A cohort study of 4,190 patients treated with low-intensity pulsed ultrasound (LIPUS): findings in the elderly versus all patients

Latest Progress of LIPUS in Fracture Healing: A Mini-Review

The use of low-intensity pulsed ultrasound (LIPUS) for promoting fracture healing has been Food and Drug Administration (FDA)-approved since 1994 due to largely its non-thermal effects of sound flow sound radiation force and so on. Numerous clinical and animal studies have shown that LIPUS can accelerate the healing of fresh fractures, nonunions, and delayed unions in pulse mode regardless of LIPUS devices or circumstantial factors. Rare clinical studies show limitations of LIPUS for treating fractures with intramedullary nail fixation or low patient compliance. The biological effect is achieved by regulating various cellular behaviors involving mesenchymal stem/stromal cells (MSCs), osteoblasts, chondrocytes, and osteoclasts and with dose dependency on LIPUS intensity and time. Specifically, LIPUS promotes the osteogenic differentiation of MSCs through the ROCK-Cot/Tpl2-MEK-ERK signaling. Osteoblasts, in turn, respond to the mechanical signal of LIPUS through integrin, angiotensin type 1 (AT1), and PIEZO1 mechano-receptors, leading to the production of inflammatory factors such as COX-2, MCP-1, and MIP-1β fracture repair. LIPUS also induces CCN2 expression in chondrocytes thereby coordinating bone regeneration. Finally, LIPUS suppresses osteoclast differentiation and gene expression by interfering with the ERK/c-Fos/NFATc1 cascade. This mini-review revisits the known effects and mechanisms of LIPUS on bone fracture healing and strengthens the need for further investigation into the underlying mechanisms.

The potential role of mechanotransduction in the management of pediatric calvarial bone flap repair

Pediatric patients suffering traumatic brain injuries may require a decompressive craniectomy to accommodate brain swelling by removing a portion of the skull. Once the brain swelling subsides, the preserved calvarial bone flap is ideally replaced as an autograft during a cranioplasty to restore protection of the brain, as it can reintegrate and grow with the patient during immature skeletal development. However, pediatric patients exhibit a high prevalence of calvarial bone flap resorption post-cranioplasty, causing functional and cosmetic morbidity. This review examines possible solutions for mitigating pediatric calvarial bone flap resorption by delineating methods of stimulating mechanosensitive cell populations with mechanical forces. Mechanotransduction plays a critical role in three main cell types involved with calvarial bone repair, including mesenchymal stem cells, osteoblasts, and dural cells, through mechanisms that could be exploited to promote osteogenesis. In particular, physiologically relevant mechanical forces, including substrate deformation, external forces, and ultrasound, can be used as tools to stimulate bone repair in both in vitro and in vivo systems. Ultimately, combating pediatric calvarial flap resorption may require a combinatorial approach using both cell therapy and bioengineering strategies.

Pulsed frequency modulated ultrasound promotes therapeutic effects of osteoporosis induced by ovarian failure in mice

Low-intensity pulsed ultrasound (LIPUS) has been proved to be an effective technique for the treatment of osteoporosis. To better activate the bone formation-related markers, promote the different stages of osteogenesis, and further enhance the therapeutic effects of ultrasound, this study employed pulsed frequency modulated ultrasound (pFMUS) to treat mice with osteoporosis, which was caused by ovarian failure due to 4-vinylcyclohexene dioxide (VCD) injection. Healthy 8-week-old female C57BL/6J mice were randomly divided into four groups: Sham (S), VCD-control (V), VCD + LIPUS (VU), and VCD + pFMUS (VFU). VU and VFU groups were treated by LIPUS and pFMUS, respectively. Serum analysis, micro-computed tomography (micro-CT), mechanical testing and hematoxylin and eosin (HE) staining were performed to evaluate the therapeutic effects of ultrasound. Quantitative reverse-transcription PCR (qRT-PCR) and western blot analysis were used to explore the mechanism of ultrasound on osteoporosis. Results showed that pFMUS might have better therapeutic effects than traditional LIPUS in terms of bone microstructure and bone strength. In addition, pFMUS could promote bone formation by activating phosphoinositide-3 kinase/protein kinase B (PI3K/Akt) pathway, and slow down bone resorption by increasing osteoprotegerin/receptor activator of nuclear factor κB ligand (OPG/RANKL) ratio. This study is of positive prognostic significance when understanding the mechanism of ultrasound regulation on osteoporosis and establishing novel treatment plan of osteoporosis by multi-frequency ultrasound.

Efficacy of low-intensity pulsed ultrasound for the treatment of viral pneumonia: study protocol for a randomized controlled trial

BACKGROUND

Viral pneumonia has always been a problem faced by clinicians because of its insidious onset, strong infectivity, and lack of effective drugs. Patients with advanced age or underlying diseases may experience more severe symptoms and are prone to severe ventilation dysfunction. Reducing pulmonary inflammation and improving clinical symptoms is the focus of current treatment. Low-intensity pulsed ultrasound (LIPUS) can mitigate inflammation and inhibit edema formation. We aimed to investigate the efficacy of therapeutic LIPUS in improving lung inflammation in hospitalized patients with viral pneumonia.

METHODS

Sixty eligible participants with clinically confirmed viral pneumonia will be assigned to either (1) intervention group (LIPUS stimulus), (2) control group (null stimulus), or (3) self-control group (LIPUS stimulated areas versus non-stimulated areas). The primary outcome will be the difference in the extent of absorption and dissipation of lung inflammation on computed tomography. Secondary outcomes include changes in lung inflammation on ultrasonography images, pulmonary function, blood gas analysis, fingertip arterial oxygen saturation, serum inflammatory factor levels, the sputum excretion volume, time to the disappearance of pulmonary rales, pneumonia status score, and course of pneumonia. Adverse events will be recorded.

DISCUSSION

This study is the first clinical study of the efficacy of therapeutic LIPUS in the treatment of viral pneumonia. Given that the current clinical recovery mainly depends on the body's self-limiting and conventional symptomatic treatment, LIPUS, as a new therapy method, might be a major advance in the treatment of viral pneumonia.

TRIAL REGISTRATION

ChiCTR2200059550 Chinese Clinical Trial Registry, May 3, 2022.

Biophysical Enhancement in Fracture Healing: A Review of the Literature

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

Does low-intensity pulsed ultrasound accelerate phasic calcium phosphate ceramic-induced bone formation?

PURPOSE

Low-intensity pulsed ultrasound (LIPUS) has been used to stimulate the healing of the fresh fracture, delayed union, and non-union in both animal and clinical studies. Besides, biphasic calcium phosphate ceramic (BCP) is a promising biomaterial for bone repair as it shows favorable biocompatibility, osteoinduction, and osteoconduction. However, scarcity is known about the combined effect of LIPUS and BCP on bone formation.

METHODS

The combined effect of LIPUS and BCP was studied in a beagle model. Twelve dogs were used. BCP granules without any additions were implanted into bilateral erector spinae muscles. One side is the BCP group, while the counterlateral side is LIPUS + BCP group. Histological and histomorphometric analyses, and quantitative real-time polymerase chain reaction were evaluated.

RESULTS

Compared with BCP alone, the LIPUS + BCP showed no advantages in early bone formation. Furthermore, the Notch signaling pathway-related mRNA has no significant difference between the two groups.

CONCLUSIONS

The preliminary results showed that the BCP, which has intrinsic osteoinduction nature, was an effective and promising material. However, LIPUS has no enhanced effect in BCP induced ectopic bone formation. Furthermore, LIPUS has no effect on the Notch signaling pathway. Whether costly LIPUS could be used in combination with BCP should be a rethink.

LIPUS as a potential strategy for periodontitis treatment: A review of the mechanisms

Periodontitis is a chronic inflammatory condition triggered by oral bacteria. A sustained inflammatory state in periodontitis could eventually destroy the alveolar bone. The key objective of periodontal therapy is to terminate the inflammatory process and reconstruct the periodontal tissues. The traditional Guided tissue regeneration (GTR) procedure has unstable results due to multiple factors such as the inflammatory environment, the immune response caused by the implant, and the operator's technique. Low-intensity pulsed ultrasound (LIPUS), as acoustic energy, transmits the mechanical signals to the target tissue to provide non-invasive physical stimulation. LIPUS has positive effects in promoting bone regeneration, soft-tissue regeneration, inflammation inhibition, and neuromodulation. LIPUS can maintain and regenerate alveolar bone during an inflammatory state by suppressing the expression of inflammatory factors. LIPUS also affects the cellular behavior of periodontal ligament cells (PDLCs), thereby protecting the regenerative potential of bone tissue in an inflammatory state. However, the underlying mechanisms of the LIPUS therapy are still yet to be summarized. The goal of this review is to outline the potential cellular and molecular mechanisms of periodontitis-related LIPUS therapy, as well as to explain how LIPUS manages to transmit mechanical stimulation into the signaling pathway to achieve inflammatory control and periodontal bone regeneration.

Low-Intensity Pulsed Ultrasound Therapy in Patients With Post-traumatic Delayed Union and Non-union

Background Fracture non-union can lead to significant patient morbidity with poor quality of life. Due to the cost, complexity, and potential risks of revision surgery, there has been an increased popularity in the use of low-intensity pulsed ultrasound therapy (LIPUS), which accelerates and promotes bone consolidation. There is an ongoing debate regarding the use and efficacy of LIPUS in delayed union and non-union. This study aims to assess the success rate of LIPUS therapy in patients treated for delayed and non-union fractures, explicitly focusing on the impact of patient co-morbidities and fracture characteristics. Method A retrospective observational study was performed of all consecutive patients who received LIPUS therapy in a single institution from January 2016 to September 2022. Of 127 identified patients, only 99 patients met our inclusion criteria. Data collection entailed reviewing the clinical notes to assess patients' sex, age, co-morbidities, initial treatment method, time to initiate LIPUS, whether a CT was performed to diagnose non-union, time to union and whether revision surgery was needed. Two independent senior orthopedic doctors reviewed the patients' radiographs, measured the interfragmentary bone gap of all fractures, and assessed whether the radiographic union was achieved. Results The mean age of the included patients was 52.5 (SD±16.9) years with a male-to-female ratio of 1:1.6. At initial presentation, 65 (out of 99) patients were treated surgically, whereas the rest were managed conservatively. 80.8% of patients developed atrophic non-union. All 99 included patients were fitted with LIPUS once delayed/ non-union was diagnosed; the average time to fitting was 5.1 (SD±3.9) months. Of these, 61.6% of patients were successfully treated with LIPUS with a clinical and radiological union at an average of 4.3 (SD±1.9) months. The rest of the patients needed further surgical intervention due to ongoing non-union. The interfragmentary bone gap was the only statistically significant factor influencing the success of LIPUS therapy (p=0.003). In contrast, no statistically significant association was identified between the outcome of LIPUS therapy and the patient's age, sex, diabetes, and smoking status. Conclusion This study demonstrated a 61.6% progression to union rate of patients treated with LIPUS therapy for delayed union and non-union. The interfragmentary bone gap was identified as the only statistically significant factor influencing the success of LIPUS therapy. In the current climate post-lockdown and with ongoing Covid 19 outbreaks impacting elective waiting lists negatively, there is increased value and demand for non-surgical treatment options. LIPUS therapy represents an important complementary non-surgical and low-risk treatment pathway for delayed union and non-union.

A Retrospective Study: Is Low-Intensity Pulsed Ultrasound (LIPUS) an Effective Alternate Treatment Option for Non-union?

Background

There is ongoing controversy regarding the use of low-intensity pulsed ultrasound (LIPUS) therapy in patients with delayed union or non-union. Exogen (Bioventus, Durham, NC) is a well-known brand of LIPUS, and according to their data, 86% of non-union fractures will heal without the need for surgery. A few independent retrospective studies reported much lower healing rates.

Method

A retrospective observational study was performed assessing all the patients who underwent Exogen therapy in a single centre. All patients who were initiated on Exogen after three months with radiographic signs of the delayed union were included in the study. Routine follow-up appointments were organised until clinical and radiological healing could be confirmed. Daily 20-minute Exogen sessions were continued until the fracture was healed or up to a maximum of four months as recommended by the manufacturer.

Results

A total of 37 patients received Exogen therapy from 2012 to 2021, of which only 28 patients met our inclusion criteria and were subsequently analysed. The mean age of the patients was 52.0 (SD ± 20.2) with a male to female ratio of 1.7:1. The average time to healing was 115 (±51.2) days with a success rate of 82.14%. The average interfragmentary gap was 7.5 mm (±5.8) for the fractures that healed whereas the failed treatment was 16.1 mm (±13.8). There was no obvious association between outcomes after Exogen therapy and the patient’s age, sex, time to initiate Exogen, diabetes, and smoking status.

Conclusion

This study demonstrated a high success rate of LIPUS therapy for patients with delayed union and non-union. LIPUS represents a safe, non-invasive alternative to revision surgery. An independent risk factor for a potentially poor outcome is an increased interfragmentary gap.

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

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

Low-intensity pulsed ultrasound (LIPUS) for stimulation of bone healing - A narrative review

The use of low intensity pulsed ultrasound (LIPUS) to accelerate the fracture repair process in humans was first reported by Xavier & Duarte in 1983 [1]. This success led to clinical trials and the 1994 approval of LIPUS in the United States for the accelerated healing of certain fresh fractures. LIPUS was approved in the US for the treatment of established non-unions in 2000, and is also approved around the world. In this article, we present relevant literature on the effect of LIPUS on bone healing in patients with acute fractures and non-unions and provide a molecular explanation for the effects of LIPUS on bone healing. Data on LIPUS accelerated fracture repair is controversial with many controlled studies showing a positive effect. However, the largest trial in acute tibial fractures stabilized with an intramedullary nail failed to show significant differences in accelerated healing and in functional outcomes. Uncontrolled data from prospective case series suggest a positive effect of LIPUS in non united fractures with healing rates of around 85%. Evaluation of results from studies, both positive and negative, has enabled an understanding that the patient population with potentially the greatest benefit from receiving LIPUS are those at-risk for fracture healing, e.g. diabetic & elderly patients. The elucidation of a pathway to activate the Rac-1 pathway by LIPUS might explain this beneficial effect. Overall, there is a strong need for further clinical trials, particularly for acute fractures at risk of progressing to non-union and in established non-unions including a comparison to the current standard of care.

Longitudinal effects of low-intensity pulsed ultrasound on osteoporosis and osteoporotic bone defect in ovariectomized rats

Low-intensity pulsed ultrasound (LIPUS) with an intensity (spatial average temporal average, I_SATA) of 30 mW/cm² has been widely proved to be effective on impaired bone healing, but showing little effectiveness in the treatment of osteoporosis. We hypothesized that the intensity of LIPUS may be a key factor in explaining this difference, thus two intensity levels, the widely used 30 mW/cm² and a higher 150 mW/cm², were used to simultaneously treat osteoporosis and osteoporotic bone defect in ovariectomized (OVX) rats with a 1-mm drill hole on their left femurs.Results showed that 150 mW/cm² LIPUS augmented the healing rate of the drill hole than 30 mW/cm² after 3-week LIPUS treatment, although did not further enhance the healing rate after 6-week LIPUS treatment. For ameliorating osteoporosis, 150 mW/cm² LIPUS achieved more advantages over 30 mW/cm² in improving bone density, microstructure and biomechanics 6 weeks after LIPUS intervention. In conclusion, LIPUS with an intensity of 30 mW/cm² was sufficient to facilitate bone defect healing, but a higher intensity can be considered as a rapid trigger for osteoporotic bone repair. In addition, improving the intensity of LIPUS may be a potentially effective consideration for alleviation of osteoporosis, and the LIPUS regimen in the treatment of osteoporosis remains to be optimized.

The use of low intensity pulsed ultrasound in the foot and ankle

Low intensity pulsed ultrasound (LIPUS) therapy has demonstrated clinical effectiveness in achieving union in a variety of fracture situations.Few studies have investigated the effectiveness of LIPUS therapy in foot and ankle surgery.The overall rate of union in all published studies relating to the use of LIPUS in a variety of foot and ankle fracture and fusion situations is 95%.Some studies suggest lower healing rates (~ 67%) when LIPUS therapy is used to treat hindfoot fusion nonunion.A well-powered, high-quality, randomized controlled trial is needed to demonstrate the clinical and cost effectiveness of LIPUS therapy in foot and ankle surgery. Cite this article: EFORT Open Rev 2021;6:217-224. DOI: 10.1302/2058-5241.6.200045.

Evaluation and management of atypical femoral fractures: an update of current knowledge

Atypical femoral fractures are often attributed to the use of anti-resorptive medications such as bisphosphonates (BP). Whilst they have proven effects on fragility fracture prevention, clinical and laboratory evidence is evolving linking BP-related suppression of bone remodelling to the development of atypical stress-related sub-trochanteric fractures (Shane et al. in JBMR 29:1-23, 2014; Odvina et al. in JCEM 90:1294-301, 2005; Durchschlag et al. in JBMR 21(10):1581-1590, 2006; Donnelly et al. in JBMR 27:672-678, 2012; Mashiba et al. in Bone 28(5):524-531, 2001; Dell et al. in JBMR 27(12):2544-2550, 2012; Black et al. in Lancet 348:1535-1541, 1996; Black et al. in NEJM 356:1809-1822, 2007; Black et al. in JAMA 296:2927-2938, 2006; Schwartz et al. in JBMR 25:976-82, 2010). Injuries may present asymptomatically or with prodromal thigh pain and most can be successfully managed with cephalomedullary nailing and discontinuation of BP therapy. Such injuries exhibit a prolonged time to fracture union with high rates of non-union and metal-work failure when compared to typical subtrochanteric osteoporotic femoral fractures. Despite emerging literature on AFFs, their management continues to pose a challenge to the orthopaedic and extended multi-disciplinary team. The purpose of this review includes evaluation of the current evidence supporting the management of AFFs, clinical and radiological features associated with their presentation and a review of reported surgical strategies to treat and prevent these devastating injures.

Application of low-intensity pulsed therapeutic ultrasound on mesenchymal precursors does not affect their cell properties

Ultrasound is considered a safe and non-invasive tool in regenerative medicine and has been used in the clinic for more than twenty years for applications in bone healing after the approval of the Exogen device, also known as low-intensity pulsed ultrasound (LIPUS). Beyond its effects on bone health, LIPUS has also been investigated for wound healing of soft tissues, with positive results for various cell processes including cell proliferation, migration and angiogenesis. As LIPUS has the potential to treat chronic skin wounds, we sought to evaluate the effects produced by a conventional therapeutic ultrasound device at low intensities (also considered LIPUS) on the migration capacity of mouse and human skin mesenchymal precursors (s-MPs). Cells were stimulated for 3 days (20 minutes per day) using a traditional ultrasound device with the following parameters: 100 mW/cm2 with 20% duty cycle and frequency of 3 MHz. At the parameters used, ultrasound failed to affect s-MP proliferation, with no evident changes in morphology or cell groupings, and no changes at the cytoskeletal level. Further, the migration and invasion ability of s-MPs were unaffected by the ultrasound protocol, and no major changes were detected in the gene/protein expression of ROCK1, integrin β1, laminin β1, type I collagen and transforming growth factor β1. Finally, RNA-seq analysis revealed that only 10 genes were differentially expressed after ultrasound stimulation. Among them, 5 encode for small nuclear RNAs and 2 encode for proteins belonging to the nuclear pore complex. Considering the results overall, while the viability of s-MPs was not affected by ultrasound stimulation and no changes were detected in proliferation/migration, RNA-seq analysis would suggest that s-MPs do respond to ultrasound. The use of 100 mW/cm2 intensity or conventional therapeutic ultrasound devices might not be optimal for the stimulation the properties of cell populations. Future studies should investigate the potential application of ultrasound using variations of the tested parameters.

Can low intensity pulsed ultrasound (LIPUS) be used as an alternative to revision surgery for patients with non-unions following fracture fixation?

BACKGROUND

Non-union is a significant complication of fracture fixation surgery, and can negatively impact a patient's quality of life. Low intensity pulsed ultrasound (LIPUS) has been used to treat delayed or non-unions previously in the literature. The aim of this study was to determine the success rate of LIPUS treatment in patients with chronic fracture non-unions, and to establish the effect of systemic or local factors on its success.

METHODS

This was a retrospective, observational study which included all patients undergoing LIPUS treatment in a single institution. Patients deemed suitable for LIPUS underwent treatment for a period of 6 months from initiation. They were followed up with sequential radiographs to assess union at intervals of 6 weeks, 3 months, 6 months and 1 year. LIPUS treatment was considered to be successful when patients achieved clinical and radiological union, without the need for revision surgery.

RESULTS

A total of 46 patients were included in the study; 8 were lost to follow - up, leaving 38 patients for the final analysis. The mean age of patients was 47.03 ± 19.7 with a male to female ratio of 1.2:1. Union was achieved in 57.89%; the rest underwent revision surgery. There was no significant association between outcomes after LIPUS treatment and patients' age, gender, smoking status or type of non-union. Patients with a small inter-fragment bone gap were more likely to have a successful outcome after LIPUS (p = 0.041). Time to treatment did not have a statistically significant impact on outcomes after LIPUS. Interestingly, all 6 patients with diabetes in the study managed to achieve union after LIPUS.

CONCLUSIONS

This study demonstrates that LIPUS is not successful in a large proportion of patients with established fracture non-unions. However, it does represent a low risk treatment modality as an alternative to revision surgery, especially for patients with diabetes who have a small inter - fragment bone gap. More research in the form of large randomised controlled trials needs to be carried out to further assess the role of LIPUS in the treatment of non-unions.

The effect of low intensity pulsed ultrasound on dentoalveolar structures during orthodontic force application in diabetic ex-vivo model

OBJECTIVE

This study aimed to investigate the effect of the low intensity pulsed ultrasound (LIPUS) on the dentoalveolar structures during orthodontic force application in ex-vivo model using mandible slice organ culture (MSOC) of diabetic rats.

DESIGN

18 male Wistar rats with a mean weight (275 g) were randomly divided into three main groups: 1) normal rats, 2) Insulin treated diabetic rats, and 3) diabetic rats. Diabetes mellitus (DM) was induced by streptozotocin. Four weeks later, rats were euthanized, mandibles were dissected, divided into 1.5-mm slices creating mandible slice organ cultures (MSOCs). MSOCs were cultured at 37 °C in air with 5 % CO₂. The following day, orthodontic spring delivering a 50-g of force was applied to each slice. In each group, rats were randomly assigned to 2 subgroups; one received 10 min of LIPUS daily and the other was the control. Culture continued for 7 days, and then the sections were prepared for histological and histomorphometric analysis.

RESULTS

For all study groups (Normal, Insulin Treated Diabetic and Diabetic), LIPUS treatment significantly increased the thickness of predentin, cementum, and improved bone remodeling on the tension side and increased odontoblast, sub-odontoblast, and periodontal ligaments cell counts and bone resorption lacunae number on the compression side.

CONCLUSIONS

Application of LIPUS treatment for 10 min daily for a week enhanced bone remodeling and repair of cementum and dentin in normal as well as diabetic MSOCs.

Impact of COVID-19 on orthopaedic care: a call for nonoperative management

BACKGROUND

Surgical specialties face unique challenges caused by SARS-COV-2 (COVID-19). These disruptions will call on clinicians to have greater consideration for non-operative treatment options to help manage patient symptoms and provide therapeutic care in lieu of the traditional surgical management course of action. This study aimed to summarize the current guidance on elective surgery during the COVID-19 pandemic, assess how this guidance may impact orthopaedic care, and review any recommendations for non-operative management in light of elective surgery disruptions.

METHODS

A systematic search was conducted, and included guidance were categorized as either "Selective Postponement" or "Complete Postponement" of elective surgery. Selective postponement was considered as guidance that suggested elective cases should be evaluated on a case-by-case basis, whereas complete postponement suggested that all elective procedures be postponed until after the pandemic, with no case-by-case consideration. In addition, any statements regarding conservative/non-operative management were summarized when provided by included reports.

RESULTS

A total of 11 reports from nine different health organizations were included in this review. There were seven (63.6%) guidance reports that suggested a complete postponement of non-elective surgical procedures, whereas four (36.4%) reports suggested the use of selective postponement of these procedures. The guidance trends shifted from selective to complete elective surgery postponement occurred throughout the month of March. The general guidance provided by these reports was to have an increased consideration for non-operative treatment options whenever possible and safe. As elective surgery begins to re-open, non-operative management will play a key role in managing the surgical backlog caused by the elective surgery shutdown.

CONCLUSION

Global guidance from major medical associations are in agreement that elective surgical procedures require postponement in order to minimize the risk of COVID-19 spread, as well as increase available hospital resources for managing the influx of COVID-19 patients. It is imperative that clinicians and patients consider non-operative, conservative treatment options in order to manage conditions and symptoms until surgical management options become available again, and to manage the increased surgical waitlists caused by the elective surgery shutdowns.

Therapeutic Effects of Low-Intensity Pulsed Ultrasound on Osteoporosis in Ovariectomized Rats: Intensity-Dependent Study

This study investigated the effects of low-intensity pulsed ultrasound (LIPUS) of different spatial-average-temporal-average intensity (I_SATA) ranging from 15-150 mW/cm² on the treatment of osteoporosis in ovariectomized rats. Healthy 3-mo-old female Sprague-Dawley rats were randomly divided into nine groups (n = 12 per group): sham-ovariectomy (OVX) control group, OVX control group and OVX groups treated with LIPUS at seven different intensities (I_SATA: 15, 30, 50, 75, 100, 125 and 150 mW/cm², respectively). LIPUS was applied to bilateral femurs 12 wk post-OVX for 20 min/d for 6 wk. Micro-computed tomography, biomechanical tests, serum biochemical analysis and grip strength tests were performed to evaluate the therapeutic effects of LIPUS at different intensities. Results revealed that LIPUS intensity yielded strong correlations with bone mineral density and bone microstructure (R² = 0.57-0.83) and bone mechanical strength (R² = 0.80-0.97), and that the intensity of 150 mW/cm², instead of the 30 mW/cm² widely used in bone fracture healing, was most effective in maintaining bone mass among all the LIPUS signals between 15 and 150 mW/cm². This suggests that higher ultrasound intensity (i.e., 150 mW/cm²) may be more effective than lower intensity in mitigation of osteopenia and osteoporosis.

Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment

Background

The restoration and repair method in the clinic of delayed fracture healing and non-union after comminuted fractures are urgently needed to improve the prognosis of patients. The recruitment of endogenous stem cells has been considered a promising approach in bone defect repair.

Propose

The aim of this study was to generate a de novel MSCs aptamer and developed the first, feasible, economical, bio-compatible, and functional MSCs aptamer-directed nanoparticles without complex manufacture to recruit mesenchymal stem cells (MSCs) for bone defect regeneration.

Methods

Whole-cell SELEX was used to generate a de novel MSCs aptamer. Flow cytometry was applied to assess the binding specificities, affinities and sorting abilities of the aptamers. Nano-Aptamer Ball (NAB) was constructed by NHS/EDC reaction. The diameter and zeta of NAB were assessed by dynamic light scattering. CCK8 assay was utilized to evaluate whether NAB could cause non-specific cytotoxicity and induce cell proliferation. To evaluate the bone repair capacity of NAB, histomorphological staining, alizarin red and micro X-ray were used to observe the repair degree of defect in vivo. ELISA was used to detect osteopontin (OPN), osteocalcin (BGP) by, and alkaline phosphatase (ALP) in peripheral blood.

Results

MSCs aptamer termed as HM69 could bind with MSCs with high specificity and Kd of 9.67 nM, while has minimal cross-reactivities to other negative cells. HM69 could capture MSCs with a purity of >89%. In vitro, NAB could bind and capture MSCs effectively, whereas did not cause obvious cytotoxicity. In vivo, serum OPN, BGP, and ALP levels in the NAB group of rats were increased at both 2 and 4 weeks, indicating the repair and osteogenesis generation. The healing of bone defects in the NAB group was significantly better than control groups, the defects became blurred, and local trabecular bone growth could be observed in X-ray. The organized hematoma and cell growth in the bone marrow of the NAB group were more vigorous in bone sections staining.

Conclusion

These suggested that HM69 and HM69-functionalized nanoparticles NAB exhibited the ability to recruit MSCs both in vitro and in vivo and achieved a better outcome of bone defect repair in a rat model. The findings demonstrate a promising strategy of using aptamer-functionalized bio-nanoparticles for the restoration of bone defects via aptamer-introduced homing of MSCs.

Fracture repair in the elderly: Clinical and experimental considerations

Fractures in the elderly represent a significant and rising socioeconomic problem. Although aging has been associated with delays in healing, there is little direct clinical data isolating the effects of aging on bone healing from the associated comorbidities that are frequently present in elderly populations. Basic research has demonstrated that all of the components of fracture repair-cells, extracellular matrix, blood supply, and molecules and their receptors-are negatively impacted by the aging process, which likely explains poorer clinical outcomes. Improved understanding of age-related fracture healing should aid in the development of novel treatment strategies, technologies, and therapies to improve bone repair in elderly patients.

Low-intensity pulsed ultrasound promotes alveolar bone regeneration in a periodontal injury model

Periodontitis is a common oral disease characterized by progressive destruction of periodontal tissue and loss of teeth. However, regeneration of periodontal tissue is a time-consuming process. Low-intensity pulsed ultrasound (LIPUS) is a widely used non-invasive intervention for enhancing bone healing in fractures and non-unions. With the hypothesis that LIPUS may accelerate periodontal regeneration, the effects of LIPUS on periodontal tissue regeneration were investigated both in vitro and in vivo. LIPUS (90 mw/cm², 20 min/d, 1.5 MHz) was applied to stimulate dog periodontal ligament cells (dPDLCS). The mRNA expression of BSP (P < 0.05), OPN (P < 0.05) and COL3 (P < 0.05) was increased significantly in the LIPUS group. The positive stained mineralized nodules by alizarin red in the LIPUS group were greater than in the control group (P < 0.05). Eight male beagle dogs were divided into 4 groups: guided tissue regeneration (GTR) group (G1), LIPUS + GTR group (G2), LIPUS group (G3), and control group (G4, no treatment). A 4 × 5 mm² defect was created in the buccal alveolar bone. The modeling areas in the G2 and G3 groups were then exposed to LIPUS. Eight weeks after surgery, histological assessment indicated increased periodontal tissue in the LIPUS + GTR group. Micro computed tomography (micro-CT) showed that the regenerated bone volume (BV) in the G2 was significantly higher than that in the G1, G3 and G4 groups (P < 0.05). The bone surface (BS) trabecular number (Tb.N) and trabecular thickness (Tb.Th) in G2 were markedly higher than in G4 (P < 0.05). It is concluded that LIPUS + GTR can accelerate new alveolar bone formation, with a prospective for promoting periodontal tissue repair.

Low-Intensity Pulsed Ultrasound for Nonoperative Treatment of Scaphoid Nonunions: A Meta-Analysis

Background: Scaphoid fractures progress to nonunion rates of up to 15% when non-displaced, and are even more frequent when the fracture is displaced. Standard treatment in these cases is surgery; however, individuals unable to undergo this operation, or for those who wish to try more conservative measures, there may be benefit from nonoperative options. Of these, low-intensity pulsed ultrasound (LIPUS) has been shown to improve fracture nonunion healing. The purpose of this study was to perform a comprehensive meta-analysis of relevant literature to determine success of the use of LIPUS for treatment of scaphoid nonunion. Methods: Utilizing PubMed, Embase, and Ovid databases, we performed a literature search using key terms for scaphoid nonunions. A total of 686 studies met initial search criteria. Studies reporting fewer than 5 cases, those not published in English, those not related to LIPUS nonoperative scaphoid nonunion treatment, and those without sufficient data were excluded. Five studies met these criteria, and statistical analysis was performed to determine overall union rates. Results: The use of LIPUS on 166 nonunions reported a mean healing index of 78.6%. The average time to union following LIPUS treatment was 4.2 months. Conclusions: While surgical intervention is still the standard, our results show that LIPUS may serve as a nonoperative alternative to scaphoid nonunion in certain cases. The results are encouraging in which these challenging fracture a nonunions can heal without further surgical intervention in the majority of patients.

Comparison of effects of LLLT and LIPUS on fracture healing in animal models and patients: A systematic review

The aim of this paper is to study the in vivo potency of low-level laser therapy (LLLT) and low intensity pulsed ultrasound (LIPUS) alone, accompanied by bone grafts, or accompanied by other factors on fracture healing in animal models and patients. In this paper, we aim to systematically review the published scientific literature regarding the use of LLLT and LIPUS to accelerate fracture healing in animal models and patients. We searched the PubMed database for the terms LLLT or LIPUS and/or bone, and fracture. Our analysis also suggests that both LIPUS and LLLT may be beneficial to fracture healing in patients, and that LIPUS is more effective. These finding are of considerable importance in those treatments with a LIPUS, as a laser device may reduce healing time. The most clinically relevant impact of the LIPUS treatment could be a significant reduction in the proportion of patients who go on to develop a nonunion. If it is confirmed that the therapeutic influence is true and reliable, patients will obtain benefits from LIPUS and LLLT. Further clinical trials of high methodological quality are needed in order to determine the optimal role of LIPUS and LLLT in fracture healing in patients.

Low-intensity pulsed ultrasound promotes endothelial cell-mediated osteogenesis in a conditioned medium coculture system with osteoblasts

Angiogenesis plays an important role during bone regeneration. Low-intensity pulsed ultrasound (LIPUS) has been proven to accelerate the process of bone fracture healing. However, the mechanism of the effect of LIPUS on bone regeneration is still unclear. In the present study, we used human umbilical vein endothelial cell (HUVEC) and human osteosarcoma cell (MG-63) to investigate the effect of LIPUS stimulation in an endothelial cell-osteoblast coculture system. At the same time, we used transwell and in vitro angiogenesis assay to observe how LIPUS affects endothelial cells. The results demonstrated that LIPUS could significantly increase the migratory ability and promote tube formation in angiogenesis of HUVECs. Furthermore, LIPUS could significantly elevate the expression of osteogenesis-related genes on osteoblasts such as Runt-related transcription factor 2, alkaline phosphatase, Osteorix, and Cyclin-D1, indicating the pro-osteogenesis effect of LIPUS in our coculture system. In conclusion, endothelial cell is involved in LIPUS-accelerated bone regeneration, the positive effect of LIPUS may be transferred via endothelial cells surrounding fracture healing site.

Frequency sensitive mechanism in low-intensity ultrasound enhanced bioeffects

This study presents two novel theoretical models to elucidate frequency sensitive nuclear mechanisms in low-intensity ultrasound enhanced bioeffects. In contrast to the typical 1.5 MHz pulsed ultrasound regime, our group previously experimentally confirmed that ultrasound stimulation of anchored chondrocytes at resonant frequency maximized gene expression of load inducible genes which are regulatory markers for cellular response to external stimuli. However, ERK phosphorylation displayed no frequency dependency, suggesting that the biochemical mechanisms involved in enhanced gene expression is downstream of ERK phosphorylation. To elucidate such underlying mechanisms, this study presents a theoretical model of an anchored cell, representing an in vitro chondrocyte, in an ultrasound field. The model results showed that the mechanical energy storage is maximized at the chondrocyte's resonant frequency and the energy density in the nucleus is almost twice as high as in the cytoplasm. Next, a mechanochemical model was developed to link the mechanical stimulation of ultrasound and the increased mechanical energy density in the nucleus to the downstream targets of the ERK pathway. This study showed for the first time that ultrasound stimulation induces frequency dependent gene expression as a result of altered rates of transcription factors binding to chromatin.

Low-Intensity Pulsed Ultrasound-Induced Spinal Fusion is Coupled with Enhanced Calcitonin Gene-Related Peptide Expression in Rat Model

Low-intensity pulsed ultrasound (LIPUS) has been found to accelerate fracture healing. In this study, we analyzed the role of calcitonin gene-related peptide (CGRP) in a rat spinal fusion model treated with LIPUS. The results revealed that LIPUS significantly increases bone formation, and the process was coupled with elevated CGRP innervation. CGRP was located in fibrous tissue, closely surrounding the allograft and newly formed cartilage. The density of CGRP peaked at week 3 after surgery in both the control (non-LIPUS-treated) and LIPUS-treated groups. These results suggest that LIPUS might accelerate spinal fusion by promoting sensory nerve fiber innervation.

Low-intensity pulsed ultrasound promotes cell motility through vinculin-controlled Rac1 GTPase activity

Low-intensity pulsed ultrasound (LIPUS) is a therapy used clinically to promote healing. Using live-cell imaging we show that LIPUS stimulation, acting through integrin-mediated cell-matrix adhesions, rapidly induces Rac1 activation associated with dramatic actin cytoskeleton rearrangements. Our study demonstrates that the mechanosensitive focal adhesion (FA) protein vinculin, and both focal adhesion kinase (FAK, also known as PTK2) and Rab5 (both the Rab5a and Rab5b isoforms) have key roles in regulating these effects. Inhibiting the link of vinculin to the actin-cytoskeleton abolished LIPUS sensing. We show that this vinculin-mediated link was not only critical for Rac1 induction and actin rearrangements, but was also important for the induction of a Rab5-dependent increase in the number of early endosomes. Expression of dominant-negative Rab5, or inhibition of endocytosis with dynasore, also blocked LIPUS-induced Rac1 signalling events. Taken together, our data show that LIPUS is sensed by cell matrix adhesions through vinculin, which in turn modulates a Rab5-Rac1 pathway to control ultrasound-mediated endocytosis and cell motility. Finally, we demonstrate that a similar FAK-Rab5-Rac1 pathway acts to control cell spreading upon fibronectin.

When Is a Fracture Not "Fresh"? Aligning Reimbursement With Patient Outcome After Treatment With Low-Intensity Pulsed Ultrasound

OBJECTIVE

The clinical value of low-intensity pulsed ultrasound (LIPUS) for fresh fracture is known. Yet, in the absence of a definition of what "fresh" is, payers have adopted study inclusion criteria drawn from randomized clinical trials as de facto definitions of which patients should be treated, with "fresh" defined as <1 week old. Patients with fracture may thus be ineligible for LIPUS treatment after week 1, which potentially denies access to patients who could benefit from LIPUS. We seek to characterize the inflection point at which heal rate declines.

DESIGN

Prospective cohort.

SETTING

Food and Drug Administration-mandated nationwide postmarketing surveillance registry.

PATIENTS

Observational cohort of 5983 registry enrollees.

INTERVENTION

LIPUS, 20 min/d.

MAIN OUTCOME MEASURE

Fracture heal rate. Logistic regression was used to model the odds ratio of nonunion from week 1 to week 12. Covariates in the model included age, gender, body mass index, open fracture, and smoking.

RESULTS

We estimated the time point at which a fracture responds to LIPUS as well as during the first week after fracture. There was significant bone-to-bone variation; metatarsal was "fresh" until week 7, ankle until week 9, humerus until week 10, and femur and radius until week 12. Healing was significantly impacted by patient age, body mass index, and open fracture (all, P ≤ 0.02).

CONCLUSIONS

Our results suggest that fractures of the metatarsal, femur, humerus, ankle, and radius respond to LIPUS treatment, as if they were still fresh at least 6 weeks longer than the eligibility allowed under current coverage policies.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

A nonlinear model of cell interaction with an acoustic field

A theoretical and experimental nonlinear analysis of cellular response/displacement to ultrasound excitations is presented. Linear cell models can predict the resonant frequency (f_R∼5MHz), but only a nonlinear analysis can reveal the amount of mechanical energy that couples into the cell and the bifurcation behavior of the cell when it is excited near resonance. The cell dynamics is described by the nonlinear viscoelastic constitutive behavior of the cytoplasm, nucleus and their respective membranes, in the presence of a fluid with an oscillating pressure field. The method of multiple scales is used to derive the amplitude of oscillation of the cytoplasm and nucleus as a function of frequency. A major finding is the existence of multiple solutions for a range of sub-resonant frequencies. At positive detuning (f>f_R), the mechanical energy that couples into the cell is small, it is higher at resonance but significantly higher at sub-resonant frequencies in the multiplicity range. Experimentally it was shown when 3.5MHz is approached sub- and supra-resonance and 6.5MHz is approached sub-resonance, gene expression was statistically higher than that when stimulated directly. Thus, there exists an optimal range of frequencies for ultrasound treatment - in the region of multiplicity where deformation and thus mechanical energy coupling is maximized. The ultrasound protocol must be designed to operate at the solution associated with the higher mechanical energy - thus the start-up conditions should be in the domain of attraction of the high energy solution.

Heal rate of metatarsal fractures: A propensity-matching study of patients treated with low-intensity pulsed ultrasound (LIPUS) vs. surgical and other treatments

INTRODUCTION

Whether to treat metatarsal fractures conservatively or surgically is controversial. We test a hypothesis that metatarsal fractures treated conservatively with non-invasive low-intensity pulsed ultrasound (LIPUS) obtain heal rates comparable to current surgical techniques.

PATIENTS AND METHODS

This is a retrospective observational cohort study, using patient outcomes from a prospectively-collected LIPUS registry required by the U.S. Food & Drug Administration. Registry data were collected over a 5-year period and were reviewed and validated by a registered nurse. Data required for analysis were days-to-treatment (DTT) with LIPUS and a dichotomous outcome of healed versus failed, as assessed by clinical and radiographic criteria. Registry patients (DTT<365days) were propensity-matched to metatarsal fracture patients from a health claims database that includes medical and drug expenses for ∼90.1 million patients. The propensity match was based on patient demographic data (age, gender, body weight, fracture severity, and smoking status).

RESULTS

A total of 594 metatarsal fractures were treated with LIPUS, including 161 Jones fractures. Compared to patients in the claims database, LIPUS-treated patients were more likely to: be overweight or obese; be male; have open fracture; and smoke (all, P<0.0001), suggesting that these variables were perceived as nonunion risk factors by prescribing physicians. After propensity-matching, none of these differences between the registry and the health claims database remained significant. The heal rate with LIPUS treatment was 97.3%, comparable to the heal rate of 95.3% among claims patients in 2011 who did not receive LIPUS (P=0.0654). When fresh fractures (0-90days) and delayed unions (91-365days) were analyzed separately, the LIPUS fresh fracture heal rate was superior to claims patients (P=0.0381), and the delayed union heal rate was comparable. After exclusion of registry patients who received surgery, heal rate with LIPUS alone (97.4%) was significantly better (P<0.0097) than the heal rate for matched patients in 2011 (94.2%).

CONCLUSIONS

LIPUS significantly improved the heal rate of metatarsal fractures <1year old without surgery (P=0.0097). Metatarsal fractures treated with LIPUS alone have a heal rate comparable to fractures treated by surgical intervention.

Clinical applications of low-intensity pulsed ultrasound and its potential role in urology

Low-intensity pulsed ultrasound (LIPUS) is a form of ultrasound that delivered at a much lower intensity (<3 W/cm²) than traditional ultrasound energy and output in the mode of pulse wave, and it is typically used for therapeutic purpose in rehabilitation medicine. LIPUS has minimal thermal effects due to its low intensity and pulsed output mode, and its non-thermal effects which is normally claimed to induce therapeutic changes in tissues attract most researchers’ attentions. LIPUS have been demonstrated to have a rage of biological effects on tissues, including promoting bone-fracture healing, accelerating soft-tissue regeneration, inhibiting inflammatory responses and so on. Recent studies showed that biological effects of LIPUS in healing morbid body tissues may be mainly associated with the upregulation of cell proliferation through activation of integrin receptors and Rho/ROCK/Src/ERK signaling pathway, and with promoting multilineage differentiation of mesenchyme stem/progenitor cell lines through ROCK-Cot/Tpl2-MEK-ERK signaling pathway. Hopefully, LIPUS may become an effective clinical procedure for the treatment of urological diseases, such as chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), erectile dysfunction (ED), and stress urinary incontinence (SUI) in the field of urology. It still needs an intense effort for basic-science and clinical investigators to explore the biomedical applications of ultrasound.

Treatment of chronic (>1 year) fracture nonunion: heal rate in a cohort of 767 patients treated with low-intensity pulsed ultrasound (LIPUS)

BACKGROUND

Established fracture nonunions rarely heal without secondary intervention. Revision surgery is the most common intervention, though non-surgical options for nonunion would be useful if they could overcome nonunion risk factors. Our hypothesis is that low-intensity pulsed ultrasound (LIPUS) can enhance heal rate (HR) in fractures that remain nonunion after one year, relative to the expected HR in the absence of treatment, which is expected to be negligible.

METHODS

We collated outcomes from a prospective patient registry required by the U.S. Food & Drug Administration. Patient data were collected over a 4-year period beginning in 1994 and were individually reviewed and validated by a registered nurse. Patients were only included if they had four data points available: date when fracture occurred; date when LIPUS treatment began; date when LIPUS treatment ended; and a dichotomous outcome of healed vs. failed, assessed by clinical and radiological criteria. Data were used to calculate two derived variables: days to treatment (DTT) with LIPUS, and days on treatment (DOT) with LIPUS. Every validated chronic nonunion patient (DTT>365 days) with complete data is reported.

RESULTS

Heal rate for chronic nonunion patients (N=767) treated with LIPUS was 86.2%. Heal rate was 82.7% among 98 patients with chronic nonunion ≥5 years duration, and 12 patients healed after chronic nonunion >10 years (HR=63.2%). There was more patient loss to follow-up, non-compliance, and withdrawal, comparing chronic nonunion patients to all other patients (p<0.0001). Patient age was the only factor associated with failure to heal among chronic nonunions (p<0.004). Chronic nonunion patients averaged 3.1 surgical procedures prior to LIPUS, but some LIPUS-treated patients were able to heal without revision surgery. Among 91 patients who received LIPUS ≥90 days after their last surgery, HR averaged 85.7%, and the time from last surgery to index use of LIPUS averaged 449.6 days.

CONCLUSIONS

Low-intensity pulsed ultrasound enhanced HR among fractures that had been nonunion for at least 1 year, and even healed fractures that had been nonunion >10 years. LIPUS resulted in successful healing in the majority of nonunions without further surgical intervention.