Current trends in tendinopathy: consensus of the ESSKA basic science committee. Part I: biology, biomechanics, anatomy and an exercise-based approach

Controlled Stiffness of Direct-Write, Near-Field Electrospun Gelatin Fibers Generates Differences in Tenocyte Morphology and Gene Expression

Tendinopathy is a leading cause of mobility issues. Currently, the cell-matrix interactions involved in the development of tendinopathy are not fully understood. In vitro tendon models provide a unique tool for addressing this knowledge gap as they permit fine control over biochemical, micromechanical, and structural aspects of the local environment to explore cell-matrix interactions. In this study, direct-write, near-field electrospinning of gelatin solution was implemented to fabricate micron-scale fibrous scaffolds that mimic native collagen fiber size and orientation. The stiffness of these fibrous scaffolds was found to be controllable between 1 MPa and 8 MPa using different crosslinking methods (EDC, DHT, DHT+EDC) or through altering the duration of crosslinking with EDC (1 h to 24 h). EDC crosslinking provided the greatest fiber stability, surviving up to 3 weeks in vitro. Differences in stiffness resulted in phenotypic changes for equine tenocytes with low stiffness fibers (∼1 MPa) promoting an elongated nuclear aspect ratio while those on high stiffness fibers (∼8 MPa) were rounded. High stiffness fibers resulted in the upregulation of matrix metalloproteinase (MMPs) and proteoglycans (possible indicators for tendinopathy) relative to low stiffness fibers. These results demonstrate the feasibility of direct-written gelatin scaffolds as tendon in vitro models and provide evidence that matrix mechanical properties may be crucial factors in cell-matrix interactions during tendinopathy formation.

The effect of extracorporeal shock-wave therapy on pain in patients with various tendinopathies: a systematic review and meta-analysis of randomized control trials

OBJECTIVES

Tendinopathy is a common condition that affects the body's tendon structures, causing discomfort, restricted movement, and reduced functionality. In this study, we looked at how extracorporeal shock wave therapy (ESWT) affected pain levels in individuals with various forms of tendinopathy around the world.

DESIGN

This study is a comprehensive review and meta-analysis of previously published randomized controlled trials. To gather relevant data, the researchers performed keyword searches in international databases, including PubMed (Medline), Scopus, Web of Sciences, Cochrane Central Register of Controlled Trials (CENTRAL), Research Registers of ongoing trials (ClinicalTrials.gov), as well as Embase. The search was conducted up until March 2023. The quality of the selected articles was assessed using the Cochrane risk-of-bias method for randomized trials (RoB2).

RESULTS

Based on the results of the meta-analysis, which included 45 clinical studies, the use of ESWT was found to have a significant impact on reducing pain in various conditions. The standardized mean difference (SMD) in patients with plantar fasciitis (PF) was reduced by 1.63 (SMD: -1.63, 95% CI: -3.04, -0.21; I2: 77.36%; P heterogeneity: 0.0001). For lateral epicondylitis (LE), the SMD was 0.63 (SMD: -0.63, 95% CI: -1.11, -0.16; I2: 67.50%; P heterogeneity: 0.003). In the case of chronic Achilles tendinopathy, the SMD was 1.38 (SMD: -1.38, 95% CI: -1.66, -1.10; I2: 96.44%; P heterogeneity: 0.0001). Additionally, in individuals with rotator cuff tendinopathy, the SMD for pain reduction was 2.37 units (SMD: -2.37, 95% CI: -3.58, -1.15; I2: 98.46%; P heterogeneity: 0.0001).

CONCLUSION

This study suggests that ESWT can be a highly effective therapy option for relieving pain in people with tendinopathy. Nonetheless, it is encouraged to make additional recommendations based on high-quality clinical research and more accurate information in order to define the optimal therapeutic options for each type of tendinopathy.

Enthesis repair - State of play

The fibrocartilaginous enthesis is a highly specialised tissue interface that ensures a smooth mechanical transfer between tendon or ligament and bone through a fibrocartilage area. This tissue is prone to injury and often does not heal, even after surgical intervention. Enthesis augmentation approaches are challenging due to the complexity of the tissue that is characterised by the coexistence of a range of cellular and extracellular components, architectural features and mechanical properties within only hundreds of micrometres. Herein, we discuss enthesis repair and regeneration strategies, with particular focus on elegant interfacial and functionalised scaffold-based designs.

Imaging Features of Plantar Vein Thrombosis: An Easily Overlooked Condition in the Differential Diagnosis of Foot Pain

Plantar vein thrombosis is a venous disorder affecting deep plantar veins that can manifest with non-specific localized pain, plantar foot pain, swelling, and sensation of fullness. Plantar veins are not routinely assessed during sonographic scans for deep venous thrombosis, which makes plantar venous thrombosis a commonly missed diagnosis. This paper provides a comprehensive review of the venous anatomy of the foot and imaging findings of plantar venous thrombosis as well as discusses the current literature on the topic and its differential diagnoses.

Unraveling the link: locomotor activity exerts a dual role in predicting Achilles tendon healing and boosting regeneration in mice

Introduction

Tendon disorders present significant challenges in the realm of musculoskeletal diseases, affecting locomotor activity and causing pain. Current treatments often fall short of achieving complete functional recovery of the tendon. It is crucial to explore, in preclinical research, the pathways governing the loss of tissue homeostasis and its regeneration. In this context, this study aimed to establish a correlation between the unbiased locomotor activity pattern of CRL:CD1 (ICR) mice exposed to uni- or bilateral Achilles tendon (AT) experimental injuries and the key histomorphometric parameters that influence tissue microarchitecture recovery.

Methods

The study involved the phenotyping of spontaneous and voluntary locomotor activity patterns in male mice using digital ventilated cages (DVC®) with access to running wheels either granted or blocked. The mice underwent non-intrusive 24/7 long-term activity monitoring for the entire study period. This period included 7 days of pre-injury habituation followed by 28 days post-injury.

Results and discussion

The results revealed significant variations in activity levels based on the type of tendon injury and access to running wheels. Notably, mice with bilateral lesions and unrestricted wheel access exhibited significantly higher activity after surgery. Extracellular matrix (ECM) remodeling, including COL1 deposition and organization, blood vessel remodeling, and metaplasia, as well as cytological tendon parameters, such as cell alignment and angle deviation were enhanced in surgical (bilateral lesion) and husbandry (free access to wheels) groups. Interestingly, correlation matrix analysis uncovered a strong relationship between locomotion and microarchitecture recovery (cell alignment and angle deviation) during tendon healing. Overall, this study highlights the potential of using mice activity metrics obtained from a home-cage monitoring system to predict tendon microarchitecture recovery at both cellular and ECM levels. This provides a scalable experimental setup to address the challenging topic of tendon regeneration using innovative and animal welfare-compliant strategies.

Exercise therapy for tendinopathy: a mixed-methods evidence synthesis exploring feasibility, acceptability and effectiveness

Background

Tendinopathy is a common, painful and functionally limiting condition, primarily managed conservatively using exercise therapy.

Review questions

(i) What exercise interventions have been reported in the literature for which tendinopathies? (ii) What outcomes have been reported in studies investigating exercise interventions for tendinopathy? (iii) Which exercise interventions are most effective across all tendinopathies? (iv) Does type/location of tendinopathy or other specific covariates affect which are the most effective exercise therapies? (v) How feasible and acceptable are exercise interventions for tendinopathies?

Methods

A scoping review mapped exercise interventions for tendinopathies and outcomes reported to date (questions i and ii). Thereafter, two contingent systematic review workstreams were conducted. The first investigated a large number of studies and was split into three efficacy reviews that quantified and compared efficacy across different interventions (question iii), and investigated the influence of a range of potential moderators (question iv). The second was a convergent segregated mixed-method review (question v). Searches for studies published from 1998 were conducted in library databases (n = 9), trial registries (n = 6), grey literature databases (n = 5) and Google Scholar. Scoping review searches were completed on 28 April 2020 with efficacy and mixed-method search updates conducted on 19 January 2021 and 29 March 2021.

Results

Scoping review - 555 included studies identified a range of exercise interventions and outcomes across a range of tendinopathies, most commonly Achilles, patellar, lateral elbow and rotator cuff-related shoulder pain. Strengthening exercise was most common, with flexibility exercise used primarily in the upper limb. Disability was the most common outcome measured in Achilles, patellar and rotator cuff-related shoulder pain; physical function capacity was most common in lateral elbow tendinopathy. Efficacy reviews - 204 studies provided evidence that exercise therapy is safe and beneficial, and that patients are generally satisfied with treatment outcome and perceive the improvement to be substantial. In the context of generally low and very low-quality evidence, results identified that: (1) the shoulder may benefit more from flexibility (effect sizeResistance:Flexibility = 0.18 [95% CrI 0.07 to 0.29]) and proprioception (effect sizeResistance:Proprioception = 0.16 [95% CrI -1.8 to 0.32]); (2) when performing strengthening exercise it may be most beneficial to combine concentric and eccentric modes (effect sizeEccentricOnly:Concentric+Eccentric = 0.48 [95% CrI -0.13 to 1.1]; and (3) exercise may be most beneficial when combined with another conservative modality (e.g. injection or electro-therapy increasing effect size by ≈0.1 to 0.3). Mixed-method review - 94 studies (11 qualitative) provided evidence that exercise interventions for tendinopathy can largely be considered feasible and acceptable, and that several important factors should be considered when prescribing exercise for tendinopathy, including an awareness of potential barriers to and facilitators of engaging with exercise, patients' and providers' prior experience and beliefs, and the importance of patient education, self-management and the patient-healthcare professional relationship.

Limitations

Despite a large body of literature on exercise for tendinopathy, there are methodological and reporting limitations that influenced the recommendations that could be made.

Conclusion

The findings provide some support for the use of exercise combined with another conservative modality; flexibility and proprioception exercise for the shoulder; and a combination of eccentric and concentric strengthening exercise across tendinopathies. However, the findings must be interpreted within the context of the quality of the available evidence.

Future work

There is an urgent need for high-quality efficacy, effectiveness, cost-effectiveness and qualitative research that is adequately reported, using common terminology, definitions and outcomes.

Study registration

This project is registered as DOI: 10.11124/JBIES-20-00175 (scoping review); PROSPERO CRD 42020168187 (efficacy reviews); https://osf.io/preprints/sportrxiv/y7sk6/ (efficacy review 1); https://osf.io/preprints/sportrxiv/eyxgk/ (efficacy review 2); https://osf.io/preprints/sportrxiv/mx5pv/ (efficacy review 3); PROSPERO CRD42020164641 (mixed-method review).

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) HTA programme and will be published in full in HTA Journal; Vol. 27, No. 24. See the NIHR Journals Library website for further project information.

Effect of resistance exercise dose components for tendinopathy management: a systematic review with meta-analysis

OBJECTIVE

To investigate potential moderating effects of resistance exercise dose components including intensity, volume and frequency, for the management of common tendinopathies.

DESIGN

Systematic review with meta-analysis and meta-regressions.

DATA SOURCES

Including but not limited to: MEDLINE, CINAHL, SPORTDiscus, ClinicalTrials.gov and ISRCTN Registry.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised and non-randomised controlled trials investigating resistance exercise as the dominant treatment class, reporting sufficient information regarding ≥2 components of exercise dose.

RESULTS

A total of 110 studies were included in meta-analyses (148 treatment arms (TAs), 3953 participants), reporting on five tendinopathy locations (rotator cuff: 48 TAs; Achilles: 43 TAs; lateral elbow: 29 TAs; patellar: 24 TAs; gluteal: 4 TAs). Meta-regressions provided consistent evidence of greater pooled mean effect sizes for higher intensity therapies comprising additional external resistance compared with body mass only (large effect size domains: β BodyMass: External = 0.50 (95% credible interval (CrI): 0.15 to 0.84; p=0.998); small effect size domains (β BodyMass: External = 0.04 (95% CrI: -0.21 to 0.31; p=0.619)) when combined across tendinopathy locations or analysed separately. Greater pooled mean effect sizes were also identified for the lowest frequency (less than daily) compared with mid (daily) and high frequencies (more than once per day) for both effect size domains when combined or analysed separately (p≥0.976). Evidence for associations between training volume and pooled mean effect sizes was minimal and inconsistent.

SUMMARY/CONCLUSION

Resistance exercise dose is poorly reported within tendinopathy management literature. However, this large meta-analysis identified some consistent patterns indicating greater efficacy on average with therapies prescribing higher intensities (through inclusion of additional loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery.

Patient ratings in exercise therapy for the management of tendinopathy: a systematic review with meta-analysis

OBJECTIVE

To synthesise exercise therapy intervention data investigating patient rating outcomes for the management of tendinopathy.

DESIGN

A systematic review and meta-analysis of randomized controlled trials investigating exercise therapy interventions and reporting patient rating outcomes.

SETTING

Any setting in any country listed as very high on the human development index.

PARTICIPANTS

People with a diagnosis of any tendinopathy of any severity or duration.

INTERVENTIONS

Exercise therapy for the management of tendinopathy comprising five different therapy classes: 1) resistance; 2) plyometric; 3) vibration; 4) flexibility, and 5) movement pattern retraining modalities, were considered for inclusion.

MAIN OUTCOME MEASURES

Outcomes measuring patient rating of condition, including patient satisfaction and Global Rating of Change (GROC).

RESULTS

From a total of 124 exercise therapy studies, 34 (Achilles: 41%, rotator cuff: 32%, patellar: 15%, elbow: 9% and gluteal: 3%) provided sufficient information to be meta-analysed. The data were obtained across 48 treatment arms and 1246 participants. The pooled estimate for proportion of satisfaction was 0.63 [95%CrI: 0.53-0.73], and the pooled estimate for percentage of maximum GROC was 53 [95%CrI: 38-69%]. The proportion of patients reporting positive satisfaction and perception of change increased with longer follow-up periods from treatment onset.

CONCLUSION

Patient satisfaction and GROC appear similar and are ranked moderately high demonstrating that patients generally perceive exercise therapies positively. Further research including greater consistency in measurement tools is required to explore and where possible, identify patient- and exercise-related moderating factors that can be used to improve person-centred care.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO ID=CRD42020168187 CONTRIBUTION OF PAPER.

Comparability of the Effectiveness of Different Types of Exercise in the Treatment of Achilles Tendinopathy: A Systematic Review

Achilles tendinopathy (AT) is a common condition both in athletes and the general population. The purpose of this study is to highlight the most effective form of exercise in managing pain-related symptoms and functional capacity as well as in a return to life activities, ensuring the quality of life of patients with AT, and creating a protocol to be used in rehabilitation. We conducted a systematic review of the published literature in Pubmed, Scopus, Science Direct, and PEDro for Randomised Controlled Trials concerning interventions that were based exclusively on exercise and delivered in patients 18-65 years old, athletes and non-athletes. An amount of 5235 research articles generated from our search. Five met our inclusion criteria and were included in the review. Research evidence supports the effectiveness of a progressive loading eccentric exercise program based on Alfredson's protocol, which could be modified in intensity and pace to fit the needs of each patient with AT. Future research may focus on the optimal dosage and load of exercise in eccentric training and confirm the effectiveness of other type of exercise, such as a combination of eccentric-concentric training or heavy slow resistance exercise. Pilates could be applied as an alternative, useful, and friendly tool in the rehabilitation of AT.

Exploring the role of intratendinous pressure in the pathogenesis of tendon pathology: a narrative review and conceptual framework

Despite the high prevalence of tendon pathology in athletes, the underlying pathogenesis is still poorly understood. Various aetiological theories have been presented and rejected in the past, but the tendon cell response model still holds true. This model describes how the tendon cell is the key regulator of the extracellular matrix and how pathology is induced by a failed adaptation to a disturbance of tissue homeostasis. Such failure has been attributed to various kinds of stressors (eg, mechanical, thermal and ischaemic), but crucial elements seem to be missing to fully understand the pathogenesis. Importantly, a disturbance of tissue pressure homeostasis has not yet been considered a possible factor, despite it being associated with numerous pathologies. Therefore, we conducted an extensive narrative literature review on the possible role of intratendinous pressure in the pathogenesis of tendon pathology. This review explores the current understanding of pressure dynamics and the role of tissue pressure in the pathogenesis of other disorders with structural similarities to tendons. By bridging these insights with known structural changes that occur in tendon pathology, a conceptual model was constituted. This model provides an overview of the possible mechanism of how an increase in intratendinous pressure might be involved in the development and progression of tendon pathology and contribute to tendon pain. In addition, some therapies that could reduce intratendinous pressure and accelerate tendon healing are proposed. Further experimental research is encouraged to investigate our hypotheses and to initiate debate on the relevance of intratendinous pressure in tendon pathology.

Pathways driving tendinopathy and enthesitis: siblings or distant cousins in musculoskeletal medicine?

Tendinopathy and enthesitis share clinical, anatomical, and molecular parallels. However, their relationship is complex, presenting challenges in diagnosis and treatment. The biomechanics underlying these pathologies, together with relative immune and stromal contributions to pathology, are characterised by crucial comparative elements. However, methodologies used to study enthesitis and tendinopathy have been divergent, which could account for discrepancies in how these conditions are perceived and treated. In this Review, we summarise key clinical parallels between these two common presentations in musculoskeletal medicine and address factors that currently preclude development of more effective therapeutics. Furthermore, we describe molecular similarities and disparities that govern pathological mechanisms in tendinopathy and enthesitis, thus informing translational studies and treatment strategies.

Biomechanical Properties of Knee Medial Collateral Ligament Compared to Palmaris Longus for Ulnar Collateral Ligament Reconstruction

Ulnar collateral ligament reconstruction (UCLR) is frequently performed among injured overhead-throwing athletes. One of the most common graft choices when performing a UCLR is the ipsilateral palmaris longus tendon (PL). The purpose of this study was to investigate the material properties of aseptically processed cadaveric knee collateral ligaments (kMCL) as a potential graft source for UCLR and compare them to the gold standard PL autograft. Each PL and kMCL cadaveric sample was subjected to cyclic preconditioning, stress relaxation, and load-to-failure testing, and the mechanical properties were recorded. PL samples exhibited a greater average decrease in stress compared to the kMCL samples during the stress-relaxation test (p < 0.0001). PL samples also demonstrated a greater average Young's modulus in the linear region of the stress-strain curve compared to the kMCL samples (p < 0.01). The average yield strain and maximum strain of kMCL samples were significantly greater than the PL, p = 0.03 and 0.02, respectively. Both graft materials had comparable maximum toughness and demonstrated a similar ability to deform plastically without rupture. The clinical significance of our result is that prepared knee medial collateral ligament allografts may provide a viable graft material for use in the reconstruction of elbow ligaments.

What are small, medium and large effect sizes for exercise treatments of tendinopathy? A systematic review and meta-analysis

Objective

To quantify and describe effect size distributions from exercise therapies across a range of tendinopathies and outcome domains to inform future research and clinical practice through conducting a systematic review with meta-analysis.

Design

Systematic review with meta-analysis exploring moderating effects and context-specific small, medium and large thresholds.

Eligibility criteria

Randomised and quasi-randomised controlled trials involving any persons with a diagnosis of rotator cuff, lateral elbow, patellar, Achilles or gluteal tendinopathy of any severity or duration.

Methods

Common databases, six trial registries and six grey literature databases were searched on 18 January 2021 (PROSPERO: CRD42020168187). Standardised mean difference (SMD_pre) effect sizes were used with Bayesian hierarchical meta-analysis models to calculate the 0.25 (small), 0.5 (medium) and 0.75 quantiles (large) and compare pooled means across potential moderators. Risk of bias was assessed with Cochrane's Risk of Bias tool.

Results

Data were obtained from 114 studies comprising 171 treatment arms 4104 participants. SMD_pre effect sizes were similar across tendinopathies but varied across outcome domains. Greater threshold values were obtained for self-reported measures of pain (small=0.5, medium=0.9 and large=1.4), disability (small=0.6, medium=1.0 and large=1.5) and function (small=0.6, medium=1.1 and large=1.8) and lower threshold values obtained for quality of life (small=-0.2, medium=0.3 and large=0.7) and objective measures of physical function (small=0.2, medium=0.4 and large=0.7). Potential moderating effects of assessment duration, exercise supervision and symptom duration were also identified, with greater pooled mean effect sizes estimated for longer assessment durations, supervised therapies and studies comprising patients with shorter symptom durations.

Conclusion

The effect size of exercise on tendinopathy is dependent on the type of outcome measure assessed. Threshold values presented here can be used to guide interpretation and assist with further research better establishing minimal important change.

Comparative short-term effectiveness of non-surgical treatments for insertional Achilles tendinopathy: a systematic review and network meta-analysis

BACKGROUND

The incidence of Achilles tendinopathy has risen over the past decades. Insertional Achilles tendinopathy is characterised by tissue degeneration of the Achilles tendon from its insertion in the calcaneus to up to 2 cm proximally. This clinical condition is accompanied by pain, loss of function and diminished exercise tolerance. Numerous conservative treatment modalities are available to participants with insertional Achilles tendinopathy, including eccentric exercises, extracorporeal shockwave therapy, laser therapy, cryotherapy, therapeutic ultrasound, and orthotics. Eccentric exercise and extracorporeal shockwave therapy may reduce pain in participants with non-calcified insertional Achilles tendinopathy. However, no specific treatment is recommended over another due to the low methodological quality of trials. Given the lack of standard or preferred non-surgical treatment and the potential risks of surgical treatment, there is an imminent need to reassess different non-surgical treatments based on the newest evidence. Thus, this systematic review aims to evaluate the clinical effectiveness of the various non-surgical treatments for insertional Achilles tendinopathy.

METHODS

AMED EBSCOhost, CINAHL, EBSCOhost, EMBASE, PEDro, PubMed, Web of Science, and Clinicaltrials.gov were searched from 1992 to 14th October 2022, randomised controlled trials of adults with insertional Achilles tendinopathy investigating non-surgical treatments compared with each other or no treatment, placebo/sham control. Two reviewers independently screened and extracted the data. Random effects of network meta-analysis immediately after treatments were used to report comparative treatment effects. The surface under the cumulative ranking probabilities was calculated to assess the relative ranking of treatments.

RESULTS

Nine trials (total n = 464 participants) were included. This review recommended the combination of eccentric exercise and soft tissue therapy to manage insertional Achilles tendinopathy. With the highest SUCRA values of 84.8, and the best mean rank of 1.9, Eccentric exercise plus soft tissue treatment ranked as the most effective treatment for short-term pain.

CONCLUSIONS

This is the first NMA of non-surgical treatment focusing on short-term pain control for IAT which eccentric exercise plus soft-tissue therapy was found to be the most effective treatment combination. However, the overall confidence in non-surgical treatments from all included trials was very low. No recommendation of the best treatment option can be made from this review.

Do people with musculoskeletal pain differ from healthy cohorts in terms of global measures of strength? A systematic review and meta-analysis

OBJECTIVE

It is currently unknown if people with musculoskeletal pain display different multi-joint strength capacities than healthy cohorts. The aim was to investigate whether people with musculoskeletal pain show differences in global measures of strength in comparison to healthy cohorts.

DATA SOURCES

A systematic review was conducted using three databases (Medline, CINAHL and SPORTDiscus) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

REVIEW METHODS

Studies involving participants with painful musculoskeletal conditions and multi-joint strength assessment measured at baseline were included. A meta-analysis was also performed to compute standardized mean differences (± 95% confidence intervals), using Hedge's g, and examined the differences in multi-joint strength at baseline between participants with painful musculoskeletal conditions and healthy participants.

RESULTS

In total, 5043 articles were identified, of which 20 articles met the inclusion criteria and were included in the qualitative analysis. The available evidence revealed that multi-joint strength values were limited to knee osteoarthritis, fibromyalgia, chronic low back pain, and rheumatoid arthritis. Only four studies were included in the quantitative synthesis and revealed that only small differences in both chest press (g = -0.34, 95% CI [-0.64, -0.03]) and leg press (g = -0.25, 95% CI [-0.49, -0.02]) existed between adult women with fibromyalgia and active community women.

CONCLUSION

There is a paucity of multi-joint strength values in participants with musculoskeletal pain. Quantitative comparison with healthy cohorts was limited, except for those with fibromyalgia. Adult women with fibromyalgia displayed reduced multi-joint strength values in comparison to active community women.

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.

Are models of plantar heel pain suitable for competitive runners? A narrative review

Background

Plantar heel pain (PHP), or plantar fasciopathy, is a common condition in active and sedentary populations, contributing to short- and long-term reductions in quality of life. The condition's aetiology and pathophysiology are the subjects of a significant body of research. However, much of this research has been conducted with sedentary participants, and comparatively little research exists in a population of highly-trained athletes focused on performance outcomes. Models for PHP and proposed mechanisms, such as high body mass index or systemic disease, are mostly absent from an athletic population. Even less is known about the origins of pain in PHP. Pain is believed to be a complex multifactorial process and may be experienced differently by sedentary and highly active populations, particularly endurance athletes. Consequently, conservative through to surgical treatment for athletes is informed by literature for a different population, potentially hindering treatment outcomes.

Aims

The aim of this review, therefore, is to summarise what is known about PHP in athletic populations and propose potential directions for future research.

Methods

Embase, PubMed, and Scopus using MeSH search terms for PHP and competitive sport and common synonyms.

Discussion

Two explanatory models for PHP were found. These primarily propose mechanical factors for PHP. It remains unclear how gait, body composition, and psychological factors may differ in an athletic population with and without PHP. Therefore, research in these three areas is needed to inform clinical and training interventions for this population.

Efficacy of Platelet-Rich Plasma Injection in the Management of Rotator Cuff Tendinopathy: A Review of the Current Literature

Platelet-rich plasma (PRP) is being projected as a newer and superior treatment option for rotator cuff tendinopathy. With the first use of PRP in trauma and orthopedics dating back only to 1998, its advent into the field is relatively recent. Thus, data on long-term efficacy, large cohort studies, or large randomized controlled trials are fairly limited. Moreover, owing to the absence of standardized methods of platelet extraction and lack of consensus on the ideal concentration of platelets in PRP, data comparison from different studies is difficult. Things are complicated by the fact that it is also not clear whether a single injection of PRP is therapeutic or if multiple serial injections are needed to produce the desired effects. The literature on efficacy and pain relief is also obtained from studies with low sample sizes and short follow-ups. The dropout rate and noncompliance rate were also found to be high in some studies. Thus, the data is often not clinically significant and may also be biased due to the non-standardized inclusion and exclusion criteria of the studies. Though multiple studies have suggested good pain control with PRP injection, many studies have found that PRP injection therapy may not be any better than the physical therapy regimen prescribed to patients with rotator cuff tendinopathy. Also, the data on the efficacy of PRP on shoulder function and shoulder range of motion is at variance. This submission aims to evaluate the efficacy and use of PRP in the management of rotator cuff tendinopathy.

Effects of corticosteroids and platelet-rich plasma on synoviocytes in IL-1ß-induced inflammatory condition

AIMS

Corticosteroid injections are used to treat shoulder pain. Platelet-rich plasma (PRP) is known to have anti-inflammatory and anabolic effects, as well as cytoprotective effects against corticosteroids. Thus, this study was to investigate the effects of co-treatment of corticosteroid and PRP on anti-inflammatory and matrix homeostasis of synoviocytes in IL-1ß-induced inflammatory conditions.

MATERIALS AND METHODS

Synoviocytes were cultured with 1 ng/mL IL-1β, 1 μM dexamethasone, and 10% (vol/vol) Platelet-poor plasma (PPP), PRP200, PRP1000, and PRP4000 X 10³/μL. Gene expressions of pro-inflammatory and anti-inflammatory cytokines, degradative enzymes, and their inhibitors were evaluated and protein synthesis of degradative enzymes and their inhibitors were also examined.

RESULTS

Corticosteroid modulated anti-inflammatory and pro-inflammatory cytokines, and subsequent PRP treatment did not interfere with the effect of a corticosteroid and modulated the gene expressions of cytokines such as TNF-α and IL-4, which were not regulated by the corticosteroid alone. Gene expressions and protein expressions of degradative enzymes and their inhibitors were suppressed by corticosteroid. Additional PRPs did not alter the gene expression and protein regulated by the corticosteroid and inhibited the gene expression of ADAMTS-5 and protein synthesis of MMP-9 and ADAMTS-5, which were not modulated by the corticosteroid alone.

CONCLUSION

Corticosteroid regulated the inflammation and synovial homeostasis. When PRP and the corticosteroid were used together, it exhibited synergistic effects on synoviocytes by regulating the parts that were not controlled by corticosteroid alone while not interfering with the effects of the corticosteroid in an inflammatory condition.

Autoregulation in Resistance Training for Lower Limb Tendinopathy: A Potential Method for Addressing Individual Factors, Intervention Issues, and Inadequate Outcomes

Musculoskeletal disorders, such as tendinopathy, are placing an increasing burden on society and health systems. Tendinopathy accounts for up to 30% of musculoskeletal disorders, with a high incidence in athletes and the general population. Although resistance training has shown short-term effectiveness in the treatment of lower limb tendinopathy, more comprehensive exercise protocols and progression methods are required due to poor long-term outcomes. The most common resistance training protocols are predetermined and standardized, which presents significant limitations. Current standardized protocols do not adhere to scientific resistance training principles, consider individual factors, or take the importance of individualized training into account. Resistance training programs in case of tendinopathy are currently not achieving the required intensity and dosage, leading to high recurrence rates. Therefore, better methods for individualizing and progressing resistance training are required to improve outcomes. One potential method is autoregulation, which allows individuals to progress training at their own rate, taking individual factors into account. Despite the finding of their effectiveness in increasing the strength of healthy athletes, autoregulation methods have not been investigated in case of tendinopathy. The purpose of this narrative review was 3-fold: firstly, to give an overview and a critical analysis of the individual factors involved in tendinopathy and current resistance training protocols and their limitations. Secondly, to give an overview of the history, methods, and application of autoregulation strategies both in sports performance and physiotherapy. Finally, a theoretical adaptation of a current tendinopathy resistance training protocol using autoregulation methods is presented, providing an example of how the method could be implemented in clinical practice or future research.

Local shifts in inflammatory and resolving lipid mediators in response to tendon overuse

Tendon inflammation has been implicated in both adaptive connective tissue remodeling and overuse-induced tendinopathy. Lipid mediators control both the initiation and resolution of inflammation, but their roles within tendon are largely unknown. Here, we profiled local shifts in intratendinous lipid mediators via liquid chromatography-tandem mass spectrometry in response to synergist ablation-induced plantaris tendon overuse. Sixty-four individual lipid mediators were detected in homogenates of plantaris tendons from ambulatory control rats. This included many bioactive metabolites of the cyclooxygenase (COX), lipoxygenase (LOX), and epoxygenase (CYP) pathways. Synergist ablation induced a robust inflammatory response at day 3 post-surgery characterized by epitenon infiltration of polymorphonuclear leukocytes and monocytes/macrophages (MΦ), heightened expression of inflammation-related genes, and increased intratendinous concentrations of the pro-inflammatory eicosanoids thromboxane B₂ and prostaglandin E₂ . By day 7, MΦ became the predominant myeloid cell type in tendon and there were further delayed increases in other COX metabolites including prostaglandins D₂ , F_2α , and I₂ . Specialized pro-resolving mediators including protectin D1, resolvin D2 and D6, as well as related pathway markers of D-resolvins (17-hydroxy-docosahexaenoic acid), E-resolvins (18-hydroxy-eicosapentaenoic acid), and lipoxins (15-hydroxy-eicosatetraenoic acid) were also increased locally in response to tendon overuse, as were anti-inflammatory fatty acid epoxides of the CYP pathway (eg, epoxy-eicosatrienoic acids). Nevertheless, intratendinous prostaglandins remained markedly increased even following 28 days of tendon overuse together with a lingering MΦ presence. These data reveal a delayed and prolonged local inflammatory response to tendon overuse characterized by an overwhelming predominance of pro-inflammatory eicosanoids and a relative lack of specialized pro-resolving lipid mediators.

Expanded adipose derived mesenchymal stromal cells are effective in treating chronic insertional patellar tendinopathy: clinical and MRI evaluations of a pilot study

Purpose

Effect of ultrasound guided injections of autologous ASCs in chronic recalcitrant patellar tendinopathy.

Methods

Fourteen patients (16 knees, 12/2 males/females) with chronic, recalcitrant (unsuccessfully treated with nonoperative treatments) insertional PT underwent clinical evaluation and magnetic resonance imaging (MRI) before intervention. Stromal vascular fraction cells (SVF) were expanded by in-vitro culture and characterized by flow cytometry. Players were injected with three bi-weekly injections of ASCs followed by physiotherapy. They underwent serial clinical evaluations during a 12-month period with repeated MRI at 6-month post-injection.

Results

Victorian Institute of sports assessment-patellar tendon questionnaire (VISA-P) scores improved from 43.8 ± 4.9 at baseline to 58.1 ± 7.1, 70.3 ± 7.9 and 78.7 ± 7.5 at 3, 6, and12months follow-up, respectively. (p = 0.0004 comparing each variable with the previous one). Mean Visual analogue pain in sports (VAS-sport) score during practice significantly decreased from 7.4 ± 0.5 at baseline to 5.2 ± 1.5 9 (p = 0.0005), 3.3 ± 1.1 (p = 0.0004) and 1.5 ± 0.7 (P = 0.0004) at 3, 6, and 12 months, respectively. Mean Tegner-scores for patients were 8.0 ± 0.8 before injury and 2.3 ± 0.9 before treatment, thereafter, improving to 4.8 ± 0.8 and 7.2 ± 0.7 at 6- and 12- months, respectively (p = 0.0001). MRI assessed tendon width’ did not change over the first 6 months post-intervention. Significant changes were observed for: tendon thickness (12.8 ± 1.1 to 10.9 ± 0.7, P = 0.0001); tear length (9.3 ± 1.3 to 2.3 ± 0.7, P = 0.0001), tear width (6.3 ± 0.8 to 3.4 ± 0.4, P = 0.0001), and tear thickness (4.6 ± 0.4 to 2.6 ± 0., P = 0.0001) at baseline and 6 months, respectively.

Conclusion

Patients with recalcitrant insertional PT showed significant clinical improvement and structural repair at the patellar insertional tendinopathy after injections of autologous ASCs. Results of this study are promising and open a new biological therapeutic modality to treat PT.

Exercise therapy for the treatment of tendinopathies: a scoping review protocol

OBJECTIVE

The aim of the review is to provide a map of exercise interventions and outcomes that have been reported for the treatment of any tendinopathy.

INTRODUCTION

Tendinopathy is a common condition that affects athletic and non-athletic populations. Exercise is the mainstay of conservative management of tendinopathy, and a range of different exercise types are recommended. There is a significant body of literature on exercise for tendinopathy, but to date no scoping review has provided a clear map of interventions used and outcomes reported in the literature.

INCLUSION CRITERIA

We will include people of any age or gender with a diagnosis of tendinopathy of any severity or duration at any anatomical location. We will exclude full-thickness/massive tears and plantar fasciitis. The exercise therapy may take place at any location, including hospital, community, or people's homes, and may be supervised or unsupervised. We will include systematic reviews, quantitative, qualitative, and mixed-methods studies conducted in any developed nation.

METHODS

We will search MEDLINE, CINAHL, AMED, Embase, SPORTDiscus, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, JBI Evidence Synthesis, Epistemonikos, four trial registries, and six gray literature databases. We will use Scopus to search for cited/citing articles from included studies and will perform hand searching where relevant. We will include literature from 1998 to 2020 in any language for which we can access translation. Studies will be screened by two independent reviewers at title/abstract and full-text screening stages; a third reviewer will resolve conflicts. Data will be extracted into a bespoke charting form and will be presented as figures/tables with accompanying narrative.

Species variations in tenocytes' response to inflammation require careful selection of animal models for tendon research

For research on tendon injury, many different animal models are utilized; however, the extent to which these species simulate the clinical condition and disease pathophysiology has not yet been critically evaluated. Considering the importance of inflammation in tendon disease, this study compared the cellular and molecular features of inflammation in tenocytes of humans and four common model species (mouse, rat, sheep, and horse). While mouse and rat tenocytes most closely equalled human tenocytes’ low proliferation capacity and the negligible effect of inflammation on proliferation, the wound closure speed of humans was best approximated by rats and horses. The overall gene expression of human tenocytes was most similar to mice under healthy, to horses under transient and to sheep under constant inflammatory conditions. Humans were best matched by mice and horses in their tendon marker and collagen expression, by horses in extracellular matrix remodelling genes, and by rats in inflammatory mediators. As no single animal model perfectly replicates the clinical condition and sufficiently emulates human tenocytes, fit-for-purpose selection of the model species for each specific research question and combination of data from multiple species will be essential to optimize translational predictive validity.

The implementation of resistance training principles in exercise interventions for lower limb tendinopathy: A systematic review

OBJECTIVES

The primary purpose of this systematic review is to examine the literature on resistance training interventions for lower limb tendinopathy to evaluate the proportion of interventions that implemented key resistance training principles (specificity, progression, overload, individualisation) and reported relevant prescription components (frequency, intensity, sets, repetitions) and reported intervention adherence.

METHODS

Two reviewers performed a systematic review after screening titles and abstracts based on eligibility criteria. Identified papers were obtained in full text, with data extracted regarding the implementation of resistance training principles. Included articles were evaluated by the Cochrane risk of bias tool, with a scoring tool out of 10 used for implementation and reporting of the 5 key principles. Scientific databases were searched in November 2020 and included Medline, CINAHL, AMED, and Sportsdiscus.

RESULTS

52 randomised controlled trials investigating resistance training in five different lower limb tendinopathies were included. Although most studies considered the principles of progression (92%) and individualisation (88%), only 19 studies (37%) appropriately described how this progression in resistance was achieved, and only 18 studies (35%) reported specific instruction on how individualisation was applied. Adherence was considered in 27 studies (52%), with only 17 studies (33%) reporting the levels of adherence. In the scoring criteria, only 5 studies (10%) achieved a total maximum score of 10, with 17 studies (33%) achieving a maximum score of 8 for implementing and reporting the principles of specificity, overload, progression and individualisation.

CONCLUSION

There is meaningful variability and methodological concerns regarding the application and reporting of resistance training principles, particularly progression and individualisation, along with intervention adherence throughout studies. Collectively, these findings have important implications for the prescription of current resistance training interventions, including the design and implementation of future interventions for populations with lower limb tendinopathies.

Ultrasound-guided versus blind interventions in patellar tendon lesions: a cadaveric study

PURPOSE

The present study aims to analyze the accuracy of injections aimed to hit the proximal and depth part of the patellar tendon "target point" in patellar tendinopathy, comparing ultrasound-guided or non-ultrasound-guided (blind) injections.

METHODS

A cadaver randomized study was carried out. Injections were performed under ultrasound control, as well as blinded. There were 26 knees from fresh cadavers and injections were placed by 26 practitioners with experience in the use of musculoskeletal ultrasound and injection treatment. Each participant performed 6 ultrasound-guided and 6 blind punctures in different cadaveric specimens. This provided 312 injections that were analyzed in 2 different anatomical cuts, thus providing a database of 624 measurements for statistical analysis.

RESULTS

Statistically significant differences were observed (p < 0.0001) in the distance from the target point between the ultrasound-guided and the non-guided infiltrations. The "unguided" injections were considered to have been performed on average 10 mm away from the target point compared to the "ultrasound-guided" injections. The ultrasound-guided injections obtained an accuracy of 74.36% while the "non-ultrasound-guided" injections obtained an accuracy of 11.54% (p < 0.0001).

CONCLUSION

The use of ultrasound to guide the positioning of injections on the dorsal side of the proximal patellar tendon had a significantly higher accuracy compared to blind injections. The finding provides knowledge of importance for injection treatment.

Mitochondrial Transplantation Modulates Inflammation and Apoptosis, Alleviating Tendinopathy Both In Vivo and In Vitro

Tendinopathy is a common musculoskeletal condition causing pain and dysfunction. Conventional treatment and surgical procedures for tendinopathy are insufficient; accordingly, recent research has focused on tendon-healing regenerative approaches. Tendon injuries usually occur in the hypoxic critical zone, characterized by increased oxidative stress and mitochondrial dysfunction; thus, exogenous intact mitochondria may be therapeutic. We aimed to assess whether mitochondrial transplantation could induce anti-inflammatory activity and modulate the metabolic state of a tendinopathy model. Exogenous mitochondria were successfully delivered into damaged tenocytes by centrifugation. Levels of Tenomodulin and Collagen I in damaged tenocytes were restored with reductions in nuclear factor-κB and matrix metalloproteinase 1. The dysregulation of oxidative stress and mitochondrial membrane potential was attenuated by mitochondrial transplantation. Activated mitochondrial fission markers, such as fission 1 and dynamin-related protein 1, were dose-dependently downregulated. Apoptosis signaling pathway proteins were restored to the pre-damage levels. Similar changes were observed in a collagenase injection-induced rat model of tendinopathy. Exogenous mitochondria incorporated into the Achilles tendon reduced inflammatory and fission marker levels. Notably, collagen production was restored. Our results demonstrate the therapeutic effects of direct mitochondrial transplantation in tendinopathy. These effects may be explained by alterations in anti-inflammatory and apoptotic processes via changes in mitochondrial dynamics.

Promising improvement of chronic lateral elbow tendinopathy by using adipose derived mesenchymal stromal cells: a pilot study

Purpose

Study the effect of Adipose derived stromal cells (ASCs) injection as therapeutic procedure on the common extensor tendinopathy.

Methods

Eighteen Tennis players with chronic, recalcitrant LET (who have previously been unsuccessfully treated with nonoperative treatments) underwent clinical evaluation and magnetic resonance imaging (MRI) before intervention. Stromal vascular fraction cells (SVF) were expanded by in vitro culture and ASCs were obtained and characterized by flow cytometry. ASCs were injected into the site of tendinopathy (identified by ultrasound imaging at the origin of the common extensor tendon) on a single occasion followed by physiotherapy. Players underwent serial clinical evaluations during a 12-month period and repeated MRI at 6-month post-injection.

Results

At 6-month clinical evaluation revealed significant improvements compared to baseline in mean Visual Analog Scale (VAS) scores for: (1) maximum pain score (from 6.28 ± 1.65, to 1.0 ± 0.43; p < .001); (2) Mean quick Disabilities of the Arm, Shoulder and Hand (QuickDASH-Compulsory score: 51.38 ± 12.02 to 12.33 ± 4.66; p < .001); (3) QuickDASH-Sport score: 56.94 ± 15.44 to 8.68 ± 8.86; p < .001). Validated MRI scoring system grade of tendinopathy also improved significantly: 4.22 ± 0.26 to 2.22 ± 0.10 (p < .001). At 12-month from injection, VAS maximun pain score further decreased to 0.74 ± 0.44 (p < .001) and QuickDASH-Compulsory score to 5.56 ± 3.58 (p < .001). Average time to return to play tennis was 3,31 ± 0,61 month post-intervention.

Conclusion

Tennis players with recalcitrant LET showed significant clinical improvement and structural repair at the origin of the common tendon origin after injection of autologous ASCs. Results of this study are promising and open a new biological therapeutic modality to treat LET. Even if the results of this pilot study are positive, future well-designed studies, i.e. prospective randomized trials are needed to define the role of cell therapy in treating LET.

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.

Sclerotherapy and prolotherapy for chronic patellar tendinopathies - a promising therapy with limited available evidence, a systematic review

Chronic Patellar tendinopathy (CPT) is a frequent overuse disorder in athletes and active people. Sclerotherapy (ST) and prolotherapy (PT) are, among a wide range of conservative treatment options, two promising therapies and have shown positive results in other tendinopathies. Since the treatments' efficacy and safety are still not defined, this review sought to answer questions on recommendations for use in clinical utility, safety, and how to perform the injection in the most effective way. An electronic database search was conducted following the PRISMA guidelines. Inclusion criteria were set up according to the PICOS-scheme. Included were athletes and non-athletes of all ages with diagnosed painful CPT. Studies including patients suffering from patellar tendinopathy which can be originated to any systemic condition affecting the musculoskeletal system (e.g. disorders associated with rheumatism) and animal studies were excluded. Methodological quality (modified Coleman Methodology Score) and risk of bias (Cochrane Risk of Bias Assessment Tool 2.0) were assessed by two independent reviewers, with disagreements resolved with a third reviewer. The search yielded a total of 416 entries. After screening titles, abstracts, and full texts, ten articles were found for qualitative analysis. The mean Coleman Score was 64.57. Three randomized-controlled trials showed positive results with an increase in VISA-P score or a decrease in VAS or NPPS, respectively. The non-randomized studies confirmed the positive results as well. Among all ten studies no serious adverse events were reported. Based on this limited set of studies, there seems to be some evidence that ST and PT may be effective treatment options to treat pain and to improve function in patients with CPT. To strengthen this recommendation, more research is needed with larger volume studies and randomized controlled studies with long term follow up. LEVEL OF EVIDENCE: IV.

Regeneration of a full-thickness defect in rotator cuff tendon with umbilical cord-derived mesenchymal stem cells in a rat model

Although rotator cuff disease is a common cause of shoulder pain, there is still no treatment method that could halt or reveres its development and progression. The purpose of this study was to investigate the efficacy of umbilical cord-derived mesenchymal stem cells (UC MSCs) on the regeneration of a full-thickness rotator cuff defect (FTD) in a rat model. We injected either UC MSCs or saline to the FTD and investigated macroscopic, histological and biomechanical results and cell trafficking. Treatment with UC MSCs improved macroscopic appearance in terms of tendon thickness at two weeks, and inflammation, defect size, swelling/redness and connection surrounding tissue and slidability at four weeks compared to the saline group. Histologically, UC MSCs induced the tendon matrix formation recovering collagen organization, nuclear aspect ratio and orientation angle of fibroblast as well as suppressing cartilage-related glycosaminoglycan compared to saline group at four weeks. The UC MSCs group also improved ultimate failure load by 25.0% and 19.0% and ultimate stress by 27.3% and 26.8% at two and four weeks compared to saline group. UC MSCs labeled with PKH26 exhibited 5.3% survival at four weeks compared to three hours after injection. This study demonstrated that UC MSCs regenerated the FTD with tendon tissue similar properties to the normal tendon in terms of macroscopic, histological and biomechanical characteristics in a rat model.

Regeneration of a full-thickness defect of rotator cuff tendon with freshly thawed umbilical cord-derived mesenchymal stem cells in a rat model

BACKGROUND

It is difficult to immediately use mesenchymal stem cells (MSCs) for the patient with rotator cuff disease because isolation and culture time are required. Thus, the MSCs would be prepared in advanced in cryopreserved condition for an "off-the-shelf" usage in clinic. This study investigated the efficacy of freshly thawed MSCs on the regeneration of a full-thickness tendon defect (FTD) of rotator cuff tendon in a rat model.

METHODS

We evaluated morphology, viability, and proliferation of cultured umbilical cord-derived MSCs (C-UC MSCs) and freshly thawed umbilical cord-derived MSCs (T-UC MSCs) at passage 10 in vitro. In animal experiments, we created a FTD in the supraspinatus of rats and injected the injured tendon with saline, cryopreserved agent (CPA; control), C-UC MSCs, and T-UC MSCs, respectively. Two and 4 weeks later, macroscopic, histological, biomechanical, and cell trafficking were evaluated. T test and ANOVA were used with SPSS. Differences with p < .05 were considered statistically significant.

RESULTS

T-UC MSCs had fibroblast-like morphology and showed greater than 97% viability and stable proliferation comparable to the C-UC MSCs at passage 10. In animal experiments, compared with the control group, the macroscopic appearance of the T-UC MSCs was more recovered at 2 and 4 weeks such as inflammation, defect size, neighboring tendon, swelling/redness, the connecting surrounding tissue and slidability. Histologically, the nuclear aspect ratio, orientation angle of fibroblasts, collagen organization, and fiber coherence were improved by 33.33%, 42.75%, 1.86-fold, and 1.99-fold at 4 weeks, and GAG-rich area decreased by 88.13% and 94.70% at 2 and 4 weeks respectively. Further, the T-UC MSCs showed enhanced ultimate failure load by 1.55- and 1.25-fold compared with the control group at both 2 and 4 weeks. All the improved values of T-UC MSCs were comparable to those of C-UC MSCs. Moreover, T-UC MSCs remained 8.77% at 4 weeks after injury, and there was no significant difference between C-UC MSCs and T-UC MSCs.

CONCLUSIONS

The morphology, viability, and proliferation of T-UC MSCs were comparable to those of C-UC MSCs. Treatment with T-UC MSCs could induce tendon regeneration of FTD at the macroscopic, histological, and biomechanical levels comparable to treatment with C-UC MSCs.

Hip abductor tendon tears: where are we now?

Hip abductor tendon tear is a difficult problem to manage. The hip abductor mechanism is made up of the gluteus medius and minimus muscles, both of which contribute to stabilising the pelvis through the gait cycle. Tears of these tendons are likely due to iatrogenic injury during arthroplasty and chronic degenerative tendinopathy. Ultrasound and magnetic resonance imaging have provided limited clues regarding the pattern of disease and further work is required to clarify both the macro and microscopic pattern of disease. While surgery has been attempted over the last 2 decades, the outcomes are variable and the lack of high-quality studies have limited the uptake of surgical repair. Hip abductor tendon tears share many features with rotator cuff tears, hence, innovations in surgical techniques, materials and biologics may apply to both pathologies.

[Efficacy of ultrasound guided suprascapular block in patients with chronic shoulder pain: retrospective observational study]

INTRODUCTION

Painful shoulder syndrome is a frequent condition among the elderly and an important cause of functional disability. As the conservative is not always effective, ultrasound guided suprascapular nerve blockade presents as an important alternative treatment.

OBJECTIVE

To evaluate the efficacy and safety of the use of 0.25% levobupivacaine and 40 mg of triamcinolone in the suprascapular nerve blockade in patients with chronic pain in the shoulder.

METHODS

A retrospective, descriptive and analytical study of 71 patients submitted to suprascapular nerve infiltration between August 2014 and March 2017. Surveys were carried out to patients before the technique was performed, after 72 hours, at 1, 3 and 6 months. Pain intensity was assessed using a numeric pain scale (NPS).

RESULTS

Out of the 71 patients who underwent a blockade of the suprascapular nerve, 81.2% reported a decrease in pain at 72 hours. In the first, third and sixth month, respectively, 89.8%, 76.1% and 61.8% of the patients presented pain relief. A statistically significant difference (p<0.001) was verified between NPS and the 4 moments assessed after the technique. 43.7% had total pain remission (NPS=0) at six months. Global effectiveness of suprascapular nerve blockade was 60.6% and for the subgroup of patients with rotators' cuff patology was 62.2%. No complications were reported regarding the suprascapular nerve block.

CONCLUSION

The results show that ultrasound-guided blockade of the suprascapular nerve using 0.25% levobupivacaine and 40 mg of triamcinolone is a safe and effective treatment in patients with chronic shoulder pain.

Spectrum of Tendon Pathologies: Triggers, Trails and End-State

The biggest compartment of the musculoskeletal system is the tendons and ligaments. In particular, tendons are dense tissues connecting muscle to bone that are critical for the integrity, function and locomotion of this system. Due to the increasing age of our society and the overall rise in engagement in extreme and overuse sports, there is a growing prevalence of tendinopathies. Despite the recent advances in tendon research and due to difficult early diagnosis, a multitude of risk factors and vague understanding of the underlying biological mechanisms involved in the progression of tendon injuries, the toolbox of treatment strategies remains limited and non-satisfactory. This review is designed to summarize the current knowledge of triggers, trails and end state of tendinopathies.

[Efficacy of ultrasound guided suprascapular block in patients with chronic shoulder pain: retrospective observational study]

INTRODUCTION

Painful shoulder syndrome is a frequent condition among the elderly and an important cause of functional disability. As the conservative treatment is not always effective, ultrasound guided suprascapular nerve blockade presents as an important alternative treatment.

OBJECTIVE

To evaluate the efficacy and safety of the use of 0.25% levobupivacaine and 40 mg of triamcinolone in the suprascapular nerve blockade in patients with chronic pain in the shoulder.

METHODS

A retrospective, descriptive and analytical study of 71 patients submitted to suprascapular nerve infiltration between August 2014 and March 2017. Surveys were carried out to patients before the technique was performed, after 72 hours and at 1, 3 and 6 months. Pain intensity was assessed using a numeric pain scale (NPS).

RESULTS

Out of the 71 patients who underwent a blockade of the suprascapular nerve, 81.2% reported a decrease in pain at 72 hours. In the first, third and sixth month, respectively, 89.8%, 76.1% and 61.8% of the patients presented pain relief. A statistically significant difference (p < 0.001) was verified between NPS and the 4 moments assessed after the technique. 43.7% had total pain remission (NPS = 0) at six months. Global effectiveness of suprascapular nerve blockade was 60.6% and for the subgroup of patients with rotators’ cuff patology was 62.2%. No complications were reported regarding the suprascapular nerve block.

CONCLUSION

The results show that ultrasound-guided blockade of the suprascapular nerve using 0.25% levobupivacaine and 40 mg of triamcinolone is a safe and effective treatment in patients with chronic shoulder pain.

[Damage to periarticular soft tissues in real clinical practice: frequency, nature, effectiveness of non - steroidal anti - inflammatory drugs]

Damage to periarticular soft tissues is a common pathology that causes severe pain and impaired function of the musculoskeletal system.

AIM

To determine the frequency, nature and clinical features of damage to periarticular soft tissues in real clinical practice, as well as the effectiveness of non - steroidal anti - inflammatory drugs (NSAIDs) in the debut of treatment of this pathology.

MATERIALS AND METHODS

During the observational study, the frequency of defeat of the periarticular soft tissues in the structure of visits to 68 outpatient orthopedic surgeons in different cities of Russia for 1 month was estimated. Assessed the nature and dynamics of clinical manifestations during treatment in 1227 patients with defeat of the periarticular soft tissues. NSAIDs, mainly the original meloxicam, were used as a "first line" treatment for damage of the periarticular soft tissues. The results of treatment were evaluated after 10-14 days at a repeat visit of patients.

RESULTS

The proportion of patients with damage of the periarticular soft tissues was 15.8% of the total number of people who applied for outpatient care. Among 1227 patients (men 57.5%, average age 51.3±15.5 years) who were observed in the dynamics, prevailed were those with damage of the periarticular soft tissues of the knee joint area (knee joint enthesopathy, prepatellar bursitis, tendonitis/ bursitis of the goose foot area) - 21.2%, feet (plantar fasciitis, calcaneal spur) - 16.9%, shoulder (tendonitis of the muscles of the shoulder rotators) - 16.4% and the elbow (lateral and medial epicondylitis) - 15.3%. During treatment, there was a significant decrease in the total severity of pain - from 6.58±1.61 to 2.48±1.60 points on an 11-point numerical rating scale (p.

Ankle Joint Position and the Reliability of Ultrasound Tissue Characterization of the Achilles Tendon: A Pilot Study

Background

Imaging of the Achilles tendon using ultrasound tissue characterization (UTC) involves taking up the slack of the tendon by including dorsiflexion of the ankle. This pilot study aimed to determine whether different longitudinal tension applied to the Achilles tendon during imaging affected the reliability of UTC.

Material/Methods

Nine asymptomatic active volunteers, aged between 23–49 years underwent imaging of 17 Achilles tendons. Three positions of tension included plantar grade, 50%, and 100% of maximal dorsiflexion, with a range of 18–32°. Ranges were established and standardized using an isokinetic dynamometer. A test and re-test process was conducted at each position to determine the intraclass correlation coefficients (ICCs) and minimum detectable change (MDC) per echotype. Images were analyzed using UTC software.

Results

Plantar grade positioning images could not be obtained. ICCs for each echotype I–IV between test 1 and test 2 were 0.965, 0.962, 0.858, 0.739 at 100% dorsiflexion (95% CI, 0.86–0.99, 0.84–0.99, 0.51–0.97, and 0.2–0.94), and 0.771, 0.551, 0.569, 0.429 at 50% dorsiflexion (95% CI, 0.29–0.94, −0.09–0.88, −0.01–0.88, and −0.15–0.82). The MDC per echotype I–IV ranged between 4.1–1.0% of echotype data at 100% dorsiflexion, and 17.2–6.3% at 50% dorsiflexion.

Conclusions

Testing at maximum dorsiflexion provided improved reliability when using UTC in healthy individuals. The ICC at 100% dorsiflexion was increased, and the MDC was reduced for all echotypes. Therefore, standardizing test positions when using UTC is advisable for reliable comparison of results between studies.

Patellar Tendon Strain Associates to Tendon Structural Abnormalities in Adolescent Athletes

High mechanical strain is thought to be one of the main factors for the risk of tendon injury, as it determines the mechanical demand placed upon the tendon by the working muscle. The present study investigates the association of tendon mechanical properties including force, stress and strain, and measures of tendon micromorphology and neovascularization, which are thought to be indicative of tendinopathy in an adolescent high-risk group for overuse injury. In 16 adolescent elite basketball athletes (14–15 years of age) we determined the mechanical properties of the patellar tendon by combining inverse dynamics with magnetic resonance and ultrasound imaging. Tendon micromorphology was determined based on a spatial frequency analysis of sagittal plane ultrasound images and neovascularization was quantified as color Doppler area. There was a significant inverse relationship between tendon strain and peak spatial frequency (PSF) in the proximal tendon region (r = −0.652, p = 0.006), indicating locally disorganized collagen fascicles in tendons that are subjected to high strain. No such associations were present at the distal tendon site and no significant correlations were observed between tendon force or stress and tendon PSF as well as between tendon loading and vascularity. Our results suggest that high levels of tendon strain might associate to a micromorphological deterioration of the collagenous network in the proximal patellar tendon, which is also the most frequent site affected by tendinopathy. Neovascularization of the tendon on the other hand seems not to be directly related to the magnitude of tendon loading and might be a physiological response to a high frequency of training in this group. Those findings have important implications for our understanding of the etiology of tendinopathy and for the development of diagnostical tools for the assessment of injury risk.

S100A8 & S100A9: Alarmin mediated inflammation in tendinopathy

Alarmins S100A8 and S100A9 are endogenous molecules released in response to environmental triggers and cellular damage. They are constitutively expressed in immune cells such as monocytes and neutrophils and their expression is upregulated under inflammatory conditions. The molecular mechanisms that regulate inflammatory pathways in tendinopathy are largely unknown therefore identifying early immune effectors is essential to understanding the pathology. Based on our previous investigations highlighting tendinopathy as an alarmin mediated pathology we sought evidence of S100A8 & A9 expression in a human model of tendinopathy and thereafter, to explore mechanisms whereby S100 proteins may regulate release of inflammatory mediators and matrix synthesis in human tenocytes. Immunohistochemistry and quantitative RT-PCR showed S100A8 & A9 expression was significantly upregulated in tendinopathic tissue compared with control. Furthermore, treating primary human tenocytes with exogenous S100A8 & A9 significantly increased protein release of IL-6, IL-8, CCL2, CCL20 and CXCL10; however, no alterations in genes associated with matrix remodelling were observed at a transcript level. We propose S100A8 & A9 participate in early pathology by modulating the stromal microenvironment and influencing the inflammatory profile observed in tendinopathy. S100A8 and S100A9 may participate in a positive feedback mechanism involving enhanced leukocyte recruitment and release of pro-inflammatory cytokines from tenocytes that perpetuates the inflammatory response within the tendon in the early stages of disease.

The immediate sensorimotor effects of elbow orthoses in patients with lateral elbow tendinopathy: a prospective crossover study

BACKGROUND

Counterforce orthoses are used to manage lateral elbow tendinopathy, and their effectiveness in improving motor function has been documented. Little is known about the impact of bracing on sensory function. The objective of this study was to investigate the immediate effectiveness of 2 counterforce orthoses in improving the sensorimotor abilities of the hand in patients with lateral elbow tendinopathy.

METHODS

In this crossover, randomized controlled trial, elbow proprioception, pain severity, pain-free grip strength, and finger dexterity were measured in 50 participants with a diagnosis of lateral elbow tendinopathy. Outcomes were measured in 3 randomized conditions (no brace, forearm band, or elbow sleeve). Data were analyzed using 1-way repeated-measures analysis of variance for each outcome measure.

RESULTS

Better scores were observed with the forearm band, as compared with no orthosis, for multiple outcomes including joint position reproduction score at 70° of elbow flexion (P = .006), pain (P < .001), grip strength (P = .01), and dexterity (P < .001). The elbow sleeve yielded better scores than no orthosis for the following outcomes: joint position reproduction score at 110° (P < .001), pain (P < .001), and grip strength (P = .012). No statistically significant difference was found between the orthoses' effects on pain reduction and grip strength (P > .05). The forearm band showed better scores on joint position reproduction at 70° compared with the elbow sleeve (P = .006), whereas the elbow sleeve showed better scores at 110° (P < .001).

CONCLUSION

Our results support the mechanisms occurring with the use of either of the described orthotic interventions. Future randomized trials with longer-term outcomes that include sensorimotor mechanisms might enhance our understanding of the comparative effectiveness.

Current trends in tendinopathy: consensus of the ESSKA basic science committee. Part II: treatment options

The treatment of painful chronic tendinopathy is challenging. Multiple non-invasive and tendon-invasive methods are used. When traditional non-invasive treatments fail, the injections of platelet-rich plasma autologous blood or cortisone have become increasingly favored. However, there is little scientific evidence from human studies supporting injection treatment. As the last resort, intra- or peritendinous open or endoscopic surgery are employed even though these also show varying results. This ESSKA basic science committee current concepts review follows the first part on the biology, biomechanics and anatomy of tendinopathies, to provide a comprehensive overview of the latest treatment options for tendinopathy as reported in the literature.

Hyaluronic Acid

In recent times, the field of tissue engineering and regenerative medicine (TERM) has considerably increased the extent of therapeutic strategies for clinical application in orthopedics. However, TERM approaches have its rules and requirements, in the respect of the biologic response of each tissue and bioactive agents which need to be considered, respected, and subject of ongoing studies. Different medical devices/products have been prematurely available on the market and used in clinics with limited success. However, other therapeutics, when used in a serious and evidence-based approach, have achieved considerable success, considering the respect for solid expectations from doctors and patients (when properly informed).Orthobiologics has appeared as a recent technological trend in orthopedics. This includes the improvement or regeneration of different musculoskeletal tissues by means of using biomaterials (e.g., hyaluronic acid), stem cells, and growth factors (e.g., platelet-rich plasma). The potential symbiotic relationship between biologic therapies and surgery makes these strategies suitable to be used in one single intervention.However, herein, the recent clinical studies using hyaluronic acid (HA) in the treatment of orthopedic conditions will mainly be overviewed (e.g., osteochondral lesions, tendinopathies). The possibilities to combine different orthobiologic agents as TERM clinical strategies for treatment of orthopedic problems will also be briefly discussed.