Treatment of tendinopathy: what works, what does not, and what is on the horizon

Preoperative Increases in T2-Weighted Fat-Suppressed Magnetic Resonance Imaging Signal Intensities Associated With Advanced Tissue Degeneration and Mitochondrial Dysfunction in Rotator Cuff Tears

PURPOSE

To investigate the relationship between magnetic resonance imaging (MRI) signal intensities and mitochondrial function in patients undergoing arthroscopic rotator cuff repair, assessed through histological and genetic profiling of tendon tissue.

METHODS

This study, conducted between April 2022 and January 2023, included 20 patients undergoing rotator cuff repair for atraumatic/degenerative tears. Rotator cuff tendon edge samples were obtained during arthroscopic rotator cuff repair. Patients were classified based on signal intensity from preoperative T2-weighted fat suppressed MRI. Specifically, they were categorized as having either high or low signal intensity at the rotator cuff tendon edge, with the deltoid muscle serving as a reference. Comparative analyses specifically compared the histological features and genetic profiles of the tendon tissue at the rotator cuff tendon edge. Histological evaluation of harvested tendon specimens during arthroscopic rotator cuff repair employed the modified Bonar score. Real-time polymerase chain reaction was used to assess expression of various mitochondrial and apoptosis-related genes. The mitochondrial morphology of the rotator cuff torn site was examined using electron microscopy.

RESULTS

The higher signal intensity group showed significantly higher modified Bonar scores (P = .0068), decreased mitochondrial gene expression, increased TdT-mediated dUTP-biotin nick end labeling-positive cells (P = .032), lower superoxide dismutase activity (P = .011), reduced ATP5A (P = .031), and increased cleaved caspase-9 activity (P = .026) compared with the lower signal intensity group. Electron microscopy revealed fewer mitochondrial cristae in the higher signal intensity group.

CONCLUSIONS

Our results suggest correlations between high MRI signal intensities and the presence of degeneration, mitochondrial dysfunction, and increased apoptosis in rotator cuff tissues. This underscores the utility of MRI signal intensity as an indicator of tissue condition.

CLINICAL RELEVANCE

This work builds on the premise that elevated preoperative MRI signal intensities may indicate higher rates of postoperative rotator cuff re-tears, substantiating these findings from a mitochondrial function perspective.

Editorial Commentary: Magnetic Resonance Imaging Reveals Rotator Cuff Tear Size, Retraction, Length, and Geometry; Muscle Volume and Degeneration; and Tendon Quality

Magnetic resonance imaging (MRI) of the shoulder is commonly used for evaluating muscle bulk and fatty degeneration, as well as tendon tear size, geometry, retraction, and length. However, MRI can also be used to evaluate tendon quality. Increased rotator cuff tendon signal on T2-weighted fat-suppressed MRI appears to be a marker of tendon degeneration and potentially of impaired healing potential. Tendon signal intensity merits closer attention and may be especially relevant when selecting chronic degenerative tears for repair in patients with other risk factors for nonhealing.

Photobiomodulation Controls the Expression of Lipoxin Receptors, Promoting the Resolution of the Inflammatory Process in an Experimental Tendinitis Model

Tendinopathies are a significant global health issue due to their detrimental effects on mobility and quality of life. Pharmacological treatments, although widely used for pain management, often demonstrate limited efficacy. Photobiomodulation therapy (PBM) has emerged as a potential adjunctive treatment due to its capacity to modulate inflammation and alleviate pain. Nevertheless, further research is required to elucidate its mechanisms of action, particularly concerning the resolution of the inflammatory process. This study aimed to evaluate the effects of PBM on inflammation control in an experimental tendinitis model by analyzing inflammatory infiltrate, myeloperoxidase (MPO) activity, the expression of inflammatory and resolution markers (TNF-α, TGF-β, COX-2, and ALX), and protein levels of PGE2 and COX-2 in rat Achilles tendons with type I collagen-induced tendinitis. Male Wistar rats were randomized into five groups: healthy control (CTL), untreated tendinitis (NT), PBM-treated tendinitis (830 nm; 3 J; 30 mW; 64 J/cm²), or tendinitis treated with sodium diclofenac (DIC; 1 mg/kg IM). After 2 or 12 h, tissues and blood were collected for biochemical and histological analysis. The NT group exhibited increased inflammatory infiltrate, MPO activity (p < 0.001), COX-2, TNF-α (p < 0.001), and PGE2 expression (p < 0.01) but lacked ALX receptor upregulation. PBM and DIC treatments significantly reduced inflammatory infiltrate and MPO activity (PBM: p < 0.001; DIC: p < 0.01). PBM enhanced ALX and TGF-β expression (p < 0.001) and maintenance of COX-2 similar to the NT group, suggesting lipoxin involvement in inflammation resolution. These findings highlight PBM as a promising therapy for tendinopathies by targeting both inflammatory and resolution pathways.

Valdecoxib Ameliorates Apoptosis and Ferroptosis in Tenocytes via the SIRT6/NRF2-Mediated Suppression of Oxidative Stress

BACKGROUND AND AIMS

Valdecoxib (VAL), a nonsteroidal anti-inflammatory drug (NSAID), is widely used in the treatment of osteoarthritis and rheumatoid arthritis. In addition to its anti-inflammatory properties, VAL has been shown to improve skeletal muscle insulin resistance and attenuate hepatic steatosis in obese individuals. However, its potential effects on oxidative stress injury in tenocytes remain unclear. This study aims to explore novel functions of VAL by investigating its impact on cell death in oxidative stress-exposed tenocytes and elucidating the underlying molecular mechanisms, with a focus on its therapeutic potential for the treatment of tendinopathy.

METHODS

Apoptosis was assessed using cell viability assays, caspase-3 activity measurements, and TUNEL staining. Hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels in tenocytes were quantified using appropriate assay kits, while reactive oxygen species (ROS) were detected by DCFDA staining. Tenocyte migration was evaluated using a scratch assay, and protein expression levels were analyzed by Western blotting.

RESULTS AND CONCLUSION

In the present study, we found that VAL treatment suppressed apoptosis and ferroptosis and normalized the expression of extracellular matrix (ECM) degradation markers, and enhanced cell migration in H2O2-treated tenocytes. VAL treatment increased the expression of SIRT6 and NRF2 and the activities of antioxidant enzymes. SIRT6-targeted siRNA abrogated the effects of VAL on tenocytes treated with H2O2. It also reduced VAL-induced NRF2 expression and antioxidant enzyme activities. These results suggest that VAL ameliorates oxidative stress induced tenocyte dysfunction through SIRT6/NRF2-mediated signaling. Therefore, this study highlights a potential therapeutic strategy for the treatment of overuse-induced tendinopathy.

Commercial Biomaterial-Based Products for Tendon Surgical Augmentation: A Scoping Review on Currently Available Medical Devices

Tendon defect is one of the common clinical diseases related to the growing population mean age and the number of athletes. Due to an increasing demand for tendon repair surgical interventions, several tendon augmentation products, capable of guaranteeing the necessary biological and visco-elasticity properties and mechanical support, have been developed. In this regard, commercially available products may be grouped into three main categories: (i) natural, (ii) synthetic, and (iii) hybrid biomaterial-based products. Firstly, to better define the research area of this work, common search engines were employed to acquire information from reports or website portfolios of important competitors in the global tendon repair market. Secondly, public registries and bibliographic databases were also employed to analyse data from registered clinical trials and published clinical studies performed to evaluate the safety and efficacy of each product. Ten new products have been launched on the market in the last fifteen years: advantages, disadvantages, and future perspectives regarding their use for tendon augmentation treatment are discussed. Although hybrid biomaterial-based products may be considered as more oriented to the new frontiers of tendon augmentation technology, future improvements, especially focused on both mechanical properties and biocompatibility, are needed. However, scientific innovations must navigate convoluted clinical regulatory paths, which, due to high costs for investors, long development timelines, and funding shortages, hinder the translation of many scientific discoveries into routine clinical practice.

Effects of Autologous Tenocyte Injection for Overuse and Degenerative Tendinopathies: A Systematic Review

Background: The term tendinopathy commonly describes a series of alterations in the tendon, leading in functional impairment and pain, treated with several approaches, including exercises, physical agents, and injection therapies. Among the latter, autologous tenocyte injection (ATI) involves harvesting tenocytes from a healthy tendon of the patients and then isolating the tenocytes and culturing for 4-5 weeks. To date, there is still a lack of consensus about the efficacy of ATI in improving pain and function; therefore, the present review aimed to assess the role of ATI in the treatment of chronic tendinopathies. Methods: Two authors conducted a comprehensive search across PubMed Medline, Web of Science, Scopus, Cochrane Library, and Google Scholar (PROSPERO: CRD42024565211). From 174 articles, we finally included 5 articles. Results: The main effect obtained was the pain relief and, consequently, the improvement of patients' quality of life. The clinical improvement is also evident at MRI in which it is possible to see a progressive reduction with a general disappearance of the T2 signal hyperintensity between 4 months and 1 year. All the articles agree on the safety of ATI in chronic tendinopathies. Conclusions: ATI might represent a safe and valuable option in the management of chronic tendinopathies as a second line treatment in the case of resistant tendinopathies, with a minimal risk of side effects.

State-of the-art and future perspective in co-culture systems for tendon engineering

Tendon is a connective tissue that links bone to muscle, allowing for maintenance of skeleton posture, joint movement, energy storage and transmission of muscle force to bone. Tendon is a hypocellular and hypovascular tissue of poor self-regeneration capacity. Current surgical treatments are of limited success, frequently resulting in reinjury. Upcoming cell therapies are primarily based on tenocytes, a cell population of limited self-renewal capacity in vitro or mesenchymal stromal cells, a cell population prone to ectopic bone formation in vivo. Over the years mono- or multi- factorial cell culture technologies have failed to effectively maintain tenocyte phenotype in culture during expansion or to prime mesenchymal stromal cells towards tenogenic lineage prior to implantation. Upon these limitations the concept of co-culture was conceived. Here, we comprehensively review and discuss tenogenic differentiation of mesenchymal stromal cells through direct or indirect culture with tenocytes in an attempt to generate a tenocyte or a tendon-like cell population for regenerative medicine purposes.

Mature murine supraspinatus tendons demonstrate regional differences in multiscale structure, function and gene expression

The hierarchical structure of tendon dictates its ability to effectively transmit loads from muscle to bone. Tendon- and site-specific differences in mechanical loading result in the establishment and remodeling of structure, as well as associated changes in composition throughout development and healing. Previous work has demonstrated region-specific differences in the response of collagen fibrils to mechanical loading within the insertion region and midsubstance regions of mouse supraspinatus tendons using atomic force microscopy. However, multiscale structure, function, and gene expression differences between the insertion and midsubstance of the supraspinatus tendon have not yet been linked together in a comprehensive study. Therefore, the purpose of this study was to elucidate site-specific hierarchical structure, function, and gene expression differences in mouse supraspinatus tendons. Supraspinatus tendons from day 150 wild-type C57BL/6 mice were harvested for regional mechanics, histology, transmission electron microscopy (TEM), and quantitative polymerase chain reaction (qPCR). Mechanical testing revealed that the midsubstance region demonstrated a greater modulus and increased collagen fiber realignment compared to the insertion region. Histological scoring demonstrated greater cellularity and more rounded cells in the insertion region. TEM analysis showed differences in collagen fibril diameter distributions between the two regions, with a shift towards smaller diameters observed at the insertion region. Gene expression analysis identified several genes that were differentially expressed between regions, with principal component analysis revealing distinct clustering based on region. These findings provide insight into the regional heterogeneity of the supraspinatus tendon and underscore the importance of considering these differences in the context of tendon injury and repair, contributing to a better understanding of tendon structure-function and guiding future studies aimed at elucidating the mechanisms underlying tendon pathology.

The comparison of the efficacy of intramuscular tetracosactide and subacromial triamcinolone injection in rotator cuff tendinitis: a randomized trial

Objectives

Rotator cuff tendinitis (RCT) is a tendon inflammation often following subacromial impingement syndrome. One of the non-surgical management modalities for RCT is subacromial injection of corticosteroids. Some studies have claimed a correlation between ACTH (Adrenocorticotropic Hormone) deficiency and rotator cuff lesions; hence, intramuscular ACTH analogue injection has been recommended as an option. This research aimed to compare the effectiveness of these two treatment methods.

Methods

We conducted a study with 86 patients suffering from RCT. The patients were randomly divided into two groups of 43; one group received a subacromial injection of 40 mg of triamcinolone acetonide, while the other group received 1 mg of intramuscular tetracosactide injection. We recorded the Constant-Murley (CM) and visual analogue scale (VAS) scores for each patient before and 4 weeks after injections to measure pain acuity and joint functionality. Later, we compared and analysed the two scores in each group.

Results

Based on the statistical analysis, the mean ages of the participants in the triamcinolone and tetracosactide groups were 53.21 ± 11.37 and 54.56 ± 11.98, respectively. Both groups demonstrated an improvement in VAS for pain and CM scores (P < 0.05). However, the VAS for pain score decreased, and the CM score increased more significantly in the triamcinolone group than in the tetracosactide group (P < 0.05).

Conclusion

Although both treatment methods exhibit promise for pain relief, subacromial injection of triamcinolone appears more efficacious than intramuscular injection of tetracosactide in patients with RCT, based on a 4-week follow-up.

Trial registration

Iranian Registry of Clinical Trials, https://irct.behdasht.gov.ir, IRCT20240110060673N1.

Evaluating the effect of VersaWrap tendon protector on functional outcomes in operative tendon repairs

Background

Tendon repairs often result in adhesion formation which can cause persisting functional deficits. Close proximity of healing tissues increases friction during tendon excursion, often leading to tendon tethering postoperatively. Despite continued improvements in techniques for tendon repairs, there is currently no consensus on the most effective modality to reduce adhesion formation. The VersaWrap Tendon Protector is a bioresorbable hydrogel that is FDA-cleared for use in tendon repair by separating healing tendons from surrounding tissues and improving tendon gliding. We conducted a study to assess the efficacy of VersaWrap in improving clinical outcomes related to adhesions and tethering in tendon repairs involving the hand.

Materials & methods

Age, sex, injury type, mechanism of injury, visual analogue scale (VAS) pain scores, active and passive range of motion (ROM), percent return to normal function, and patient-reported outcomes forms (QuickDASH) were collected at baseline and routine follow up visits. Functional outcomes were classified according to Strickland and Glogovac grading system.

Results

90 patients were included, with an average age of 39.8 years and a 44% female gender. The most common mechanism of injury was sharp laceration, and the majority of repairs involved the extensor mechanism (58.8% extensor, 35.3% flexor, 5.8% both). At a mean follow-up of 4.6 months, the mean active and passive ROM was 88.8% and 94.3%, respectively. Mean percent return of function was 87.7%. Good or Excellent functional outcomes were achieved in 92.3% of patients - 70.5% Excellent, 21.8% Good, 6.4% Fair, 1.3% Poor. The average QuickDASH score was 30.7, and the average final VAS pain score was 1.3.

Conclusions

Tendon repairs and tenolysis procedures often result in reduced functionality due to impeded tendon gliding, and there is currently no consensus on optimal treatment to prevent tethering to surrounding tissues. The VersaWrap Tendon Protector creates a gelatinous layer between the tendon and surrounding soft tissue to improve gliding resistance, thereby limiting tendon sheath adhesions. Our data suggests that VersaWrap may be a useful adjunct in preventing tendon tethering adhesion post-repair.

Ultrasound-guided suprascapular nerve block with lidocaine vs. saline combined with physical exercises for the rehabilitation of supraspinatus tendinitis: a randomized double-blind controlled trial

Introduction

Shoulder pain is the third leading cause of musculoskeletal complaints in primary care clinics. Its prevalence varies from 14% to 34%. Among all the structures that can cause shoulder pain, the most vulnerable to injury is the tendon of the supraspinatus muscle. The ideal management protocol is still unknown. To date, little is known in the literature about the use of ultrasound-guided suprascapular nerve block as a treatment for supraspinatus muscle tendinitis. Our objective was to assess the effects of the association of a single ultrasound-guided suprascapular nerve block combined with home-based rotator cuff exercises to reduce pain and improve shoulder functioning in patients with supraspinatus tendinitis.

Methods

We evaluated the effect of a single ultrasound-guided suprascapular nerve block on pain and functioning of people with supraspinatus tendinitis. Diagnosis was performed using the positive Jobe test. Due to large disparity between clinical and radiological findings, only clinical diagnostic criteria were used to select patients. This was a double-blind, randomized, controlled, clinical study in which patients in the intervention group (n = 42) received a single injection of 5 ml of 2% lidocaine, while in the control group (n = 41) patients underwent the same procedure receiving saline solution 0.9%. All patients received face to face instructions by an experienced physiotherapist and a leaflet explaining home-based exercises. Pain and functioning were assessed using the Shoulder Pain and Disability Index (SPADI) questionnaire before the procedure, one week and 12 weeks after the procedure.

Results

Patients in both groups improved significantly since the initial evaluation until the 12th week. Intervention group SPADI (pre, 1 week, 12 weeks): 75.80 ± 18.96, 56.25 ± 31.37, 46.31 ± 31.41 (p < 0.001); Control group SPADI: 75.49 ± 16.67, 50.51 ± 27.58, 49.37 ± 30.90 (p < 0.001). However, there were no significant differences between groups (p = 0.291).

Discussion/conclusion

We concluded that both lidocaine and saline ultrasound-guided suprascapular nerve blocks reduce pain and improve shoulder functioning in patients with supraspinatus tendinitis. Unexpectedly, the same block performed with saline showed similar results and effects.

Clinical Trial Registration

ClinicalTrials.gov, identifier [NCT02495818].

Mitochondrial destabilization in tendinopathy and potential therapeutic strategies

Tendinopathy is a prevalent aging-related disorder characterized by pain, swelling, and impaired function, often resulting from micro-scarring and degeneration caused by overuse or trauma. Current interventions for tendinopathy have limited efficacy, highlighting the need for innovative therapies. Mitochondria play an underappreciated and yet crucial role in tenocytes function, including energy production, redox homeostasis, autophagy, and calcium regulation. Abnormalities in mitochondrial function may lead to cellular senescence. Within this context, this review provides an overview of the physiological functions of mitochondria in tendons and presents current insights into mitochondrial dysfunction in tendinopathy. It also proposes potential therapeutic strategies that focus on targeting mitochondrial health in tenocytes. These strategies include: (1) utilizing reactive oxygen species (ROS) scavengers to mitigate the detrimental effects of aberrant mitochondria, (2) employing mitochondria-protecting agents to reduce the production of dysfunctional mitochondria, and (3) supplementing with exogenous normal mitochondria. In conclusion, mitochondria-targeted therapies hold great promise for restoring mitochondrial function and improving outcomes in patients with tendinopathy. The translational potential of this article: Tendinopathy is challenging to treat effectively due to its poorly understood pathogenesis. This review thoroughly analyzes the role of mitochondria in tenocytes and proposes potential strategies for the mitochondrial treatment of tendinopathy. These findings establish a theoretical basis for future research and the clinical translation of mitochondrial therapy for tendinopathy.

The Use of Platelet-Rich Plasma in De Quervain's Tenosynovitis: A Systematic Review

De Quervain's disease (DQVD) is the stenosing tenosynovitis of tendons in the first extensor compartment of the forearm. It is a common inflammatory condition that is often treated conservatively. While conservative therapy is an effective modality of treatment for a large number of patients suffering from DQVD, some patients do not improve with conservative measures. Many alternative treatment modalities are recognized in the treatment of DQVD. One of the non-surgical treatment strategies that is currently on the rise is platelet-rich plasma (PRP) injections into the first dorsal extensor compartment. It is thought that PRP injections contain growth factors that may provide a regenerative stimulus to tendon healing. Various studies evaluated as a treatment modality for different tendinopathies including DQVD. There remains, however, controversy as to the efficacy of its benefit and efficacy in treating DQVD. This paper is a systematic review of the literature conducted to evaluate the effectiveness of PRP in the treatment of DQVD. The review was conducted in line with PRISMA guidelines for systematic reviews. The review included a systematic search through PubMed, Embase, Cochrane Library, Medline, Amed, and the Web of Sciences, and was supplemented by manual search through other published online resources. The period of search was defined as January 2013 to October 2023, and the search included all studies that evaluated the use of PRP in the treatment of DQVD. A total of 1,029 records were screened; only eight studies met the inclusion criteria and were included in the study. Three randomized clinical trials and five experimental studies were included in the review. A systematic review of the evidence suggested that PRP is a promising and safe alternative to conventional steroid injections in the treatment of De Quervain's tenosynovitis. Further large sample studies are needed prior to the definitive recommendation of PRP as the gold standard for the treatment of De Quervain's tenosynovitis.

Effects of Conditioned Media From Human Umbilical Cord-Derived Mesenchymal Stem Cells on Tenocytes From Degenerative Rotator Cuff Tears in an Interleukin 1β-Induced Tendinopathic Condition

Background

Evidence suggests that mesenchymal stem cells (MSCs) are safe for treating different tendinopathies. Synovial fluid is a pooled environment of biomarkers from the inflammatory and degenerative joint cavity. Understanding the effects of synovial fluid on MSCs is important, as it is the first microenvironment that administered MSCs encounter. Several studies have reported that exposure to osteoarthritic synovial fluid-activated MSCs increased the release of soluble factors; however, the paracrine effects of shoulder synovial fluid-stimulated umbilical cord-derived MSCs (SF-UC-MSCs) on tendinopathy have yet to be investigated.

Purpose

To assess the effects of the conditioned media from SF-UC-MSCs on tenocytes from degenerative rotator cuff tears in an interleukin-1β (IL-1β)-induced tendinopathic condition.

Study Design

Controlled laboratory study.

Methods

UC-MSCs were isolated and cultured from healthy, full-term deliveries by cesarean section. Tenocytes were isolated and cultured from patients with degenerative rotator cuff tears. Conditioned media were obtained from UC-MSCs stimulated with synovial fluid. To evaluate the gene expression of proinflammatory and anti-inflammatory cytokines, enzymes and their inhibitors, matrix molecules, and growth factors, the tenocytes were cultured with IL-1β and 50% of the conditioned media from the SF-UC-MSCs; quantitative, real-time, reverse transcriptase polymerase chain reaction was also performed. A prostaglandin E2 (PGE2) assay was performed to investigate the PGE2 level secreted by the tenocytes. Western blotting was performed to examine protein synthesis of collagen type I and III. Cell viability, senescence, and apoptosis assays were also performed.

Results

The conditioned media from the SF-UC-MSCs interfered with the inflammatory gene expression on tenocytes induced by IL-1β, but it increased the gene expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-3. Meanwhile, the conditioned media decreased the PGE2 level on cells induced by IL-1β. It did increase the type I/III ratio of gene expression and protein synthesis, mainly through the induction of type I collagen. Conditioned media of SF-UC-MSCs reversed senescence and apoptosis induced by IL-1β.

Conclusion

Study findings indicated that the conditioned media from SF-UC-MSCs had anti-inflammatory effects and cytoprotective effects on IL-1β-treated tenocytes from degenerative rotator cuff tears.

Clinical Relevance

UC-MSCs have useful potential for the treatment of tendinopathy in practice.

Comprehensive assessment of heavy slow resistance training and high-dose therapeutic ultrasound in managing patellar tendinopathy, a randomized single-blind controlled trial

BACKGROUND

Patellar tendinopathy (PT) is a common sport injury prone to recurrence. Heavy Slow Resistance Training (HSR) and High-Dose Therapeutic Ultrasound (TUS) are frequently used interventions for PT. However, the combined effectiveness of these therapies remains unclear. This study investigated the impact of combination therapy on functional outcomes in patients with PT.

METHODS

Fifty-one college students aged 18-25, diagnosed with PT via musculoskeletal ultrasound, were randomly assigned to one of three groups (n = 17 per group): combined HSR and high-dose TUS, HSR training alone, or high-dose TUS alone. The eight-week intervention included assessments using the Victorian Institute of Sport Assessment-Patella (VISA-P), Visual Analogue Scale (VAS), Y-balance Test (YBT), Modified Thomas Test (MTT), Horizontal Jumping Distance, Maximum Isometric Muscle Strength Test, and musculoskeletal ultrasound for patellar tendon thickness and blood flow. Assessments were conducted at baseline and post-intervention, with a follow-up VISA-P assessment at week 16. This randomized, single-blind controlled trial was registered on ISRCTN11447397 ( www.ISRCTN.com ) on February 17, 2024 (retrospectively registered).

RESULTS

All groups demonstrated significant improvements in VISA-P scores at the end of the intervention compared to baseline (p < 0.01), with the combined group showing the greatest improvement (21 points). Follow-up at week 16 revealed continued improvement in VISA-P scores for the combined and HSR groups, while the TUS group showed a slight decrease (from 74 to 70). All groups displayed significantly reduced VAS scores post-intervention (p < 0.01) compared to baseline, indicating decreased pain. While no significant between-group differences were observed in pre-intervention VAS scores, post-intervention results revealed significant differences between the combined and HSR groups (p < 0.05), as well as between the combined and TUS groups (p < 0.01).

CONCLUSION

Both exercise intervention and high-dose TUS appear effective in reducing pain and improving motor function in individuals with PT. However, the therapeutic effect of high-dose TUS alone seems limited compared to exercise intervention. The combined application of both methods yielded the most significant improvements in pain relief and motor function enhancement.

Effectiveness of Percutaneous Needle Tenotomy for Tendinopathies: A Systematic Review

CONTEXT

Tendinopathy is a disease state characterized by tendon disorder with pain or decreased function that can cause significant disability. Multiple treatment modalities exist; however, no single treatment is superior. Ultrasound-guided percutaneous needle tenotomy (PNT) and TENEX are emerging as promising treatment options for tendinopathy.

OBJECTIVE

To review the current literature of reported outcomes for PNT, TENEX, and TENJET, for the treatment of tendinopathy, including pain relief, change in function, and patient-reported outcomes.

DATA SOURCES

A comprehensive search was conducted from database inception to September 2023 in Ovid Medline, Ovid Embase, and Cochrane Library.

STUDY SELECTION

Keywords and index terms related to tendon injury, ultrasound, and tenotomy were used in combination to identify relevant literature that included ultrasound-guidance, treatment of tendinopathy, and treatment with PNT, TENEX, or TENJET. Covidence Systematic Review Software used to screen for relevant studies. Only English-language studies were included.

STUDY DESIGN

Systematic Review using PICO framework as defined and registered with the International Prospective Register of Systematic Reviews (PROSPERO ID CRD42022321307).

LEVEL OF EVIDENCE

Level 4 (evidence from a systematic review graded to the lowest level of study included).

DATA EXTRACTION

Articles meeting the inclusion criteria were reviewed. Type and region of tendinopathy studied, outcome measures, and complications were recorded. Clinical and self-reported outcomes data were compared across studies.

RESULTS

A total of 10 studies, representing 11 tendon sites, were included. The studies overall report improvements in pain, function, and quality of life after undergoing PNT or TENEX, with minimal adverse effects. Mean risk of bias assessment scores were 8.35 out of 10 assessing internal and external validity for included studies.

CONCLUSION

PNT and TENEX are safe, beneficial, and minimally invasive treatment option for patients, especially for conditions refractory to more conservative treatments options.

A Practical Guide to Injection Therapy in Hand Tendinopathies: A Systematic Review of Randomized Controlled Trials

Hand tendinopathies represent a pathological condition associated with significant disability. However, due to this high heterogeneity of the treatments and their efficacy, there is still a lack of consensus on the infiltrative therapy of the hand. This systematic review aimed to investigate the efficacy of injection techniques in the treatment of pain related to the main hand tendinopathies. We searched online medical databases (PubMed, Pedro, Cochrane Library, Scopus, and WoS). Only RCTs published in the last 10 years (up to 5 August 2024), written in English, and related to infiltrative treatment in wrist and hand tendinopathies were evaluated. The risk of bias in RCTs was assessed with Version 2 of the Cochrane Risk of Bias tool for randomized trials (RoB 2). Out of 641 articles identified, 23 were included in the final synthesis: 14 RCTs on trigger finger, and 9 RCTs on de Quervain's tenosynovitis. The present systematic review showed that infiltrative therapy of trigger finger and de Quervain's tenosynovitis constitutes a fundamental element in the treatment of these pathological conditions, in terms of pain reduction and improvement in the functionality of the hand.

Photobiomodulation and amniotic membrane for treat tendon injury in rats

Tendons, complex fibrous structures, are subjected to great tensions, which can give rise to the so-called tendinopathies. This study aimed to evaluate photobiomodulation and human Amniotic Membrane applied as single or combined therapies to treat induced Achilles tendon lesions. Seventy-five rats were divided into five groups (n=15): C- control Sham surgery; I- tendon injury; LA- tendon injury treated with photobiomodulation; AM- tendon injury treated with Amniotic Membrane; LAM- tendon injury + photobiomodulation and Amniotic Membrane, subdivided into three groups (n=5) with analysis at 3, 7, and 14 days. The tendon injuries were made with a 20 g weight released from a mini guillotine onto the ankle in dorsiflexion. AM and LAM groups received an Amniotic Membrane fragment while LA and LAM groups received transcutaneous photobiomodulation, using a 660 nm wavelength laser. The inflammatory cells showed statistical differences between groups C and I (p<0.05), I and AM (p<0.01), I and LA (p<0.05), and I and LAM (p<0.01). Both photobiomodulation and Amniotic Membrane were shown to enhance tendon repair, and the association of photobiomodulation plus Amniotic Membrane was the most effective treatment. We conclude that the association of photobiomodulation plus Amniotic Membrane was effective in accelerating and improving the tendon regeneration process.

Efficacy and safety of extracorporeal shock wave therapy for upper limb tendonitis: a systematic review and meta-analysis of randomized controlled trials

Objective

This study synthesized the highest level of evidence to analyse the effectiveness and safety of using extracorporeal shock wave therapy (ESWT) to treat upper limb tendonitis, which was unknown.

Design

We conducted a systematic review and meta-analysis of 18 randomized controlled trials (RCTs) in PubMed, Embase, Web of Science, Medline, and the Cochrane Library.

Methods

Two researchers performed the screening, data extraction, literature quality assessment, and heterogeneity analysis of the searched RCTs.

Results

The main types of morbidity included rotator cuff tendonitis, lateral epicondylitis, finger tendonitis, and long bicipital tendonitis. The results of the meta-analysis showed that ESWT was effective in relieving pain in all four types of tendonitis. In addition, ESWT was more effective in relieving pain in patients with upper limb tendonitis than placebo at the 3- and 6-month follow-ups, especially with radial ESWT (RESWT). Data analysis of the forest plot showed that the experimental group with ESWT as an intervention had a significant improvement in function in patients with rotator cuff tendonitis at the 3-month follow-up. However, subgroup analysis showed that low-energy ESWT was effective in improving function in patients with calcified and non-calcified rotator cuff tendonitis, whereas it was not effective in relieving pain.

Conclusion

ESWT can effectively improve the functional activity in patients with rotator cuff tendonitis and may produce positive analgesic effects in patients with upper limb tendonitis. The incidence of adverse effects is low.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023403594, identifier: PROSPERO, CRD42023403594.

Anti-Inflammatory and Antioxidant Properties of a New Mixture of Vitamin C, Collagen Peptides, Resveratrol, and Astaxanthin in Tenocytes: Molecular Basis for Future Applications in Tendinopathies

Tendinopathy is one of the most frequent musculoskeletal disorders characterized by sustained tissue inflammation and oxidative stress, accompanied by extracellular matrix remodeling. Patients suffering from this pathology frequently experience pain, swelling, stiffness, and muscle weakness. Current pharmacological interventions are based on nonsteroidal anti-inflammatory drugs; however, the effectiveness of these strategies remains ambiguous. Accumulating evidence supports that oral supplementation of natural compounds can provide preventive, and possibly curative, effects. Vitamin C (Vit C), collagen peptides (Coll), resveratrol (Res), and astaxanthin (Asx) were reported to be endowed with potential beneficial effects based on their anti-inflammatory and antioxidant activities. Here, we analyzed the efficacy of a novel combination of these compounds (Mix) in counteracting proinflammatory (IL-1β) and prooxidant (H2O2) stimuli in human tenocytes. We demonstrated that Mix significantly impairs IL-6-induced IL-1β secretion, NF-κB nuclear translocation, and MMP-2 production; notably, a synergistic effect of Mix over the single compounds could be observed. Moreover, Mix was able to significantly counteract H2O2-triggered ROS production. Together, these results point out that Mix, a novel combination of Vit C, Coll, Resv, and Asx, significantly impairs proinflammatory and prooxidant stimuli in tenocytes, mechanisms that contribute to the onset of tendinopathies.

Assessment of shoulder joint derangements with magnetic resonance imaging in adult Nigerians

Objectives

Shoulder pain secondary to various aetiologies is a common musculoskeletal complaint worldwide, and Magnetic Resonance Imaging (MRI) is the most accurate imaging method for evaluating shoulder pain in all age groups. While the patterns of shoulder MRI abnormalities in various demographics have been reported, data on sub-Sahara African populations are still sparse. This study aims to describe the imaging features and spectrum of shoulder joint pathologies on MRI in adult Nigerians.

Materials and Methods

This was a retrospective review of the shoulder MRI of 100 adult Nigerians (with and without trauma) from September 2020 to December 2021. Their clinical data and shoulder MRI findings were extracted and analysed. Statistical significance was set at P ≤ 0.05.

Results

There were 64 males and 36 females aged 18-82 years. Right shoulder MRI was done in 53 subjects (53%), while the left shoulder was studied in 47 (47%). Supraspinatus tendinopathy (73%), acromioclavicular joint arthropathy (68%), and subacromial-subdeltoid (SASD) bursitis (64%) were the most frequently detected pathologies. Other demonstrated derangements include glenohumeral joint effusion (24%), long head of biceps tendon sheath effusion (18%), labral abnormalities (16%), subcoracoid bursitis (4%), Hill Sach's deformity (3%), anterior glenohumeral dislocation (2%), fatty degeneration of the supraspinatus/infraspinatus muscles (2%), adhesive capsulitis (1%), and other bony abnormalities (contusion, erosion, subchondral cysts). There was no significant difference in the frequency of shoulder abnormalities between the male and female subjects.

Conclusion

Acromioclavicular joint arthropathy, SASD bursitis, and rotator cuff disorders were the dominant pathologies in the participants' shoulders.

Mechanisms, Efficacy, and Clinical Applications of Platelet-Rich Plasma in Tendinopathy: A Comprehensive Review

Tendinopathy poses a significant clinical challenge characterized by chronic tendon pain, swelling, and impaired function, affecting athletes and the general population. Current treatments often provide limited success, necessitating exploration into regenerative therapies such as platelet-rich plasma (PRP). PRP harnesses the regenerative potential of autologous platelets and growth factors to promote tendon healing. This review aims to comprehensively examine the mechanisms, efficacy, and clinical applications of PRP in tendinopathy. We discuss the pathophysiology of tendinopathy, highlighting collagen disorganization, increased ground substance, and inflammatory changes. PRP's action mechanism involves releasing bioactive molecules that stimulate cellular proliferation, collagen synthesis, and tissue remodeling. Clinical studies and trials evaluating PRP in various tendinopathies, including Achilles, patellar, and rotator cuff tendinopathy, are reviewed to assess its efficacy and effectiveness compared to traditional therapies. Practical aspects, such as preparation methods, injection techniques, and safety considerations, are discussed to provide insights into optimal PRP administration. Challenges, including protocol variability and evidence gaps, are addressed, and future research and clinical practice directions are proposed. By synthesizing current knowledge, this review aims to guide clinicians in enhancing treatment strategies and advancing the field of tendon regenerative medicine.

A causal association between lipid-lowering medications and rotator cuff syndrome: a drug-targeted mendelian randomization study

Background: Previous research has suggested that dyslipidemia may be a risk factor for rotator cuff syndrome (RCS), and lipid-lowering drugs may aid in its treatment, though conclusions have not been definitive. Mendelian randomization is a statistical method that explores the causal relationships between exposure factors and diseases. It overcomes the confounding issues inherent in traditional observational studies, thereby providing more reliable causal inferences. We employed this method to investigate whether hyperlipidemia is a risk factor for rotator cuff syndrome and whether lipid-lowering drugs can effectively treat this condition. Methods: Genetic variations linked to lipid traits low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and total cholesterol (TC) were acquired from the UK Biobank and the Global Lipids Genetics Consortium (GLGC). Data on genetic variation in rotator cuff syndrome were obtained from FinnGen, including 24,061 patients and 275,212 controls. In the next step, we carried out two-sample Mendelian randomization analyses to determine whether lipid traits correlate with rotator cuff syndrome risk. Additionally, we performed drug-target Mendelian randomization (MR) analyses on 10 drug targets related to rotator cuff syndrome. For the drug targets that showed significant results, further analysis was done using Summary-data-based Mendelian Randomization (SMR) and colocalization techniques. We performed a mediation analysis to identify potential mediators between HMG-CoA reductase (HMGCR) and RCS. Results: No causative link was established between these lipid traits and rotator cuff syndrome. However, a significant association has been identified where HMGCR inhibition corresponds to a reduced risk of rotator cuff disease (OR = 0.68, [95% CI, 0.56-0.83], p = 1.510 × 10-4). Additionally, enhanced expression of HMGCR in muscle tissues is also linked to a decreased risk of rotator cuff syndrome (OR = 0.88, [95% CI, 0.76-0.99], p = 0.03). Body mass index (BMI) mediated 22.97% of the total effect of HMGCR on RCS. Conclusion: This study does not support low-density LDL-C, TG, and TC as risk factors for rotator cuff syndrome. HMGCR represents a potential pharmaceutical target for preventing and treating rotator cuff syndrome. The protective action of statins on the rotator cuff syndrome might not be associated with their lipid-lowering properties.

Tissue-engineered mesenchymal stem cell constructs alleviate tendinopathy by suppressing vascularization

Tendinopathy leads to low-grade tissue inflammation and chronic damage, which progresses due to pathological imbalance in angiogenesis. Reducing early pathological vascularization may be a new approach in helping to regenerate tendon tissue. Conventional stem cell therapy and tissue engineering scaffolds have not been highly effective at treating tendinopathy. In this study, tissue engineered stem cells (TSCs) generated using human umbilical cord mesenchymal stem cells (hUC-MSCs) were combined with microcarrier scaffolds to limit excessive vascularization in tendinopathy. By preventing VEGF receptor activation through their paracrine function, TSCs reduced in vitro angiogenesis and the proliferation of vascular endothelial cells. TSCs also decreased the inflammatory expression of tenocytes while promoting their anabolic and tenogenic characteristics. Furthermore, local injection of TSCs into rats with collagenase-induced tendinopathy substantially reduced early inflammation and vascularization. Mechanistically, transcriptome sequencing revealed that TSCs could reduce the progression of pathological angiogenesis in tendon tissue, attributed to Rap1-mediated vascular inhibition. TSCs may serve as a novel and practical approach for suppressing tendon vascularization, and provide a promising therapeutic agent for early-stage clinical tendinopathy.

Stem Cell‐Based Therapies and Tissue Engineering Innovations for Tendinopathy: A Comprehensive Review of Current Strategies and Future Directions

Tendon diseases commonly lead to physical disability, exerting a profound impact on the routine of affected patients. These conditions respond poorly to existing treatments, presenting a substantial challenge for orthopedic scientists. Research into clinical translational therapy has yet to yield highly versatile interventions capable of effectively addressing tendon diseases, including tendinopathy. Stem cell‐based therapies have emerged as a promising avenue for modifying the biological milieu through the secretion of regenerative and immunomodulatory factors. The current review provides an overview of the intricate tendon microenvironment, encompassing various tendon stem progenitor cells within distinct tendon sublocations, gene regulation, and pathways pertinent to tendon development, and the pathology of tendon diseases. Subsequently, the advantages of stem cell‐based therapies are discussed that utilize distinct types of autologous and allogeneic stem cells for tendon regeneration at the translational level. Moreover, this review outlines the challenges, gaps, and future innovations to propose a consolidated stem cell‐based therapy to treat tendinopathy. Finally, regenerative soluble therapies, insoluble bio‐active therapies, along with insoluble bio‐active therapies, and implantable 3D scaffolds for tendon tissue engineering are discussed, thereby presenting a pathway toward enhanced tissue regeneration and engineering.

Extracorporeal Shockwave Therapy for the Treatment of Noncalcific Rotator Cuff Tendinopathy: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the systematically review the short-, intermediate-, and long-term effects of extracorporeal shockwave therapy on pain intensity and shoulder function in individuals with noncalcific rotator cuff tendinopathy.

DESIGN

The MEDLINE, CINAHL, SPORTDiscus, and Embase were searched from inception up to June 2023. We included randomized controlled trials that investigated the effects of extracorporeal shockwave therapy on pain intensity and shoulder function.

RESULTS

Nine studies were included with a total sample of 543 individuals. Extracorporeal shockwave therapy was superior to sham extracorporeal shockwave therapy in improving pain intensity at short-term follow-up (standardized mean difference = -0.28; 95% confidence interval, -0.55 to -0.01). Extracorporeal shockwave therapy was not superior to sham extracorporeal shockwave therapy in improving pain intensity at intermediate- and long-term follow-ups ( P > 0.05). Extracorporeal shockwave therapy was not superior to other treatments in improving pain intensity at short- and intermediate-term follow-ups ( P > 0.05). Extracorporeal shockwave therapy was not superior to sham extracorporeal shockwave therapy and other treatments in improving shoulder function at short-, intermediate-, and long-term follow-ups ( P > 0.05).

CONCLUSIONS

Moderate-certainty evidence indicated that extracorporeal shockwave therapy showed small improvement in shoulder pain over sham extracorporeal shockwave therapy at short-term follow-up. In addition, extracorporeal shockwave therapy was not superior to sham extracorporeal shockwave therapy in improving function, and it was not superior to other treatments in improving shoulder pain and function.

Advances in non-coding RNA in tendon injuries

Tendons serve as important weight-bearing structures that smoothly transfer forces from muscles to skeletal parts, allowing contracted muscle movements to be translated into corresponding joint movements. For body mechanics, tendon tissue plays an important role. If the tendons are damaged to varying degrees, it can lead to disability or pain in patients. That is to say, tendon injuries havea significant impact on quality of life and deserve our high attention. Compared to other musculoskeletal tissues, tendons are hypovascular and hypo-cellular, and therefore have a greater ability to heal, this will lead to a longer recovery period after injury or even disability, which will significantly affect the quality of life. There are many causes of tendon injury, including trauma, genetic factors, inflammation, aging, and long-term overuse, and the study of related mechanisms is of great significance. Currently, tendon there are different treatment modalities, like injection therapy and surgical interventions. However, they have a high failure rate due to different reasons, among which the formation of adhesions severely weakens the tissue strength, affecting the functional recovery and the patient's quality of life. A large amount of data has shown that non coding RNAs can play a huge role in this field, thus attracting widespread attention from researchers from various countries. This review summarizes the relevant research progress on non-coding RNAs in tendon injuries, providing new ideas for a deeper understanding of tendon injuries and exploring new diagnostic and therapeutic approaches.

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.

Evaluation of Anti-Nociceptive, Anti-Inflammatory, and Anti-Fibrotic effects of noscapine against a rat model of Achilles tendinopathy

During tendinopathy, prolonged inflammation results in fibrosis and the adherence of tendons to the adjacent tissues, causing discomfort and movement disorders. As a natural compound, noscapine has several anti-inflammatory and anti-fibrotic properties. Therefore, we aimed to investigate the effects of noscapine against a rat model of tendinopathy. We created a surgical rat model of Achilles tendon damage to emulate tendinopathy. Briefly, an incision was made on the Achilles tendon, and it was then sutured using an absorbable surgical thread. Immediately, the injured area was topically treated with the vehicle, noscapine (0.2, 0.6, and 1.8 mg/kg), or dexamethasone (0.1 mg/kg) as a positive control. During the 19-day follow-up period, animals were assessed for weight, behavior, pain, and motor coordination testing. On day 20th, the rats were sacrificed, and the tendon tissue was isolated for macroscopic scoring, microscopic (H&E, Masson's trichrome, Ki67, p53) analyses, and cytokine secretion levels. The levels of macroscopic parameters, including thermal hyperalgesia, mechanical and cold allodynia, deterioration of motor coordination, tendon adhesion score, and microscopic indices, namely histological adhesion, vascular prominence and angiogenesis, and Ki67 and p53 levels, as well as fibrotic and inflammatory biomarkers (IL-6, TNF-α, TGF-β, VEGF) were significantly increased in the vehicle group compared to the sham group (P < 0.05-0.001 for all cases). In contrast, the administration of noscapine (0.2, 0.6, and 1.8 mg/kg) attenuated the pain, fibrosis, and inflammatory indices in a dose-dependent manner compared to the vehicle group (P < 0.05-0.001). Histological research indicated that noscapine 0.6 and 1.8 mg/kg had the most remarkable healing effects. Interestingly, two higher doses of noscapine had impacts similar to those of the positive control group in both clinical and paraclinical assessments. Taken together, our findings suggested that noscapine could be a promising medicine for treating tendinopathies.

Focused ultrasound as an alternative to dry needling for the treatment of tendinopathies: A murine model

Tendinopathies account for 30% of 102 million annual musculoskeletal injuries occurring annually in the United States. Current treatments, like dry needling, induce microdamage to promote healing but produce mixed success rates. Previously, we showed focused ultrasound can noninvasively create microdamage while preserving mechanical properties in ex vivo murine tendons. This present study compared growth factor, histological, and mechanical effects after focused ultrasound or dry needling treatments in an in vivo murine tendon injury model. Partial Achilles tenotomy was performed in 26 rats. One-week postsurgery, tendons were treated with focused ultrasound (1.5 MHz, 1-ms pulses at 10 Hz for 106 s, p+  = 49 MPa, p-  = 19 MPa) or dry needling (30 G needle, 5 fenestrations over 20 s) and survived for 1 additional week. Blood was collected immediately before and after treatment and before euthanasia; plasma was assayed for growth factors. Treated tendons and contralateral controls were harvested for histology or mechanical testing. No differences were found between treatments in release of insulin growth factor 1 and transforming growth factor beta; vascular endothelial growth factor A concentrations were too low for detection. Histologically, focused ultrasound and dry needling tendons displayed localized fibroblast infiltration without collagen proliferation with no detectable differences between treatments. Mechanically, stiffness and percent relaxation of dry needling tendons were lower than controls (p = 0.0041, p = 0.0441, respectively), whereas stiffness and percent relaxation of focused ultrasound tendons were not different from controls. These results suggest focused ultrasound should be studied further to determine how this modality can be leveraged as a therapy for tendinopathies.

Regenerative Medicine Solutions for Rotator Cuff Injuries in Athletes: Indications and Outcomes

Rotator cuff (RC) injuries include a wide range of pathologic states. Athletes are perhaps the most susceptible to RC injuries ranging from tendinopathy to partial or full-thickness tears, due to functional overload and repetitive movements, causing abstention from sports for long periods. Regenerative medicine keeps giving us multiple choices to fight the disability caused by these pathologies. A literature search was performed, and findings related to the structure-function of rotator cuff units, pathophysiology of injuries, regenerative medicine treatments, and future strategies were outlined. Platelet-rich plasma (PRP) has a greater number of articles and clinical trials, accompanied by stem cells progenitor, prolotherapy, and new approaches such as microfragmented adipose tissue and exosomes. RC injuries in athletes can cause pain, functional impotence, and the risk of recurrence, and can lead them to stop playing sports. Regenerative medicine offers a range of treatments, but some of them need further studies to underline their actual validity.

Rehabilitation of Supraspinatus Impingement in a Volleyball Athlete: A Case Report

Volleyball players with supraspinatus tendinopathy commonly present with a spectrum of symptoms, including shoulder pain, especially during the overhead phases of the game. They may experience pain during serves, spikes, or attempting to block at the net. Weakness in the affected shoulder and limited range of motion can impede performance and overall playing experience. Physiotherapy plays a crucial role in managing supraspinatus tendinopathy, focusing on reducing pain, improving shoulder joint range and function, and preventing recurrence. The research question arises as to how the rehabilitation process impacts the recovery and performance outcomes in a volleyball athlete with supraspinatus impingement which is explained as detailed in a case report. The present case is a 21-year-old male volleyball athlete complaining of pain in the anterolateral and posterior aspects of the right shoulder joint and a restricted range of motion while doing abduction and flexion at the shoulder joint for three months. After the orthopedic physical assessment, the patient was diagnosed with supraspinatus tendinopathy. This case report introduces an exact understanding of the rehabilitation tailored specifically to volleyball athletes with supraspinatus impingement.

TRIM54 alleviates inflammation and apoptosis by stabilizing YOD1 in rat tendon-derived stem cells

Tendinopathy is a disorder of musculoskeletal system that primarily affects athletes and the elderly. Current treatment options are generally comprised of various exercise and loading programs, therapeutic modalities, and surgical interventions and are limited to pain management. This study is to understand the role of TRIM54 (tripartite motif containing 54) in tendonitis through in vitro modeling with tendon-derived stem cells (TDSCs) and in vivo using rat tendon injury model. Initially, we observed that TRIM54 overexpression in TDSCs model increased stemness and decreased apoptosis. Additionally, it rescued cells from tumor necrosis factor α-induced inflammation, migration, and tenogenic differentiation. Further, through immunoprecipitation studies, we identified that TRIM54 regulates inflammation in TDSCs by binding to and ubiquitinating YOD1. Further, overexpression of TRIM54 improved the histopathological score of tendon injury as well as the failure load, stiffness, and young modulus in vivo. These results indicated that TRIM54 played a critical role in reducing the effects of tendon injury. Consequently, these results shed light on potential therapeutic alternatives for treating tendinopathy.

Physical therapy interventions used to treat individuals with biceps tendinopathy: a scoping review

BACKGROUND

Shoulder pain related to pathology of the long head of the biceps tendon (LHBT) can be debilitating. Chronic LHBT tendinopathy is a common condition that is difficult to treat. Little consensus exists regarding the optimal approach to treating individuals with LHBT tendinopathy.

OBJECTIVE

To systematically scope the literature to identify and present the available information regarding physical therapist interventions used for the management of individuals with LHBT tendinopathy including types of interventions used or recommended.

METHODS

A scoping review of physical therapist interventions used to treat LHBT was conducted of the CINAHL, Embase, Medline, and SportDiscus databases. Full text records reporting physical therapist-based interventions in individuals with proximal LHBT pathology were included. Articles not written in English were excluded.

RESULTS

Of the 4059 records identified, 14 articles met the inclusion criteria. Interventions used to treat LHBT tendinopathy identified in quantitative studies included: extracorporeal shock wave therapy, polarized light, ultrasound, low-level laser, iontophoresis, general exercise, eccentric training, stretching, dry needling, and joint mobilization. Interventions described in literature reviews, clinical commentaries, and a Delphi study included: therapeutic modalities, manual therapy, exercise, dry needling, and patient education.

CONCLUSION

This scoping review reported interventions primarily based on therapeutic modalities in quantitative studies while literature reviews, clinical commentaries, and a Delphi study described the addition of manual therapy, patient education, exercise, and dry needling. Overall, there is a dearth of evidence detailing the conservative management of LHBT tendinopathy.

Preclinical assessment of IL-1β primed human umbilical cord mesenchymal stem cells for tendon functional repair through TGF-β/IL-10 signaling

Background

Inadequate repair capacity and disturbed immune compartments are the main pathological causes of tendinopathy. Transplantation of mesenchymal stem cells (MSCs) become an effective clinic option to alleviate tendinopathy. Interleukin-1β (IL-1β) could confer on MSCs enhanced immunoregulatory capability to remodel the repair microenvironment favoring tissue repair. Therefore, IL-1β activated UC-MSCs (1βUC-MSCs) may exert favorable efficacy in promoting tendon repair in a preclinical tendinopathy rat model.

Methods

Tendon-derived stem cells (TDSCs) were isolated and characterized. In vitro, the levels of immunoregulatory-related cytokines such as IL-1β, IL-6, IL-10, and TGF-β secreted by 1βUC-MSCs and unprimed UC-MSCs was measured. And tendon-specific markers expressed by TDSCs cultured with primed cultured medium (CM) or unprimed CM were detected. In vivo, Achilles tendinopathy was induced by 30 μL collagenase I injection in Sprague Dawley rats. One week later, the rats were randomly injected with UC-MSCs primed with IL-1β (106 cells per tendon), UC-MSCs, or PBS. After rats were sacrificed, histological evaluation, electron microscopy, biomechanical tests, gait performance were conducted to evaluate the structural and functional recovery of Achilles tendons. The inflammation and metabolic state of the extracellular matrix, and the potential mechanism were assessed by immunohistochemical staining and Western blot.

Results

UC-MSCs were activated by IL-1β to secrete higher levels of IL-10 and TGF-β while the secretion levels of IL-6 and IL-1β were not changed significantly, promoting a higher expression level of COL I and TNMD in TDSCs under proinflammatory environment. In vivo, the transplanted 1βUC-MSCs could survive up to 5 weeks after injection with tenogenic differentiation and improved tendon healing histologically semi-quantified by modified Bonar scores. This structural regeneration was further confirmed by observation of ultrastructural morphology, and led to good functional recovery including improved biomechanical properties and gait performance. During this process, the inflammatory response and metabolism of the extracellular matrix was improved through TGF-β/IL-10 pathway.

Conclusion

This study demonstrated that the transplantation of UC-MSCs activated by IL-1β exhibited satisfactory ability for promoting tendon functional repair in a tendinopathy rat model. During this process, the balance of inflammatory response and extracellular matrix metabolism was remodeled, and the TGF-β/Smad2/3 and IL-10 signaling pathways were activated simultaneously. We cautiously conclude that the IL-1β primed UC-MSCs could be a promising strategy for enhancing the ability of MSCs to treat tendinopathy.

Transcatheter arterial embolisation for the relief of shoulder and elbow chronic joint pain refractory to conventional treatment: Systematic review

Angiogenesis and accompanying nerve fibres might cause unsettling joint pain. Studies have suggested that transcatheter arterial embolisation (TAE) of these abnormal neovessels could relieve pain and symptoms in patients with upper limb joint pain refractory to conventional treatment. This study aims to investigate the efficacy and safety of TAE in treating chronic pain of shoulder and elbow joints that have been resistant to other treatments. Using six databases, a systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The primary outcome involved changes in the visual analogue scale (VAS) after TAE; while secondary outcomes involved comparing other parameters where relevant. Average VAS decreased from baseline, then at 1 day, 1 week, 1 month, 3 months, 4 months, 6 months, 1 year, 2 years and 44 months (7.5 at baseline vs. 4.7, 4.3, 3.4, 2.1, 2.5, 1.2, 0.7, 1.1 and 0.1, respectively). Average Quick-DASH scores decreased from baseline, then at 1, 3 and 6 months (61.3 at baseline vs. 30.6, 19.3 and 6.9, respectively). Minor adverse events were reported in 27/143 (18.9%) patients, where they resolved spontaneously or with oral analgesia. TAE is a possible treatment option for refractory shoulder and elbow joint pain; however, randomised controlled trials are still required.

Exogenous Crosslinking of Tendons as a Strategy for Mechanical Augmentation and Repair: A Narrative Review

Collagens constitute a family of triple-helical proteins with a high level of structural polymorphism and a broad diversity of structural and chemical characteristics. Collagens are designed to form supporting aggregates in the extracellular spaces of our body, but they can be isolated from animal sources and processed to become available as biomaterials with wide applications in biomedicine and bioengineering. Collagens can be conveniently modified chemically, and their propensity for participating in crosslinking reactions is an important feature. While the crosslinking promoted by a variety of agents provides a range of collagen-based products, there has been minor interest for therapies based on the crosslinking of collagen while located within living connective tissues, known as exogenous crosslinking. Currently, there is only one such treatment in ocular therapeutics (for keratoconus), and another two in development, all based on mechanical augmentation of tissues due to ultraviolet (UV)-induced crosslinking. As seen in this review, there was some interest to employ exogenous crosslinking in order to reinforce mechanically the lax tendons with an aim to arrest tear propagation, stabilize the tissue, and facilitate the healing. Here we reviewed in details both the early stages and the actual status of the experimental research dedicated to the topic. Many results have not been encouraging, however there is sufficient evidence that tendons can be mechanically reinforced by chemical or photochemical exogenous crosslinking. We also compare the exogenous crosslinking using chemical agents, which was predominant in the literature reviewed, to that promoted by UV radiation, which was rather neglected but might have some advantages.

Role of platelet-rich plasma in the treatment of rotator cuff tendinopathy

Shoulder pain is a common musculoskeletal complaint, and rotator cuff (RC) pathologies are one of the main causes. The RC undergoes various tendinopathic and avascular changes during the aging process. Other degenerative changes affecting its healing potential make it an appealing target for biological agents. Platelet-rich plasma (PRP) has demonstrated the potential to deliver a high concentration of several growth factors and anti-inflammatory mediators, and its clinical use is mainly supported by experiments that demonstrated its positive effect on muscle, ligaments, and tendinous cells. This review aimed to specify the role of PRP and its future applications in RC tendinopathies based on the current clinical evidence. Due to the different characteristics and conflicting outcomes, clinicians should use PRP with moderate expectations until more consistent evidence is available. However, it is reasonable to consider PRP in patients with contraindications to corticosteroid injections or those with risk factors for inadequate healing. Its autologous origin makes it a safe treatment, and its characteristics make it a promising option for treating RC tendinopathy, but the efficacy has yet to be established.

The Effects of High-Load Slow-Velocity Resistance Exercise Training in Athletes With Tendinopathy: A Critically Appraised Topic

CLINICAL SCENARIO

Tendinopathy is a musculoskeletal pathological condition experienced by athletes that can result in pain, impaired muscle performance, and loss of physical function and can hinder return to sports. Various types of resistance exercise training are effective for treating tendinopathy, including isometric, concentric, eccentric, and high-load slow-velocity resistance exercise.

CLINICAL QUESTION

What are the effects of high-load slow-velocity resistance exercise training, compared with other forms of resistance exercise, on tendon morphology and patient-reported outcomes in athletes with tendinopathy?

SUMMARY OF KEY FINDINGS

The findings of 4 randomized clinical trials were included. One study compared high-load slow-velocity resistance exercise with moderate-load slow-velocity resistance exercise. Two studies investigated the effects of high-load slow-velocity resistance exercise versus eccentric resistance exercise. The fourth study compared high-load slow-velocity resistance exercise with inertia-based resistance exercise. In all of the studies, high-load slow-velocity resistance exercise was as effective as the other forms of resistance exercise for improving patient-reported outcomes and pain. Three studies found no significant differences in changes in tendon morphology between patients who received high-load slow-velocity resistance exercise versus those who received the other forms of resistance exercise. One study showed that high-load slow-velocity resistance exercise was more effective than eccentric exercise for improving tendon morphology outcomes.

CLINICAL BOTTOM LINE

Current evidence supports the use of high-load slow-velocity resistance exercise as a treatment option for patellar and Achilles tendinopathy in athletes.

STRENGTH OF RECOMMENDATION

Results from level 2 studies suggest grade B evidence in support of high-load slow-velocity resistance exercise for treating athletes with tendinopathy.

Evolution of somatosensory processing signs after nociceptive targeted surgery in patients with musculoskeletal disorders: a systematic review

ABSTRACT

Surgery is often advised when conservative treatment fails in musculoskeletal pain conditions, but a substantial proportion still suffers chronic pain after surgery. Somatosensory processing system (SPS) signs were previously studied as potential predictors for chronic postsurgical pain, but results are inconsistent. Therefore, studying the evolution of SPS signs could be of added value. The aim was to summarize all studies that measured how SPS signs evolved after nociceptive targeted surgery in musculoskeletal disorders and to find preoperative, perioperative, and postoperative predictors for the evolution of these SPS signs. Data were summarized, and risk of bias and level of evidence and recommendation were determined. Twenty-one studies were included. Five scored a low, 3 a moderate, and 13 a high risk of bias. In general, no consistent evolution of SPS signs comparing preoperative and postoperative values and predictors for this evolution in musculoskeletal disorders could be found. In most cases, static quantitative sensory testing (QST) did not change or conflicting results were found. On the other hand, dynamic QST mostly improved after surgery. Worthfully mentioning is that worsening of SPS signs was only seen at a follow-up of <3 months after surgery, that conclusions are stronger when evaluating dynamic QST with a follow-up of ≥3 months after surgery, and that pain improvement postsurgery was an important predictor. Future high-quality research should focus on the evolution of SPS signs after nociceptive targeted surgery, accounting for pain improvement groups and focusing on preoperative, perioperative, and postoperative predictors of this evolution.

Insertional biceps tendinopathy palliated successfully with intra-articular triamcinolone acetonide injection in a dog: A case report

This report describes a dog diagnosed with insertional biceps tendinopathy that was palliated with intra-articular triamcinolone acetonide injections. The patient was a 6-year-old spayed female Chihuahua dog that had left thoracic limb lameness for 3 months before presentation. On physical examination, moderate pain was elicited by performing the biceps test and isolated full elbow extension on the left thoracic limb. Gait analysis showed asymmetrical peak vertical force and vertical impulse between thoracic limbs. Computed tomography (CT) revealed enthesophyte formation on the ulnar tuberosity of the left elbow joint. Ultrasonography showed a heterogeneous fibre pattern at the biceps tendon insertion site on the left elbow joint. These findings confirmed insertional biceps tendinopathy based on physical examination, CT and ultrasonography results. The dog received an intra-articular triamcinolone acetonide injection with hyaluronic acid in the left elbow joint. Clinical signs improved after the first injection, including a range of motion, pain and gait. A second injection was given in the same manner because of recurring mild lameness 3 months later. No clinical signs were observed during the follow-up period.

Antinociceptive Action of Thymoquinone-Loaded Liposomes in an In Vivo Model of Tendinopathy

Tendinopathies represent about 45% of musculoskeletal lesions and they are a big burden in clinics characterized by activity-related pain, focal tendon tenderness and intra-tendinous imaging changes. Many approaches have been proposed for tendinopathies' management (e.g., nonsteroidal anti-inflammatory drugs, corticosteroids, eccentric exercises, laser therapy), unfortunately with very little support of efficacy or serious side effects, thus making the identification of new treatments fundamental. The aim of the study was to test the protective and pain reliever effect of thymoquinone (TQ)-loaded formulations in a rat model of tendinopathy induced by carrageenan intra-tendon injection (20 µL of carrageenan 0.8% on day 1). Conventional (LP-TQ) and hyaluronic acid (HA)-coated TQ liposomes (HA-LP-TQ) were characterized and subjected to in vitro release and stability studies at 4 °C. Then, TQ and liposomes were peri-tendon injected (20 µL) on days 1, 3, 5, 7 and 10 to evaluate their antinociceptive profile using mechanical noxious and non-noxious stimuli (paw pressure and von Frey tests), spontaneous pain (incapacitance test) and motor alterations (Rota rod test). Liposomes containing 2 mg/mL of TQ and covered with HA (HA-LP-TQ2) reduced the development of spontaneous nociception and hypersensitivity for a long-lasting effect more than the other formulations. The anti-hypersensitivity effect matched with the histopathological evaluation. In conclusion, the use of TQ encapsulated in HA-LP liposomes is suggested as a new treatment for tendinopathies.

Irreversible Electroporation Improves Tendon Healing in a Rat Model of Collagenase-Induced Achilles Tendinopathy

BACKGROUND

Treatment of painful chronic tendinopathy is challenging, and there is an urgent need to develop new regenerative methods. Irreversible electroporation (IRE) can lead to localized cell ablation by electrical pulses and induce new cell and tissue growth. Previously, the authors' group reported that electroporation-ablated tendons fully regenerated.

PURPOSE

To assess the efficiency of IRE in improving tendon healing using a collagenase-induced Achilles tendinopathy rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

After screening for the IRE ablation parameters, a collagenase-induced Achilles tendinopathy rat model was used to assess the efficacy of IRE in improving tendon healing via biomechanical, behavioral, histological, and immunofluorescence assessments.

RESULTS

The experiments showed that the parameter of 875 V/cm 180 pulses could ablate most tenocytes, and apoptosis was the main type of death in vitro. In vivo, IRE promoted the healing process of chronic tendinopathy in the Achilles tendon of rats, based on biomechanical, behavioral, and histological assessments. Finally, immunofluorescence results revealed that IRE improved blood supply in the early stages of tendon repair and could potentially reduce neuropathic pain.

CONCLUSION

IRE enhanced tendon tissue healing in a rat model of collagenase-induced Achilles tendinopathy.

CLINICAL RELEVANCE

IRE may as a potential alternative treatment for tendinopathy in clinical usage.

The effectiveness of percutaneous ultrasound-guided needle tenotomy compared to alternative treatments for chronic tendinopathy: a systematic review

OBJECTIVES

To compare percutaneous ultrasound-guided needle tenotomy (PUNT) to alternative treatments for chronic tendinopathy.

MATERIALS AND METHODS

A systematic literature search was performed with the following combination of keywords: ultrasound-guided, percutaneous, needling, tenotomy, Tenex, tendinopathy, and fasciotomy. Original studies comparing PUNT to alternative treatments for chronic tendinopathy were included in this systematic review.

RESULTS

Twelve (n = 12) studies with 481 subjects were included. Two (2/12) articles compared PUNT to surgical tenotomy and concluded that PUNT provides the same outcomes as surgical tenotomy. Six (6/12) studies compared PUNT to platelet-rich plasma (PRP) injections, and two of them found both treatment modalities effective with no significant between-group differences. Three trials claimed that PUNT followed by PRP injections showed superior clinical outcomes compared to PUNT alone. However, the difference at long-term follow-up was statistically significant only in one of them. One study found PUNT superior to PUNT + PRP injection at short-term follow-up, although there were no between-group differences at long-term follow-up. Four (4/12) studies compared PUNT to steroid injection (SI) and showed that SI causes fast (2 weeks) but temporary pain relief, PUNT results in persistent but relatively slower improvement to SI, and the combined procedure has a more rapid and steady reduction in symptoms.

CONCLUSION

PUNT is an effective treatment technique for chronic tendinopathy and should be considered when non-invasive treatments have failed. Effects of PRP and SI are transient and dissipate over time and do not contribute to long-term outcome.

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.

Nonoperative Treatment of the Biceps-Labral Complex

The long head of the biceps and superior labrum should be evaluated as an interdependent functional unit. A focused patient history and physical examination including multiple provocative tests should be performed alongside advanced imaging studies to obtain an accurate diagnosis. Nonoperative treatment modalities including nonsteroidal anti-inflammatory drugs, glucocorticoid injections, and a standardized physical therapy regimen should be exhausted before operative intervention. Significant improvements in pain, functional outcomes, and quality of life are achieved in patients treated nonoperatively. Although these outcomes are less consistent for overhead athletes, return to play and performance metrics seem comparable to those who undergo surgery.

In Achilles Tendinopathy the Symptomatic Tendon Differs from the Asymptomatic Tendon While Exercise Therapy Has Little Effect on Asymmetries-An Ancillary Analysis of Data from a Controlled Clinical Trial

BACKGROUND

As inter-limb asymmetries can be associated with higher injury risk, we aimed to investigate their role in Achilles tendinopathy patients.

METHODS

In Achilles tendinopathy patients (n = 41), we assessed inter-limb asymmetries of mechanical, material, and morphological musculoskeletal properties and function and how those were affected by 12 weeks of exercise intervention (high-load protocol, n = 13; Alfredson protocol, n = 11). Moreover, we assessed whether asymmetry reductions correlated with improved Patient-Reported Outcomes (VISA-A score).

RESULTS

At baseline, tendinopathic tendons demonstrated lower tendon force (p = 0.017), lower tendon stress (p < 0.0001), larger tendon cross-sectional area (CSA) (p < 0.001), and increased intratendinous (p = 0.042) and tendon overall (p = 0.021) vascularization. For the high-load group, PRE-to-POST asymmetry comparisons revealed an asymmetry increase for the counter-movement jump (CMJ) (p = 0.034) and PRE-to-POST VISA-A score improvements correlated with CSA asymmetry reductions (p = 0.024). Within the Alfredson group, PRE-to-POST VISA-A score improvements correlated with CMJ asymmetry reductions (p = 0.044) and tendon stiffness asymmetry increases (p = 0.037). POST-to-POST in-between group comparisons revealed lower asymmetry in the high-load group for tendon elongation (p = 0.021) and tendon strain (p = 0.026).

CONCLUSIONS

The tendinopathic limb differs from the asymptomatic limb while therapeutic exercise interventions have little effect on asymmetries. Asymmetry reductions are not necessarily associated with tendon health improvements.

The roles and therapeutic potentialof mesenchymal stem/stromal cells and their extracellular vesicles in tendinopathies

Tendinopathies encompass a highly prevalent, multi-faceted spectrum of disorders, characterized by activity-related pain, compromised function, and propensity for an extended absence from sport and the workplace. The pathophysiology of tendinopathy continues to evolve. For decades, it has been related primarily to repetitive overload trauma but more recently, the onset of tendinopathy has been attributed to the tissue's failed attempt to heal after subclinical inflammatory and immune challenges (failed healing model). Conventional tendinopathy management produces only short-term symptomatic relief and often results in incomplete repair or healing leading to compromised tendon function. For this reason, there has been increased effort to develop therapeutics to overcome the tissue's failed healing response by targeting the cellular metaplasia and pro-inflammatory extra-cellular environment. On this basis, stem cell-based therapies have been proposed as an alternative therapeutic approach designed to modify the course of the various tendon pathologies. Mesenchymal stem/stromal cells (MSCs) are multipotent stem cells often referred to as "medicinal signaling cells" due to their immunomodulatory and anti-inflammatory properties that can produce a pro-regenerative microenvironment in pathological tendons. However, the adoption of MSCs into clinical practice has been limited by FDA regulations and perceived risk of adverse events upon infusion in vivo. The introduction of cell-free approaches, such as the extracellular vesicles of MSCs, has encouraged new perspectives for the treatment of tendinopathies, showing promising short-term results. In this article, we review the most recent advances in MSC-based and MSC-derived therapies for tendinopathies. Preclinical and clinical studies are included with comment on future directions of this rapidly developing therapeutic modality, including the importance of understanding tissue loading and its relationship to any treatment regimen.