Healing in the new millennium: bone stimulators: an overview of where we've been and where we may be heading

Remote coupling of electrical and mechanical cues by diurnal photothermal irradiation synergistically promotes bone regeneration

Recapitulating the natural extracellular physical microenvironment has emerged as a promising method for tissue regeneration, as multiple physical interventions, including ultrasound, thermal and electrical therapy, have shown great potential. However, simultaneous coupling of multiple physical cues to highly bio-mimick natural characteristics for improved tissue regeneration still remains formidable. Coupling of intrinsic electrical and mechanical cues has been regarded as an effective way to modulate tissue repair. Nevertheless, precise and convenient manipulation on coupling of mechano-electrical signals within extracellular environment to facilitate tissue regeneration remains challengeable. Herein, a photothermal-sensitive piezoelectric membrane was designed for simultaneous integration of electrical and mechanical signals in response to NIR irradiation. The high-performance mechano-electrical coupling under NIR exposure synergistically triggered the promotion of osteogenic differentiation of stem cells and enhances bone defect regeneration by increasing cellular mechanical sensing, attachment, spreading and cytoskeleton remodeling. This study highlights the coupling of mechanical signals and electrical cues for modulation of osteogenesis, and sheds light on alternative bone tissue engineering therapies with multiple integrated physical cues for tissue repair.

Signalling pathways underlying pulsed electromagnetic fields in bone repair

Pulsed electromagnetic field (PEMF) stimulation is a prospective non-invasive and safe physical therapy strategy for accelerating bone repair. PEMFs can activate signalling pathways, modulate ion channels, and regulate the expression of bone-related genes to enhance osteoblast activity and promote the regeneration of neural and vascular tissues, thereby accelerating bone formation during bone repair. Although their mechanisms of action remain unclear, recent studies provide ample evidence of the effects of PEMF on bone repair. In this review, we present the progress of research exploring the effects of PEMF on bone repair and systematically elucidate the mechanisms involved in PEMF-induced bone repair. Additionally, the potential clinical significance of PEMF therapy in fracture healing is underscored. Thus, this review seeks to provide a sufficient theoretical basis for the application of PEMFs in bone repair.

Resource Utilization and the Use of Bone Stimulators among Operatively and Nonoperatively Managed Scaphoid Nonunion Patients

The prevalence of bone stimulator use among nonoperatively and operatively managed scaphoid nonunion patients is unknown. We hypothesize that bone stimulators are a relatively underutilized treatment for scaphoid nonunion patients.

Methods

We used the 2009-2017 Truven Marketscan Research Databases to identify patients with closed scaphoid fractures and performed an analysis of variance test to determine resource utilization and bone stimulator use among these patients.

Results

A total of 36,611 patients with scaphoid fractures were identified: 30,143 were managed nonoperatively and 6468 were managed operatively. Nonunion was diagnosed in 500 (1.66%) nonoperatively and in 1211 (19%) operatively managed patients. Bone stimulators were used in less than 2% of nonoperatively and operatively managed scaphoid nonunion patients.

Conclusion

Lack of trust in the technology and heterogenous (and occasionally burdensome) requirements for insurance approval are barriers to bone stimulator use; however, surgeons should examine how this technology may fit into the treatment algorithm for these difficult cases.

Electrical Stimulation of Acute Fractures: A Narrative Review of Stimulation Protocols and Device Specifications

Orthopedic fractures have a significant impact on patients in the form of economic loss and functional impairment. Beyond the standard methods of reduction and fixation, one adjunct that has been explored since the late 1970s is electrical stimulation. Despite robust evidence for efficacy in the preclinical arena, human trials have mixed results, and this technology is not widely accepted. The purpose of this review is to examine the body of literature supporting electrical stimulation for the purpose of fracture healing in humans with an emphasis on device specifications and stimulation protocols and delineate a minimum reporting checklist for future studies of this type. We have isolated 12 studies that pertain to the administration of electrical stimulation for the purpose of augmenting fracture healing in humans. Of these, one was a direct current electrical stimulation study. Six studies utilized pulsed electromagnetic field therapy and five used capacitive coupling. When examining these studies, the device specifications were heterogenous and often incomplete in what they reported, which rendered studies unrepeatable. The stimulation protocols also varied greatly study to study. To demonstrate efficacy of electrical stimulation for fractures, the authors recommend isolating a fracture type that is prone to nonunion to maximize the electrical stimulation effect, a homogenous study population so as to not dilute the effect of electrical stimulation, and increasing scientific rigor in the form of pre-registration, blinding, and sham controls. Finally, we introduce the critical components of minimum device specification reporting for repeatability of studies of this type.

Comparative effects of systemic administration of levofloxacin and cephalexin on fracture healing in rats

Objectives

This study aimed to compare the effects of systemic administration of levofloxacin or cephalexin on fracture healing in rats.

Materials and Methods

In this animal study, tibial fractures not requiring fixation were artificially induced in 30 male Wistar albino rats using a 1.1 mm surgical bur. The rats were randomly divided into 6 groups (n=5). Groups 1 and 2 received daily subcutaneous saline injections. Groups 3 and 4 received subcutaneous injections of 25 mg/kg levofloxacin twice daily. Groups 5 and 6 received daily subcutaneous injections of 20 mg/kg cephalexin. The rats in Groups 1, 3, and 5 were sacrificed after 1 week, while the rats in Groups 2, 4, and 6 were sacrificed after 4 weeks. The score of fracture healing was determined through histological assessment of sections from the fracture site according to Perry and colleagues. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests.

Results

The mean score of fracture healing at 4 weeks was significantly higher than that at 1 week in the saline, levofloxacin, and cephalexin groups (P<0.001). At 1 week, no significant difference was noted among the three groups of saline, levofloxacin, and cephalexin in the mean score of fracture healing (P=0.360). However, this difference was significant at 4 weeks (P=0.018), and the mean score in the saline group was significantly higher compared to that in the levofloxacin group (P=0.015).

Conclusion

It is recommended not to prescribe levofloxacin for more than 1 week after surgical management of bone fractures due to its possible adverse effects on fracture healing.

Six month nonunion tibial diaphysis osteotomy treated with conventional pulsed therapeutic ultrasound: a case report

Background: a large tibial defect significantly increases the chances of nonunion fractures, changes in the quality of life, and pain. Tibial osteotomy with a large gap size is an unfavorable condition to complete healing. Purpose: to describe the treatment of a complex case of a six-month nonunion tibial diaphysis osteotomy using conventional pulsed ultrasound therapy (cput). Case description: a 46-year-old man, 1.65 m tall, weighing 63 kg, and homeless was diagnosed with a nonunion tibial diaphysis fracture and underwent osteotomy of the tibial diaphysis with an opening gap and external fixation with circular rings and thin wires (ilizarov). An interdisciplinaty approach including social work, nutrition, and physiotherapy including exercise reconditioning was initiated over a period of two years. After six months of nonunion following a tibial osteotomy, cput was used with a frequency of 1 mhz, duty cycle of 20%, spatially averaged temporally averaged (sata) intensity of 0.1 w/cm², frequency of 100 hz, 20 min of duration, for 2-3 times for 20 weeks. Outcomes: there was an improvement in the amount of bone in the fracture gap with a total restoration of function, resolution of pain, and gait without crutches after 35 sessions of cput. Conclusion: an interdisciplinary approach including mechanical stimulus from cput assisted in the healing process in a patient with chronic tibial osteotomy nonunion.

Therapeutic application of light and electromagnetic fields to reduce hyper-inflammation triggered by COVID-19

COVID-19 - related morbidity is associated with exaggerated inflammation and cytokine production in the lungs, leading to acute respiratory failure. The cellular mechanisms underlying these so-called 'cytokine storms' are regulated through the Toll-like receptor 4 (TLR4) signaling pathway and by ROS (Reactive Oxygen Species). Both light (Photobiomodulation) and magnetic fields (e.g., Pulsed Electro Magnetic Field) stimulation are noninvasive therapies known to confer anti-inflammatory effects and regulate ROS signaling pathways. Here we show that daily exposure to two 10-minute intervals of moderate intensity infra-red light significantly lowered the inflammatory response induced via the TLR4 receptor signaling pathway in human cell cultures. Anti-inflammatory effects were likewise achieved by electromagnetic field exposure of cells to daily 10-minute intervals of either Pulsed Electromagnetic Fields (PEMF), or to Low-Level static magnetic fields. Because current illumination and electromagnetic field therapies have no known side effects, and are already approved for some medical uses, we have here developed protocols for verification in clinical trials of COVID-19 infection. These treatments are affordable, simple to implement, and may help to resolve the acute respiratory distress of COVID-19 patients both in the home and in the hospital.

Therapeutic Nuclear Magnetic Resonance affects the core clock mechanism and associated Hypoxia-inducible factor-1

The influence of low intensity electromagnetic fields on circadian clocks of cells and tissues has gained increasing scientific interest, either as a therapeutic tool or as a potential environmental hazard. Nuclear Magnetic Resonance (NMR) refers to the property of certain atomic nuclei to absorb the energy of radio waves under a corresponding magnetic field. NMR forms the basis for Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy and, in a low-intensity form, for NMR therapy (tNMR). Since the circadian clock is bi-directionally intertwined with hypoxic signaling in vertebrates and mammals, we hypothesized that low intensity electromagnetic fields, such as tNMR, might not only affect circadian clocks but also Hypoxia-Inducible Factor-1α (HIF-1α). As master regulator of the hypoxic signaling pathway, HIF-1α is known to dampen the circadian amplitude under reduced oxygen availability, while the hypoxic response of cells and organisms, itself, is tightly clock controlled. In a first experiment, we investigated if tNMR is able to act as Zeitgeber for the core clock mechanism of unsynchronized zebrafish and mouse fibroblast cells, using direct light irradiation and treatment with the glucocorticoid Dexamethasone as references. tNMR significantly affected the cell autonomous clocks of unsynchronized mouse fibroblast cells NIH3-T3, but did not act as a Zeitgeber. Similar to light irradiation and in contrast to treatment with Dexamethasone, tNMR did not synchronize expression profiles of murine clock genes. However, irradiation with tNMR as well as light significantly altered mRNA and protein expression levels of Cryptochrome1, Cryptochrome2 and Clock1 for more than 24 h. Changes in mRNA and protein after different treatment durations, namely 6 and 12 h, appeared to be nonlinear. A nonlinear dose-response relationship is known as hallmark of electromagnetic field induced effects on biological systems. The most prominent alterations were detected in murine HIF-1α protein, again in a nonlinear dose-response. In contrast to murine cells, zebrafish fibroblasts did not respond to tNMR at all. Light, a potent Zeitgeber for the peripheral clocks of fish, led to the expected synchronized clock gene oscillations of high amplitude, as did Dexamethasone. Hence, we conclude, mammalian peripheral clocks are more susceptible to tNMR than the direct light entrainable fish fibroblasts. Although light and tNMR did not act as Zeitgebers for the circadian clocks of unsynchronized murine cells, the significant observed effects might indicate downstream cell-physiological ramifications, which are worth future investigation. However, beside the effects tNMR exerts on the core clock mechanism of mammalian cells, the technology might be the first non-pharmacological approach to modify HIF-1α protein in cells and tissues. HIF-1α and the associated circadian clock play key roles in diseases with underlying ischemic background, such as infarct, stroke, and cancer and, also infectious diseases, such as Covid-19. Hence, low intensity magnetic fields such as tNMR might be of significant medical interest.

HEK293 cell response to static magnetic fields via the radical pair mechanism may explain therapeutic effects of pulsed electromagnetic fields

PEMF (Pulsed Electromagnetic Field) stimulation has been used for therapeutic purposes for over 50 years including in the treatment of memory loss, depression, alleviation of pain, bone and wound healing, and treatment of certain cancers. However, the underlying cellular mechanisms mediating these effects have remained poorly understood. In particular, because magnetic field pulses will induce electric currents in the stimulated tissue, it is unclear whether the observed effects are due to the magnetic or electric component of the stimulation. Recently, it has been shown that PEMFs stimulate the formation of ROS (reactive oxygen species) in human cell cultures by a mechanism that requires cryptochrome, a putative magnetosensor. Here we show by qPCR analysis of ROS-regulated gene expression that simply removing cell cultures from the Earth’s geomagnetic field by placing them in a Low-Level Field condition induces similar effects on ROS signaling as does exposure of cells to PEMF. This effect can be explained by the so-called Radical Pair mechanism, which provides a quantum physical means by which the rates and product yields (e.g. ROS) of biochemical redox reactions may be modulated by magnetic fields. Since transient cancelling of the Earth’s magnetic field can in principle be achieved by PEMF exposure, we propose that the therapeutic effects of PEMFs may be explained by the ensuing modulation of ROS synthesis. Our results could lead to significant improvements in the design and therapeutic applications of PEMF devices.

Extracorporal shock wave therapy for the treatment of arthrodesis non-unions

INTRODUCTION

Non-union is a regular complication of arthrodeses. Standard treatment includes revision surgery with frequent need for re-revision due to persistent non-union. Particularly patients with concomitant diseases are at risk of secondary complications. There is a need for evaluation of alternative treatment options. The aim of this study is to provide first evidence on union-rate and pain course after focussed extracorporeal shock-wave therapy of arthrodesis non-unions.

PATIENTS AND METHODS

In a retrospective single-centre study, 25 patients with non-union following arthrodesis received one session of focussed extracorporeal shock-wave therapy (energy flux density 0.36 mJ/mm², 3000 impulses, 23 kV, 4 Hz). Radiographic and clinical results were recorded 6, 12 and 24 weeks after treatment.

RESULTS

24 patients were followed-up. After 24 weeks arthrodeses of the hand healed in 80%, of the upper ankle in 50%, of subtalar joint in 27.2% and of the midfoot in 0% of the cases. Pain decreased from 4.8 (± 2.8) points on the visual analogue scale to 3.4 (± 2.3), 2.9 (± 2.5) and 2.4 (± 2.8) points after 6, 12 and 24 weeks, respectively (p < 0.0001).

CONCLUSION

Our data indicate that the effect of focussed, high-energy shock wave therapy depends on body region and is effective for the treatment of non-unions of the hand as well as for pain relief.

LEVEL OF EVIDENCE

Level IV.

Smoking Increases Postoperative Complications After Distal Radius Fracture Fixation: A Review of 417 Patients From a Level 1 Trauma Center

Background: Unstable distal radius fractures that undergo surgical stabilization have varying complication rates in the literature. Smoking is known to affect bone healing and implant fixation rates but has never been definitively shown to affect postoperative outcomes of surgically managed distal radius fractures. Methods: A retrospective review was performed of patients with surgically treated distal radius fractures at a Level 1 Trauma Center who had at least 6 weeks of follow-up over a 5-year period. Charts were reviewed for basic demographic information, comorbidities, details about the operative procedure, and early complications. Notable physical examination findings were noted, such as wrist stiffness and distal radius tenderness to palpation. Statistical analysis was performed to compare the smoking and nonsmoking groups. To control for confounding differences, a hierarchical multivariable regression analysis was performed. Results: Four hundred seventeen patients were included in the study, and 24.6% were current smokers at the time of surgery. The overall complication rate for smokers was 9.8% compared with 5.6% in nonsmokers. The smoking cohort showed significantly higher rates of hardware removal, nonunion, revision procedures, wrist stiffness, and distal radius tenderness. When controlling for the confounding variables of diabetes and obesity, smokers still had significantly higher rates of the same complications. Conclusion: Patients who smoke have a statistically significant higher rate of postoperative distal radius tenderness, wrist stiffness, nonunion, hardware removal, and revision procedures compared with those who do not smoke in a review of 417 total patients undergoing surgical fixation for distal radius fractures.

The effect of two phosphodiesterase inhibitors on bone healing in mandibular fractures (animal study in rats)

OBJECTIVES

Despite advances in maxillofacial surgery, impaired bone healing remains a concern for surgical teams. Many studies have evaluated the effects of sildenafil and pentoxifylline on bone healing. However, their effects on healing of bone fractures have not been well investigated. This study aimed to assess the effects of the phosphodiesterase inhibitors sildenafil and pentoxifylline on healing of mandibular fractures in rats.

MATERIALS AND METHODS

A total of 60 rats were randomly divided into six groups of 10. Mandibular fracture was induced in all rats. After the surgical procedure, group C1 received saline, group S1 received 10 mg/kg sildenafil and group P1 received 50 mg/kg pentoxifylline. The rats were sacrificed after 1 week. Groups C4, S4, and P4 received pharmaceutical therapy as in groups C1, S1, and P1 but were sacrificed after 4 weeks. The samples then underwent histological analysis.

RESULTS

The mean rate of bone healing of mandibular fractures in groups S1 and P1 was significantly higher than in group C1 at 1 week (P<0.001). The mean rate of bone healing of mandibular fractures in group P1 was higher than in group S1 at 1 week (P=0.04). The mean rate of bone healing of mandibular fractures in groups S4 (P=0.001) and P4 (P=0.004) was significantly higher than in group C4 at 4 weeks, but no significant difference was noted in the rate of healing between groups P4 and S4 (P=0.53).

CONCLUSION

Sildenafil and pentoxifylline can be used as adjuncts to enhance bone healing in rats.

Electrical stimulation in bone tissue engineering treatments

Electrical stimulation (EStim) has been shown to promote bone healing and regeneration both in animal experiments and clinical treatments. Therefore, incorporating EStim into promising new bone tissue engineering (BTE) therapies is a logical next step. The goal of current BTE research is to develop combinations of cells, scaffolds, and chemical and physical stimuli that optimize treatment outcomes. Recent studies demonstrating EStim's positive osteogenic effects at the cellular and molecular level provide intriguing clues to the underlying mechanisms by which it promotes bone healing. In this review, we discuss results of recent in vitro and in vivo research focused on using EStim to promote bone healing and regeneration and consider possible strategies for its application to improve outcomes in BTE treatments. Technical aspects of exposing cells and tissues to EStim in in vitro and in vivo model systems are also discussed.

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.

Smoking Increases Postoperative Complications After Distal Radius Fracture Fixation: A Review of 417 Patients From a Level 1 Trauma Center

Background: Unstable distal radius fractures that undergo surgical stabilization have varying complication rates in the literature. Smoking is known to affect bone healing and implant fixation rates but has never been definitively shown to affect postoperative outcomes of surgically managed distal radius fractures. Methods: A retrospective review was performed of patients with surgically treated distal radius fractures at a Level 1 Trauma Center who had at least 6 weeks of follow-up over a 5-year period. Charts were reviewed for basic demographic information, comorbidities, details about the operative procedure, and early complications. Notable physical examination findings were noted, such as wrist stiffness and distal radius tenderness to palpation. Statistical analysis was performed to compare the smoking and nonsmoking groups. To control for confounding differences, a hierarchical multivariable regression analysis was performed. Results: Four hundred seventeen patients were included in the study, and 24.6% were current smokers at the time of surgery. The overall complication rate for smokers was 9.8% compared with 5.6% in nonsmokers. The smoking cohort showed significantly higher rates of hardware removal, nonunion, revision procedures, wrist stiffness, and distal radius tenderness. When controlling for the confounding variables of diabetes and obesity, smokers still had significantly higher rates of the same complications. Conclusion: Patients who smoke have a statistically significant higher rate of postoperative distal radius tenderness, wrist stiffness, nonunion, hardware removal, and revision procedures compared with those who do not smoke in a review of 417 total patients undergoing surgical fixation for distal radius fractures.

Low-intensity electromagnetic fields induce human cryptochrome to modulate intracellular reactive oxygen species

Exposure to man-made electromagnetic fields (EMFs), which increasingly pollute our environment, have consequences for human health about which there is continuing ignorance and debate. Whereas there is considerable ongoing concern about their harmful effects, magnetic fields are at the same time being applied as therapeutic tools in regenerative medicine, oncology, orthopedics, and neurology. This paradox cannot be resolved until the cellular mechanisms underlying such effects are identified. Here, we show by biochemical and imaging experiments that exposure of mammalian cells to weak pulsed electromagnetic fields (PEMFs) stimulates rapid accumulation of reactive oxygen species (ROS), a potentially toxic metabolite with multiple roles in stress response and cellular ageing. Following exposure to PEMF, cell growth is slowed, and ROS-responsive genes are induced. These effects require the presence of cryptochrome, a putative magnetosensor that synthesizes ROS. We conclude that modulation of intracellular ROS via cryptochromes represents a general response to weak EMFs, which can account for either therapeutic or pathological effects depending on exposure. Clinically, our findings provide a rationale to optimize low field magnetic stimulation for novel therapeutic applications while warning against the possibility of harmful synergistic effects with environmental agents that further increase intracellular ROS.

Repetitive low-intensity magnetic stimulation has been used in the treatment of disease for over 50 years. Associated benefits have included alleviation of depression, memory loss, and symptoms of Parkinson disease, as well as accelerated bone and wound healing and the treatment of certain cancers, independently of surgery or drugs. However, the cellular mechanisms underlying these effects remain unclear. Here, we demonstrate that repetitive magnetic field exposure in human cells stimulates production of biological stress response chemicals known as reactive oxygen species (ROS). At moderate doses, we find that reactive oxygen actively stimulates cellular repair and stress response pathways, which might account for the observed therapeutic effects to repetitive magnetic stimulation. We further show that this response requires the function of a well-characterized, evolutionarily conserved flavoprotein receptor known as cryptochrome, which has been implicated in magnetic sensing in organisms ranging from plants to flies, including migratory birds. We conclude that exposure to weak magnetic fields induces the production of ROS in human cells and that this process requires the presence of the cryptochrome receptor.

Staged Treatment of Infected Tibiotalar Fusion Using a Combination Antibiotic Spacer and Antibiotic-Coated Intramedullary Nail

Pilon fractures are notoriously difficult injuries to treat. The current published data on salvage procedures after failed pilon fractures includes both total ankle arthroplasty (TAA) and tibiotalar fusion, each with its own specific indications. However, no acceptable treatment algorithm addressing the complications of these limb salvage procedures is available. We present the case of a 23-year-old patient, who sustained a complex pilon fracture after a motor vehicle accident. The patient was referred to our institution after an initial fixation attempt, followed by subsequent failed TAA, which was complicated by an infected fusion attempt. We describe a staged treatment approach to clearing the infection and obtaining the final fusion goals.

Combined treatment with electrical stimulation and insulin-like growth factor-1 promotes bone regeneration in vitro

Electrical stimulation (ES) and insulin-like growth factor-1 (IGF-1) are widely used in bone regeneration because of their osteogenic activity. However, the combined effects of ES and supplemental IGF-1 on the whole bone formation process remain unclear. In this study, fluorescence staining and an MTT assay were first utilized to observe the influence of ES and IGF-1 on MC3T3-E1 cell proliferation and adhesion in vitro. Subsequently, osteogenic differentiation was evaluated by the alkaline phosphatase activity (ALP) and the expression of osteogenic marker genes. In addition, cell mineralization was determined by alizarin red staining and scanning electron microscopy (SEM). We demonstrated that the MC3T3-E1 cell proliferation was significantly higher for treatments combining IGF-1 and ES than for treatments with IGF-1 alone. The combination of IGF-1 and ES increased the MC3T3-E1 cell ALP activity, the expression of osteogenesis-related genes and the calcium deposition with a clear dose-dependent effect. Our data show the synergistic effect of IGF-1 and ES in promoting the proliferation, differentiation and mineralization of MC3T3-E1 cells, which suggests that it would be more effective to combine the proper dose of IGF-1 with ES to promote local bone damage repair and regeneration.

Static magnetic fields promote osteoblastic/cementoblastic differentiation in osteoblasts, cementoblasts, and periodontal ligament cells

Purpose

Although static magnetic fields (SMFs) have been used in dental prostheses and osseointegrated implants, their biological effects on osteoblastic and cementoblastic differentiation in cells involved in periodontal regeneration remain unknown. This study was undertaken to investigate the effects of SMFs (15 mT) on the osteoblastic and cementoblastic differentiation of human osteoblasts, periodontal ligament cells (PDLCs), and cementoblasts, and to explore the possible mechanisms underlying these effects.

Methods

Differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, mineralized nodule formation based on Alizarin red staining, calcium content, and the expression of marker mRNAs assessed by reverse transcription polymerase chain reaction (RT-PCR). Signaling pathways were analyzed by western blotting and immunocytochemistry.

Results

The activities of the early marker ALP and the late markers matrix mineralization and calcium content, as well as osteoblast- and cementoblast-specific gene expression in osteoblasts, PDLCs, and cementoblasts were enhanced. SMFs upregulated the expression of Wnt proteins, and increased the phosphorylation of glycogen synthase kinase-3β (GSK-3β) and total β-catenin protein expression. Furthermore, p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB) pathways were activated.

Conclusions

SMF treatment enhanced osteoblastic and/or cementoblastic differentiation in osteoblasts, cementoblasts, and PDLCs. These findings provide a molecular basis for the beneficial osteogenic and/or cementogenic effect of SMFs, which could have potential in stimulating bone or cementum formation during bone regeneration and in patients with periodontal disease.

The effects of low-intensity pulsed ultrasound on fresh fracture: A meta-analysis

BACKGROUND

Low-intensity pulsed ultrasonography (LIPUS) is a form of mechanical stimulation that is delivered via a special device to the fracture site for the acceleration of fracture healing. We conducted a meta-analysis to assess the effect of LIPUS for fresh fractures in adults.

METHODS

MEDLINE, EMBASE and the Cochrane Library searched between Jan 1980 and Nov 2016. Studies should be quasi-randomized and randomized controlled trials (RCTs) comparing treatment with LIPUS to placebo or no treatment in adults with fresh fractures, reporting outcomes such as function; time to union; delayed union or non-union. Summary standard mean difference (SMD) and the risk ratio (RR) with their 95% confidence interval (CI) calculated with a random effects model. I statistic was used to assess the heterogeneity. Risk of bias was assessed by the Cochrane risk-of-bias tool. The GRADE system was used to evaluate the evidence quality.

RESULTS

A total of 12 trials with 1099 patients were included. The pooled results showed that LIPUS significantly reduced the time to fracture union (SMD: 0.65, 95% CI: 1.13 to 0.17), improved the quality of life (SMD: 0.20, 95% CI: 0.03-0.37) without affecting the time to full weight bearing (SMD: 0.76, 95% CI: 1.92 to 0.4), the time to return to work (SMD: 0.06, 95% CI: 0.14 to 0.27), or the incidence rate of delayed union and nonunion (RR: 1.02, 95% CI: 0.60-1.74).

CONCLUSIONS

Moderate-to-high quality evidence shows that LIPUS treatment reduces the time to fracture union and improves the quality of life without affecting functional recovery and incident rate of delayed union and nonunion, suggesting that LIPUS treatment may be a good treatment modality for adults with fresh fractures. However, there are some methodological limitations in the eligible trials, further studies are needed to determine the clinical circumstances under which LIPUS is truly valid and to examine the optimal approach for the use of this adjunctive therapy.

American College of Foot and Ankle Surgeons® Clinical Consensus Statement: Perioperative Management

A wide range of factors contribute to the complexity of the management plan for an individual patient, and it is the surgeon's responsibility to consider the clinical variables and to guide the patient through the perioperative period. In an effort to address a number of important variables, the American College of Foot and Ankle Surgeons convened a panel of experts to derive a clinical consensus statement to address selected issues associated with the perioperative management of foot and ankle surgical patients.

Efficacy of Electrical Stimulators for Bone Healing: A Meta-Analysis of Randomized Sham-Controlled Trials

Electrical stimulation is a common adjunct used to promote bone healing; its efficacy, however, remains uncertain. We conducted a meta-analysis of randomized sham-controlled trials to establish the efficacy of electrical stimulation for bone healing. We identified all trials randomizing patients to electrical or sham stimulation for bone healing. Outcomes were pain relief, functional improvement, and radiographic nonunion. Two reviewers assessed eligibility and risk of bias, performed data extraction, and rated the quality of the evidence. Fifteen trials met our inclusion criteria. Moderate quality evidence from 4 trials found that stimulation produced a significant improvement in pain (mean difference (MD) on 100-millimeter visual analogue scale = -7.7 mm; 95% CI -13.92 to -1.43; p = 0.02). Two trials found no difference in functional outcome (MD = -0.88; 95% CI -6.63 to 4.87; p = 0.76). Moderate quality evidence from 15 trials found that stimulation reduced radiographic nonunion rates by 35% (95% CI 19% to 47%; number needed to treat = 7; p < 0.01). Patients treated with electrical stimulation as an adjunct for bone healing have less pain and are at reduced risk for radiographic nonunion; functional outcome data are limited and requires increased focus in future trials.

Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a) a bone growth factor; (b) an antibiotic for prophylactic or anti-infective purposes; (c) a bisphosphonate as an antiresorptive compound; (d) a viral vector to enable the intracellular delivery of therapeutics; (e) a luminescent dye; (f) a radiographic component; (g) an imaging contrast agent; (h) a magnetic domain; and (i) polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a) produce tunable drug release profiles; (b) take the form of viscous and injectable, self-setting pastes; (c) be naturally osteo-inductive and inhibitory for osteoclastogenesis; (d) intracellularly deliver bioactive compounds; (e) accommodate an array of functional ions; (f) be processed into macroporous constructs for tissue engineering; and (g) be naturally antimicrobial. All in all, we see in calcium phosphates the presence of a protean nature whose therapeutic potentials have been barely tapped into.

Effects of static magnetic fields on bone regeneration of implants in the rabbit: micro-CT, histologic, microarray, and real-time PCR analyses

OBJECTIVES

The aim of this study was to investigate the effects of static magnetic fields (SMFs) on bone regeneration around titanium implants by μCT, histologic analysis, microarrays, and quantitative real-time PCR (qRT-PCR).

MATERIALS AND METHODS

Neodymium magnets provided the source of SMFs, the specimens were grade 5 titanium implants, and the animals were twenty-seven adult male New Zealand white rabbits. These implants were divided into six groups according to the presence of a magnet and predetermined healing period (1, 4, and 8 weeks). Each group comprised six specimens for μCT (n = 6) and histologic examination, and three specimens (n = 3) for microarrays and qRT-PCR, yielding a total of 54 specimens.

RESULTS

The μCT data showed that SMFs increased bone volume fraction (bone volume/total volume, BV/TV), trabecular number (Tb.N), and trabecular thickness (Tb.Th). Histologic observation indicated that SMFs promoted new bone formation and direct bony contact with implants. Microarray analysis identified 293 genes upregulated (>twofold) in response to SMFs. The upregulated genes included extracellular matrix (ECM)-related genes (COL10A1, COL9A1, and COL12A1) and growth factor (GF)-related genes (CTGF and PDGFD), and the upregulation was confirmed by qRT-PCR. Gene Ontology (GO) and pathway analysis revealed the involvement of the mitogen-activated protein kinase (MAPK), Wnt, and PPAR-gamma signaling pathways in implant healing.

CONCLUSIONS

μCT, histology, microarrays, and real-time PCR indicate that SMFs could be an effective approach to improving bone regeneration around dental implants.

Pentoxifylline and electromagnetic field improved bone fracture healing in rats

Background

The aim of this study was to evaluate the effects of a phosphodiesterase inhibitor pentoxifylline (PTX), electromagnetic fields (EMFs), and a mixture of both materials on bone fracture healing in a rat model.

Materials and methods

Eighty male Wistar rats were randomly divided into four groups: Group A, femur fracture model with no treatment; Group B, femur fracture model treated with PTX 50 mg/kg/day intraperitoneal injection; Group C, femur fracture model treated with EMF 1.5±0.2 Mt/50 Hz/6 hours/day; and Group D, femur fracture model treated with PTX 50 mg/kg/day intraperitoneal injection and EMF 1.5±0.2 Mt/50 Hz/6 hours/day.

Results

Bone fracture healing was significantly better in Group B and Group C compared to Group A (P<0.05), but Group D did not show better bone fracture healing than Group A (P>0.05).

Conclusion

It can be concluded that both a specific EMF and PTX had a positive effect on bone fracture healing but when used in combination, may not be beneficial.