Microcurrent Therapy in the Management of Chronic Tennis Elbow: Pilot Studies to Optimize Parameters

Enhancing regeneration and repair of long-distance peripheral nerve defect injuries with continuous microcurrent electrical nerve stimulation

Introduction

Peripheral nerve injuries, especially those involving long-distance deficits, pose significant challenges in clinical repair. This study explores the potential of continuous microcurrent electrical nerve stimulation (cMENS) as an adjunctive strategy to promote regeneration and repair in such cases.

Methods

The study initially optimized cMENS parameters and assessed its impact on Schwann cell activity, neurotrophic factor secretion, and the nerve regeneration microenvironment. Subsequently, a rat sciatic nerve defect-bridge repair model was employed to evaluate the reparative effects of cMENS as an adjuvant treatment. Functional recovery was assessed through gait analysis, motor function tests, and nerve conduction assessments. Additionally, nerve regeneration and denervated muscle atrophy were observed through histological examination.

Results

The study identified a 10-day regimen of 100uA microcurrent stimulation as optimal. Evaluation focused on Schwann cell activity and the microenvironment, revealing the positive impact of cMENS on maintaining denervated Schwann cell proliferation and enhancing neurotrophic factor secretion. In the rat model of sciatic nerve defect-bridge repair, cMENS demonstrated superior effects compared to control groups, promoting motor function recovery, nerve conduction, and sensory and motor neuron regeneration. Histological examinations revealed enhanced maturation of regenerated nerve fibers and reduced denervated muscle atrophy.

Discussion

While cMENS shows promise as an adjuvant treatment for long-distance nerve defects, future research should explore extended stimulation durations and potential synergies with tissue engineering grafts to improve outcomes. This study contributes comprehensive evidence supporting the efficacy of cMENS in enhancing peripheral nerve regeneration.

Physiological effects of microcurrent and its application for maximising acute responses and chronic adaptations to exercise

Microcurrent is a non-invasive and safe electrotherapy applied through a series of sub-sensory electrical currents (less than 1 mA), which are of a similar magnitude to the currents generated endogenously by the human body. This review focuses on examining the physiological mechanisms mediating the effects of microcurrent when combined with different exercise modalities (e.g. endurance and strength) in healthy physically active individuals. The reviewed literature suggests the following candidate mechanisms could be involved in enhancing the effects of exercise when combined with microcurrent: (i) increased adenosine triphosphate resynthesis, (ii) maintenance of intercellular calcium homeostasis that in turn optimises exercise-induced structural and morphological adaptations, (iii) eliciting a hormone-like effect, which increases catecholamine secretion that in turn enhances exercise-induced lipolysis and (iv) enhanced muscle protein synthesis. In healthy individuals, despite a lack of standardisation on how microcurrent is combined with exercise (e.g. whether the microcurrent is pulsed or continuous), there is evidence concerning its effects in promoting body fat reduction, skeletal muscle remodelling and growth as well as attenuating delayed-onset muscle soreness. The greatest hindrance to understanding the combined effects of microcurrent and exercise is the variability of the implemented protocols, which adds further challenges to identifying the mechanisms, optimal patterns of current(s) and methodology of application. Future studies should standardise microcurrent protocols by accurately describing the used current [e.g. intensity (μA), frequency (Hz), application time (minutes) and treatment duration (e.g. weeks)] for specific exercise outcomes, e.g. strength and power, endurance, and gaining muscle mass or reducing body fat.

Combination Therapy of Polydeoxyribonucleotide and Microcurrent in Muscle Regeneration on Cast-Induced Muscle Atrophy in Rabbit

Background. The aim of this study was to evaluate how polydeoxyribonucleotide (PDRN) and microcurrent therapy (MT) functioned synergistically in a cast-immobilized rabbit model with an atrophied calf muscle. Methods. At the age of 12 weeks, 32 male New Zealand rabbits were enrolled in four groups. After 2 weeks of cast-immobilization, 4 procedures were performed on atrophied calf muscle [weekly two injections normal saline 0.2 ml injection group 1 (G1-NS), weekly two injections 0.2 ml PDRN injection group 2 (G2-PDRN), MT group 3 (G3-MT), and 0.2 ml PDRN injection with MT group 4 (G4-PDRN+MT)]. For 2 weeks, MT was used for 60 minutes each day. The calf circumference (CC), the thickness of gastrocnemius muscle (TGCM), and the tibial nerve compound muscle action potential (CMAP) were evaluated using ultrasound before and after 2 weeks of treatment. Proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor, and platelet endothelial cell adhesion molecule-1 (PECAM-1) of GCM fibers (type I, type II, and total) were measured. Statistical analyses were performed using ANOVA. Results. The mean atrophic alterations of right CC, CMAP, and TGCM (medial/lateral) were substantially lower in G4-PDRN+MT than in the G1-NS, G2-PDRN, and G3-MT, respectively ( $p<0.05$ ). Furthermore, mean CSAs (type I, type II, and total) of medial and lateral GCM muscle fibers in G4-PDRN+MT were significantly higher when compared to other three groups ( $p<0.05$ ). In terms of the PCNA-, VEGF-, and PECAM-1-positive cell ratio of medial and lateral GCM muscle fibers, G4-PDRN+MT was considerably higher than G1-NS, G2-PDRN, and G3-MT ( $p<0.05$ ). Conclusions. On the atrophied calf muscle of the rabbit model, PDRN injection combined with MT was more effective than PDRN injection alone, MT alone, and normal saline injection separately.

Position statement: nonoperative management of lateral epicondylitis in adults

We sought to compare methods of nonsurgical treatment of lateral epicondylitis in men and women older than 18 years to develop a guideline intended for orthopedic surgeons and other health care providers who assess, counsel and care for these patients. We searched Medline, Embase and Cochrane through to Mar. 9, 2021, and included all English-language studies comparing nonsurgical approaches. We compared physiotherapy versus no active treatment, corticosteroids versus placebo, platelet-rich plasma (PRP) versus placebo, and autologous blood injection versus placebo. Outcomes of interest were pain outcomes (visual analogue scale scores) and functional outcomes. We rated the quality of the evidence and strength of recommendations using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. This guideline will benefit patients seeking nonsurgical intervention for lateral epicondylitis by improving counselling on nonsurgical treatment options and possible outcomes. It will also benefit surgical providers by improving their knowledge of various nonsurgical approaches. Data presented could be used to develop frameworks and tools for shared decision-making.

Analgesic and Functional Efficiency of High-Voltage Electrical Stimulation in Patients with Lateral Epicondylitis-A Report with a 180-Day Follow-Up

The available publications describing the beneficial effects of electrostimulation does not unequivocally confirm the clinical utility of high-voltage electrical stimulation (HVES) in the treatment of the lateral epicondylitis (LE). The aim of this study was the estimation of the effect of HVES on pain intensity and functional efficiency, both in the short and long term in patients with LE. The trial was registered by the Australian and New Zealand Clinical Trials Registry (ACTRN12621001389897). There were 58 patients allocated into two groups: the HVES group (n = 29, mean age 49.9 ± 11.0 years), treated with HVES (pulse duration: 200μs, frequency: 100 Hz, current amplitude in the range of 18-25 mA, voltage amplitude: 100 V), and the NORM group (n = 29, mean age 48.0 ± 12.6 years), who were healthy and untreated patients. The treatments were performed 5 days a week (from Monday to Friday) for two weeks. Treatment progress was measured by the visual analogue scale (VAS) for rest pain, night pain, and pain during activity; the Laitinen Pain Scale (LPS); and hand grip strength (HGS) before and after the treatment, as well as after 3, 6, 12, and 24 weeks. The reduction of pain (according to the VAS and LPS) and increase in the functional condition (according to the HGS) were observed in all HVES patients in the short- and long-term observation. Therefore, the HVES in treatment of LE was found to be effective and safe.

Regeneration of Chronic Rotator Cuff Tear in a Rabbit Model: Synergetic Benefits of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells, Polydeoxyribonucleotides, and Microcurrent Therapy

Objective

To investigate synergic therapeutic effects of combined injection of intralesional mesenchymal stem cells derived from human umbilical cord blood (UCB-MSCs) and polydeoxyribonucleotide (PDRN) combined with microcurrent therapy (MIC) on full thickness rotator cuff tendon tear (FTRCTT) in rabbit models.

Methods

Thirty-two rabbit models were assigned to 4 different groups. FTRCTT in the supraspinatus tendon was created. After 6 weeks, 4 types of procedures (0.2 mL normal saline injection, group 1 (G1-NS); 0.2 mL SC injection, group 2 (G2-MSC); 0.2 mL SC and weekly four injections of 0.2 mL PDRN with sham MIC, group 3 (G3-MSC+PDRN+sham MIC); and 0.2 mL SC and weekly four injections of 0.2 mL PDRN with MIC for four weeks, group 4 (G4-MSC+PDRN+MIC)) were performed in FTRCTT. Gross morphologic and histological changes of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule (PECAM-1) and motion analysis were performed.

Results

There was a significant difference in gross morphologic changes between baseline and week 4 posttreatment in group 4 compared to the other three groups (p = 0.01). In groups 3 and 4, all parameters of histochemical and motion analysis have been found to be significantly greater than the ones in groups 1 and 2 (p < 0.05). In group 4, PCNA-, VEGF-, and PECAM-1-stained cells, as well as walking distance, were significantly greater than the ones in group 3 (p < 0.05).

Conclusion

The treatment with UCB-MSCs and PDRN combined with MIC might be the most effective in rabbit models' traumatic FRTCTT.

Microcurrent Therapy as a Therapeutic Modality for Musculoskeletal Pain: A Systematic Review Accelerating the Translation From Clinical Trials to Patient Care

Objective

To summarize the level of knowledge regarding the effects of microcurrent therapy (MCT) on musculoskeletal pain in adults.

Data Sources

The PubMed, Physiotherapy Evidence Database, Cumulative Index to Nursing Allied Health Literature, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi database were searched from the time of their inception to December 2020.

Study Selection

Randomized controlled trials (RCTs) investigating the effects of MCT on musculoskeletal pain were included. Additionally, non-RCTs were included to assess the adverse events.

Data Extraction

The primary outcomes were pain and adverse events related to MCT. To assess the reproducibility of MCT, we evaluated the completeness of treatment description using the Template for Intervention Description and Replication (TIDieR) checklist. We also assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

Data Synthesis

A comprehensive assessment of 4 RCTs and 5 non-RCTs that met the inclusion criteria revealed that MCT significantly improved shoulder pain (1 study, 40 patients) and knee pain (1 study, 52 patients) compared with sham MCT without any severe adverse events. MCT has clinically significant benefits for knee pain. This study also revealed a clinically significant placebo response in treating knee pain. This evidence highlights the substantial effect of placebo response in clinical care. These treatment effects on knee pain are further supported by the high quality of evidence in GRADE with high reproducibility in TIDieR.

Conclusions

The findings of this meta-analysis highlight the effect of placebo response in treating knee pain. MCT is a potential, core nonpharmacologic treatment option in clinical care with minimal adverse events and should be further investigated. This study proposes a framework for the future investigation of the effect of MCT on musculoskeletal pain to enhance the study quality and reproducibility.

Efficacy of microcurrent therapy for treatment of acute knee pain: A randomized double-blinded controlled clinical trial

Objective:

We would like to determine whether electrotherapy, specifically microcurrent therapy, increases function and decreases pain in people who have acute knee pain.

Design:

Randomized, double-blinded, placebo-controlled clinical trial.

Setting:

University laboratory and patient home.

Subjects:

A total of 52 subjects (35 females and 17 males) with acute knee pain.

Intervention:

Treatment group (n = 26) wore the active microcurrent therapy device at home for 3 hours per day for 4 weeks and the control group (n = 26) wore the placebo for 3 hours per day for 4 weeks.

Main Measures:

Numeric Pain Rating Scale (NPRS) and Short Form 12 (SF-12) health scale were used to measure the pain level and the functionality of the participants. Secondary assessments included musculoskeletal ultrasound imaging (MSK US) and Lower Extremity Functional Scale (LEFS).

Results:

A total of 52 subjects completed the study; 26 in the treatment group and 26 in the control group. Microcurrent therapy significantly reduced pain over 4 weeks. Especially week three was significant (P < 0.01) after adjusting for the family-wise error rate. The analysis on SF-12 revealed those with microcurrent therapy showed an increasing trend in the improvement of physical function score until week three.

Conclusion:

An active microcurrent therapy device decreased knee pain and increased function. Microcurrent therapy may be an alternative or used with a pharmacological approach for people with acute knee pain.

Microcurrent therapy in the treatment of knee osteoarthritis: could it be more than a placebo effect? A randomized controlled trial

BACKGROUND

Microcurrent therapy (MCT) is a novel electrotherapy modality with very low current-levels that may reduce pain especially in joints and muscles.

AIM

The aim of this study is to explore potential effects of MCT on pain in patients with knee osteoarthritis, to explore effects of different treatment parameters and to distinguish them from placebo-effects.

DESIGN

Randomized four arms controlled clinical trial.

SETTING

Outpatient tertiary medical care center.

POPULATION

Fifty-six patients with knee OA (Kellgren-Lawrence Score II or III, 14 male and 38 female, mean age: 71.7±7.3 years, pain intensity higher than Numeric Rating Scale [NRS] score 3 from 10).

METHODS

Patients were randomized into four groups: MCT with 100 µA (group A), MCT with 25 µA (group B), sham-treatment (group C) and a control-group without intervention. Treatment groups received 10 sessions of MCT for 30 minutes each over a period of 22 days. The primary outcome was daily pain intensity throughout the treatment period measured by a NRS from 0-10. Second outcome measurements were the Knee Osteoarthritis Outcome Score (KOOS), the SF-36 Questionnaire, the Six-Minute Walking Test and the Get-Up-and-Go Test.

RESULTS

Evening pain was reduced significantly in the verum-groups compared to sham group (Group A vs. Group C: P<0.001, Group B vs. Group C: P=0.006) and to no intervention (Group A vs. Group D: P<0.001, Group B vs. Group D: P=0.002). The difference between sham-therapy and no therapy was not significant. In the pre-post analysis of the KOOS group A improved significantly in the subscale Symptoms. Group A and B and D improved in the Activities of Daily Living subscale.

CONCLUSIONS

The results of this RCT suggest that MCT has beneficial effects on pain in patients with knee osteoarthritis that are not explained by a placebo effect. Due to the explorative, pilot character of the study, further confirmation is needed before clear recommendations can be given.

CLINICAL REHABILITATION IMPACT

More high-quality RCTs with transparent parameters should be investigated to elucidate potential effects of MCT in the field of physical medicine and rehabilitation. At the present time MCT is a treatment option that could be helpful, in particular for patients who are afraid of unpleasant sensations from electrotherapy with stronger currents.

Synergic regenerative effects of polydeoxyribonucleotide and microcurrent on full-thickness rotator cuff healing in a rabbit model

BACKGROUND

Rotator cuff tendon tears (RCTTs) are common adult injuries. We hypothesized that a local injection of polydeoxyribonucleotide (PDRN) and microcurrent therapy (MIC) would be more effective in regenerating a tendon tear than PDRN administration alone.

OBJECTIVES

To evaluate the effect of PDRN combined with MIC on the regeneration of RCTTs in a rabbit subscapularis tendon chronic RCTT model.

METHODS

Rabbits (n=24) were allocated to 3 groups at 6 weeks after full-thickness RCTT (FTRCTT): 0.2mL normal saline (G1-SAL); 0.2mL PDRN with Sham MIC (G2-PDRN+Sham MIC); and 0.2mL PDRN with MIC (G3-PDRN+MIC). All treatments were performed under ultrasound guidance. PDRN was injected weekly for 4 weeks and sham MIC or MIC was applied daily for 4 weeks after the first PDRN injection.

RESULTS

In the G3-PDRN+MIC group, the mean (SD) subscapularis tendon tear size was continuously reduced from 1 week post-treatment to 4 weeks and was significantly decreased as compared with the other 2 groups [6.0 (1.5) vs. G1: 11.5 (1.8) and G2: 9.1 (1.6) mm²; G3 vs. G1, P<0.001; G3 vs. G2, P=0.018]. The gross morphologic mean tendon tear size was significantly smaller in the G3-PDRN+MIC group than G1-SAL and G2-PDRN+ Sham MIC groups [8.8 (3.5) vs. 15.9 (2.3) and 12.4 (1.6) mm²; G3 vs. G1, P<0.001; G3 vs. G2, P=0.03]. Mean values for regenerated collagen type 1 fibers, angiogenesis, and walking parameters were all greater for the G3-PDRN+MIC group than the other 2 groups based on histological examination and motion analysis [collagen type 1, G3: 1.60 (0.80) vs. G1: 0.45 (0.60), G2: 1.10 (0.74), G3 vs. G1, P<0.001; G3 vs. G2, P=0.002] [angiogenesis, G3: 2.44 (0.73) vs. G1: 0.80 (0.82) and G2: 2.06 (0.81), G3 vs. G1, P<0.001; G3 vs. G2, P=0.006] [walking distance, G3: 6391.4 (196.9) vs. G1: 4852.8 (137.3) and G2: 5514.4 (257.3) cm; G3 vs. G1, P<0.001; G3 vs. G2, P<0.001].

CONCLUSIONS

On gross morphologic, histological, and motion analysis, combined PDRN with MIC therapy was more effective than PDRN alone treating a rabbit model of chronic traumatic FTRCTT.

Low-intensity microcurrent therapy promotes regeneration of atrophied calf muscles in immobilized rabbits

The purpose of this study was to investigate the intensity-specific regenerative effects of microcurrent therapy on gastrocnemius muscle atrophy induced by cast-immobilization in rabbits. Fifteen rabbits were randomly allocated to 3 groups after cast removal: cast-immobilization and sham microcurrent therapy for 2 weeks (group 1); cast-immobilization and microcurrent therapy (25 μA) for 2 weeks (group 2); cast-immobilization and microcurrent therapy (5,000 μA) for 2 weeks (group 3). Clinical parameters [calf circumference, compound muscle action potential (CMAP) of the tibial nerve, thickness of gastrocnemius muscle], cross sectional area of gastrocnemius muscle fibres, and immunohistochemistry was evaluated. The clinical parameters representing mean atrophic changes in group 2 were significantly lower than those in group 3. The cross sectional area of the gastrocnemius muscle fibres and immunohistochemical parameters in group 2 were significantly greater than those in group 3. The results showed that low-intensity microcurrent therapy can more effectively promote regeneration in atrophied gastrocnemius muscle than high-intensity microcurrent therapy.

What is the clinical effectiveness and cost-effectiveness of conservative interventions for tendinopathy? An overview of systematic reviews of clinical effectiveness and systematic review of economic evaluations

BACKGROUND

Lateral elbow tendinopathy (LET) is a common complaint causing characteristic pain in the lateral elbow and upper forearm, and tenderness of the forearm extensor muscles. It is thought to be an overuse injury and can have a major impact on the patient's social and professional life. The condition is challenging to treat and prone to recurrent episodes. The average duration of a typical episode ranges from 6 to 24 months, with most (89%) reporting recovery by 1 year.

OBJECTIVES

This systematic review aims to summarise the evidence concerning the clinical effectiveness and cost-effectiveness of conservative interventions for LET.

DATA SOURCES

A comprehensive search was conducted from database inception to 2012 in a range of databases including MEDLINE, EMBASE and Cochrane Databases.

METHODS AND OUTCOMES

We conducted an overview of systematic reviews to summarise the current evidence concerning the clinical effectiveness and a systematic review for the cost-effectiveness of conservative interventions for LET. We identified additional randomised controlled trials (RCTs) that could contribute further evidence to existing systematic reviews. We searched MEDLINE, EMBASE, Allied and Complementary Medicine Database, Cumulative Index to Nursing and Allied Health Literature, Web of Science, The Cochrane Library and other important databases from inception to January 2013.

RESULTS

A total of 29 systematic reviews published since 2003 matched our inclusion criteria. These were quality appraised using the Assessment of Multiple Systematic Reviews (AMSTAR) checklist; five were considered high quality and evaluated using a Grading of Recommendations, Assessment, Development and Evaluation approach. A total of 36 RCTs were identified that were not included in a systematic review and 29 RCTs were identified that had only been evaluated in an included systematic review of intermediate/low quality. These were then mapped to existing systematic reviews where further evidence could provide updates. Two economic evaluations were identified.

LIMITATIONS

The summary of findings from the review was based only on high-quality evidence (scoring of > 5 AMSTAR). Other limitations were that identified RCTs were not quality appraised and dichotomous outcomes were also not considered. Economic evaluations took effectiveness estimates from trials that had small sample sizes leading to uncertainty surrounding the effect sizes reported. This, in turn, led to uncertainty of the reported cost-effectiveness and, as such, no robust recommendations could be made in this respect.

CONCLUSIONS

Clinical effectiveness evidence from the high-quality systematic reviews identified in this overview continues to suggest uncertainty as to the effectiveness of many conservative interventions for the treatment of LET. Although new RCT evidence has been identified with either placebo or active controls, there is uncertainty as to the size of effects reported within them because of the small sample size. Conclusions regarding cost-effectiveness are also unclear. We consider that, although updated or new systematic reviews may also be of value, the primary focus of future work should be on conducting large-scale, good-quality clinical trials using a core set of outcome measures (for defined time points) and appropriate follow-up. Subgroup analysis of existing RCT data may be beneficial to ascertain whether or not certain patient groups are more likely to respond to treatments.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013003593.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.