Biophysical stimulation of bone and cartilage: state of the art and future perspectives

Three predictive scores compared in a retrospective multicenter study of nonunion tibial shaft fracture

BACKGROUND

Delayed union, malunion, and nonunion are serious complications in the healing of fractures. Predicting the risk of nonunion before or after surgery is challenging.

AIM

To compare the most prevalent predictive scores of nonunion used in clinical practice to determine the most accurate score for predicting nonunion.

METHODS

We collected data from patients with tibial shaft fractures undergoing surgery from January 2016 to December 2020 in three different trauma hospitals. In this retrospective multicenter study, we considered only fractures treated with intramedullary nailing. We calculated the tibia FRACTure prediction healING days (FRACTING) score, Nonunion Risk Determination score, and Leeds-Genoa Nonunion Index (LEG-NUI) score at the time of definitive fixation.

RESULTS

Of the 130 patients enrolled, 89 (68.4%) healed within 9 months and were classified as union. The remaining patients (n = 41, 31.5%) healed after more than 9 months or underwent other surgical procedures and were classified as nonunion. After calculation of the three scores, LEG-NUI and FRACTING were the most accurate at predicting healing.

CONCLUSION

LEG-NUI and FRACTING showed the best performances by accurately predicting union and nonunion.

Unraveling the transcriptome profile of pulsed electromagnetic field stimulation in bone regeneration using a bioreactor-based investigation platform

INTRODUCTION

Human mesenchymal stem cells (hMSCs) sense and respond to biomechanical and biophysical stimuli, yet the involved signaling pathways are not fully identified. The clinical application of biophysical stimulation including pulsed electromagnetic field (PEMF) has gained momentum in musculoskeletal disorders and bone tissue engineering.

METHODOLOGY

We herein aim to explore the role of PEMF stimulation in bone regeneration by developing trabecular bone-like tissues, and then, culturing them under bone-like mechanical stimulation in an automated perfusion bioreactor combined with a custom-made PEMF stimulator. After selecting the optimal cell seeding and culture conditions for inspecting the effects of PEMF on hMSCs, transcriptomic studies were performed on cells cultured under direct perfusion with and without PEMF stimulation.

RESULTS

We were able to identify a set of signaling pathways and upstream regulators associated with PEMF stimulation and to distinguish those linked to bone regeneration. Our findings suggest that PEMF induces the immune potential of hMSCs by activating and inhibiting various immune-related pathways, such as macrophage classical activation and MSP-RON signaling in macrophages, respectively, while promoting angiogenesis and osteogenesis, which mimics the dynamic interplay of biological processes during bone healing.

CONCLUSIONS

Overall, the adopted bioreactor-based investigation platform can be used to investigate the impact of PEMF stimulation on bone regeneration.

Magnetic hydrogel applications in articular cartilage tissue engineering

Articular cartilage defects afflict millions of individuals worldwide, presenting a significant challenge due to the tissue's limited self-repair capability and anisotropic nature. Hydrogel-based biomaterials have emerged as promising candidates for scaffold production in artificial cartilage construction, owing to their water-rich composition, biocompatibility, and tunable properties. Nevertheless, conventional hydrogels typically lack the anisotropic structure inherent to natural cartilage, impeding their clinical and preclinical applications. Recent advancements in tissue engineering (TE) have introduced magnetically responsive hydrogels, a type of intelligent hydrogel that can be remotely controlled using an external magnetic field. These innovative materials offer a means to create the desired anisotropic architecture required for successful cartilage TE. In this review, we first explore conventional techniques employed for cartilage repair and subsequently delve into recent breakthroughs in the application and utilization of magnetic hydrogels across various aspects of articular cartilage TE.

Comparative Analysis of Stromal Vascular Fraction and Alternative Mechanisms in Bone Fracture Stimulation to Bridge the Gap between Nature and Technological Advancement: A Systematic Review

BACKGROUND

Various stimulation methods, including electrical, ultrasound, mechanical, and biological interventions, are explored, each leveraging intricate cellular and molecular dynamics to expedite healing. The advent of stromal vascular fraction (SVF) marks a significant stride, offering multifarious benefits in bone healing, from enhanced bone formation to optimal vascular integration, drawing a harmonious balance between innate mechanisms and scientific advancements.

METHODS

This systematic review was conducted focusing on literature from 2016 to 2023 and encompassing various bone healing stimulation mechanisms like SVF, electrical, ultrasound, and mechanical stimulation. The extracted data underwent meticulous synthesis and analysis, emphasizing comparative evaluations of mechanisms, applications, and outcomes of each intervention.

RESULTS

The reviewed studies reveal the potential of SVF in bone fracture healing, with its regenerative and anti-inflammatory effects. The purification of SVF is crucial for safe therapeutic use. Characterization involves flow cytometry and microscopy. Studies show SVF's efficacy in bone regeneration, versatility in various contexts, and potential for clinical use. SVF appears superior to electrical, ultrasound, and mechanical stimulation, with low complications.

CONCLUSIONS

This review compares bone healing methods, including SVF. It provides valuable insights into SVF's potential for bone regeneration. However, due to limited human studies and potential bias, cautious interpretation is necessary. Further research is essential to validate these findings and determine the optimal SVF applications in bone healing.

Musculoskeletal Diseases: From Molecular Basis to Therapy

Musculoskeletal diseases (MSDs) comprise a plethora of different disorders (more than 150 conditions) affecting the locomotor system [...].

Effect of the pulsed electromagnetic field in the repair of a calvaria critical bone defect in rats: cone beam computed tomographic and histomorphometric analysis.: PEMF in the repair of a calvaria critical bone defect: CBCT analyses

INTRODUCTION

The present study evaluated the effect of two protocols of Pulsed Electromagnetic Field (PEMF) therapy on bone neoformation on calvaria critical defects in rats.

MATERIAL & METHODS

96 rats were randomly divided into 3 groups: Control Group (CG; n=32); Test Group - PEMF 1 hour (TG1h; n=32) and Test Group - PEMF 3 hour (TG3h; n=32). A Critical-size Bone Defect (CSD) was surgically created in the calvaria of rats. The animals in the test groups were exposure to PEMF for 5 days a week. The animals were euthanized at 14, 21, 45 and 60 days. The specimens were processed for volume and texture (TAn) analysis, by Cone Beam Computed Tomography (CBCT) and histomorphometric analysis, RESULTS: Histomorphometric and volume analyses revealed that there was no statistically significant difference in the repair of bone defects between groups receiving PEMF therapy and CG. TAn revealed a statistically significant difference between the groups only for the entropy parameter, in which TG1h group presented a higher value compared to CG on 21 days. TG1h and TG3h did not accelerate bone repair in calvarial critical size defect and the parameters of PEMF should be considered.

DISCUSSION

This study showed that PEMF application on CSD in rats does not accelerate bone repair. Although literature showed a positive association in biostimulation on bone tissue with the parameters applied, studies with other PEMF parameters are essential to verify improving this study design.

Role of biophysical stimulation in multimodal management of vertebral compression fractures

Raised life expectancy and aging of the general population are associated with an increased concern for fragility fractures due to factors such as osteoporosis, reduced bone density, and an higher risk of falls. Among these, the most frequent are vertebral compression fractures (VCF), which can be clinically occult. Once the diagnosis is made, generally thorough antero-posterior and lateral views of the affected spine at the radiographs, a comprehensive workup to assess the presence of a metabolic bone disease or secondary causes of osteoporosis and bone frailty is required. Treatment uses a multimodal management consisting of a combination of brace, pain management, bone metabolism evaluation, osteoporosis medication and has recently incorporated biophysical stimulation, a noninvasive technique that uses induced electric stimulation to improve bone recovery through the direct and indirect upregulation of bone morphogenic proteins, stimulating bone formation and remodeling. It contributes to the effectiveness of the therapy, promoting accelerated healing, supporting the reduction of bed rest and pain medications, improving patients' quality of life, and reducing the risk to undergo surgery in patients affected by VCFs. Therefore, the aim of this review is to outline the fundamental concepts of multimodal treatment for VCF, as well as the present function and significance of biophysical stimulation in the treatment of VCF patients.

The role of exosomes and their enhancement strategies in the treatment of osteoarthritis

With the increasingly prominent problem of population aging, osteoarthritis (OA), which is closely related to aging, has become a serious illness affecting the lives and health of elderly individuals. However, effective treatments are still lacking. OA is typically considered a low-grade inflammatory state. The inflammatory infiltration of macrophages, neutrophils, T cells, and other cells is common in diseased joints. These cells create the inflammatory environment of OA and are involved in the onset and progression of the disease. Exosomes, a type of complex vesicle containing abundant RNA molecules and proteins, play a crucial role in the physiological and pathological processes of an organism. In comparison to other therapeutic methods such as stem cells, exosomes have distinct advantages of precise targeting and low immunogenicity. Moreover, research and techniques related to exosomes are more mature, indicating a promising future in disease treatment. Many studies have shown that the impact of exosomes on the inflammatory microenvironment directly or indirectly leads to the occurrence of various diseases. Furthermore, exosomes can be helpful in the management of illnesses. This article provides a comprehensive review and update on the research of exosomes, a type of extracellular vesicle, in the treatment of OA by modulating the inflammatory microenvironment. It also combines innovative studies on the modification of exosomes. In general, the application of exosomes in the treatment of OA has been validated, and the introduction of modified exosome technology holds potential for enhancing its therapeutic efficacy.

Musculoskeletal Biomaterials: Stimulated and Synergized with Low Intensity Pulsed Ultrasound

Clinical biophysical stimulating strategies, which have significant effects on improving the function of organs or treating diseases by causing the salutary response of body, have shown many advantages, such as non-invasiveness, few side effects, and controllable treatment process. As a critical technique for stimulation, the low intensity pulsed ultrasound (LIPUS) has been explored in regulating osteogenesis, which has presented great promise in bone repair by delivering a combined effect with biomaterials. This review summarizes the musculoskeletal biomaterials that can be synergized with LIPUS for enhanced biomedical application, including bone regeneration, spinal fusion, osteonecrosis/osteolysis, cartilage repair, and nerve regeneration. Different types of biomaterials are categorized for summary and evaluation. In each subtype, the verified biological mechanisms are listed in a table or graphs to prove how LIPUS was effective in improving musculoskeletal tissue regeneration. Meanwhile, the acoustic excitation parameters of LIPUS that were promising to be effective for further musculoskeletal tissue engineering are discussed, as well as their limitations and some perspectives for future research. Overall, coupled with biomimetic scaffolds and platforms, LIPUS may be a powerful therapeutic approach to accelerate musculoskeletal tissue repair and even in other regenerative medicine applications.

Dose dependent effects of extracorporeal shockwave therapy on pain and function in osteonecrosis of femoral head: A systematic review

Purpose

To investigate the effectiveness of different dosages of extracorporeal shockwave therapy (ESWT) on pain, function and radiographic outcomes in patients with osteonecrosis of femoral head (ONFH).

Procedure

The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta Analysis) guidelines were followed to conduct this review. The systematic literature search was done by using six different electronic databases include MEDLINE (assessed by Pubmed) CENTRAL (Cochrane Library Central Register of Controlled Trials), Web of Science, PEDro (Physiotherapy Evidence Database), Scopus and Science Direct. Retrospective and prospective cohort studies; case control study, randomized clinical trials were included. Screening conducted by two independent authors along with inclusion and exclusion criteria of included studies. The methodological quality assessment for cohort studies and randomized clinical trials was done by using Structured Effectiveness Quality Evaluation Scale (SEQES) and Newcastle-Ottawa Scale for case control study.

Result

Total 1410 articles were found from various databases. After duplicates removed 450 articles remained. Followed by title and abstract screening 53 articles eligible for full text reading, out of them 13 articles met the inclusion criteria and included in this review.

Conclusion

High energy flux densities of ESWT found to be more effective followed by low and moderate energy flux densities in earlier course of the disease compared to later stages in terms of pain relief, functional improvement and disease progression. Due to high variability among study design, ESWT dosages, patient characteristics and considering the paucity of well conducted studies, the present study cannot be conclusive.

The current status of stimuli-responsive nanotechnologies on orthopedic titanium implant surfaces

With the continuous innovation and breakthrough of nanomedical technology, stimuli-responsive nanotechnology has been gradually applied to the surface modification of titanium implants to achieve brilliant antibacterial activity and promoted osteogenesis. Regarding to the different physiological and pathological microenvironment around implants before and after surgery, these surface nanomodifications are designed to respond to different stimuli and environmental changes in a timely, efficient, and specific way/manner. Here, we focus on the materials related to stimuli-responsive nanotechnology on titanium implant surface modification, including metals and their compounds, polymer materials and other materials. In addition, the mechanism of different response types is introduced according to different activation stimuli, including magnetic, electrical, photic, radio frequency and ultrasonic stimuli, pH and enzymatic stimuli (the internal stimuli). Meanwhile, the associated functions, potential applications and developing prospect were discussion.

Myths and truths on biophysics-based approach in rehabilitation of musculoskeletal disorders

Musculoskeletal disorders (MSD) are a crucial issue in current literature due to their impact on physical function, social, and economic costs. Rehabilitation plays a pivotal role in the therapeutic management of these disabling conditions with growing evidence underlining positive effects in improving functional outcomes. However, to date, several questions are still open about the mechanisms underpinning functional improvements while recent research is now focusing on a deeper understanding of the biophysical processes underpinning the macroscopical effects of these treatments. Thus, this narrative review aims at providing a comprehensive overview about the state of the art of biophysical dimensions of currently available treatments for MSD. PubMed, Scopus, CENTRAL, PEDro, and Web of Science were searched between March 2022 and October 2022 for in vitro and in vivo studies, clinical trials, systematic reviews, and meta-analysis addressing the issue of biophysics-based approach in rehabilitation of MSD. Our findings showed that a biophysical approach might be integrated into regenerative rehabilitation, aiming at enhancing regenerative processes by mechanical and biophysical stimuli. In addition, a biophysical-based approach has been proposed to improve knowledge about several instrumental physical therapies, including shock wave therapies, low-level laser therapy, ultrasound, short-wave diathermy, electrical stimulation, pulsed electromagnetic field, and vibration therapy. In accordance, emerging research is now focusing on the biophysical properties of several medical procedures to improve pain management in patients with MSD. Taken together, our results showed promising results of the integration of a biophysical-based approach in rehabilitation, albeit several limitations currently limit its implementation in routine clinical setting. Unfortunately, the state of the art is still inconclusive, and the low quality of clinical studies based on the biophysical approach did not provide clear treatment protocols. Further studies are needed to promote a precise rehabilitation approach targeting biological modification and enhancing the functional improvement of patients with MSDs.

Pulsed Electromagnetic Fields (PEMF)-Physiological Response and Its Potential in Trauma Treatment

Environmental biophysical interactions are recognized to play an essential part in the human biological processes associated with trauma recovery. Many studies over several decades have furthered our understanding of the effects that Pulsed Electromagnetic Fields (PEMF) have on the human body, as well as on cellular and biophysical systems. These investigations have been driven by the observed positive clinical effects of this non-invasive treatment on patients, mainly in orthopedics. Unfortunately, the diversity of the various study setups, with regard to physical parameters, molecular and cellular response, and clinical outcomes, has made it difficult to interpret and evaluate commonalities, which could, in turn, lead to finding an underlying mechanistic understanding of this treatment modality. In this review, we give a birds-eye view of the vast landscape of studies that have been published on PEMF, presenting the reader with a scaffolded summary of relevant literature starting from categorical literature reviews down to individual studies for future research studies and clinical use. We also highlight discrepancies within the many diverse study setups to find common reporting parameters that can lead to a better universal understanding of PEMF effects.

Quantum Molecular Resonance Inhibits NLRP3 Inflammasome/Nitrosative Stress and Promotes M1 to M2 Macrophage Polarization: Potential Therapeutic Effect in Osteoarthritis Model In Vitro

This study aimed to investigate the anti-inflammatory effects of Quantum Molecular Resonance (QMR) technology in an in vitro model of osteoarthritis-related inflammation. The study used THP-1-derived macrophages stimulated with lipopolysaccharide and hyaluronic acid fragments to induce the expression of inflammatory cytokines and nitrosative stress. QMR treatment inhibited COX-2 and iNOS protein expression and activity and reduced NF-κB activity. Furthermore, QMR treatment led to a significant reduction in peroxynitrite levels, reactive nitrogen species that can form during inflammatory conditions, and restored tyrosine nitration values to those similar to sham-exposed control cells. We also investigated the effect of QMR treatment on inflammasome activation and macrophage polarization in THP-1-derived macrophages. Results showed that QMR treatment significantly decreased NLRP3 and activated caspase-1 protein expression levels and downregulated IL-18 and IL-1β protein expression and secretion. Finally, our findings indicate that QMR treatment induces a switch in macrophage polarization from the M1 phenotype to the M2 phenotype.

Targeting Adenosine Signalling in Knee Chondropathy: The Combined Action of Polydeoxyribonucleotide and Pulsed Electromagnetic Fields: A Current Concept Review

Chondropathy of the knee is one of the most frequent degenerative cartilage pathologies with advancing age. Scientific research has, in recent years, advanced new therapies that target adenosine A2 receptors, which play a significant role in human health against many disease states by activating different protective effects against cell sufferance and damage. Among these, it has been observed that intra-articular injections of polydeoxyribonucleotides (PDRN) and Pulsed Electromagnetic Fields (PEMF) can stimulate the adenosine signal, with significant regenerative and healing effects. This review aims to depict the role and therapeutic modulation of A2A receptors in knee chondropathy. Sixty articles aimed at providing data for our study were included in this review. The present paper highlights how intra-articular injections of PDRN create beneficial effects by reducing pain and improving functional clinical scores, thanks to their anti-inflammatory action and the important healing and regenerating power of the stimulation of cell growth, production of collagen, and the extracellular matrix. PEMF therapy is a valid option in the conservative treatment of different articular pathologies, including early OA, patellofemoral pain syndrome, spontaneous osteonecrosis of the knee (SONK), and in athletes. PEMF could also be used as a supporting therapy after an arthroscopic knee procedure total knee arthroplasty to reduce the post-operative inflammatory state. The proposal of new therapeutic approaches capable of targeting the adenosine signal, such as the intra-articular injection of PDRN and the use of PEMF, has shown excellent beneficial results compared to conventional treatments. These are presented as an extra weapon in the fight against knee chondropathy.

The Effects of Novel Pulsed Electromagnetic Field Therapy Device on Acute Distal Radius Fractures: A Prospective, Double-Blind, Sham-Controlled, Randomized Pilot Study

BACKGROUND

this pilot study aimed at determining whether the application of a novel new method of generating pulsed electromagnetic field (PEMF), the Fracture Healing Patch (FHP), accelerates the healing of acute distal radius fractures (DRF) when compared to a sham treatment.

METHODS

41 patients with DRFs treated with cast immobilization were included. Patients were allocated to a PEMF group (n = 20) or a control (sham) group (n = 21). All patients were assessed with regard to functional and radiological outcomes (X-rays and CT scans) at 2, 4, 6 and 12 weeks.

RESULTS

fractures treated with active PEMF demonstrated significantly higher extent of union at 4 weeks as assessed by CT (76% vs. 58%, p = 0.02). SF12 mean physical score was significantly higher in PEMF treated group (47 vs. 36, p = 0.005). Time to cast removal was significantly shorter in PEMF treated patients, 33 ± 5.9 days in PEMF vs. 39.8 ± 7.4 days in sham group (p = 0.002).

CONCLUSION

early addition of PEMF treatment may accelerate bone healing which could lead to a shorter cast immobilization, thus allowing an earlier return to daily life activities and work. There were no complications related to the PEMF device (FHP).

Stimulation of Chondrogenesis in a Developmental Model of Endochondral Bone Formation by Pulsed Electromagnetic Fields

Notable characteristics of the skeleton are its responsiveness to physical stimuli and its ability to remodel secondary to changing biophysical environments and thereby fulfill its physiological roles of stability and movement. Bone and cartilage cells have many mechanisms to sense physical cues and activate a variety of genes to synthesize structural molecules to remodel their extracellular matrix and soluble molecules for paracrine signaling. This review describes the response of a developmental model of endochondral bone formation which is translationally relevant to embryogenesis, growth, and repair to an externally applied pulsed electromagnetic field (PEMF). The use of a PEMF allows for the exploration of morphogenesis in the absence of distracting stimuli such as mechanical load and fluid flow. The response of the system is described in terms of the cell differentiation and extracellular matrix synthesis in chondrogenesis. Emphasis is placed upon dosimetry of the applied physical stimulus and some of the mechanisms of tissue response through a developmental process of maturation. PEMFs are used clinically for bone repair and have other potential clinical applications. These features of tissue response and signal dosimetry can be extrapolated to the design of clinically optimal stimulation.

Pulsed Electromagnetic Field (PEMF) Treatment Ameliorates Murine Model of Collagen-Induced Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease of the joint synovial membranes. RA is difficult to prevent or treat; however, blocking proinflammatory cytokines is a general therapeutic strategy. Pulsed electromagnetic field (PEMF) is reported to alleviate RA's inflammatory response and is being studied as a non-invasive physical therapy. In this current study, PEMF decreased paw inflammation in a collagen-induced arthritis (CIA) murine model. PEMF treatment at 10 Hz was more effective in ameliorating arthritis than at 75 Hz. In the PEMF-treated CIA group, the gross inflammation score and cartilage destruction were lower than in the untreated CIA group. The CIA group treated with PEMF also showed lower serum levels of IL-1β but not IL-6, IL-17, or TNF-α. Serum levels of total anti-type II collagen IgG and IgG subclasses (IgG1, IgG2a, and IgG2b) remained unchanged. In contrast, tissue protein levels of IL-1β, IL-6, TNF-α, receptor activator of nuclear factor kappa-Β (RANK), RANK ligand (RANKL), IL-6 receptor (IL-6R), and TNF-α receptor1 (TNFR1) were all lower in the ankle joints of the PEMF-treated CIA group compared with the CIA group. The results of this study suggest that PEMF treatment can preserve joint morphology cartilage and delay the occurrence of CIA. PEMF has potential as an effective adjuvant therapy that can suppress the progression of RA.

Periodontal ligament stem cell-based bioactive constructs for bone tissue engineering

Objectives: Stem cell-based tissue engineering approaches are promising for bone repair and regeneration. Periodontal ligament stem cells (PDLSCs) are a promising cell source for tissue engineering, especially for maxillofacial bone and periodontal regeneration. Many studies have shown potent results via PDLSCs in bone regeneration. In this review, we describe recent cutting-edge researches on PDLSC-based bone regeneration and periodontal tissue regeneration. Data and sources: An extensive search of the literature for papers related to PDLSCs-based bioactive constructs for bone tissue engineering was made on the databases of PubMed, Medline and Google Scholar. The papers were selected by three independent calibrated reviewers. Results: Multiple types of materials and scaffolds have been combined with PDLSCs, involving xeno genic bone graft, calcium phosphate materials and polymers. These PDLSC-based constructs exhibit the potential for bone and periodontal tissue regeneration. In addition, various osteo inductive agents and strategies have been applied with PDLSCs, including drugs, biologics, gene therapy, physical stimulation, scaffold modification, cell sheets and co-culture. Conclusoin: This review article demonstrates the great potential of PDLSCs-based bioactive constructs as a promising approach for bone and periodontal tissue regeneration.

The Role of Low-Frequency Electromagnetic Fields on Mesenchymal Stem Cells Differentiation: A Systematic Review

BACKGROUND

Low-frequency electromagnetic fields (EMFs) influence biological processes. This present study was aimed at the scientific literature on the use of EMFs in the mesenchymal stem cell differentiation process.

MATERIALS AND METHODS

The electronic search was carried out in PubMed and Web of Science, a database with a combination of the sinusoidal and pulsed low- and extremely low-frequency electromagnetic fields stimulation and mesenchymal stem cells differentiation, considering the period of publication until December 2021. The literature search identified 118 references in PubMed and Web of Science of which 46 articles were selected, respectively, according to the eligibility requirements.

CONCLUSION

The analysis of research indicated that EMFs are an easy-to-apply and practical way in cell therapy and tissue engineering when regulation of stem cells is required. Studies have shown that EMFs have positive effects on stem cell differentiation, accelerating its process regardless of the parameters and type of stem cells. However, the exact amplitude, frequency, duration of the electrical field, and application method remain elusive and need more study in future work.

The Role of PEMFs on Bone Healing: An In Vitro Study

Bone responses to pulsed electromagnetic fields (PEMFs) have been extensively studied by using devices that expose bone cells to PEMFs to stimulate extracellular matrix (ECM) synthesis for bone and cartilage repair. The aim of this work was to highlight in which bone healing phase PEMFs exert their action. Specifically, we evaluated the effects of PEMFs both on human adipose mesenchymal stem cells (hASCs) and on primary human osteoblasts (hOBs) by testing gene and protein expression of early bone markers (on hASCs) and the synthesis of late bone-specific proteins (on hOBs) as markers of bone remodeling. Our results indicate that PEMFs seem to exert their action on bone formation, acting on osteogenic precursors (hASCs) and inducing the commitment towards the differentiation pathways, unlike mature and terminally differentiated cells (hOBs), which are known to resist homeostasis perturbation more and seem to be much less responsive than mesenchymal stem cells. Understanding the role of PEMFs on bone regenerative processes provides important details for their clinical application.

Polymeric Orthosis with Electromagnetic Stimulator Controlled by Mobile Application for Bone Fracture Healing: Evaluation of Design Concepts for Medical Use

Background: The occurrence of bone fractures is increasing worldwide, mainly due to the health problems that follow the aging population. The use of additive manufacturing and electrical stimulators can be applied for bioactive achievements in bone healing. However, such technologies are difficult to be transferred to medical practice. This work aims to develop an orthosis with a combined magnetic field (CFM) electrostimulator that demonstrates concepts and design aspects that facilitate its use in a real scenario. Methods: A 3D-printed orthosis made of two meshes was manufactured using PLA for outer mechanical stabilization mesh and TPU for inner fixation mesh to avoid mobilization. A CFM stimulator of reduced dimension controlled by a mobile application was coupled onto the orthosis. The design concepts were evaluated by health professionals and their resistance to chemical agents commonly used in daily activities were tested. Their thermal, chemical and electrical properties were also characterized. Results: No degradation was observed after exposure to chemical agents. The CMF achieved proper intensity (20-40 µT). The thermal analysis indicated its appropriate use for being modelled during clinical assessment. Conclusion: An orthosis with a coupled electrostimulator that works with a combined magnetic field and is controlled by mobile application was developed, and it has advantageous characteristics when compared to traditional techniques for application in real medical environments.

Biophysical Stimulation in Delayed Fracture Healing of Hand Phalanx: A Radiographic Evaluation

Phalangeal fractures are common events among the upper limbs accounting for 10% of all human body fractures. Fracture complete healing process may persevere several months or years. Most phalangeal fractures present favorable union within 3 to 6 weeks. In the literature, biophysical stimulation has yielded favorable outcomes in the treatment of hand fractures. A survey involving hospitals in the US reported the use of biophysical stimulation (72%) in relation to nonhealing fractures at three months after trauma. A noninvasive procedure such as biophysical stimulation may be preferential prior to consideration of invasive procedures. In this retrospective study, we analyzed 80 phalangeal fractures, 43 of which did not show any radiographic sign of healing 30 days after surgery; on radiograms, we calculated radiographic data and the total active motion (TAM) for clinical comparison. All radiographic images were evaluated using Adobe Photoshop CS3 (version 10.0, Adobe Systems Inc., San Jose, CA, USA). We calculated the index of relative bone healing each month after surgery starting from 30 days, which was considered as T1, and followed up for a total of 6 months after stimulation (T6) with better results in stimulated groups. We concluded that prompt administration of biophysical stimulation supports fracture healing and yields an important improvement in the union rate compared with nontreatment. Above all, our patients experienced less injury-related distress between the fracture and repair period, which consequently reduced immobilization time, envisaging an early rehabilitation interval, with a better patient hand outcome.

Pulsed electromagnetic fields improve pain management and clinical outcomes after medial unicompartmental knee arthroplasty: A prospective randomised controlled trial

BACKGROUND

To assess pain relief and clinical outcomes in patients undergoing unicompartmental knee arthroplasty (UKA) stimulated with pulsed electromagnetic fields (PEMFs) compared to a control group.

METHODS

A prospective randomised controlled trial (RCT) was performed in which 72 patients undergoing medial UKA were randomised into a control group or an experimental PEMFs group. The patients allocated to the experimental group were instructed to use PEMFs for 4 h per day for 60 days. They were evaluated before a surgery and then during the time points corresponding to 1 month, 2 months, 6 months, 12 months, and 36 months after the surgery. No placebo group was included in the RCT. Clinical assessment included the Visual Analogue Scale (VAS) for pain, Oxford Knee Score (OKS), the Short Form 36 (SF-36) health survey questionnaire, and joint swelling. During each follow-up visit, the consumption of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) was recorded.

RESULTS

The VAS decreased on follow-up visits in both the groups; a statistically significant difference between the groups was observed during the 6 (p = 0.0297), 12 (p = 0.0003), and 36 months (p = 0.0333) follow-ups in favour of the PEMFs group. One month after UKA, the percentages of patients using NSAIDs in the PEMFs and control group were 71% and 92%, respectively (p = 0.0320). At the 2 months point, 15% of the patients in the PEMFs group used NSAIDs compared to 39% in the control group (p = 0.0317). The objective knee girth evaluation showed a statistically significant difference at 6 (p = 0.0204), 12 (p = 0.0005), and 36 (p = 0.0005) months with improved values observed in the PEMFs group. The subjective assessment of the swelling demonstrated a statistically significant difference at 2 (p = 0.0073), 6 (p = 0.0006), 12 (p = 0.0001), and 36 (p = 0.0011) months with better values noted in the PEMFs group. Last, the OKS result was significant higher in the experimental group during all the follow-ups (1mth: p = 0.0295; 2mths: p = 0.0012; 6mths: p = 0.0001; 12mths: p < 0.0001; 36mths: p = 0.0061).

CONCLUSIONS

The use of PEMFs leads to significant pain relief, better clinical improvement, and lower NSAIDs consumption after medial UKA when compared to the control group.

LEVEL OF EVIDENCE

II.

Pulsed Electrical Stimulation Affects Osteoblast Adhesion and Calcium Ion Signaling

An extensive research field in regenerative medicine is electrical stimulation (ES) and its impact on tissue and cells. The mechanism of action of ES, particularly the role of electrical parameters like intensity, frequency, and duration of the electric field, is not yet fully understood. Human MG-63 osteoblasts were electrically stimulated for 10 min with a commercially available multi-channel system (IonOptix). We generated alternating current (AC) electrical fields with a voltage of 1 or 5 V and frequencies of 7.9 or 20 Hz, respectively. To exclude liquid-mediated effects, we characterized the AC-stimulated culture medium. AC stimulation did not change the medium’s pH, temperature, and oxygen content. The H2O2 level was comparable with the unstimulated samples except at 5 V_7.9 Hz, where a significant increase in H2O2 was found within the first 30 min. Pulsed electrical stimulation was beneficial for the process of attachment and initial adhesion of suspended osteoblasts. At the same time, the intracellular Ca2+ level was enhanced and highest for 20 Hz stimulated cells with 1 and 5 V, respectively. In addition, increased Ca2+ mobilization after an additional trigger (ATP) was detected at these parameters. New knowledge was provided on why electrical stimulation contributes to cell activation in bone tissue regeneration.

Evaluation of Microstructure and Mechanical Properties of a Ti10Mo8Nb Alloy for Biomedical Applications

The growth of the elderly population is urging for more suitable biomaterials to allow the performance of better surgical and implant procedures and accelerate the patient’s healing because the elderly are more vulnerable to orthopedic and dental problems. β-phase Ti alloys can improve the mechanical properties of implants by reducing their elastic modulus and, consequently, the effects of stress shielding within bones. Therefore, the objective of this article is to study a novel ternary β-phase alloy of Ti10Mo8Nb produced by an electric arc furnace and rotary forge. The microstructure and mechanical properties of the Ti10Mo8Nb alloy were investigated in order to evaluate its suitability for biomedical applications and compare its characteristics with those present in Ti-alloys commerced or widely researched for prosthetic purposes. A tensile test, Vickers microhardness test, use of microstructure of optical microscopy for examination of microstructure, X-ray diffraction and hemolysis analysis were carried out. Thus, the Ti10Mo8Nb alloy showed suitable properties for biomedical applications, as well as having the potential to reduce the possibility to occur stress shielding after prosthetic implantations, especially for orthopedics and dentistry.

Effect of Photobiomodulation Therapy on Peri-Implant Bone Healing in Extra-Short Implants in a Rabbit Model: A Pilot Study

Objective: To evaluate the effects of photobiomodulation therapy (PBMT) at distinct energy levels on peri-implant bone healing in extra-short implants in a experimental rabbit model. Background: The effect of PBMT on peri-implant bone healing in short implants remains unclear. This explored the effect of PBMT on extra-short implants in terms of bone-implant contact (BIC) length and rate, and implant stability quotient (ISQ). Methods: Fifteen white New Zealand rabbits were randomly divided into five groups. In all groups, extra-short implants (3.5 × 4 mm; Nucleoss T6, İzmir/Turkey) were placed in both tibias of the rabbits. PBMT was performed in four groups (group 1, 5 J/cm2; group 2, 10 J/cm2; group 3, 20 J/cm2; and group 4, 25 J/cm2); no PBMT was performed in the control group. On the 30th day, the rabbits were sacrificed and peri-implant tissue samples were obtained to determine the BIC length and BIC rate. Implant stability levels were measured by resonance frequency analysis using the Osstell penguin device and were determined as ISQ values on the 1st and 30th days of the study. Results: PBMT significantly increased the BIC length and BIC rate in groups 3 and 4 (p < 0.001). For the ISQ values, there were significant differences between the 1st and 30th day (p < 0.001). On the 30th day, the ISQ values were significantly higher in groups 3 and 4 compared with the remaining groups (p < 0.001). Conclusions: In this study, PBMT improved peri-implant bone healing through increase in BIC length, BIC rate, and ISQ parameter values in extra-short implants.

Overview of Physical and Pharmacological Therapy in Enhancing Bone Regeneration Formation During Distraction Osteogenesis

Distraction osteogenesis (DO) is a kind of bone regeneration technology. The principle is to incise the cortical bone and apply continuous and stable distraction force to the fractured end of the cortical bone, thereby promoting the proliferation of osteoblastic cells in the tension microenvironment and stimulating new bone formation. However, the long consolidation course of DO presumably lead to several complications such as infection, fracture, scar formation, delayed union and malunion. Therefore, it is of clinical significance to reduce the long treatment duration. The current treatment strategy to promote osteogenesis in DO includes gene, growth factor, stem-cell, physical and pharmacological therapies. Among these methods, pharmacological and physical therapies are considered as safe, economical, convenience and effective. Recently, several physical and pharmacological therapies have been demonstrated with a decent ability to enhance bone regeneration during DO. In this review, we have comprehensively summarized the latest evidence for physical (Photonic, Waves, Gas, Mechanical, Electrical and Electromagnetic stimulation) and pharmacological (Bisphosphonates, Hormone, Metal compounds, Biologics, Chinese medicine, etc) therapies in DO. These evidences will bring novel and significant information for the bone healing during DO in the future.

Low-Intensity Pulsed Ultrasound in the Treatment of Nonunions and Fresh Fractures: A Case Series

It is estimated that approximately 5% to 10% of fractures will evolve into nonunions. Nonunions have a significant impact on patient quality of life and on socioeconomic costs. Low-intensity pulsed ultrasound (LIPUS) is a non-invasive therapy widely used within the orthopedic community to accelerate the healing of fresh fractures, to minimize delayed healing, and to promote healing of nonunions. In this case series, 46 nonunions and 19 fresh fractures were treated with LIPUS for at least three months or until fracture healing. Bone healing was assessed both at a radiological and a functional level. Of the nonunions healed, 89% had a mean healing time of 89 ± 53 days. In the group of fresh fractures, the healing percentage was 95% with a mean healing time of 46 ± 28 days. LIPUS treatment is proven to be safe and well tolerated; there were no adverse events related to the use of the device, even in the presence of internal fixations and infections. LIPUS therapy should be considered a low-risk option both as an adjunct to surgery or as a standalone therapy in the management of nonunion and fresh fractures.

Electrical stimulation to promote osseointegration of bone anchoring implants: a topical review

Electrical stimulation has shown to be a promising approach for promoting osseointegration in bone anchoring implants, where osseointegration defines the biological bonding between the implant surface and bone tissue. Bone-anchored implants are used in the rehabilitation of hearing and limb loss, and extensively in edentulous patients. Inadequate osseointegration is one of the major factors of implant failure that could be prevented by accelerating or enhancing the osseointegration process by artificial means. In this article, we reviewed the efforts to enhance the biofunctionality at the bone-implant interface with electrical stimulation using the implant as an electrode. We reviewed articles describing different electrode configurations, power sources, and waveform-dependent stimulation parameters tested in various in vitro and in vivo models. In total 55 English-language and peer-reviewed publications were identified until April 2020 using PubMed, Google Scholar, and the Chalmers University of Technology Library discovery system using the keywords: osseointegration, electrical stimulation, direct current and titanium implant. Thirteen of those publications were within the scope of this review. We reviewed and compared studies from the last 45 years and found nonuniform protocols with disparities in cell type and animal model, implant location, experimental timeline, implant material, evaluation assays, and type of electrical stimulation. The reporting of stimulation parameters was also found to be inconsistent and incomplete throughout the literature. Studies using in vitro models showed that osteoblasts were sensitive to the magnitude of the electric field and duration of exposure, and such variables similarly affected bone quantity around implants in in vivo investigations. Most studies showed benefits of electrical stimulation in the underlying processes leading to osseointegration, and therefore we found the idea of promoting osseointegration by using electric fields to be supported by the available evidence. However, such an effect has not been demonstrated conclusively nor optimally in humans. We found that optimal stimulation parameters have not been thoroughly investigated and this remains an important step towards the clinical translation of this concept. In addition, there is a need for reporting standards to enable meta-analysis for evidence-based treatments.

Numerical study on the effect of capacitively coupled electrical stimulation on biological cells considering model uncertainties

Electrical stimulation of biological samples such as tissues and cell cultures attracts growing attention due to its capability of enhancing cell activity, proliferation, and differentiation. Eventually, a profound knowledge of the underlying mechanisms paves the way for innovative therapeutic devices. Capacitive coupling is one option of delivering electric fields to biological samples that has advantages regarding biocompatibility. However, its biological mechanism of interaction is not well understood. Experimental findings could be related to voltage-gated channels, which are triggered by changes of the transmembrane potential. Numerical simulations by the finite element method provide a possibility to estimate the transmembrane potential. Since a full resolution of the cell membrane within a macroscopic model would lead to prohibitively expensive models, we suggest the adaptation of an approximate finite element method. Starting from a basic 2.5D model, the chosen method is validated and applied to realistic experimental situations. To understand the influence of the dielectric properties on the modelling outcome, uncertainty quantification techniques are employed. A frequency-dependent influence of the uncertain dielectric properties of the cell membrane on the modelling outcome is revealed. This may have practical implications for future experimental studies. Our methodology can be easily adapted for computational studies relying on experimental data.

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.

Effect of Amniotic Membrane/Collagen-Based Scaffolds on the Chondrogenic Differentiation of Adipose-Derived Stem Cells and Cartilage Repair

Objectives: Repairing articular cartilage damage is challenging. Clinically, tissue engineering technology is used to induce stem cell differentiation and proliferation on biological scaffolds to repair defective joints. However, no ideal biological scaffolds have been identified. This study investigated the effects of amniotic membrane/collagen scaffolds on the differentiation of adipose-derived stem cells (ADSCs) and articular cartilage repair.

Methods: Adipose tissue of New Zealand rabbits was excised, and ADSCs were isolated and induced for differentiation. An articular cartilage defect model was constructed to identify the effect of amniotic membrane/collagen scaffolds on cartilage repair. Cartilage formation was analyzed by imaging and toluene blue staining. Knee joint recovery in rabbits was examined using hematoxylin and eosin, toluidine, safranine, and immunohistochemistry at 12 weeks post-operation. Gene expression was examined using ELISA, RT-PCR, Western blotting, and immunofluorescence.

Results: The adipose tissue was effectively differentiated into ADSCs, which further differentiated into chondrogenic, osteogenic, and lipogenic lineages after 3 weeks’ culture in vitro. Compared with platelet-rich plasmon (PRP) scaffolds, the amniotic membrane scaffolds better promoted the growth and differentiation of ADSCs. Additionally, scaffolds containing the PRP and amniotic membrane efficiently enhanced the osteogenic differentiation of ADSCs. The levels of COL1A1, COL2A1, COL10A1, SOX9, and ACAN in ADSCs + amniotic membrane + PRP group were significantly higher than the other groups both in vitro and in vivo. The Wakitani scores of the ADSC + amniotic membrane + PRP group were lower than that in ADSC + PRP (4.4 ± 0.44**), ADSC + amniotic membrane (2.63 ± 0.38**), and control groups (6.733 ± 0.21) at week 12 post-operation. Osteogenesis in rabbits of the ADSC + amniotic membrane + PRP group was significantly upregulated when compared with other groups. Amniotic membranes significantly promoted the expression of cartilage regeneration-related factors (SOX6, SOX9, RUNX2, NKX3-2, MEF2C, and GATA4). The ADSC + PRP + amniotic membrane group exhibited the highest levels of TGF-β, PDGF, and FGF while exhibiting the lowest level of IL-1β, IL6, and TNF-α in articular cavity.

Conclusion: Amniotic membrane/collagen combination-based scaffolds promoted the proliferation and cartilage differentiation of ADSCs, and may provide a new treatment paradigm for patients with cartilage injury.

A ligament tensor-guided extramedullary alignment technique for distal femoral cut in total knee replacement: results at a minimum 3 years follow-up

BACKGROUND

Femoral intramedullary canal referencing is used by most knee arthroplasty systems for distal femoral cut; to avoid the opening of the femoral canal different solutions have been presented such as navigation, patient-specific instruments (PSI) or the use of an extramedullary device. The FuZion^® system is a tensor device, created to merge the two main techniques for performing a total knee arthroplasty: the ligament balancing and measured resection techniques. Our idea was to use the tensor as an extramedullary cutting guide for the distal femoral cut, based on a 90° tibial resection.

METHODS

A total of 110 patients were operated on with this technique. Patients were evaluated with weight-bearing long-standing X-rays, knee a-p and lateral views, validated PROMs (Oxford Knee Score, EQ-5D and EQ-VAS), the Knee Society Scoring System (KSS) and the Forgotten Joint Score (FJS). Minimum follow up was 3 years (range 38-50 months).

RESULTS

Complete results were available for 104 patients (5 were lost in follow up and 1 died). Significant improvements were registered for all the evaluated scores from pre-op to the final follow up. Pre-op long-standing X-rays showed 21 valgus knees (20%) with a mean HKA of 187.6° (± 3.2°), 70 varus knees (62%) with a mean 172.2° (± 3.7°) HKA and 19 neutrally aligned knees, with a mean HKA of 179.5° (0 ± 2°). The radiographic evaluation at 3 months post-op showed 20 valgus knees (mean HKA 183.7° ± 1.5°), 67 varus knees (mean HKA 176.1° ± 1.8°) and 23 neutrally aligned knees with a mean HKA of 179.3° (0 ± 2°). At final follow up the survival rate was 100% for revision of the implant as the endpoint. With any reoperation as the endpoint Kaplan-Meier survival estimate showed a survival rate of 95.1% at 3 years.

CONCLUSIONS

This technique for performing a ligament driven alignment in total knee arthroplasty showed encouraging clinical outcomes at mid-term follow up leaving a residual deformity on the coronal plane.

Capacitive interdigitated system of high osteoinductive/conductive performance for personalized acting-sensing implants

Replacement orthopedic surgeries are among the most common surgeries worldwide, but clinically used passive implants cannot prevent failure rates and inherent revision arthroplasties. Optimized non-instrumented implants, resorting to preclinically tested bioactive coatings, improve initial osseointegration but lack long-term personalized actuation on the bone-implant interface. Novel bioelectronic devices comprising biophysical stimulators and sensing systems are thus emerging, aiming for long-term control of peri-implant bone growth through biointerface monitoring. These acting-sensing dual systems require high frequency (HF) operations able to stimulate osteoinduction/osteoconduction, including matrix maturation and mineralization. A sensing-compatible capacitive stimulator of thin interdigitated electrodes and delivering an electrical 60 kHz HF stimulation, 30 min/day, is here shown to promote osteoconduction in pre-osteoblasts and osteoinduction in human adipose-derived mesenchymal stem cells (hASCs). HF stimulation through this capacitive interdigitated system had significant effects on osteoblasts' collagen-I synthesis, matrix, and mineral deposition. A proteomic analysis of microvesicles released from electrically-stimulated osteoblasts revealed regulation of osteodifferentiation and mineralization-related proteins (e.g. Tgfb3, Ttyh3, Itih1, Aldh1a1). Proteomics data are available via ProteomeXchange with the identifier PXD028551. Further, under HF stimulation, hASCs exhibited higher osteogenic commitment and enhanced hydroxyapatite deposition. These promising osteoinductive/conductive capacitive stimulators will integrate novel bioelectronic implants able to monitor the bone-implant interface and deliver personalized stimulation to peri-implant tissues.

Hydrogel-hydroxyapatite-monomeric collagen type-I scaffold with low-frequency electromagnetic field treatment enhances osteochondral repair in rabbits

BACKGROUND

Cartilage damage is a common medical issue in clinical practice. Complete cartilage repair remains a significant challenge owing to the inferior quality of regenerative tissue. Safe and non-invasive magnetic therapy combined with tissue engineering to repair cartilage may be a promising breakthrough.

METHODS

In this study, a composite scaffold made of Hydroxyapatite-Collagen type-I (HAC) and PLGA-PEG-PLGA thermogel was produced to match the cartilage and subchondral layers in osteochondral defects, respectively. Bone marrow mesenchymal stem cells (BMSC) encapsulated in the thermogel were stimulated by an electromagnetic field (EMF). Effect of EMF on the proliferation and chondrogenic differentiation potential was evaluated in vitro. 4 mm femoral condyle defect was constructed in rabbits. The scaffolds loaded with BMSCs were implanted into the defects with or without EMF treatment. Effects of the combination treatment of the EMF and composite scaffold on rabbit osteochondral defect was detected in vivo.

RESULTS

In vitro experiments showed that EMF could promote proliferation and chondrogenic differentiation of BMSCs partly by activating the PI3K/AKT/mTOR and Wnt1/LRP6/β-catenin signaling pathway. In vivo results further confirmed that the scaffold with EMF enhances the repair of osteochondral defects in rabbits, and, in particular, cartilage repair.

CONCLUSION

Hydrogel-Hydroxyapatite-Monomeric Collagen type-I scaffold with low-frequency EMF treatment has the potential to enhance osteochondral repair.

Biophysical Stimulation in Athletes' Joint Degeneration: A Narrative Review

Osteoarthritis (OA) is the most prevalent degenerative joint disease and the main cause of pain and disability in elderly people. OA currently represents a significant social health problem, since it affects 250 million individuals worldwide, mainly adults aged over 65. Although OA is a multifactorial disease, depending on both genetic and environmental factors, it is reported that joint degeneration has a higher prevalence in former athletes. Repetitive impact and loading, joint overuse and recurrent injuries followed by a rapid return to the sport might explain athletes' predisposition to joint articular degeneration. In recent years, however, big efforts have been made to improve the prevention and management of sports injuries and to speed up the athletes' return-to-sport. Biophysics is the study of biological processes and systems using physics-based methods or based on physical principles. Clinical biophysics has recently evolved as a medical branch that investigates the relationship between the human body and non-ionizing physical energy. A physical stimulus triggers a biological response by regulating specific intracellular pathways, thus acting as a drug. Preclinical and clinical trials have shown positive effects of biophysical stimulation on articular cartilage, subchondral bone and synovia. This review aims to assess the role of pulsed electromagnetic fields (PEMFs) and extracorporeal shockwave therapy (ESWT) in the prevention and treatment of joint degeneration in athletes.

Pulsed electromagnetic fields after intramedullary nailing of tibial fractures: a case control study

PURPOSE

To compare clinical and functional outcomes of two groups of patients undergoing reduction and nailing fixation for diaphyseal fractures of the tibia with (PEMF group) and without (control group) post-operative pulsed electromagnetic field (PEMF) application.

METHODS

This is a retrospective study on 50 patients (mean age 43.3 years, 28 males and 22 females) with diaphyseal tibial fractures managed between 2017 and 2019. Twenty-five patients underwent reduction, nailing fixation, and PEMF application post-operatively (PEMF group) and 25 patients underwent nailing fixation. Radiographic imaging assessment was performed every month until fracture healing had been evident. Use of analgesics, fracture healing time, post-operative lower limb alignment, and post-operative complications were recorded. Patients were asked about return to preinjury activity. All patients were assessed at 3 months and at an average follow-up of 13 months. The VAS scale and Johner-Wruhs criteria were used for pain assessment and functional recovery, respectively.

RESULTS

Comparing groups, VAS values were significantly lower in the PEMF group at three months and comparable at one year. The patients in the PEMF group took an average of 4.1 months to resume their preinjury activities, and control patients took an average of 5.3 months (P < 0.0001). According to the Johner-Wruhs score, the effective rate was 100% (25/25) in the PEMF group and 92% (23/25) in the control group (P = 0.14).

CONCLUSIONS

PEMF application after intramedullary nailing is safe and reduces post-operative pain, use of analgesics, and the time of healing fracture. At one year, there is no difference in outcome measures, regardless of PEMF application.

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.

Pulsed Electromagnetic Fields Modulate miRNAs During Osteogenic Differentiation of Bone Mesenchymal Stem Cells: a Possible Role in the Osteogenic-angiogenic Coupling

Despite the high intrinsic ability of bone tissue to regenerate, bone healing fails in some pathological conditions and especially in the presence of large defects. Due to the strong relationship between bone development and vascularization during in vivo bone formation and repair, strategies promoting the osteogenic-angiogenic coupling are crucial for regenerative medicine. Increasing evidence shows that miRNAs play important roles in controlling osteogenesis and bone vascularization and are important tool in medical research although their clinical use still needs to optimize miRNA stability and delivery. Pulsed electromagnetic fields (PEMFs) have been successfully used to enhance bone repair and their clinical activity has been associated to their ability to promote the osteogenic differentiation of human mesenchymal stem cells (hMSCs). In this study we investigated the potential ability of PEMF exposure to modulate selected miRNAs involved in the osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs). We show that, during in vitro hBMSC differentiation, PEMFs up-modulate the expression of miR-26a and miR-29b, which favor osteogenic differentiation, and decrease miR-125b which acts as an inhibitor miRNA. As PEMFs promote the expression and release of miRNAs also involved in angiogenesis, we conclude that PEMFs may represent a noninvasive and safe strategy to modulate miRNAs with relevant roles in bone repair and with the potential to regulate the osteogenic-angiogenic coupling.

Pulsed electromagnetic field (PEMF) transiently stimulates the rate of mineralization in a 3-dimensional ring culture model of osteogenesis

Pulsed Electromagnetic Field (PEMF) has shown efficacy in bone repair and yet the optimum characteristics of this modality and its molecular mechanism remain unclear. To determine the effects of timing of PEMF treatment, we present a novel three-dimensional culture model of osteogenesis that demonstrates strong de novo generation of collagen and mineral matrix and exhibits stimulation by PEMF in multiple stages over 62 days of culture. Mouse postnatal day 2 calvarial pre-osteoblasts were cast within and around Teflon rings by polymerization of fibrinogen and cultured suspended without contact with tissue culture plastic. Ring constructs were exposed to PEMF for 4h/day for the entire culture (Daily), or just during Day1-Day10, Day11-Day 27, or Day28-Day63 and cultured without PEMF for the preceding or remaining days, and compared to no-PEMF controls. PEMF was conducted as HF Physio, 40.85 kHz frequency with a 67 ms burst period and an amplitude of 1.19 mT. Osteogenesis was kinetically monitored by repeated fluorescence measurements of continuously present Alizarin Red S (ARS) and periodically confirmed by micro-CT. PEMF treatment induced early-onset and statistically significant transient stimulation (~4-fold) of the mineralization rate when PEMF was applied Daily, or during D1-D10 and D11-D27. Stimulation was apparent but not significant between D28-D63 by ARS but was significant at D63 by micro-CT. PEMF also shifted the micro-CT density profiles to higher densities in each PEMF treatment group. Ring culture generated tissue with a mineral:matrix ratio of 2.0 by thermogravimetric analysis (80% of the calvaria control), and the deposited crystal structure was 50% hydroxyapatite by X-ray diffraction (63% of the calvaria and femur controls), independent of PEMF. These results were consistent with backscatter, secondary electron, and elemental analysis by scanning electron microscopy. Thus, in a defined, strong osteogenic environment, PEMF applied at different times was capable of further stimulation of osteogenesis with the potential to enhance bone repair.

Does Capacitively Coupled Electric Fields Stimulation Improve Clinical Outcomes After Instrumented Spinal Fusion? A Multicentered Randomized, Prospective, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Lumbar spinal fusion (LSF) is used to treat lumbar degenerative disorders. Methods to improve the functional recovery of patients undergoing LSF is one of the main goals in daily clinical practice. The objective of this study is to assess whether biophysical stimulation with capacitively coupled electric fields (CCEF) can be used as adjuvant therapy to enhance clinical outcome in LSF-treated patients.

METHODS

Forty-two patients undergoing LSF were assessed and randomly allocated to either the active or to the placebo group. Follow-up visits were performed at 1, 3, 6, and 12 months after surgery; long-term follow-up was performed at year 10. Visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the 36-item Short Form Health Survey (SF-36) questionnaire were recorded.

RESULTS

This study demonstrates a significant improvement in CCEF-treated patients at 6 and 12 months' follow-up for SF-36, and at 12 months' follow-up for ODI values. Based on SF-36 and ODI scores, we reported a significantly higher percentage of successful treatments at 12 months in the active compared with the placebo group. Moreover, in a subset of patients at 10 years' follow-up, a significant difference was reported in VAS and ODI scores between groups.

CONCLUSIONS

The results demonstrate that 3 months of CCEF treatment immediately after surgery is effective in reducing ODI and improving SF-36 score, and that these benefits can be maintained up to 12 months. In a subset of patients, these positive outcomes are retained up to 10 years.

LEVEL OF EVIDENCE

I.

CLINICAL RELEVANCE

This study suggests that CCEF stimulation can be used as an adjunct to LSF for spine diseases, for increasing overall quality of life and improving patients' functional recovery. CCEF is safe and well tolerated, compatible with activities of daily living.

Pulsed Electromagnetic Field Stimulation in Osteogenesis and Chondrogenesis: Signaling Pathways and Therapeutic Implications

Mesenchymal stem cells (MSCs) are the main cell players in tissue repair and thanks to their self-renewal and multi-lineage differentiation capabilities, they gained significant attention as cell source for tissue engineering (TE) approaches aimed at restoring bone and cartilage defects. Despite significant progress, their therapeutic application remains debated: the TE construct often fails to completely restore the biomechanical properties of the native tissue, leading to poor clinical outcomes in the long term. Pulsed electromagnetic fields (PEMFs) are currently used as a safe and non-invasive treatment to enhance bone healing and to provide joint protection. PEMFs enhance both osteogenic and chondrogenic differentiation of MSCs. Here, we provide extensive review of the signaling pathways modulated by PEMFs during MSCs osteogenic and chondrogenic differentiation. Particular attention has been given to the PEMF-mediated activation of the adenosine signaling and their regulation of the inflammatory response as key player in TE approaches. Overall, the application of PEMFs in tissue repair is foreseen: (1) in vitro: to improve the functional and mechanical properties of the engineered construct; (2) in vivo: (i) to favor graft integration, (ii) to control the local inflammatory response, and (iii) to foster tissue repair from both implanted and resident MSCs cells.

Sustained Acoustic Medicine Combined with A Diclofenac Ultrasound Coupling Patch for the Rapid Symptomatic Relief of Knee Osteoarthritis: Multi-Site Clinical Efficacy Study

BACKGROUND

Sustained Acoustic Medicine (SAM) is an emerging, non-invasive, non-narcotic, home-use ultrasound therapy for the daily treatment of joint pain. The aim of this multi-site clinical study was to examine the efficacy of long-duration continuous ultrasound combined with a 1% diclofenac ultrasound gel patch in treating pain and improving function in patients with knee osteoarthritis.

METHODS

The Consolidated Standards of Reporting Trials (CONSORT) were followed. Thirty-two (32) patients (18-males, 14-females) 54 years of average age with moderate to severe knee pain and radiographically confirmed knee osteoarthritis (Kellgren-Lawrence (KL) grade II/III) were enrolled for treatment with the SAM device and diclofenac patch applied daily to the treated knee. SAM ultrasound (3 MHz, 0.132 W/cm2, 1.3 W) and 6 grams of 1% diclofenac were applied with a wearable device for 4 hours daily for 1 week, delivering 18,720 Joules of ultrasound energy per treatment. The primary outcome was the daily change in pain intensity using a numeric rating scale (NRS 0-10), which was assessed prior to intervention (baseline, day 1), before and after each daily treatment, and after 1 week of daily treatment (day 7). Rapid responders were classified as those patients exhibiting greater than a 1-point reduction in pain following the first treatment. Change in Western Ontario McMaster Osteoarthritis Questionnaire (WOMAC) score from baseline to day 7 was the secondary functional outcome measure. Additionally, a series of daily usability and user experience questions related to devising ease of use, functionality, safety, and effectiveness, were collected. Data were analyzed using t-tests and repeated measure ANOVAs.

RESULTS

The study had a 94% retention rate, and there were no adverse events or study-related complaints across 224 unique treatment sessions. Rapid responders included 75% of the study population. Patients exhibited a significant mean NRS pain reduction over the 7-day study of 2.06-points (50%) for all subjects (n=32, p<0.001) and 2.96-points (70%) for rapid responders (n=24, p<0.001). The WOMAC functional score significantly improved by 351 points for all subjects (n=32, p<0.001), and 510 points for rapid responders (n=24, p<0.001). Over 95% of patients found the device safe, effective and easy to use, and would continue treatment for their knee OA symptoms.

CONCLUSION

Sustained Acoustic Medicine combined with 1% topical diclofenac rapidly reduced pain and improved function in patients with moderate to severe osteoarthritis-related knee pain. The clinical findings suggest that this treatment approach may be used as a conservative, non-invasive treatment option for patients with knee osteoarthritis. Additional research is warranted on non-weight bearing joints of the musculoskeletal system as well as different topical drugs that could benefit from improved localized delivery.Clinical Trial Registry Number: (NCT04391842).

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.