Topical glyceryl trinitrate for the treatment of tendinopathies: a systematic review

Making Sense of Topical Pain Relief Options: Comparing Topical Analgesics in Efficacy and Safety

CONTEXT

In patients with musculoskeletal (MSK) conditions, pain is the leading contributor to disability and significantly limits mobility and dexterity. This narrative review describes the efficacy and safety of topical analgesics in common use today.

EVIDENCE ACQUISITION

Secondary literature gained via a literature search using PubMed.gov and the Cochrane library were used.

STUDY DESIGN

Recent literature (2000-2023) on several major classes of topical analgesics and topical delivery systems were reviewed to provide strength of recommendation taxonomy (SORT) levels. A total of 86 articles were reviewed.

LEVEL OF EVIDENCE

Level 2.

RESULTS

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) and cabbage leaf wraps (CLW) appear to be best suited for multiple types of acute MSK pain, and topical nitroglycerin is helpful when used specifically for rotator cuff pain in patients seeking relief while performing activities of daily living and willing to treat for long periods of time. For compounded topical formulations, it may be better to offer single agent creams based on patient preferences. Little data support the use of cryotherapy. Traumeel could be a promising natural analgesic that compares with diclofenac. Topical lidocaine appears best suited for postherpetic neuropathic pain. O24 is a reasonable alternative with a low risk profile to treat pain in patients with fibromyalgia syndrome.

CONCLUSION

Choice of topical agents should be guided by current evidence accounting for type of pain, medication side effects, patient comorbidities, as well as patient preference, convenience, and cost.

STRENGTH-OF-RECOMMENDATION TAXONOMY (SORT)

Of the topical analgesics and modalities reviewed, SORT level A evidence was found for topical NSAID use in decreasing MSK pain, topical lidocaine for postherpetic neuralgia, and nitroglycerin patches for treating rotator cuff pain if used for prolonged periods of time. Alternative treatments such as CLW and Traumeel show promising results (SORT level B).

Topical glyceryl trinitrate (GTN) and eccentric exercises in the treatment of mid-portion achilles tendinopathy (the NEAT trial): a randomised double-blind placebo-controlled trial

OBJECTIVES

To investigate if daily treatment with glyceryl trinitrate (GTN) ointment, over 24 weeks combined with a 12-week eccentric exercise programme is more effective for chronic mid-portion Achilles tendinopathy than placebo ointment and eccentric exercise.

METHODS

This was a single-site randomised double-blind placebo-controlled trial at an acute hospital, Dublin, Ireland. Patients with chronic mid-portion Achilles tendinopathy were randomised to either 24 weeks of daily GTN ointment or placebo ointment. Both groups received an identical 12-week eccentric exercise programme. The primary outcome measure was the Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire at 24 weeks, which measures pain, function and activity. Secondary outcomes included pain severity, self-reported physical function, calf muscle function, pressure pain thresholds and ultrasound changes. Statistical analyses were performed according to intention-to-treat principles.

RESULTS

76 patients (30 women; 46 men, mean age±SD, 45.6±8.2 years) were recruited for the trial. Significant improvements in VISA-A scores occurred in both groups at 6-week, 12-week and 24-week follow-up. The increase was not significantly different between groups, adjusted mean between-group difference from baseline to week 6, -1.33 (95% CI -6.96 to 4.31); week 12, -1.25 (95% CI -8.0 to 5.49) and week 24, -3.8 (95% CI -10.6 to 3.0); negative values favour GTN. There was no significant between-group difference in any of the secondary outcome measures at 6, 12 and 24 weeks.

CONCLUSIONS

Adding daily GTN ointment over 24 weeks to a 12-week eccentric exercise programme did not improve pain, function and activity level in patients with chronic mid-portion Achilles tendinopathy when compared with placebo ointment.

Effectiveness of Exercise Treatments with or without Adjuncts for Common Lower Limb Tendinopathies: A Living Systematic Review and Network Meta-analysis

INTRODUCTION

Exercise therapy is usually prescribed as first-line treatment for lower limb tendinopathies. The multitude of exercise- and non-exercise-based management options can be overwhelming for the treating sports professional and patient alike. We chose to investigate the comparative effectiveness of exercise therapy with or without adjuncts for managing the commonest lower limb tendinopathies.

METHODS

Through an extensive systematic literature search using multiple databases, we aimed to identify eligible randomised controlled trials (RCTs) on Achilles tendinopathy, patellar tendinopathy or greater trochanteric pain syndrome (GTPS) that included at least one exercise intervention in their treatment arms. Our primary outcomes were patient-reported pain and function (Victorian Institute of Sport Assessment; VISA). Follow-up was defined as short-term (≤ 12 weeks), mid-term (> 12 weeks to < 12 months) and long-term (≥ 12 months). The risk of bias and strength of evidence were assessed with the Cochrane Collaboration and GRADE-NMA tools, respectively. Analyses were performed separately for each one of the three tendinopathies.

RESULTS

A total of 68 RCTs were included in the systematic review. All pairwise comparisons that demonstrated statistically and clinically significant differences between interventions were based on low or very low strength of evidence. Based on evidence of moderate strength, the addition of extracorporeal shockwave therapy to eccentric exercise in patellar tendinopathy was associated with no short-term benefit in pain or VISA-P. From the network meta-analyses, promising interventions such as slow resistance exercise and therapies administered alongside eccentric exercise, such as topical glyceryl trinitrate for patellar tendinopathy and high-volume injection with corticosteroid for Achilles tendinopathy were based on low/very low strength of evidence.

CONCLUSION

In this network meta-analysis, we found no convincing evidence that any adjuncts administered on their own or alongside exercise are more effective than exercise alone. Therefore, we recommend that exercise monotherapy continues to be offered as first-line treatment for patients with Achilles and patellar tendinopathies and GTPS for at least 3 months before an adjunct is considered. We provide treatment recommendations for each tendinopathy. PROSPERO registration number CRD42021289534.

Present situation and development prospects of the diagnosis and treatment of rotator cuff tears

Rotator cuff tears are an important cause of shoulder pain and are caused by degeneration or trauma of the shoulder tendon at the anatomical neck of the humeral head. The understanding and research of rotator cuff tears have a history of hundreds of years, and their etiology, diagnosis, and treatment have a complete system, but some detailed rules of diagnosis and treatment still have room for development. This research paper briefly introduces the diagnosis and treatment of rotator cuff tears. The current situation and its valuable research direction are described.

Human hair follicle-derived mesenchymal stem cells promote tendon repair in a rabbit Achilles tendinopathy model

BACKGROUND

Hair follicles are easily accessible and contain stem cells with different developmental origins, including mesenchymal stem cells (MSCs), that consequently reveal the potential of human hair follicle (hHF)-derived MSCs in repair and regeneration. However, the role of hHF-MSCs in Achilles tendinopathy (AT) remains unclear. The present study investigated the effects of hHF-MSCs on Achilles tendon repair in rabbits.

METHODS

First, we extracted and characterized hHF-MSCs. Then, a rabbit tendinopathy model was constructed to analyze the ability of hHF-MSCs to promote repair in vivo . Anatomical observation and pathological and biomechanical analyses were performed to determine the effect of hHF-MSCs on AT, and quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical staining were performed to explore the molecular mechanisms through which hHF-MSCs affects AT. Furthermore, statistical analyses were performed using independent sample t test, one-way analysis of variance (ANOVA), and one-way repeated measures multivariate ANOVA as appropriate.

RESULTS

Flow cytometry, a trilineage-induced differentiation test, confirmed that hHF-derived stem cells were derived from MSCs. The effect of hHF-MSCs on AT revealed that the Achilles tendon was anatomically healthy, as well as the maximum load carried by the Achilles tendon and hydroxyproline proteomic levels were increased. Moreover, collagen I and III were upregulated in rabbit AT treated with hHF-MSCs (compared with AT group; P  < 0.05). Analysis of the molecular mechanisms revealed that hHF-MSCs promoted collagen fiber regeneration, possibly through Tenascin-C (TNC) upregulation and matrix metalloproteinase (MMP)-9 downregulation.

CONCLUSIONS

hHF-MSCs can be a treatment modality to promote AT repair in rabbits by upregulating collagen I and III. Further analysis revealed that treatment of AT using hHF-MSCs promoted the regeneration of collagen fiber, possibly because of upregulation of TNC and downregulation of MMP-9, thus suggesting that hHF-MSCs are more promising for AT.

Challenges and perspectives of tendon-derived cell therapy for tendinopathy: from bench to bedside

Tendon is composed of dense fibrous connective tissues, connecting muscle at the myotendinous junction (MTJ) to bone at the enthesis and allowing mechanical force to transmit from muscle to bone. Tendon diseases occur at different zones of the tendon, including enthesis, MTJ and midsubstance of the tendon, due to a variety of environmental and genetic factors which consequently result in different frequencies and recovery rates. Self-healing properties of tendons are limited, and cell therapeutic approaches in which injured tendon tissues are renewed by cell replenishment are highly sought after. Homologous use of individual’s tendon-derived cells, predominantly differentiated tenocytes and tendon-derived stem cells, is emerging as a treatment for tendinopathy through achieving minimal cell manipulation for clinical use. This is the first review summarizing the progress of tendon-derived cell therapy in clinical use and its challenges due to the structural complexity of tendons, heterogeneous composition of extracellular cell matrix and cells and unsuitable cell sources. Further to that, novel future perspectives to improve therapeutic effect in tendon-derived cell therapy based on current basic knowledge are discussed.

New frontiers of tendon augmentation technology in tissue engineering and regenerative medicine: a concise literature review

Tissue banking programs fail to meet the demand for human organs and tissues for transplantation into patients with congenital defects, injuries, chronic diseases, and end-stage organ failure. Tendons and ligaments are among the most frequently ruptured and/or worn-out body tissues owing to their frequent use, especially in athletes and the elderly population. Surgical repair has remained the mainstay management approach, regardless of scarring and adhesion formation during healing, which then compromises the gliding motion of the joint and reduces the quality of life for patients. Tissue engineering and regenerative medicine approaches, such as tendon augmentation, are promising as they may provide superior outcomes by inducing host-tissue ingrowth and tendon regeneration during degradation, thereby decreasing failure rates and morbidity. However, to date, tendon tissue engineering and regeneration research has been limited and lacks the much-needed human clinical evidence to translate most laboratory augmentation approaches to therapeutics. This narrative review summarizes the current treatment options for various tendon pathologies, future of tendon augmentation, cell therapy, gene therapy, 3D/4D bioprinting, scaffolding, and cell signals.

Management of the master endurance athlete with stable coronary artery disease

Master endurance athletes are individuals > 35 years of age who either train for or participate in competitions. Considering the potential burden of coronary artery disease in this population, clinicians should be aware of the inherent dangers of exercise. A tailored approach with shared decision-making, balancing risks and benefits of exercise, is recommended to ensure safe exercise in these individuals.

Patellar Tendinopathy: Critical Analysis Review of Current Nonoperative Treatments

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Patellar tendinopathy is an attritional injury of the patellar tendon that is frequently identified in jumping athletes. Through repetitive or explosive movements, considerable loads and high peak strains are generated across the patellar tendon.

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This leads to microinjury of tendon fibers, local mucoid degeneration, and loss of the fibrocartilaginous tissue that attaches tendon to bone.

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Management of patellar tendinopathy often begins with nonoperative modalities: progressive tendon loading and eccentric rehabilitative exercise programs are the most effective. While a variety of additional treatment modalities are available, the comparative efficacy of these supportive treatments is not well differentiated at this time.

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In this article, we analyze the existing literature regarding nonoperative treatment of patellar tendinopathy and provide additional insight on the effectiveness of current modalities.

Management of patellar tendinopathy: a systematic review and network meta-analysis of randomised studies

Objectives

We performed a systematic review and network meta-analysis (NMA) of randomised controlled trials (RCTs) to provide insights into the effectiveness of available treatment modalities in patellar tendinopathy(PT).

Methods

Several databases were searched in May 2021 for RCTs assessing the effectiveness of any intervention compared with any other intervention, placebo or no treatment for pain and/or function in PT. The risk of bias and strength of evidence were assessed with the Cochrane Collaboration and GRADE (Grading of Recommendations, Assessment, Development and Evaluations)/GRADE-NMA tools.

Results

A total of 37 RCTs were eligible that assessed 33 different interventions and their combinations, most represented by single studies. Based on pairwise meta-analyses of two RCTs, extracorporeal shockwave therapy (ESWT) does not appear to be superior to sham ESWT (eccentric exercise in both groups) for short-term pain (mean differences (MD) +0.1, 95% CI (−0.8 to 1), p=0.84) or function (MD −1.8, 95% CI (–8 to 4.4), p=0.57). Based on a pairwise meta-analysis of three RCTs, isometric exercise appears as effective as isotonic exercise for immediate postintervention pain relief (MD −1.03, 95% CI (−2.6 to 0.5), p=0.19). Our NMA showed that topical glyceryl trinitrate (GTN) and hyaluronic acid injection, both combined with eccentric exercise and moderate, slow resistance exercise had the highest probability of being the most effective interventions (low/very low strength of evidence).

Conclusions

Promising interventions with inadequate evidence, such as topical GTN, hyaluronic acid injections and isometric and slow resistance exercise, should be further investigated through high-quality RCTs. Meanwhile, eccentric loading with or without adjuncts should remain the first-line treatment for all individuals with patellar tendinopathy.

Achilles Tendinopathy, A Brief Review and Update of Current Literature

ABSTRACT

Chronic pain in the Achilles tendon is a common problem in both athletes and nonathletes alike. The etiology for the development of Achilles tendinopathy has not been fully elucidated, and there remains multiple theories to explain the pain and dysfunction accompanying this condition. The diagnosis of Achilles tendon problems continues to rely on the clinical history and physical examination. The optimal management of pain, restoration of function, and return-to-sports participation with Achilles tendinopathy are evolving because of the advancement in technologies and research regarding its pathophysiology. This article aims to provide a brief review of the relevant anatomy, differential diagnosis, imaging findings, and an update of the literature on conservative and minimally invasive managements of chronic Achilles tendinopathy.

Effectiveness of topical glyceryl trinitrate in treatment of tendinopathy - systematic review and meta-analysis

PURPOSE

The objective of this meta-analysis was to evaluate the evidence on the effectiveness of glycerin trinitrate (NTG) measured by pain severity.

MATERIALS AND METHODS

CENTRAL, MEDLINE, EMBASE, SCOPUS, and WEB of SCIENCE databases were searched in November 2020. The study selection was performed by two independent reviewers. The risk of systematic bias was assessed according to the Cochrane Collaboration's domain-based evaluation framework.

RESULTS

Of 87 identified records, the meta-analysis was conducted on eight RCTs. When grouping by the type of tendinopathy and combining the estimates obtained from all available time points, the pooled standardized difference in means (SMD) was -0.80 (95% CI -1.34 to -0.26), and the number needed to treat 3.53 (95% upper confidence limit 12.4). When combining all the available data (all types of tendinopathy and all time points), the pooled SMD was -1.57 (95% CI -2.47 to -0.67). Overall heterogeneity was high. The risk of systematic bias was low in most of the selected studies.

CONCLUSIONS

There is no evidence that NTG is more effective to reduce pain in tendinopathy than placebo. The effects of NTG were insignificant or borderline significant (probably insignificant clinically) concerning rotator cuff tendinopathy, Achilles tendinopathy, patellar tendinopathy, and lateral epicondylitis.IMPLICATIONS FOR REHABILITATIONA meta-analysis conducted on eight RCTs found no evidence that topical glycerin trinitrate is more effective to reduce pain in tendinitis than placebo.The effects were insignificant or borderline significant concerning rotator cuff tendinitis, Achilles tendinitis, patellar tendinitis, and lateral epicondylitis.The effects were independent of the dosage used.

Dutch multidisciplinary guideline on Achilles tendinopathy

Objective

To provide a comprehensive, evidence-based overview of the risk factors, prevention, diagnosis, imaging, treatment and prognosis for Achilles tendinopathy. To make clinical recommendations for healthcare practitioners and patients.

Design

Comprehensive multidisciplinary guideline process funded by the Quality Foundation of the Dutch Federation of Medical Specialists. This process included a development, commentary and authorisation phase. Patients participated in every phase.

Data sources

Multiple databases and existing guidelines were searched up to May 2019. Information from patients, healthcare providers and other stakeholders were obtained using a digital questionnaire, focus group interview and invitational conference.

Study eligibility criteria

Studies on both insertional and/or midportion Achilles tendinopathy were eligible. Specific eligibility criteria were described per module.

Data extraction and synthesis

To appraise the certainty of evidence, reviewers extracted data, assessed risk of bias and used the Grading of Recommendations Assessment, Development and Evaluation method, where applicable. Important considerations were: patient values and preferences, costs, acceptability of other stakeholders and feasibility of implementation. Recommendations were made based on the results of the evidence from the literature and the considerations.

Primary outcome measure

The primary and secondary outcome measures were defined per module and defined based on the input of patients obtained in collaboration with the Netherlands Patient Federation and healthcare providers from different professions.

Results

Six specific modules were completed: risk factors and primary prevention, diagnosis, imaging, treatment prognosis and secondary prevention for Achilles tendinopathy.

Summary/conclusion

Our Dutch multidisciplinary guideline on Achilles tendinopathy provides six modules developed according to the standards of the Dutch Federation of Medical Specialists. Evidence-based recommendations for clinical practice are given for risk factors, prevention, diagnosis, imaging, treatment and prognosis. This guideline can assist healthcare providers and patients in clinical practice.

Do we need to improve the reporting of evidence in tendinopathy management? A critical appraisal of systematic reviews with recommendations on strength of evidence assessment

Objective

To critically appraise the quality of published systematic reviews (SRs) of randomised controlled trials (RCTs) in tendinopathy with regard to handling and reporting of results with special emphasis on strength of evidence assessment.

Data sources

Medline from inception to June 2020.

Study eligibility

All SRs of RCTs assessing the effectiveness of any intervention(s) on any location of tendinopathy.

Data extraction and synthesis

Included SRs were appraised with the use of a 12-item tool devised by the authors arising from the Preferred Reporting Items in Systematic Reviews and Meta-Analyses statement and other relevant guidance. Subgroup analyses were performed based on impact factor (IF) of publishing journals and date of publication.

Results

A total of 57 SRs were included published in 38 journals between 2006 and 2020. The most commonly used risk-of-bias (RoB) assessment tool and strength of evidence assessment tool were the Cochrane Collaboration RoB tool and the Cochrane Collaboration Back Review Group tool, respectively. The mean score on the appraisal tool was 46.5% (range 0%–100%). SRs published in higher IF journals (>4.7) were associated with a higher mean score than those in lower IF journals (mean difference 26.4%±8.8%, p=0.004). The mean score of the 10 most recently published SRs was similar to that of the first 10 published SRs (mean difference 8.3%±13.7%, p=0.54). Only 23 SRs (40%) used the results of their RoB assessment in data synthesis and more than half (n=30; 50%) did not assess the strength of evidence of their results. Only 12 SRs (21%) assessed their strength of evidence appropriately.

Conclusions

In light of the poor presentation of evidence identified by our review, we provide recommendations to increase transparency and reproducibility in future SRs.

Which treatment is most effective for patients with Achilles tendinopathy? A living systematic review with network meta-analysis of 29 randomised controlled trials

OBJECTIVE

To provide a consistently updated overview of the comparative effectiveness of treatments for Achilles tendinopathy.

DESIGN

Living systematic review and network meta-analysis.

DATA SOURCES

Multiple databases including grey literature sources were searched up to February 2019.

STUDY ELIGIBILITY CRITERIA

Randomised controlled trials examining the effectiveness of any treatment in patients with both insertional and/or midportion Achilles tendinopathy. We excluded trials with 10 or fewer participants per treatment arm or trials investigating tendon ruptures.

DATA EXTRACTION AND SYNTHESIS

Reviewers independently extracted data and assessed the risk of bias. We used the Grading of Recommendations Assessment, Development and Evaluation to appraise the certainty of evidence.

PRIMARY OUTCOME MEASURE

The validated patient-reported Victorian Institute of Sport Assessment-Achilles questionnaire.

RESULTS

29 trials investigating 42 different treatments were included. 22 trials (76%) were at high risk of bias and 7 (24%) had some concerns. Most trials included patients with midportion tendinopathy (86%). Any treatment class seemed superior to wait-and-see for midportion Achilles tendinopathy at 3 months (very low to low certainty of evidence). At 12 months, exercise therapy, exercise+injection therapy and exercise+night splint therapy were all comparable with injection therapy for midportion tendinopathy (very low to low certainty). No network meta-analysis could be performed for insertional Achilles tendinopathy.

SUMMARY/CONCLUSION

In our living network meta-analysis no trials were at low risk of bias and there was large uncertainty in the comparative estimates. For midportion Achilles tendinopathy, wait-and-see is not recommended as all active treatments seemed superior at 3-month follow-up. There seems to be no clinically relevant difference in effectiveness between different active treatments at either 3-month or 12-month follow-up. As exercise therapy is easy to prescribe, can be of low cost and has few harms, clinicians could consider starting treatment with a calf-muscle exercise programme.

PROSPERO REGISTRATION NUMBER

CRD42018086467.

Tendinopathy

Tendinopathy describes a complex multifaceted pathology of the tendon, characterized by pain, decline in function and reduced exercise tolerance. The most common overuse tendinopathies involve the rotator cuff tendon, medial and lateral elbow epicondyles, patellar tendon, gluteal tendons and the Achilles tendon. The prominent histological and molecular features of tendinopathy include disorganization of collagen fibres, an increase in the microvasculature and sensory nerve innervation, dysregulated extracellular matrix homeostasis, increased immune cells and inflammatory mediators, and enhanced cellular apoptosis. Although diagnosis is mostly achieved based on clinical symptoms, in some cases, additional pain-provoking tests and imaging might be necessary. Management consists of different exercise and loading programmes, therapeutic modalities and surgical interventions; however, their effectiveness remains ambiguous. Future research should focus on elucidating the key functional pathways implicated in clinical disease and on improved rehabilitation protocols.

Recent advances in tendinopathy

Tendinopathy refers to the clinical diagnosis of activity-related pain resulting in a decline in tendon function. In the last few years, much has been published concerning the basic science and clinical investigation of tendinopathy and debates and discussions to new questions and points of view started many years ago. This advances review will discuss the current thinking on the basic science and clinical management of tendinopathy and in particular new findings in the tendon repair space that are relevant to the pathophysiology of tendinopathy. We will further discuss potential novel therapies on the horizon in human tendon disease.

Clinical management of tendinopathy: A systematic review of systematic reviews evaluating the effectiveness of tendinopathy treatments

While the pathoetiology is disputed, a wide array of treatments is available to treat tendinopathy. The most common treatments found in the literature include therapeutic modalities, exercise protocols, and surgical interventions; however, their effectiveness remains ambiguous. The purpose of this study was to perform a systematic review of systematic reviews to determine the ability of therapeutic interventions to improve pain and dysfunction in patients with tendinopathy regardless of type or location. Five databases were searched for systematic reviews containing only randomized control trials to determine the effectiveness of treatments for tendinopathies based on pain and patient-reported outcomes. Systematic reviews were assessed via the Assessment of Multiple Systematic Reviews (AMSTAR) for methodological quality. From the database search, 3,295 articles were found, 107 passed the initial inclusion criteria. After further review, 25 systematic reviews were included in the final qualitative analysis. The AMSTAR scores were relatively high (8.8 ± 1.0) across the 25 systematic reviews. Eccentric exercises were the most common and consistently effective treatment for tendinopathy across systematic reviews. Low-level laser therapy and extracorporeal shockwave therapy demonstrated moderate effectiveness, while platelet-rich plasma injections demonstrated inconclusive evidence on their ability to decrease tendinopathy-related pain and improve function. Corticosteroids also showed some effectiveness for short-term pain, but for the long-term use deemed ineffective and at times contraindicated. Regarding surgical options, minimally invasive procedures were more effective compared to open surgical interventions. When treating tendinopathy regardless of location, eccentric exercises were the best treatment option to improve tendinopathy-related pain and improve self-reported function.

Advances in the development of gene therapy, noncoding RNA, and exosome-based treatments for tendinopathy

Tendinopathy is a common musculoskeletal disorder characterized by chronic low-grade inflammation and tissue degeneration. Tendons have poor innate healing ability and there is currently no cure for tendinopathy. Studies elucidating mechanisms underlying the pathogenesis of tendinopathy and mechanisms mediating the genesis of tendons during development have provided novel targets and strategies to enhance tendon healing and repair. This review summarizes the current understanding and treatments for tendinopathy. The review also highlights recent advances in gene therapy, the potential of noncoding RNAs, such as microRNAs, and exosomes, which are nanometer-sized extracellular vesicles secreted from cells, for the treatment of tendinopathy.

Variability within the human iNOS gene and Achilles tendon injuries: Evidence for a heterozygous advantage effect

OBJECTIVES

The aim of this case control genetic association study was to explore whether two variants within the inducible nitric oxide synthase (iNOS) gene, rs2779249 (C/A) and rs2248814 (A/G), influenced the risk of Achilles tendinopathy in a British population.

DESIGN

Candidate gene, case control association study.

METHOD

We recruited 145 individuals diagnosed with Achilles tendon pathology and 132 asymptomatic controls. All participants were genotyped for the iNOS variants using qPCR and significant associations were discovered using a combination of Chi squared and ANOVA type analysis.

RESULTS

The CA genotype of the iNOS rs2779249 variant was protective and conformed to a heterozygous advantage model of inheritance as it was overrepresented in the control participants (p=0.009). In sex specific analysis the protective association persisted in male participants (p=0.016) but not in females. Unlike the rs2779249 variant, the rs2248814 variant was not associated with Achilles tendinopathy or Achilles tendon rupture.

CONCLUSION

The rs2779249 CA genotype within the human iNOS gene appears to protect individuals from Achilles tendinopathy. This study further supports a genetic contribution to modifying the risk of Achilles tendon problems. The study also infers an important role for nitric oxide in tendon healing and/or degradation.

How does surgery compare to sham surgery or physiotherapy as a treatment for tendinopathy? A systematic review of randomised trials

Purpose

To assess the effectiveness of surgery on all tendinopathies by comparing it to no treatment, sham surgery and exercise-based therapies for both mid-term (12 months) and long-term (> 12 months) outcomes.

Methods

Our literature search included EMBASE, Medline, CINAHL and Scopus. A combined assessment of internal validity, external validity and precision of each eligible study yielded its overall study quality. Results were considered significant if they were based on strong (Level 1) or moderate (Level 2) evidence.

Results

12 studies were eligible. Participants had the following types of tendinopathy: shoulder in seven studies, lateral elbow in three, patellar in one and Achilles in one. Two studies were of good, four of moderate and six of poor overall quality. Surgery was superior to no treatment or placebo, for the outcomes of pain, function, range of movement (ROM) and treatment success in the short and midterm. Surgery had similar effects to sham surgery on pain, function and range of motion in the midterm. Physiotherapy was as effective as surgery both in the midterm and long term for pain, function, ROM and tendon force, and pain, treatment success and quality of life, respectively.

Conclusion

We recommend that healthcare professionals who treat tendinopathy encourage patients to comply with loading exercise treatment for at least 12 months before the option of surgery is seriously entertained.

15-Epi-LXA4 and MaR1 counter inflammation in stromal cells from patients with Achilles tendinopathy and rupture

Resolution of inflammation is poorly understood in Achilles tendon disorders. Herein, we investigated the bioactive lipid mediator profiles of tendon-derived stromal cells isolated from patients with Achilles tendinopathy (AT) or Achilles rupture (AR) under baseline and IL-1β–stimulated conditions. We also determined whether incubating these cells with 2 of the mediators produced by tendon-derived stromal cells, 15-epi-Lipoxin A₄ (15-epi-LXA₄) or maresin (MaR)-1, moderated their proinflammatory phenotype. Under baseline conditions, AT cells showed concurrent increased levels of proinflammatory eicosanoids and proresolving mediators compared with AR cells. IL-1β treatment induced profound prostaglandin E₂ release in AR compared with AT cells. Incubation of IL-1β treated AT and AR tendon-derived stromal cells in 15-epi-LXA₄ or MaR1 reduced proinflammatory eicosanoids and potentiated the release of proresolving mediators. These mediators also induced specialized proresolving mediator (SPM) biosynthetic enzymes arachidonate lipoxygenase (ALOX) 12 and ALOX15 and up-regulated the proresolving receptor ALX compared with vehicle-treated cells. Incubation in 15-epi-LXA₄ or MaR1 also moderated the proinflammatory phenotype of AT and AR cells, regulating podoplanin, CD90, signal transducer and activator of transcription (STAT)-1, IL-6, IFN regulatory factor (IRF) 5, and TLR4 and suppressed c-Jun N-terminal kinase 1/2/3, Lyn, STAT-3, and STAT-6 phosphokinase signaling. In summary, we identify proresolving mediators that are active in AT and AR and propose SPMs, including 15-epi-LXA₄ or MaR1, as a potential strategy to counterregulate inflammatory processes in these cells.—Dakin, S. G., Colas, R. A., Newton, J., Gwilym, S., Jones, N., Reid, H. A. B., Wood, S., Appleton, L., Wheway, K., Watkins, B., Dalli, J., Carr, A. J. 15-Epi-LXA₄ and MaR1 counter inflammation in stromal cells from patients with Achilles tendinopathy and rupture.