The use of low-intensity pulsed ultrasound in hand and wrist nonunions

Exploring the Revolutionary Impact of YAP Pathways on Physical and Rehabilitation Medicine

Cellular behavior is strongly influenced by mechanical signals in the surrounding microenvironment, along with external factors such as temperature fluctuations, changes in blood flow, and muscle activity, etc. These factors are key in shaping cellular states and can contribute to the development of various diseases. In the realm of rehabilitation physical therapies, therapeutic exercise and manual treatments, etc., are frequently employed, not just for pain relief but also to support recovery from diverse health conditions. However, the detailed molecular pathways through which these therapies interact with tissues and influence gene expression are not yet fully understood. The identification of YAP has been instrumental in closing this knowledge gap. YAP is known for its capacity to perceive and translate mechanical signals into specific transcriptional programs within cells. This insight has opened up new perspectives on how physical and rehabilitation medicine may exert its beneficial effects. The review investigates the involvement of the Hippo/YAP signaling pathway in various diseases and considers how different rehabilitation techniques leverage this pathway to aid in healing. Additionally, it examines the therapeutic potential of modulating the Hippo/YAP pathway within the context of rehabilitation, while also addressing the challenges and controversies that surround its use in physical and rehabilitation medicine.

The roles of Hippo/YAP signaling pathway in physical therapy

Cellular behavior is regulated by mechanical signals within the cellular microenvironment. Additionally, changes of temperature, blood flow, and muscle contraction also affect cellular state and the development of diseases. In clinical practice, physical therapy techniques such as ultrasound, vibration, exercise, cold therapy, and hyperthermia are commonly employed to alleviate pain and treat diseases. However, the molecular mechanism about how these physiotherapy methods stimulate local tissues and control gene expression remains unknow. Fortunately, the discovery of YAP filled this gap, which has been reported has the ability to sense and convert a wide variety of mechanical signals into cell-specific programs for transcription, thereby offering a fresh perspective on the mechanisms by which physiotherapy treat different diseases. This review examines the involvement of Hippo/YAP signaling pathway in various diseases and its role in different physical therapy approaches on diseases. Furthermore, we explore the potential therapeutic implications of the Hippo/YAP signaling pathway and address the limitations and controversies surrounding its application in physiotherapy.

Multicenter consensus statements on the use of low-intensity pulsed ultrasound (LIPUS) in Hand Surgery

OBJECTIVE

The purpose of this agreement was to establish consensus statements on the use of low-intensity pulsed ultrasound (LIPUS) in hand surgery.

METHODS

Based on Delphi consensus methodology, a preliminary list of questions on the use of LIPUS in hand surgery was developed by an interdisciplinary team of hand and plastic surgeons as well as psychologists and experts from communications science. Based on these, questionnaires were invented and a total of three Delphi rounds have been conducted. Delphi panelists consisted of 11 German hand surgeons with a mean experience in hand surgery of 15 years (7-23 years). Questions and statements were revised during this process, resulting in a consensus at the end of round three.

RESULTS

After three Delphi rounds, the following recommendations could be derived. LIPUS can be applied for impaired fracture healing of the digits, metacarpals, carpal bones as well as a prophylactic procedure in order to avoid further revision surgery. LIPUS therapy can be useful in addition to revision surgery for delayed union and non-unions. In the case of certain risk factors (replantation, revascularization, osteoporosis, smoking), it can be applied directly postoperatively in order to prevent impaired fracture healing. It should be applied for 90-120 days.

CONCLUSION

There is a consensus among German hand surgeons, when and how LIPUS can be applied for improving fracture healing of the hand. Randomized controlled trials with direct comparison of fracture treatment with and without LIPUS are needed to support these statements with objective data.

Low-Intensity Pulsed Ultrasonography Plus Arthroscopic Drilling Does Not Improve Bone Healing More Than Arthroscopic Drilling Alone in Pediatric Patients With Stable Osteochondritis Dissecans of the Knee

Purpose

To determine whether adjuvant use of bone stimulation would improve the rate of healing in the operative management of stable osteochondritis dissecans (OCD) of the knee in pediatric patients.

Methods

This retrospective matched case-control study was performed at a single tertiary care pediatric hospital between January 2015 and September 2018. Patients who underwent antegrade drilling for stable femoral condyle OCD with greater than 2 years' follow-up were included. Preference was for all to receive postoperative bone stimulation; however, some were denied because of insurance coverage. This enabled us to create 2 matched groups of those who received postoperative bone stimulation and those who did not. Patients were matched on skeletal maturity, lesion location, sex, and age at surgery. The primary outcome measure was the rate of healing of the lesions determined by postoperative magnetic resonance imaging measurements at 3 months.

Results

Fifty-five patients were identified who met the inclusion and exclusion criteria. Twenty patients from the bone stimulator group (BSTIM) were matched to 20 patients from the no bone stimulator group (NBSTIM). Mean age for BSTIM at surgery was 13.2 years ± 2.0 (range, 10.9-16.7) and for NBSTIM at surgery 12.9 years ± 2.0 (range, 9.3-17.3). At 2 years, 36 patients (90%) in both groups went on to clinical healing without further interventions. In BSTIM, there was a mean decrease of 0.9 (±1.8) mm in lesion on coronal width and 12 patients (63%) had overall improved healing; in NBSTIM there was a mean decrease of 0.8 (±3.6) mm in coronal width and 14 patients (78%) had improved healing. No statistical differences in the rate of healing were found between the 2 groups (P = .706).

Conclusion

In antegrade drilling of stable knee OCD lesions in pediatric and adolescent patients, adjuvant bone stimulator use did not appear to improve radiographic or clinical healing.

Level of evidence

Level III, retrospective case-control study.

Bone Healing Gone Wrong: Pathological Fracture Healing and Non-Unions-Overview of Basic and Clinical Aspects and Systematic Review of Risk Factors

Bone healing is a multifarious process involving mesenchymal stem cells, osteoprogenitor cells, macrophages, osteoblasts and -clasts, and chondrocytes to restore the osseous tissue. Particularly in long bones including the tibia, clavicle, humerus and femur, this process fails in 2-10% of all fractures, with devastating effects for the patient and the healthcare system. Underlying reasons for this failure are manifold, from lack of biomechanical stability to impaired biological host conditions and wound-immanent intricacies. In this review, we describe the cellular components involved in impaired bone healing and how they interfere with the delicately orchestrated processes of bone repair and formation. We subsequently outline and weigh the risk factors for the development of non-unions that have been established in the literature. Therapeutic prospects are illustrated and put into clinical perspective, before the applicability of biomarkers is finally discussed.

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.

Instructional review of key factors to achieve successful outcomes when using low-intensity pulsed ultrasound in fracture repair

Low-intensity pulsed ultrasound (LIPUS) treatment of fractures has been available to the orthopaedic community for nearly three decades; however, it is still considered an experimental treatment by some clinicians, even though there is a wealth of clinical data. Based on the evaluation of clinical trial data, we have established key criteria which can lead to LIPUS success and avoid failure. These are fracture gap size and stability, accurate transducer placement and minimum treatment number. However, from a clinician's view, the correct attitude to treatment must be observed, and this has also been discussed. It is hoped, armed with this new evaluation of the clinical data, that clinicians can treat patients with LIPUS more effectively, resulting in fewer failures of treatment.

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.

Low-Intensity Pulsed Ultrasound Stimulation for Bone Fractures Healing: A Review

Low-intensity pulsed ultrasound (LIPUS) is a developing technology, which has been proven to improve fracture healing process with minimal thermal effects. This noninvasive treatment accelerates bone formation through various molecular, biological, and biomechanical interactions with tissues and cells. Although LIPUS treatment has shown beneficial effects on different bone fracture locations, only very few studies have examined its effects on deeper bones. This study provides an overview on therapeutic ultrasound for fractured bones, possible mechanisms of action, clinical evidences, current limitations, and its future prospects.

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.

Successful treatment of infectious delayed union after ulnar shortening osteotomy using once-weekly teriparatide with low-intensity pulsed ultrasound

We report a 50-year-old woman who presented with infected delayed union after ulnar shortening osteotomy. She was a chronic smoker. Implants were removed and infected tissue was debrided. Sufficient bony union was obtained after 5 months of treatment with weekly teriparatide and low-intensity pulsed ultrasound during the infection-controlled waiting period.

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.