse injuries, especially in soldiers, athletes, and performers. In contrast to various post-injury treatments, early protection against bone stress injuries can provide greater benefit. This study explored the early protection strategies against bone stress injuries by mobilization of endogenous targeted bone remodeling. The effects of various pharmaceutical/biophysical approaches, individual or combinational, were investigated by giving intervention before fatigue loading. We optimized the dosage and administration parameters and found that early intervention with pulsed electromagnetic field and parathyroid hormone (i.e., PEMF+PTH) resulted in the most pronounced protective effects among all the approaches against the bone stress injuries. In addition, the mechanisms by which the strategy mobilizes targeted bone remodeling and enhances the self-repair capacity of bone were systematically investigated. This study proposes strategies to reduce the incidence of bone stress injuries in high-risk populations (e.g., soldiers and athletes), particularly for those before sudden increased physical training.

Low-Intensity Pulsed Ultrasound for Symptomatic Pseudarthrosis After Toe Fracture with Symphalangism: A Report of 2 Cases

CASE

Distal phalangeal fractures are often treated conservatively. However, some patients experience residual pain. We report 2 cases of patients who underwent low-intensity pulsed ultrasound (LIPUS) therapy for pseudarthrosis after fracture of the distal phalanx of the fifth toe with symphalangism. Both patients (female, 63 and 33-year-old, respectively) underwent conservative treatment with buddy-taping fixation; however, bone union failed, and LIPUS therapy was initiated. In both cases, bone union was achieved and pain resolved after 3 months.

CONCLUSION

Bone union occasionally fails after conservative treatment of distal phalangeal fractures. LIPUS is a useful treatment of symptomatic pseudarthrosis after such fractures.

Biophysical Enhancement in Fracture Healing: A Review of the Literature

Bone healing constitutes a complex process involving cellular and pathophysiological mechanisms. Despite progress in osteosynthesis techniques, fracture union continues to be challenging. In some cases, it is not ultimately achieved or is delayed relative to the expected time resulting in economic and social outcomes for the patient and the health system. In addition to surgical treatment, biophysical methods have been developed to assist in fracture healing used in combination or individually. Biophysical stimulation is a non-invasive therapy used in orthopedic practice to increase and enhance tissue's reparative and anabolic activities. This study reviewed the existing literature, including electromagnetic fields, ultrasound, laser, extracorporeal shockwave therapy, and electrical stimulation, and revealed the efficacy of biophysical stimulation for bone healing. This study aims to define if these methods are helpful, especially in cases of non-union. Biophysical stimulation requires care and precision in use to ensure the success expected of it by physicians and patients.

Gait Analysis to Monitor Fracture Healing of the Lower Leg

Fracture healing is typically monitored by infrequent radiographs. Radiographs come at the cost of radiation exposure and reflect fracture healing with a time lag due to delayed fracture mineralization following increases in stiffness. Since union problems frequently occur after fractures, better and timelier methods to monitor the healing process are required. In this review, we provide an overview of the changes in gait parameters following lower leg fractures to investigate whether gait analysis can be used to monitor fracture healing. Studies assessing gait after lower leg fractures that were treated either surgically or conservatively were included. Spatiotemporal gait parameters, kinematics, kinetics, and pedography showed improvements in the gait pattern throughout the healing process of lower leg fractures. Especially gait speed and asymmetry measures have a high potential to monitor fracture healing. Pedographic measurements showed differences in gait between patients with and without union. No literature was available for other gait measures, but it is expected that further parameters reflect progress in bone healing. In conclusion, gait analysis seems to be a valuable tool for monitoring the healing process and predicting the occurrence of non-union of lower leg fractures.

Primary cilia: The central role in the electromagnetic field induced bone healing

Primary cilia have emerged as the cellular “antenna” that can receive and transduce extracellular chemical/physical signals, thus playing an important role in regulating cellular activities. Although the electromagnetic field (EMF) is an effective treatment for bone fractures since 1978, however, the detailed mechanisms leading to such positive effects are still unclear. Primary cilia may play a central role in receiving EMF signals, translating physical signals into biochemical information, and initiating various signalingsignaling pathways to transduce signals into the nucleus. In this review, we elucidated the process of bone healing, the structure, and function of primary cilia, as well as the application and mechanism of EMF in treating fracture healing. To comprehensively understand the process of bone healing, we used bioinformatics to analyze the molecular change and associated the results with other studies. Moreover, this review summarizedsummarized some limitations in EMFs-related research and provides an outlook for ongoing studies. In conclusion, this review illustrated the primary cilia and related molecular mechanisms in the EMF-induced bone healing process, and it may shed light on future research.

Treatment Effect of Platelet Gel on Reconstructing Bone Defects and Nonunions: A Review of In Vivo Human Studies

In ideal circumstances, a fractured bone can heal properly by itself or with the aid of clinical interventions. However, around 5% to 10% of bone fractures fail to heal properly within the expected time even with the aid of clinical interventions, resulting in nonunions. Platelet gel is a blood-derived biomaterial used in regenerative medicine aiming to promote wound healing and regeneration of damaged tissues. The purpose of this paper is to review relevant articles in an attempt to explore the current consensus on the treatment effect of platelet gel on reconstructing bone defects and nonunions, hoping to provide a valuable reference for clinicians to make treatment decisions in clinical practice. Based on the present review, most of the studies applied the combination of platelet gel and bone graft to reconstruct bone defects and nonunions, and most of the results were positive, suggesting that this treatment strategy could promote successful reconstruction of bone defects and nonunions. Only two studies tried to apply platelet gel alone to reconstruct bone defects and nonunions, therefore a convincing conclusion could not be made yet regarding the treatment effect of platelet gel alone on reconstructing bone defects and nonunions. Only one study applied platelet gel combined with extracorporeal shock wave therapy to reconstruct nonunions, and the results were positive; the hypothetical mechanism of this treatment strategy is reasonable and sound, and more future clinical studies are encouraged to further justify the effectiveness of this promising treatment strategy. In conclusion, the application of platelet gel could be a promising and useful treatment method for reconstructing bone defects and nonunions, and more future clinical studies are encouraged to further investigate the effectiveness of this promising treatment method.

Concepts and clinical aspects of active implants for the treatment of bone fractures

Nonunion is a complication of long bone fractures that leads to disability, morbidity and high costs. Early detection is difficult and treatment through external stimulation and revision surgery is often a lengthy process. Therefore, alternative diagnostic and therapeutic options are currently being explored, including the use of external and internal sensors. Apart from monitoring fracture stiffness and displacement directly at the fracture site, it would be desirable if an implant could also vary its stiffness and apply an intervention to promote healing, if needed. This could be achieved either by a predetermined protocol, by remote control, or even by processing data and triggering the intervention itself (self-regulated 'intelligent' or 'smart' implant). So-called active or smart materials like shape memory alloys (SMA) have opened up opportunities to build active implants. For example, implants could stimulate fracture healing by active shortening and lengthening via SMA actuator wires; by emitting pulses, waves, or electromagnetic fields. However, it remains undefined which modes of application, forces, frequencies, force directions, time durations and periods, or other stimuli such implants should ideally deliver for the best result. The present paper reviews the literature on active implants and interventions for nonunion, discusses possible mechanisms of active implants and points out where further research and development are needed to build an active implant that applies the most ideal intervention. STATEMENT OF SIGNIFICANCE: Early detection of delays during fracture healing and timely intervention are difficult due to limitations of the current diagnostic strategies. New diagnostic options are under evaluation, including the use of external and internal sensors. In addition, it would be desirable if an implant could actively facilitate healing ('Intelligent' or 'smart' implant). Implants could stimulate fracture healing via active shortening and lengthening; by emitting pulses, waves, or electromagnetic fields. No such implants exist to date, but new composite materials and alloys have opened up opportunities to build such active implants, and several groups across the globe are currently working on their development. The present paper is the first review on this topic to date.

Effects of Systemic or Local Administration of Mesenchymal Stem Cells from Patients with Osteoporosis or Osteoarthritis on Femoral Fracture Healing in a Mouse Model

The purpose of this study was to analyze the regenerative capacity of mesenchymal stem cells (MSCs) in the treatment of fractures. MSCs extracted from patients with osteoporotic hip fractures or hip osteoarthritis undergoing hip replacement surgeries were cultured and injected into mice with femoral fracture. Two experimental models were established, one for the systemic administration of MSCs (n = 29) and another one for local administration (n = 30). Fracture consolidation was assessed by micro-CT and histology. The degree of radiological consolidation and corticalization was better with MSCs from osteoporosis than from osteoarthritis, being significant after systemic administration (p = 0.0302 consolidation; p = 0.0243 corticalization). The histological degree of consolidation was also better with MSCs from osteoporosis than from osteoarthritis. Differences in histological scores after systemic infusion were as follows: Allen, p = 0.0278; Huo, p = 0.3471; and Bone Bridge, p = 0.0935. After local administration at the fracture site, differences in histological scores were as follows: Allen, p = 0.0764; Huo, p = 0.0256; and Bone Bridge, p = 0.0012. As osteoporosis and control groups were similar, those differences depended on an inhibitory influence by MSCs from patients with osteoarthritis. In conclusion, we found an unexpected impairment of consolidation induced by MSCs from patients with osteoarthritis. However, MSCs from patients with osteoporosis compared favorably with cells from patients with osteoarthritis. In other words, based on this study and previous studies, MSCs from patients with osteoporosis do not appear to have worse bone-regenerating capabilities than MSCs from non-osteoporotic individuals of similar age.

Pulsed Electro-Magnetic Field (PEMF) Effect on Bone Healing in Animal Models: A Review of Its Efficacy Related to Different Type of Damage

Simple Summary

Pulsed electromagnetic fields (PEMFs) are a type of biophysical stimulation that has been shown to be effective in improving bone regeneration and preventing bone loss. Their use dates back to the 1970s, but a gold standard treatment protocol has not yet been defined. PEMF efficacy relies on the generation of biopotentials, which activate several molecular pathways. There is currently no clear understanding of the effects on bone healing and, in addition, there are several animal models relevant to this issue. Therefore, drawing guidelines and conclusions from the analysis of the studies is difficult. In vivo investigations on PEMF stimulation are reviewed in this paper, focusing on molecular and morphological improvements in bone. Currently, there is little knowledge about the biological mechanism of PEMF and its effect on bone healing. This is due to the variability of crucial characteristics of electro-magnetic fields, such as amplitude and exposure frequency, which may influence the type of biological response. Furthermore, a different responsiveness of cells involved in the bone healing process is documented. Heterogeneous setting parameters and different outcome measures are considered in various animal models. Therefore, achieving comparable results is difficult.

Abstract

Biophysical energies are a versatile tool to stimulate tissues by generating biopotentials. In particular, pulsed electromagnetic field (PEMF) stimulation has intrigued researchers since the 1970s. To date, many investigations have been carried out in vivo, but a gold standard treatment protocol has not yet been defined. The main obstacles are represented by the complex setting of PEMF characteristics, the variety of animal models (including direct and indirect bone damage) and the lack of a complete understanding of the molecular pathways involved. In the present review the main studies about PEMF stimulation in animal models with bone impairment were reviewed. PEMF signal characteristics were investigated, as well as their effect on molecular pathways and osseous morphological features. We believe that this review might be a useful starting point for a prospective study in a clinical setting. Consistent evidence from the literature suggests a potential beneficial role of PEMF in clinical practice. Nevertheless, the wide variability of selected parameters (frequency, duration, and amplitude) and the heterogeneity of applied protocols make it difficult to draw certain conclusions about PEMF effectiveness in clinical implementation to promote bone healing. Deepening the knowledge regarding the most consistent results reported in literature to date, we believe that this review may be a useful starting point to propose standardized experimental guidelines. This might provide a solid base for further controlled trials, to investigate PEMF efficacy in bone damage conditions during routine clinical practice.

Electromagnetic field exposure as a plausible approach to enhance the proliferation and differentiation of mesenchymal stem cells in clinically relevant scenarios

Mesenchymal stem/stromal cell (MSC)‍-based therapy has been regarded as one of the most revolutionary breakthroughs in the history of modern medicine owing to its myriad of immunoregulatory and regenerative properties. With the rapid progress in the fields of osteo- and musculoskeletal therapies, the demand for MSC-based treatment modalities is becoming increasingly prominent. In this endeavor, researchers around the world have devised new and innovative techniques to support the proliferation of MSCs while minimizing the loss of hallmark features of stem cells. One such example is electromagnetic field (EMF) exposure, which is an alternative approach with promising potential. In this review, we present a critical discourse on the efficiency, practicability, and limitations of some of the relevant methods, with insurmountable evidence backing the implementation of EMF as a feasible strategy for the clinically relevant expansion of MSCs.

Effects of Personal Low-Frequency Stimulation Device on Myalgia: A Randomized Controlled Trial

Electrotherapy is commonly used for myalgia alleviation. Low-frequency stimulation (LFS) is primarily used for controlling acute and chronic pain and is a non-invasive therapy that can be easily performed with electric stimulation applied on the skin. However, little evidence exists regarding the pain alleviation effects of personal low-frequency stimulation device for home use. Moreover, no studies have compared myalgia alleviation effects between personal low-frequency stimulation (PLS) and physical therapy (PT), which are most commonly used for patients with myalgia in hospitals and clinics. Therefore, we aimed to investigate the pain alleviation effects of PLS in patients with myalgia and compare these effects with those of conventional PT (transcutaneous electrical nerve stimulation + ultrasound). In total, 39 patients with myalgia in the neck, shoulder, back, and waist areas were randomly assigned to the personal low-frequency stimulation group (PLSG: n = 20) and physical therapy group (PTG: n = 19). Both groups were treated for 3 weeks (20 min per session and 5 sessions per week). Patients were assessed for pain intensity by surface electromyography (sEMG), visual analogue scale (VAS) and a short-form McGill pain questionnaire (SF-MPQ) before and after the intervention period. Our results showed that PLSG showed a tendency of muscle relaxation with a significant decrease in sEMG in the neck (p = 0.0425), shoulder (p = 0.0425), and back (p = 0.0046) areas compared to the control group. However, there was no significant difference in waist area. Additionally, VAS scores significantly decreased between pre- and post-treatment in both PTG (p = 0.0098), and PLSG (p = 0.0304) groups, but there was no significance difference between the groups. With respect to SF-MPQ, the PLSG showed greater pain alleviation (5.23 ± 0.25) effects than the PTG (6.23 ± 0.25). Accordingly, our results suggest that PLS treatment using a home device might offer positive assistance in pain alleviation for patients with myalgia that is as equally effective as conventional PT treatment. However, further detailed studies are required considering larger samples to fully claim the effectiveness of this device.

Effect of External Mechanical Stimuli on Human Bone: a narrative review

Bone is a living composite material that has the capacity to adapt and respond to both internal and external stimuli. This capacity allows bone to adapt its structure to habitual loads and repair microdamage. Although human bone evolved to adapt to normal physiologic loading (for example from gravitational and muscle forces), these same biological pathways can potentially be activated through other types of external stimuli such as pulsed electromagnetic fields, mechanical vibration, and others. This review summarizes what is currently known about how human bone adapts to various types of external stimuli. We highlight how studies on sports-specific athletes and other exercise interventions have clarified the role of mechanical loading on bone structure. We also discuss clinical scenarios, such as spinal cord injury, where mechanical loading is drastically reduced, leading to rapid bone loss and permanent alterations to bone structure. Finally, we highlight areas of emerging research and unmet clinical need.

Articular cartilage and osteochondral tissue engineering techniques: Recent advances and challenges

In spite of the considerable achievements in the field of regenerative medicine in the past several decades, osteochondral defect regeneration remains a challenging issue among diseases in the musculoskeletal system because of the spatial complexity of osteochondral units in composition, structure and functions. In order to repair the hierarchical tissue involving different layers of articular cartilage, cartilage-bone interface and subchondral bone, traditional clinical treatments including palliative and reparative methods have showed certain improvement in pain relief and defect filling. It is the development of tissue engineering that has provided more promising results in regenerating neo-tissues with comparable compositional, structural and functional characteristics to the native osteochondral tissues. Here in this review, some basic knowledge of the osteochondral units including the anatomical structure and composition, the defect classification and clinical treatments will be first introduced. Then we will highlight the recent progress in osteochondral tissue engineering from perspectives of scaffold design, cell encapsulation and signaling factor incorporation including bioreactor application. Clinical products for osteochondral defect repair will be analyzed and summarized later. Moreover, we will discuss the current obstacles and future directions to regenerate the damaged osteochondral tissues.

In vivo study on the healing of bone defect treated with non-thermal atmospheric pressure gas discharge plasma

Medical treatment using non-thermal atmospheric pressure plasma (NTAPP) is rapidly gaining recognition. NTAPP is thought to be a new therapeutic method because it could generate highly reactive species in an ambient atmosphere which could be exposed to biological targets (e.g., cells and tissues). If plasma-generated reactive species could stimulate bone regeneration, NTAPP can provide a new treatment opportunity in regenerative medicine. Here, we investigated the impact of NTAPP on bone regeneration using a large bone defect in New Zealand White rabbits and a simple atmospheric pressure plasma (helium microplasma jet). We observed the recovery progress of the large bone defects by X-ray imaging over eight weeks after surgery. The X-ray results showed a clear difference in the occupancy of the new bone of the large bone defect among groups with different plasma treatment times, whereas the new bone occupancy was not substantial in the untreated control group. According to the results of micro-computed tomography analysis at eight weeks, the most successful bone regeneration was achieved using a plasma treatment time of 10 min, wherein the new bone volume was 1.51 times larger than that in the plasma untreated control group. Using H&E and Masson trichrome stains, nucleated cells were uniformly observed, and no inclusion was confirmed, respectively, in the groups of plasma treatment. We concluded the critical large bone defect were filled with new bone. Overall, these results suggest that NTAPP is promising for fracture treatment.

Histological Analysis of Bone Callus in Delayed Union Model Fracture Healing Stimulated with Pulsed Electromagnetic Fields (PEMF)

Delayed union and nonunion fractures are clinical challenges for orthopedic surgeons. The development of fracture complications, such as delayed union and nonunion fractures, is still difficult to predict. Various methods are being investigated to improve fracture healing and prevent complications in patients. There are various methods to promote fracture healing, broadly divided into biological, chemical, and physical methods. One of the most widely used physical methods to promote fracture healing is the pulsed electromagnetic field (PEMF). This study aimed to evaluate the healing process of delayed union fracture after being stimulated by PEMF. Twenty-four rats were randomly divided into two groups: the control group (n = 12) and the PEMF group (n = 12). Delayed union fracture was performed on the left femur of all rats. Subsequently, the PEMF group was given PEMF stimulus with a magnetic field intensity of 1.6 mT and a frequency of 50 Hz for 4 hours/day and 7 days/week. The fracture healing process was evaluated on days 5, 10, 18, and 28 based on the bone callus histology using safranin O fast green (SOFG) staining. The results of the histological analysis showed that bone cartilage was higher in the PEMF group than in the control group throughout the observation period. In addition, the PEMF group had less fibrous tissue at the beginning of the healing. This finding indicates PEMF stimulation has an effect on inducing osteogenesis on fracture healing and reducing the risk of delayed union.

Pulsed Electromagnetic Fields in Bone Healing: Molecular Pathways and Clinical Applications

In this article, we provide an extensive review of the recent literature of the signaling pathways modulated by Pulsed Electromagnetic Fields (PEMFs) and PEMFs clinical application. A review of the literature was performed on two medical electronic databases (PubMed and Embase) from 3 to 5 March 2021. Three authors performed the evaluation of the studies and the data extraction. All studies for this review were selected following these inclusion criteria: studies written in English, studies available in full text and studies published in peer-reviewed journal. Molecular biology, identifying cell membrane receptors and pathways involved in bone healing, and studying PEMFs target of action are giving a solid basis for clinical applications of PEMFs. However, further biology studies and clinical trials with clear and standardized parameters (intensity, frequency, dose, duration, type of coil) are required to clarify the precise dose-response relationship and to understand the real applications in clinical practice of PEMFs.

Effects of Pulsed Electromagnetic Field Therapy at Different Frequencies on Bone Mass and Microarchitecture in Osteoporotic Mice

A pulsed electromagnetic field (PEMF) can promote osteogenesis. However, studies have shown variation in the signal characteristics in terms of waveform type, intensity, frequency, and treatment duration. Among the factors that affect electromagnetic fields, frequency plays a major role. However, few studies have investigated the effects of PEMF at different frequencies in osteoporotic mice. Therefore, our objective was to determine the effect of PEMF frequency in osteoporotic mice. Forty 3-month-old female mice were randomly divided into the following five groups: sham, OVX, and OVX followed by 1.6-mT PEMF exposure groups (8 Hz, 50 Hz, and 75 Hz, 1.6 mT). The PEMF was applied for 1 h/day, 7 days/week, for 4 weeks. After 4 weeks, the micro-computed tomography showed that PEMF with (50 and 75 Hz) ameliorated the deterioration of bone microarchitecture. Improvements in the bone histological analysis were identified for PEMF with 50 and 75 Hz groups compared with the ovariectomy (OVX) controls. Osteoclast numbers were decreased in PEMF with (50 and 75 Hz). Moreover, the real-time PCR demonstrated PEMF with (50 and 75 Hz) significantly promoted the expression of the osteoblast-related genes (ALP, OCN, Runx2), and increased the serum PINP. PEMF with (50 and 75 Hz) exerted significant inhibitory effects on the osteoclast-related mRNA expression (CTSK, NFATc1, TRAP) and bone resorption markers CTX-I and IL-1β. Taken together, our results showed that PEMF at 50 and 75 Hz with 1.6 mT significantly ameliorate the deterioration of bone microarchitecture in OVX mice. The inhibitory effect of PEMF may be associated with IL-1β inhibition. © 2021 Bioelectromagnetics Society.

Efficacy of Pulsed Electromagnetic Fields on Experimental Osteopenia in Rodents: A Systematic Review

Osteoporosis leads to increased bone fragility and risk of fractures. Different strategies have been employed to reduce bone loss, including the use of a pulsed electromagnetic field (PEMF). Although many experimental studies have demonstrated the effect of PEMF on reduction of bone loss, the outcomes studied are varied and insufficient, and the quality of evidence is unknown. Therefore, the aim of this review was to assess the preclinical evidence on the effect of PEMF on bone loss. The existing challenges were also evaluated, and suggestions were provided to strengthen the quality of evidence in future studies. All original articles concerning the effect of PEMF on osteoporosis in animal models were included. Twenty-four studies met the inclusion criteria, 23 of which suggested that PEMF was effective in reducing bone loss, while one study failed to demonstrate any benefit. Risk of bias analysis suggested that information on key measures to reduce bias was frequently not reported. Animal models for osteoporosis, PEMF intervention regimens, outcomes, and specific bone detection sites seemed to influence the efficacy of PEMF in osteoporosis. Our results indicate the potential benefits of PEMF selection in animal models of osteoporosis. However, due to the heterogeneity of the parameters and the quality of the included literature, comprehensive studies using standardized protocols are warranted to confirm the results. © 2021 Bioelectromagnetics Society.

A review of biomimetic scaffolds for bone regeneration: Toward a cell-free strategy

In clinical terms, bone grafting currently involves the application of autogenous, allogeneic, or xenogeneic bone grafts, as well as natural or artificially synthesized materials, such as polymers, bioceramics, and other composites. Many of these are associated with limitations. The ideal scaffold for bone tissue engineering should provide mechanical support while promoting osteogenesis, osteoconduction, and even osteoinduction. There are various structural complications and engineering difficulties to be considered. Here, we describe the biomimetic possibilities of the modification of natural or synthetic materials through physical and chemical design to facilitate bone tissue repair. This review summarizes recent progresses in the strategies for constructing biomimetic scaffolds, including ion-functionalized scaffolds, decellularized extracellular matrix scaffolds, and micro- and nano-scale biomimetic scaffold structures, as well as reactive scaffolds induced by physical factors, and other acellular scaffolds. The fabrication techniques for these scaffolds, along with current strategies in clinical bone repair, are described. The developments in each category are discussed in terms of the connection between the scaffold materials and tissue repair, as well as the interactions with endogenous cells. As the advances in bone tissue engineering move toward application in the clinical setting, the demonstration of the therapeutic efficacy of these novel scaffold designs is critical.

The frequency window effect of sinusoidal electromagnetic fields in promoting osteogenic differentiation and bone formation involves extension of osteoblastic primary cilia and activation of protein kinase A

Electromagnetic fields (EMFs) have emerged as a versatile means for osteoporosis treatment and prevention. However, its optimal application parameters are still elusive. Here, we optimized the frequency parameter first by cell culture screening and then by animal experiment validation. Osteoblasts isolated from newborn rats (ROBs) were exposed 90 min/day to 1.8 mT SEMFs at different frequencies (ranging from 10 to 100 Hz, interval of 10 Hz). SEMFs of 1.8 mT inhibited ROB proliferation at 30, 40, 50, 60 Hz, but increased proliferation at 10, 70, 80 Hz. SEMFs of 10, 50, and 70 Hz promoted ROB osteogenic differentiation and mineralization as shown by alkaline phosphatase (ALP) activity, calcium content, and osteogenesis-related molecule expression analyses, with 50 Hz showing greater effects than 10 and 70 Hz. Treatment of young rats with 1.8 mT SEMFs at 10, 50, or 100 Hz for 2 months significantly increased whole-body bone mineral density (BMD) and femur microarchitecture, with the 50 Hz group showing the greatest effect. Furthermore, 1.8 mT SEMFs extended primary cilia lengths of ROBs and increased protein kinase A (PKA) activation also in a frequency-dependent manner, again with 50 Hz SEMFs showing the greatest effect. Pretreatment of ROBs with the PKA inhibitor KT5720 abolished the effects of SEMFs to increase primary cilia length and promote osteogenic differentiation/mineralization. These results indicate that 1.8 mT SEMFs have a frequency window effect in promoting osteogenic differentiation/mineralization in ROBs and bone formation in growing rats, which involve osteoblast primary cilia length extension and PKA activation.

Nanotechnological approach and bio-inspired materials to face degenerative diseases in aging

The aging of the world population is increasingly claimed as an alarming situation, since an ever-raising number of persons in advanced age but still physically active is expected to suffer from invalidating and degenerative diseases. The impairment of the endogenous healing potential provoked by the aging requires the development of more effective and personalized therapies, based on new biomaterials and devices able to direct the cell fate to stimulate and sustain the regrowth of damaged or diseased tissues. To obtain satisfactory results, also in cases where the cell senescence, typical of the elderly, makes the regeneration process harder and longer, the new solutions have to possess excellent ability to mimic the physiological extracellular environment and thus exert biomimetic stimuli on stem cells. To this purpose, the "biomimetic concept" is today recognized as elective to fabricate bioactive and bioresorbable devices such as hybrid osteochondral scaffolds and bioactive bone cements closely resembling the natural hard tissues and with enhanced regenerative ability. The review will illustrate some recent results related to these new biomimetic materials developed for application in different districts of the musculoskeletal system, namely bony, osteochondral and periodontal regions, and the spine. Further, it will be shown how new bioactive and superparamagnetic calcium phosphate nanoparticles can give enhanced results in cardiac regeneration and cancer therapy. Since tissue regeneration will be a major demand in the incoming decades, the high potential of biomimetic materials and devices is promising to significantly increase the healing rate and improve the clinical outcomes even in aged patients.

Pulsed-electromagnetic-field induced osteoblast differentiation requires activation of genes downstream of adenosine receptors A2A and A3

Pulsed-electromagnetic-field (PEMF) treatment was found to enhance cellular differentiation of the mouse preosteoblast, MC3T3-E1, to a more osteoblastic phenotype. Differentiation genes such as Alp, BSPI, cFos, Ibsp, Osteocalcin, Pthr1 and Runx2 showed increased expression in response to PEMF stimulation. Detailed molecular mechanisms linking PEMF to the activation of these genes are limited. Two adenosine receptors known to be modulated in response to PEMF, Adora2A and Adora3, were functionally impaired by CRISPR-Cas9-mediated gene disruption, and the consequences of which were studied in the context of PEMF-mediated osteoblastic differentiation. Disruption of Adora2A resulted in a delay of Alp mRNA expression, but not alkaline phosphatase protein expression, which was similar to that found in wild type cells. However, Adora3 disruption resulted in significantly reduced responses at both the alkaline phosphatase mRNA and protein levels throughout the PEMF stimulation period. Defects observed in response to PEMF were mirrored using a chemically defined growth and differentiation-inducing media (DM). Moreover, in cells with Adora2A disruption, gene expression profiles showed a blunted response in cFos and Pthr1 to PEMF treatment; whereas cells with Adora3 disruption had mostly blunted responses in AlpI, BSPI, Ibsp, Osteocalcin and Sp7 gene activation. To demonstrate specificity for Adora3 function, the Adora3 open reading frame was inserted into the ROSA26 locus in Adora3 disrupted cells culminating in rescued PEMF responsiveness and thereby eliminating the possibility of off-target effects. These results lead us to propose that there are complementary and parallel positive roles for adenosine receptor A_2A and A₃ in PEMF-mediated osteoblast differentiation.

Investigation into the effects of static and electric fields on bone healing process: An experimental tibial fracture model study in Wistar-Albino male rats

OBJECTIVE:

In this experimental study, we aimed to investigate whether 0 Hz-Static and 50 Hz-Electric fields have an effect on bone healing.

METHODS:

In this study, 45 male Wistar-Albino rats were equally and randomly separated into three groups as follows: a 0 Hz-Static electric field (SEF), a 50-Hz low-frequency electric field (LFEF) and a control group. A manual fracture was performed in the left tibia diaphysis of all rats, and fractures were fixed using circular plaster over the knee. The LFEF group was exposed to 50 Hz electric field for 30 minutes a day, five days a week, for a total of eight weeks. The SEF group was exposed to 0 Hz electric field within the same time interval. The control group was held in identical environmental conditions, without exposure to electric field. Periodic radiographs were taken from all the animals. At the end of this study, rats were sacrificed and mechanical/histopathologic examinations were performed.

RESULTS:

Radiologic, mechanical and histologic scores of the LFEF group were lower than those of the SEF and control groups; however, no significant difference was found in group comparisons in terms of average histologic and radiologic scores (p>0.05).

CONCLUSION:

Results extracted from the current study suggest that 0-hz static and 50-hz electric field exposures affect bone healing tissue of tibial fracture models in rats, although it is not significant.

Pulsed Electromagnetic Fields Ameliorate Skeletal Deterioration in Bone Mass, Microarchitecture, and Strength by Enhancing Canonical Wnt Signaling-Mediated Bone Formation in Rats with Spinal Cord Injury

Spinal cord injury (SCI) leads to extensive bone loss and high incidence of low-energy fractures. Pulsed electromagnetic fields (PEMF) treatment, as a non-invasive biophysical technique, has proven to be efficient in promoting osteogenesis. The potential osteoprotective effect and mechanism of PEMF on SCI-related bone deterioration, however, remain unknown. The spinal cord of rats was transected at vertebral level T12 to induce SCI. Thirty rats were assigned to the control, SCI, and SCI+PEMF groups (n = 10). One week after surgery, the SCI+PEMF rats were subjected to PEMF (2.0 mT, 15 Hz, 2 h/day) for eight weeks. Micro-computed tomography results showed that PEMF significantly ameliorated trabecular and cortical bone microarchitecture deterioration induced by SCI. Three-point bending and nanoindentation assays revealed that PEMF significantly improved bone mechanical properties in SCI rats. Serum biomarker and bone histomorphometric analyses demonstrated that PEMF enhanced bone formation, as evidenced by significant increase in serum osteocalcin and P1NP, mineral apposition rate, and osteoblast number on bone surface. The PEMF had no impact, however, on serum bone-resorbing cytokines (TRACP 5b and CTX-1) or osteoclast number on bone surface. The PEMF also attenuated SCI-induced negative changes in osteocyte morphology and osteocyte survival. Moreover, PEMF significantly increased skeletal expression of canonical Wnt ligands (Wnt1 and Wnt10b) and stimulated their downstream p-GSK3β and β-catenin expression in SCI rats. This study demonstrates that PEMF can mitigate the detrimental consequence of SCI on bone quantity/quality, which might be associated with canonical Wnt signaling-mediated bone formation, and reveals that PEMF may be a promising biophysical approach for resisting osteopenia/osteoporosis after SCI in clinics.

[Pathophysiological mechanisms of the therapeutic action of alternating electromagnetic fields in the treatment of osteoarticular pathology]

Treatment of osteoarticular pathology with an alternating electromagnetic field (AEMF) is used today as a promising, non-invasive and safe strategy of physiotherapy. It has been shown that the action of alternating electromagnetic fields on the musculoskeletal system triggers signaling cascades that effectively contribute to the restoration of bone and articular tissue. The pathophysiological mechanisms underlying the cellular and subcellular effects of stimulation by an alternating electromagnetic field during the restoration of bone and articular tissue are considered. It was pointed out the several key signaling pathways involved in the restoration of bone and articular tissue under the influence of electromagnetic fields with an analysis of the potential for therapeutic application of electromagnetic fields alone or in combination with other available therapies.

Moderate SMFs attenuate bone loss in mice by promoting directional osteogenic differentiation of BMSCs

Background

Osteoporosis is a common metabolic bone disease without effective treatment. Bone marrow-derived mesenchymal stem cells (BMSCs) have the potential to differentiate into multiple cell types. Increased adipogenic differentiation or reduced osteogenic differentiation of BMSCs might lead to osteoporosis. Whether static magnetic fields (SMFs) might influence the adipo-osteogenic differentiation balance of BMSCs remains unknown.

Methods

The effects of SMFs on lineage differentiation of BMSCs and development of osteoporosis were determined by various biochemical (RT-PCR and Western blot), morphological (staining and optical microscopy), and micro-CT assays. Bioinformatics analysis was also used to explore the signaling pathways.

Results

In this study, we found that SMFs (0.2–0.6 T) inhibited the adipogenic differentiation of BMSCs but promoted their osteoblastic differentiation in an intensity-dependent manner. Whole genomic RNA-seq and bioinformatics analysis revealed that SMF (0.6 T) decreased the PPARγ-mediated gene expression but increased the RUNX2-mediated gene transcription in BMSCs. Moreover, SMFs markedly alleviated bone mass loss induced by either dexamethasone or all-trans retinoic acid in mice.

Conclusions

Taken together, our results suggested that SMF-based magnetotherapy might serve as an adjunctive therapeutic option for patients with osteoporosis.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13287-020-02004-y.

Promising application of Pulsed Electromagnetic Fields (PEMFs) in musculoskeletal disorders

Increasing evidence suggests that an exogenous electromagnetic field might be involved in many biologic processes which are of great importance for therapeutic interventions. Pulsed electromagnetic fields (PEMFs) are known to be a noninvasive, safe and effective therapy agent without apparent side effects. Numerous studies have shown that PEMFs possess the potential to become a stand-alone or adjunctive treatment modality for treating musculoskeletal disorders. However, several issues remain unresolved. Prior to their widely clinical application, further researches from well-designed, high-quality studies are still required to standardize the treatment parameters and derive the optimal protocol for health-care decision making. In this review, we aim to provide current evidence on the mechanism of action, clinical applications, and controversies of PEMFs in musculoskeletal disorders.

Nanostructured Biomaterials for Bone Regeneration

This review article addresses the various aspects of nano-biomaterials used in or being pursued for the purpose of promoting bone regeneration. In the last decade, significant growth in the fields of polymer sciences, nanotechnology, and biotechnology has resulted in the development of new nano-biomaterials. These are extensively explored as drug delivery carriers and as implantable devices. At the interface of nanomaterials and biological systems, the organic and synthetic worlds have merged over the past two decades, forming a new scientific field incorporating nano-material design for biological applications. For this field to evolve, there is a need to understand the dynamic forces and molecular components that shape these interactions and influence function, while also considering safety. While there is still much to learn about the bio-physicochemical interactions at the interface, we are at a point where pockets of accumulated knowledge can provide a conceptual framework to guide further exploration and inform future product development. This review is intended as a resource for academics, scientists, and physicians working in the field of orthopedics and bone repair.

Effects of Pulsed Electromagnetic Field Therapy on Pain, Stiffness, Physical Function, and Quality of Life in Patients With Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

OBJECTIVE

Pulsed electromagnetic field (PEMF) therapy is a potentially useful treatment for osteoarthritis (OA), but its effectiveness is still controversial. This study aimed to examine the effects of PEMF therapy and PEMF parameters on symptoms and quality of life (QOL) in patients with OA.

METHODS

Cochrane Central Register of Controlled Trials, PubMed, CINAHL, EMBASE, PEDro, clinical trial registers, and reference lists were searched until April 2019. This study examined randomized, placebo-controlled trials, patients with OA, symptom and/or QOL related outcomes, and articles published in English. Two authors extracted data and completed quality assessment.

RESULTS

Sixteen studies were included in our systematic review, while 15 studies with complete data were included in the meta-analysis. Our primary outcome was the standardized mean difference, which was equal to the treatment effect in the PEMF group minus the treatment effect in the placebo group divided by the pooled standard deviation. For pain, the standardized mean difference was 1.06 (95% CI = 0.61 to 1.51), for stiffness 0.37 (95% CI = 0.07 to 0.67), for function 0.46 (95% CI = 0.14 to 0.78), and for QOL 1.49 (95% CI = -0.06 to 3.04). PEMF parameters did not influence symptoms.

CONCLUSIONS

Compared with placebo, there was a beneficial effect of PEMF therapy on pain, stiffness, and physical function in patients with OA. Duration of treatment may not be a critical factor in pain management. Further studies are required to confirm the effects of PEMF therapy on QOL.

IMPACT

Our study suggests that PEMF therapy has clinically significant effects on pain in patients with OA. The current evidence was limited to the short-term effects of PEMF therapy.

Effectiveness of Pulsed Electromagnetic Fields on Bone Healing: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The effect of pulsed electromagnetic field (PEMF) on bone healing is still uncertain and it has not been established as a standardized treatment. The aim of this systematic review and meta-analysis is to evaluate the effect of PEMF on bone healing in patients with fracture. We searched CNKI, Wan Fang, VIP, EMbase, PubMed, CENTRAL, Web of Science, Physiotherapy Evidence Database, and Open Grey websites for randomized controlled trials (published before July 2019 in English or Chinese) comparing any form of PEMF to sham. Reference lists were also searched. Related data were extracted by two investigators independently. The bias risk of the articles and the evidence strength of the outcomes were evaluated. Twenty-two studies were eligible and included in our analysis (n = 1,468 participants). The pooled results of 14 studies (n = 1,131 participants) demonstrated that healing rate in PEMF group was 79.7% (443/556), and that in the control group was 64.3% (370/575). PEMF increased healing rate (RR = 1.22; 95% confidence interval [CI] = 1.10-1.35; I²  = 48%) by the Mantel-Haenszel analysis, relieved pain (standardized mean difference (SMD) = -0.49; 95% CI = -0.88 to -0.10; I²  = 60%) by the inverse variance analysis, and accelerated healing time (SMD = -1.01; 95% CI = -2.01 to -0.00; I²  = 90%) by the inverse variance analysis. Moderate quality evidence suggested that PEMF increased healing rate and relieved pain of fracture, and very low-quality evidence showed that PEMF accelerated healing time. Larger and higher quality randomized controlled trials and pre-clinical studies of optimal frequency, amplitude, and duration parameters are needed. © 2020 Bioelectromagnetics Society.

Pulsed Electromagnetic Field Stimulation of Bone Healing and Joint Preservation: Cellular Mechanisms of Skeletal Response

The US FDA has approved pulsed electromagnetic fields (PEMFs) as a safe and effective treatment for nonunions of bone. Despite its clinical use, the mechanisms of action of electromagnetic stimulation of the skeleton have been elusive. Recently, cell membrane receptors have been identified as the site of action of PEMF and provide a mechanistic rationale for clinical use. This review highlights key processes in cell responses to PEMF as follows: (1) signal transduction through A_2A and A₃ adenosine cell membrane receptors and (2) dose-response effects on the synthesis of structural and signaling extracellular matrix (ECM) components. Through these actions, PEMF can increase the structural integrity of bone and cartilage ECM, enhancing repair, and alter the homeostatic balance of signaling cytokines, producing anti-inflammatory effects. PEMFs exert a proanabolic effect on the bone and cartilage matrix and a chondroprotective effect counteracting the catabolic effects of inflammation in the joint environment. Understanding of PEMF membrane targets, and of the specific intracellular pathways involved, culminating in the synthesis of ECM proteins and reduction in inflammatory cytokines, should enhance confidence in the clinical use of PEMF and the identification of clinical conditions likely to be affected by PEMF exposure.

Bone Morphogenetic Protein-2 Signaling in the Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells Induced by Pulsed Electromagnetic Fields

Pulsed electromagnetic fields (PEMFs) are clinically used with beneficial effects in the treatment of bone fracture healing. This is due to PEMF ability to favor the osteogenic differentiation of mesenchymal stem cells (MSCs). Previous studies suggest that PEMFs enhance the osteogenic activity of bone morphogenetic protein-2 (BMP2) which is used in various therapeutic interventions. This study investigated the molecular events associated to the synergistic activity of PEMFs and BMP2 on osteogenic differentiation. To this aim, human MSCs (hMSCs) were exposed to PEMFs (75 Hz, 1.5 mT) in combination with BMP2, upon detection of the minimal dose able to induce differentiation. Changes in the expression of BMP signaling pathway genes including receptors and ligands, as well as in the phosphorylation of BMP downstream signaling proteins, such as SMAD1/5/8 and MAPK, were analyzed. Results showed the synergistic activity of PEMFs and BMP2 on osteogenic differentiation transcription factors and markers. The PEMF effects were associated to the increase in BMP2, BMP6, and BMP type I receptor gene expression, as well as SMAD1/5/8 and p38 MAPK activation. These results increase knowledge concerning the molecular events involved in PEMF stimulation showing that PEMFs favor hMSCs osteogenic differentiation by the modulation of BMP signaling components.

Beneficial Effects of Pulsed Electromagnetic Field during Cast Immobilization in Patients with Distal Radius Fracture

To assess whether pulsed electromagnetic field therapy during cast immobilization of distal radius fractures has beneficial effects on pain and limb function, the study included 52 patients (mean age 60.8 ± 15.0 years) with distal radius fractures treated with cast immobilization. Patients were allocated to a pulsed electromagnetic field group (n = 27) or a control group (n = 25). Pain; forearm and arm circumference; range of motion; disabilities of the arm, shoulder, and hand score; and touch sensation were evaluated on the day of the plaster cast dressing and 3 and 6 weeks after. In comparison to the control group, the pulsed electromagnetic field group reported significant changes after 3 and 6 weeks of treatment: lower pain levels (p=0.0052; p < 0.0001, respectively), greater mobility of upper-limb joints, improvement in exteroceptive sensation, and reduction in disability of the upper limb (disabilities of the arm, shoulder, and hand) (p=0.0003; p < 0.0001, respectively). Our results suggest that early addition of pulsed electromagnetic field treatment, during cast immobilization of distal radius fractures, has beneficial effects on the pain, exteroceptive sensation, range of motion, and daily functioning of patients.

Topical cutaneous application of carbon dioxide via a hydrogel for improved fracture repair: results of phase I clinical safety trial

Background

Clinicians have very limited options to improve fracture repair. Therefore, it is critical to develop a new clinically available therapeutic option to assist fracture repair biologically. We previously reported that the topical cutaneous application of carbon dioxide (CO₂) via a CO₂ absorption-enhancing hydrogel accelerates fracture repair in rats by increasing blood flow and angiogenesis and promoting endochondral ossification. The aim of this study was to assess the safety and efficacy of CO₂ therapy in patients with fractures.

Methods

Patients with fractures of the femur and tibia were prospectively enrolled into this study with ethical approval and informed consent. The CO₂ absorption-enhancing hydrogel was applied to the fractured lower limbs of patients, and then 100% CO₂ was administered daily into a sealed space for 20 min over 4 weeks postoperatively. Safety was assessed based on vital signs, blood parameters, adverse events, and arterial and expired gas analyses. As the efficacy outcome, blood flow at the level of the fracture site and at a site 5 cm from the fracture in the affected limb was measured using a laser Doppler blood flow meter.

Results

Nineteen patients were subjected to complete analysis. No adverse events were observed. Arterial and expired gas analyses revealed no adverse systemic effects including hypercapnia. The mean ratio of blood flow 20 min after CO₂ therapy compared with the pre-treatment level increased by approximately 2-fold in a time-dependent manner.

Conclusions

The findings of the present study revealed that CO₂ therapy is safe to apply to human patients and that it can enhance blood flow in the fractured limbs.

Trial registration

This study has been registered in the UMIN Clinical Trials Registry (Registration number: UMIN000013641, Date of registration: July 1, 2014).

Hierarchically designed bone scaffolds: From internal cues to external stimuli

Bone tissue engineering utilizes three critical elements - cells, scaffolds, and bioactive factors - to recapitulate the bone tissue microenvironment, inducing the formation of new bone. Recent advances in materials development have enabled the production of scaffolds that more effectively mimic the hierarchical features of bone matrix, ranging from molecular composition to nano/micro-scale biochemical and physical features. This review summarizes recent advances within the field in utilizing these features of native bone to guide the hierarchical design of materials and scaffolds. Biomimetic strategies discussed in this review cover several levels of hierarchical design, including the development of element-doped compositions of bioceramics, the usage of molecular templates for in vitro biomineralization at the nanoscale, the fabrication of biomimetic scaffold architecture at the micro- and nanoscale, and the application of external physical stimuli at the macroscale to regulate bone growth. Developments at each level are discussed with an emphasis on their in vitro and in vivo outcomes in promoting osteogenic tissue development. Ultimately, these hierarchically designed scaffolds can complement or even replace the usage of cells and biological elements, which present clinical and regulatory barriers to translation. As the field progresses ever closer to clinical translation, the creation of viable therapies will thus benefit from further development of hierarchically designed materials and scaffolds.

Emerging medical applications based on non-ionizing electromagnetic fields from 0 Hz to 10 THz

The potential for using non-ionizing electromagnetic fields (EMF; at frequencies from 0 Hz up to the THz range) for medical purposes has been of interest since many decades. A number of established and familiar methods are in use all over the world. This review, however, provides an overview of applications that already play some clinical role or are in earlier stages of development. The covered methods include modalities used for bone healing, cancer treatment, neurological conditions, and diathermy. In addition, certain other potential clinical areas are touched upon. Most of the reviewed technologies deal with therapy, whereas just a few diagnostic approaches are mentioned. None of the discussed methods are having such a strong impact in their field of use that they would be expected to replace conventional methods. Partly this is due to a knowledge base that lacks mechanistic explanations for EMF effects at low-intensity levels, which often are used in the applications. Thus, the possible optimal use of EMF approaches is restricted. Other reasons for the limited impact include a scarcity of well-performed randomized clinical trials that convincingly show the efficacy of the methods and that standardized user protocols are mostly lacking. Presently, it seems that some EMF-based methods can have a niche role in treatment and diagnostics of certain conditions, mostly as a complement to or in combination with other, more established, methods. Further development and a stronger impact of these technologies need a better understanding of the interaction mechanisms between EMF and biological systems at lower intensity levels. The importance of the different physical parameters of the EMF exposure needs also further investigations.

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

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.

Electrical stimulation-based bone fracture treatment, if it works so well why do not more surgeons use it?

BACKGROUND

Electrical stimulation (EStim) has been proven to promote bone healing in experimental settings and has been used clinically for many years and yet it has not become a mainstream clinical treatment.

METHODS

To better understand this discrepancy we reviewed 72 animal and 69 clinical studies published between 1978 and 2017, and separately asked 161 orthopedic surgeons worldwide about their awareness, experience, and acceptance of EStim for treating fracture patients.

RESULTS

Of the 72 animal studies, 77% reported positive outcomes, and the most common model, bone, fracture type, and method of administering EStim were dog, tibia, large bone defects, and DC, respectively. Of the 69 clinical studies, 73% reported positive outcomes, and the most common bone treated, fracture type, and method of administration were tibia, delayed/non-unions, and PEMF, respectively. Of the 161 survey respondents, most (73%) were aware of the positive outcomes reported in the literature, yet only 32% used EStim in their patients. The most common fracture they treated was delayed/non-unions, and the greatest problems with EStim were high costs and inconsistent results.

CONCLUSION

Despite their awareness of EStim's pro-fracture healing effects few orthopedic surgeons use it in their patients. Our review of the literature and survey indicate that this is due to confusion in the literature due to the great variation in methods reported, and the inconsistent results associated with this treatment approach. In spite of this surgeons seem to be open to using this treatment if advancements in the technology were able to provide an easy to use, cost-effective method to deliver EStim in their fracture patients.