Verapamil Attenuates the Severity of Tendinopathy by Mitigating Mitochondrial Dysfunction through the Activation of the Nrf2/HO-1 Pathway

Tendinopathy is a prevalent condition in orthopedics patients, exerting a profound impact on tendon functionality. However, its underlying mechanism remains elusive and the efficacy of pharmacological interventions continues to be suboptimal. Verapamil is a clinically used medicine with anti-inflammation and antioxidant functions. This investigation aimed to elucidate the impact of verapamil in tendinopathy and the underlying mechanisms through which verapamil ameliorates the severity of tendinopathy. In in vitro experiments, primary tenocytes were exposed to interleukin-1 beta (IL-1β) along with verapamil at a concentration of 5 μM. In addition, an in vivo rat tendinopathy model was induced through the localized injection of collagenase into the Achilles tendons of rats, and verapamil was injected into these tendons at a concentration of 5 μM. The in vitro findings highlighted the remarkable ability of verapamil to attenuate extracellular matrix degradation and apoptosis triggered by inflammation in tenocytes stimulated by IL-1β. Furthermore, verapamil was observed to significantly suppress the inflammation-related MAPK/NFκB pathway. Subsequent investigations revealed that verapamil exerts a remediating effect on mitochondrial dysfunction, which was achieved through activation of the Nrf2/HO-1 pathway. Nevertheless, the protective effect of verapamil was nullified with the utilization of the Nrf2 inhibitor ML385. In summary, the in vivo and in vitro results indicate that the administration of verapamil profoundly mitigates the severity of tendinopathy through suppression of inflammation and activation of the Nrf2/HO-1 pathway. These findings suggest that verapamil is a promising therapeutic agent for the treatment of tendinopathy, deserving further and expanded research.

Study of the Synergistic Immunomodulatory and Antifibrotic Effects of Dual-Loaded Budesonide and Serpine1 siRNA Lipid-Polymer Nanoparticles Targeting Macrophage Dysregulation in Tendinopathy

Musculoskeletal diseases involving tissue injury comprise tendon, ligament, and muscle injury. Recently, macrophages have been identified as key players in the tendon repair process, but no therapeutic strategy involving dual drug delivery and gene delivery to macrophages has been developed for targeting the two main dysregulated aspects of macrophages in tendinopathy, i.e., inflammation and fibrosis. Herein, the anti-inflammatory and antifibrotic effects of dual-loaded budesonide and serpine1 siRNA lipid-polymer hybrid nanoparticles (LPNs) are evaluated in murine and human macrophage cells. The modulation of the gene and protein expression of factors associated with inflammation and fibrosis in tendinopathy is demonstrated by real time polymerase chain reaction and Western blot. Macrophage polarization to the M2 phenotype and a decrease in the production of pro-inflammatory cytokines are confirmed in macrophage cell lines and primary cells. The increase in the activity of a matrix metalloproteinase involved in tissue remodelling is proven, and studies evaluating the interactions of LPNs with T cells proved that dual-loaded LPNs act specifically on macrophages and do not induce any collateral effects on T cells. Overall, these dual-loaded LPNs are a promising combinatorial therapeutic strategy with immunomodulatory and antifibrotic effects in dysregulated macrophages in the context of tendinopathy.

Low socioeconomic status is associated with worse treatment outcomes in patients with Achilles tendinopathy

OBJECTIVE

To assess whether there is a difference in symptom severity at baseline and 24 weeks follow-up between conservatively managed patients with Achilles tendinopathy (AT) with low socioeconomic status (SES) compared with those with high SES.

METHODS

In this prospective cohort study, 200 patients with AT were included and treated according to current guidelines. We linked a neighbourhood SES indicator based on income, employment and education level and divided the patient population into quintiles, with Q1 being the highest SES and Q5 the lowest. Symptom severity at baseline and follow-up was assessed using the Victorian Institute of Sports Assessment-Achilles (VISA-A) score. Treatment adherence was not measured. We used a general linear model and the mean VISA-A scores at baseline and at 6, 12 and 24 weeks follow-up were compared between Q1 (n=45) and Q5 (n=39), while adjusting for age, sex, body mass index (BMI), Ankle Activity Score, symptom duration and baseline VISA-A score.

RESULTS

Patients had a median age of 51 years and median BMI of 25.4, 40% were female. 74%, 70% and 58% of the participants completed the VISA-A at 6, 12 and 24 weeks, respectively. VISA-A scores at baseline were similar for Q1 and Q5 (43.9 and 41.8, p=0.591). At 24 weeks, there was a mean (95% CI) difference of 11.2 (1.0 to 21.3, p=0.032) points in favour of Q1 on the VISA-A score.

CONCLUSION

AT patients with low SES may have worse outcomes when treated using the current guidelines. The difference in VISA-A score at 24 weeks is larger than the minimal clinically important difference and might be clinically relevant, but comes with uncertainty due to the large dispersion in the data. Clinicians need to consider the impact of social inequality when developing and implementing treatment plans.

Biceps Pulley Lesions: Diagnostic Accuracy of Nonarthrographic Shoulder MRI and the Value of Various Diagnostic Signs

BACKGROUND

There is limited data in the literature regarding the role of nonarthrographic MRI for detecting biceps pulley (BP) lesions.

PURPOSE

To assess the accuracy of nonarthrographic MRI for detecting BP lesions, and to evaluate the diagnostic value of various MRI signs (superior glenohumeral ligament discontinuity/nonvisibility, long head of biceps (LHB) displacement sign or subluxation/dislocation, LHB tendinopathy, and supraspinatus and subscapularis tendon lesions) in detecting such lesions.

STUDY TYPE

Retrospective.

POPULATION

84 patients (32 in BP-lesion group and 52 in BP-intact group-as confirmed by arthroscopy).

FIELD STRENGTH/SEQUENCE

1.5-T, T1-weighted turbo spin echo (TSE), T2-weighted TSE, and proton density-weighted TSE spectral attenuated inversion recovery (SPAIR) sequences.

ASSESSMENT

Three radiologists independently reviewed all MRI data for the presence of BP lesions and various MRI signs. The MRI signs and final MRI diagnoses were tested for accuracy regarding detecting BP lesions using arthroscopy results as the reference standard. Furthermore, the inter-reader agreement (IRA) between radiologists was determined.

STATISTICAL TESTS

Student's t-tests, Chi-squared, and Fisher's exact tests, and 4-fold table test were used. The IRA was calculated using Kappa statistics. A P-value <0.05 was considered statistically significant.

RESULTS

The sensitivity, specificity, and accuracy of nonarthrographic MRI for detecting BP lesions were 65.6%-78.1%, 90.4%-92.3%, and 81%-86.9%, respectively. The highest accuracy was noticed for the LHB displacement sign (84.5%-86.9%), and the highest sensitivity was registered for the LHB tendinopathy sign (87.5%). Furthermore, the highest specificity was observed for the LHB displacement sign and LHB subluxation/dislocation sign (98.1%-100%). The IRA regarding final MRI diagnosis and MRI signs of BP lesions was good to very good (κ = 0.76-0.98).

DATA CONCLUSION

Nonarthrographic shoulder MRI may show good diagnostic accuracy for detecting BP lesions. The LHB displacement sign could serve as the most accurate and specific sign for diagnosis of BP lesions.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Epidemiology of Knee Injuries in Baseball Players from the State of São Paulo

Objective  This study aimed to identify the main knee complaints and injuries associated with baseball and their prevalence in the state of São Paulo, Brazil. Methods  This epidemiological study analyzed data from an online questionnaire sent to baseball athletes from the state of São Paulo, Brazil, from 2019 to 2022. Results  Ninety-eight athletes participated in the study. Their average age was 24.3 years, and 85.72% of the subjects were men. The most prevalent ethnicities were yellow (50%) and white (42.86%). Most athletes had incomplete or complete higher education (75.5%). Most (88.77%) have been training for over 1 year, and 40.82% played in more than 1 position. More than half also practiced another sport. Most (66.32%) athletes present knee complaints or symptoms, and 37.75% had suffered a knee injury playing baseball, with several mechanisms (contact with the ground, contact with another player, or no contact). More than half (59.45%) of the athletes required time away from baseball due to complaints, symptoms, or injuries. Conclusion  Among the athletes interviewed, 66.32% had a knee complaint, and 37.75% had already had a knee injury, especially meniscal and ligament injuries. The injury rate was highest in the first year of practice.

Can Secondary Adhesive Capsulitis Complicate Calcific Tendinitis of the Rotator Cuff? An Ultrasound Imaging Analysis

BACKGROUND

Adhesive capsulitis (AC) of the glenohumeral joint is a recognized cause of pain associated with both active and passive restricted ranges of movement. AC can be subdivided into primary and secondary forms. Trauma, surgery, immobilization, and diabetes mellitus are the leading well-recognized causes of secondary AC. Calcific tendinitis/tendinitis (CT) of the rotator cuff is considered a possible trigger for AC, as reported in a few previous articles. However, there are no original investigations that assess the frequency and characteristics of this association. The aim of our research was to evaluate the presence of AC in a cohort of patients with a known CT condition of the rotator cuff by an ultrasound (US) examination.

MATERIALS AND METHODS

We prospectively enrolled all the patients admitted at our single institution (October 2022-June 2023) for the preoperative US evaluation of a known CT condition. In these patients, we searched for parameters related to secondary AC. An axillary pouch (AP) thickness equal to or greater than 4 mm (or greater than 60% of the contralateral AP) was considered diagnostic of AC. Moreover, rotator interval (RI) thickness and the presence of effusion within the long-head biceps tendon (LHBT) sheath was also assessed in all patients.

RESULTS

A total of 78 patients (54F, 24M-mean age = 50.0 and range = 31-71 y.o.) were enrolled in the study. In 26 of those patients (26/78-33.3%), US signs of AC were detected. Notably, the mean AP thickness in patients with AC and CT was 3.96 ± 1.37 mm (Group 1) and 2.08 ± 0.40 mm in patients with CT only (Group 2). RI thickness was significantly greater in patients with superimposed AC: 2.54 ± 0.38 mm in Group 1 and 1.81 ± 0.41 mm in Group 2 (p < 0.00001). Moreover, effusion within the LHBT was significantly more frequently detected in patients with AC: 84.61% in Group 1 versus 15.79% in Group 2-p < 0.00001.

CONCLUSION

US signs of AC are found in one-third of patients with CT of the rotator cuff, demonstrating that AC represents a frequent complication that should be routinely evaluated during US investigation to provide more personalized treatment strategies.

Youth Athletes with Sever's Disease Exhibit Altered Achilles Tendon Ultrasound Characteristics: A Retrospective Case-Control Study

OBJECTIVES

Calcaneal apophysitis (Sever's disease) is an overuse condition caused by repetitive traction stress to the calcaneal apophysis. Whether Achilles tendon morphology is altered in this young patient population remains unknown. Therefore, we aimed to identify differences in Achilles tendon morphology between youth athletes diagnosed with calcaneal apophysitis and healthy controls.

METHODS

This retrospective chart review included 46 patients (n = 23 Sever's disease, 15F/8M, 12.4 ± 2.3 years old) and (n = 23 healthy controls, 13F/10M, 15.9 ± 1.5 years old) who sought care in a Children's Hospital Sports Medicine/Orthopedics Department between 2012 and 2022. We measured ultrasound-derived degree of tendon thickening, Achilles tendon thickness (cm), and cross-sectional area (CSA [cm2]). Separate multivariate analyses of covariance (MANCOVAs) were used to compare degree of thickening, mass-normalized Achilles tendon thickness, and CSA between participant groups, covarying for age. Cohen's d effect sizes were used to assess the magnitude of mean differences and standard error (MDSE) between groups.

RESULTS

Young athletes with Sever's disease had a significantly greater degree of tendon thickening with a large effect compared with healthy controls (MDSE: 0.07 [0.01] mm P < .001, d = 1.39). Achilles tendon thickness and CSA did not statistically differ between groups; however, the magnitude of between-group differences for these measures (MDSE: 0.18 [0.05] cm, MDSE: 0.27 [0.07] cm2, respectively) were moderate.

CONCLUSIONS

Our findings demonstrate previously unrecognized differences in Achilles tendon morphology between young athletes with clinically diagnosed Sever's disease and healthy controls. Our study supports incorporating diagnostic ultrasound as part of a comprehensive examination to ensure appropriate diagnosis and clinical management for adolescents with heel pain.

The twisted Achilles tendon microvasculature

The Achilles tendon (AT) is reportedly the most vulnerable to rupture at the midportion, a section of relative hypovascularity. It has been postulated that the twisted structure of this tendon may constitute a critical factor contributing to increased propensity to vascular compromise, decreased regenerative capacity, and rupture in the midsection of the AT. In this review, we will give an overview of the most relevant research on AT vasculature and twist, and delve into the interplay between the two elements in the context of AT disorders. The pertinent body of research suggests a considerable variability in tendon twist among individuals, which likely constitutes a determining factor in the extent to which vessels coursing along and between AT fibers are compressed during contraction-induced elongation of the tendon. Consequently, further research is necessary to investigate the precise association between tendon torsion and blood flow within the AT.

Progression of partial to complete ruptures of the Achilles tendon during rehabilitation: A study using a finite element model

Substantial research on complete Achilles tendon ruptures is available, but guidance on partial ruptures is comparatively sparse. Conservative management is considered acceptable in partial tendon ruptures affecting less than 50% of the tendon's width, but supporting experimental evidence is currently lacking. Using a previously validated finite element model of the Achilles tendon, this study aimed to assess whether loading conditions simulating an early functional rehabilitation protocol could elicit progression to a complete rupture in partial ruptures of varying severity. In silico tendon rupture simulations were performed to locate the most likely rupture site for least, moderate, and extreme subtendon twist configurations. These three models were split at the corresponding rupture site and two sets of partial ruptures were created for each, starting from the medial and lateral sides, and ranging from 10% to 50% loss of continuity. Simulations were conducted with material parameters from healthy and tendinopathic tendons. Partial ruptures were considered to progress if the volume of elements showing a maximum principal strain above 10% exceeded 3 mm3 . To assess whether the tendinopathic tendons typical geometric characteristics could compensate for the inferior material properties found in tendinopathy, an additional model with increased cross-sectional area in the free tendon region was developed. Progression to complete ruptures occurred even with less than a 50% loss of continuity, regardless of subtendon twisting, and material parameters. The tendinopathic tendon model with increased cross-sectional area showed similar results. These findings suggest the current criteria for surgical treatment of partial ruptures should be reconsidered. Statement of clinical significance: The clinical significance and most appropriate treatment of partial ruptures of the Achilles tendon is unclear. Despite the widespread use of the "50% rule" in treatment decisions of partial tendon ruptures, experimental evidence supporting it is missing. The present study provides new data, from a validated aponeurotic and free Achilles tendon finite element model, showing that partial ruptures may progress to complete ruptures under loading conditions elicited from functional rehabilitation protocols, even for partial ruptures affecting less than 50% of the tendon's width. Under these novel findings, the current criteria for surgical treatment of partial ruptures should be reconsidered.

Challenges and opportunities of medicines for treating tendon inflammation and fibrosis: A comprehensive and mechanistic review

BACKGROUND

Tendinopathy refers to conditions characterized by collagen degeneration within tendon tissue, accompanied by the proliferation of capillaries and arteries, resulting in reduced mechanical function, pain, and swelling. While inflammation in tendinopathy can play a role in preventing infection, uncontrolled inflammation can hinder tissue regeneration and lead to fibrosis and impaired movement.

OBJECTIVES

The inability to regulate inflammation poses a significant limitation in tendinopathy treatment. Therefore, an ideal treatment strategy should involve modulation of the inflammatory process while promoting tissue regeneration.

METHODS

The current review article was prepared by searching PubMed, Scopus, Web of Science, and Google Scholar databases. Several treatment approaches based on biomaterials have been developed.

RESULTS

This review examines various treatment methods utilizing small molecules, biological compounds, herbal medicine-inspired approaches, immunotherapy, gene therapy, cell-based therapy, tissue engineering, nanotechnology, and phototherapy.

CONCLUSION

These treatments work through mechanisms of action involving signaling pathways such as transforming growth factor-beta (TGF-β), mitogen-activated protein kinases (MAPKs), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), all of which contribute to the repair of injured tendons.

Successive tendon injury in an in vivo rat overload model induces early damage and acute healing responses

Introduction: Tendinopathy is a degenerative condition resulting from tendons experiencing abnormal levels of multi-scale damage over time, impairing their ability to repair. However, the damage markers associated with the initiation of tendinopathy are poorly understood, as the disease is largely characterized by end-stage clinical phenotypes. Thus, this study aimed to evaluate the acute tendon responses to successive fatigue bouts of tendon overload using an in vivo passive ankle dorsiflexion system. Methods: Sprague Dawley female rats underwent fatigue overloading to their Achilles tendons for 1, 2, or 3 loading bouts, with two days of rest in between each bout. Mechanical, structural, and biological assays were performed on tendon samples to evaluate the innate acute healing response to overload injuries. Results: Here, we show that fatigue overloading significantly reduces in vivo functional and mechanical properties, with reductions in hysteresis, peak stress, and loading and unloading moduli. Multi-scale structural damage on cellular, fibril, and fiber levels demonstrated accumulated micro-damage that may have induced a reparative response to successive loading bouts. The acute healing response resulted in alterations in matrix turnover and early inflammatory upregulations associated with matrix remodeling and acute responses to injuries. Discussion: This work demonstrates accumulated damage and acute changes to the tendon healing response caused by successive bouts of in vivo fatigue overloads. These results provide the avenue for future investigations of long-term evaluations of tendon overload in the context of tendinopathy.

Anabolic steroids and the evaluation of patients with acute PM tendon rupture using microscopy and MRI

This study presented a pioneering investigation of the changes in the magnetic resonance imaging images of pectoralis major muscle (PMM) tendon rupture. In all, 26 men were evaluated with acute total PMM rupture (<3 months since injury) with a mean age of 37.3 years (SD = 9.7 years) and 10 control patients with a mean age of 32.6 years (SD = 4.2 years). The evaluation of the tendon PMM injuries was based on the magnetic resonance imaging exam and the histological analysis. The magnetic resonance imaging of the surgically showed two (7.1%) contralateral sides were normal, 16 (57.1%) showed superior tendinopathy, and 10 (35.7%) had total tendinopathy. Inferior tendinopathy was not observed. The tendon histology revealed degenerative changes in 16 (66.7%) fragments, with 12 (50.0%) considered as mild (<25%), and four considered as (16.7%) high (>50.0%) tendinopathy. Total acute rupture of the PMM tendon among weightlifters might be associated with tendinous degeneration prior to injury.

Behaviour change and rehabilitation adherence in adults with tendinopathy: a scoping review

PURPOSE

This scoping review aimed to identify behaviour change strategies influencing rehabilitation adherence in adults with tendinopathy, a common musculoskeletal condition requiring prolonged rehabilitation with poor adherence and variable outcomes.

METHODS

Following the Joanna Briggs Institute (JBI) methodology, seven databases were searched until April 2023. Records included reviews, intervention, and qualitative studies published in English. Behaviour change strategies were deductively coded and mapped to the capability, opportunity, and motivation model of behaviour (COM-B).

RESULTS

Eighty-six articles were retained. The primary behaviour change strategies in tendinopathy rehabilitation reports addressed Psychological Capability; from knowledge through education, instruction, and self-monitoring using exercise diaries. Also, Social Opportunity involves demonstration and monitoring of rehabilitation behaviour, and Physical Opportunity focuses on time-efficient programs with access to equipment and health professionals. Few reports addressed Automatic Motivation (positive reinforcement and habit formation). Barriers identified in the reports were Reflective Motivation (negative beliefs and fears), Physical Opportunity (time-constraints), and Physical Capability (pain and comorbidities).

CONCLUSIONS

Further research should explore the impact of education on beliefs, fears, and pain-management, as well as the effectiveness of teaching habit formation for improved time-management. Implementing these behaviour change strategies may enhance tendinopathy rehabilitation adherence, improving clinical trial efficacy, guiding clinical practice, and impacting patient outcomes.

Patellar tendon biomechanical and morphologic properties and their relationship to serum clinical variables in persons with prediabetes and type 2 diabetes

Tendon biomechanical properties and fibril organization are altered in patients with diabetes compared to healthy individuals, yet few biomarkers have been associated with in vivo tendon properties. We investigated the relationships between in vivo imaging-based tendon properties, serum variables, and patient characteristics across healthy controls (n = 14, age: 45 ± 5 years, body mass index [BMI]: 24 ± 1, hemoglobin A1c [HbA1c]: 5.3 ± 0.1%), prediabetes (n = 14, age: 54 ± 5 years, BMI: 29 ± 2; HbA1c: 5.7 ± 0.1), and type 2 diabetes (n = 13, age: 55 ± 3 years, BMI: 33 ± 2, HbA1c: 6.7 ± 0.3). We used ultrasound speckle-tracking and measurements from magnetic resonance imaging (MRI) to estimate the patellar tendon in vivo tangent modulus. Analysis of plasma c-peptide, interleukin-1β (IL-1β), IL-6, IL-8, tumor necrosis factor-α (TNF-α), adiponectin, leptin, insulin-like growth factor 1 (IGF-1), and C-reactive protein (CRP) was completed. We built regression models incorporating statistically significant covariates and indicators for the clinically defined groups. We found that tendon cross-sectional area normalized to body weight (BWN CSA) and modulus were lower in patients with type 2 diabetes than in healthy controls (p < 0.05). Our regression analysis revealed that a model that included BMI, leptin, high-density lipoprotein (HDL), low-density lipoprotein (LDL), age, and group explained ~70% of the variability in BWN CSA (R2  = 0.70, p < 0.001). For modulus, including the main effects LDL, groups, HbA1c, age, BMI, cholesterol, IGF-1, c-peptide, leptin, and IL-6, accounted for ~54% of the variability in modulus (R2  = 0.54, p < 0.05). While BWN CSA and modulus were lower in those with diabetes, group was a poor predicter of tendon properties when considering the selected covariates. These data highlight the multifactorial nature of tendon changes with diabetes and suggest that blood variables could be reliable predictors of tendon properties.

Treatment of Tendon Injuries in the Servicemember Population across the Spectrum of Pathology: From Exosomes to Bioinductive Scaffolds

Tendon injuries in military servicemembers are one of the most commonly treated nonbattle musculoskeletal injuries (NBMSKIs). Commonly the result of demanding physical training, repetitive loading, and frequent exposures to austere conditions, tendon injuries represent a conspicuous threat to operational readiness. Tendon healing involves a complex sequence between stages of inflammation, proliferation, and remodeling cycles, but the regenerated tissue can be biomechanically inferior to the native tendon. Chemical and mechanical signaling pathways aid tendon healing by employing growth factors, cytokines, and inflammatory responses. Exosome-based therapy, particularly using adipose-derived stem cells (ASCs), offers a prominent cell-free treatment, promoting tendon repair and altering mRNA expression. However, each of these approaches is not without limitations. Future advances in tendon tissue engineering involving magnetic stimulation and gene therapy offer non-invasive, targeted approaches for improved tissue engineering. Ongoing research aims to translate these therapies into effective clinical solutions capable of maximizing operational readiness and warfighter lethality.

Achilles tendinopathy research has a gender data gap: A systematic review and meta-analysis

PURPOSE

A persisting gender bias has been recently highlighted in orthopaedics and sports medicine. The aim of this study was to evaluate the volume of gender-specific data and gender-specific results in the treatment of a common tendon disease, Achilles tendinopathy.

METHODS

Pubmed, Cochrane, and Web of Science were searched to identify all clinical studies focusing on Achilles tendinopathy treatment. The Visual Analogue Scale (VAS) and Victorian Institute of Sport Assessment-Achilles (VISA-A) data of women and men of the studies that disaggregated results by gender were collected, and a meta-analysis was conducted. Treatment response within and in between gender categories was evaluated, focusing on overall gender-disaggregated data, as well as within each of the three treatment categories: conservative treatment, injective treatment and surgical treatment. A formal risk of bias analysis was conducted using Downs and Black's grading system.

RESULTS

Out of the 8796 papers screened, 178 were included after the screening. The number of female study participants grew from 20% up to 1990 to 48% in the years 2019-2022. Only 373 out of 3423 (11%) female patients and 685 of 4352 (16%) male patients were found in sex-disaggregated studies. A meta-analysis was conducted on the 14 papers that reported sex-disaggregated data for VAS and VISA-A. The meta-analysis revealed that there was no difference in the overall treatment response between women and men and that both genders showed an overall significant treatment benefit in terms of VAS and VISA-A values. However, significant differences were documented within the treatment categories. While no differences were found in surgical studies, in conservative treatment studies, men experienced lower posttreatment VAS values (p = 0.004). The largest difference was found in injective treatments, with men experiencing a larger change in VAS values (men = -3.0, women = -1.0, p = 0.016) and higher posttreatment VISA-A values (p = 0.032).

CONCLUSION

This systematic review and meta-analysis showed a lack of awareness of the importance of sex-specific data within Achilles tendinopathy treatment research. The proportion of female study subjects has grown over the years, but there is still a large data gap caused by the absence of sex-disaggregated data. The omission of sex-disaggregated data causes the loss of valuable knowledge on the true effectiveness of current Achilles tendinopathy treatment. The results of this study indicate that women profit less from available treatments, particularly injective approaches, which prompts further research for treatment adaptation by gender.

LEVEL OF EVIDENCE

Level IV.

A Novel Tendon Injury Model, Induced by Collagenase Administration Combined with a Thermo-Responsive Hydrogel in Rats, Reproduces the Pathogenesis of Human Degenerative Tendinopathy

Patellar tendinopathy is a common clinical problem, but its underlying pathophysiology remains poorly understood, primarily due to the absence of a representative experimental model. The most widely used method to generate such a model is collagenase injection, although this method possesses limitations. We developed an optimized rat model of patellar tendinopathy via the ultrasound-guided injection of collagenase mixed with a thermo-responsive Pluronic hydrogel into the patellar tendon of sixty male Wistar rats. All analyses were carried out at 3, 7, 14, 30, and 60 days post-injury. We confirmed that our rat model reproduced the pathophysiology observed in human patients through analyses of ultrasonography, histology, immunofluorescence, and biomechanical parameters. Tendons that were injured by the injection of the collagenase-Pluronic mixture exhibited a significant increase in the cross-sectional area (p < 0.01), a high degree of tissue disorganization and hypercellularity, significantly strong neovascularization (p < 0.01), important changes in the levels of types I and III collagen expression, and the organization and presence of intra-tendinous calcifications. Decreases in the maximum rupture force and stiffness were also observed. These results demonstrate that our model replicates the key features observed in human patellar tendinopathy. Collagenase is evenly distributed, as the Pluronic hydrogel prevents its leakage and thus, damage to surrounding tissues. Therefore, this model is valuable for testing new treatments for patellar tendinopathy.

MicroRNA-146a gene transfer ameliorates senescence and senescence-associated secretory phenotypes in tendinopathic tenocytes

OBJECTIVE

Tendinopathy is influenced by multiple factors, including chronic inflammation and aging. Senescent cells exhibit characteristics such as the secretion of matrix-degrading enzymes and pro-inflammatory cytokines, collectively known as senescence-associated secretory phenotypes (SASPs). Many of these SASP cytokines and enzymes are implicated in the pathogenesis of tendinopathy. MicroRNA-146a (miR-146a) blocks senescence by targeting interleukin-1β (IL-1β) receptor-associated kinase 4 (IRAK-4) and TNF receptor-associated factor 6 (TRAF6), thus inhibiting NF-κB activity. The aims of this study were to (1) investigate miR-146a expression in tendinopathic tendons and (2) evaluate the role of miR-146a in countering senescence and SASPs in tendinopathic tenocytes.

METHODS

MiR-146a expression was assessed in human long head biceps (LHB) and rat tendinopathic tendons by in situ hybridization. MiR-146a over-expression in rat primary tendinopathic tenocytes was achieved by lentiviral vector-mediated precursor miR-146a transfer (LVmiR-146a). Expression of various senescence-related markers was analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunoblotting and immunofluorescence. MiR-146a expression showed a negative correlation with the severity of tendinopathy in human and rat tendinopathic tendons (p<0.001).

RESULTS

Tendinopathic tenocyte transfectants overexpressing miR-146a exhibited downregulation of various senescence and SASP markers, as well as the target molecules IRAK-4 and TRAF6, and the inflammatory mediator phospho-NF-κB. Additionally, these cells showed enhanced nuclear staining of high mobility group box 1 (HMGB1) compared to LVmiR-scramble-transduced controls in response to IL-1β stimulation.

CONCLUSIONS

We demonstrate that miR-146a expression is negatively correlated with the progression of tendinopathy. Moreover, its overexpression protects tendinopathic tenocytes from SASPs and senescence through the IRAK-4/TRAF6/NF-kB pathway.

Rehabilitation of the painful elbow

Although lateral elbow pain and medial ulnar collateral ligament injury are common musculoskeletal pathologies in overhead athletes, the evidence supporting specific interventions for managing these conditions is scarce. Management of these conditions has been guided mostly by expert opinion rather than empirical evidence, yet the lack of comparative data in the literature has not negatively affected return-to-play rates following surgery. However, an understanding of what is known regarding unimodal and multimodal treatments for lateral elbow pain and medial ulnar collateral ligament injury is needed for clinicians to select evidence-based treatment pathways and highlight what is not known to develop future high-quality investigations.

Antioxidant and anti-inflammatory injectable hydrogel microspheres for in situ treatment of tendinopathy

Tendinopathy is a common disorder that causes local dysfunction and reduces quality of life. Recent research has indicated that alterations in the inflammatory microenvironment play a vital role in the pathogenesis of tendinopathy. Herein, injectable methacrylate gelatin (GelMA) microspheres (GM) were fabricated and loaded with heparin-dopamine conjugate (HDC) and hepatocyte growth factor (HGF). GM@HDC@HGF were designed to balance the inflammatory microenvironment by inhibiting oxidative stress and inflammation, thereby regulating extracellular matrix (ECM) metabolism and halting tendon degeneration. Combining growth factors with heparin was expected to improve the encapsulation rate and maintain the long-term efficacy of HGF. In addition, the catechol groups on dopamine have adhesion and antioxidant properties, allowing potential attachment at the injured site, and better function synergized with HGF. GM@HDC@HGF injected in situ in rat Achilles tendinopathy (AT) models significantly down-regulated oxidative stress and inflammation, and ameliorated ECM degradation. In conclusion, the multifunctional platform developed presents a promising alternative for the treatment of tendinopathy.

The Association of Tobacco Smoking and Level of Apoptosis in the Long Head of the Biceps Chronic Tendinopathy-An Immunohistochemical Study

BACKGROUND

The substances present in cigarette smoke have a negative impact on cellular integrity and metabolism, can reduce blood flow to tissues, and can disrupt collagen synthesis. Ultimately this can lead to cell death, which clinically may result in impaired tendon healing and the onset of chronic tendinopathy. Within the shoulder, the exact association between the extent of apoptosis in the long head of the biceps (LHB) tendon and harmful factors like cigarette smoke remains unclear.

OBJECTIVES

The purpose of this study was to investigate the connection between smoking, the degree of apoptosis in LHB tendinopathy, and the long-term outcomes of surgical treatment.

DESIGN

Observational, retrospective study.

METHODS

This study included 22 consecutive patients who had undergone arthroscopic biceps tenodesis or tenotomy for symptomatic LHB tendinopathy with or without concomitant rotator cuff tears (RCT). The intra-articular LHB tendon remnants were histologically examined by measuring the level of expression of apoptotic cell markers such as BCL2, cleaved caspase 3, and p53. Pre- and postoperative clinical outcomes were analyzed by collecting patient report outcome measures such as the American Shoulder and Elbow Surgeons (ASES) score and the Visual Analogue Scale (VAS) for pain.

RESULTS

The smokers group had a mean pack-year history of 13.12 (SD = 9.94), mean number of cigarettes per day of 14.77 (SD = 4.64), and a mean smoking duration of 16.38 (SD = 10.1) years. Among the smoking indexes, the number of cigarettes per day showed a positive correlation with Snyder classification (p = 0.0459, rho = 0.3682). Non-smokers and smokers did not show a statistically significant difference in the expression indexes of BCL2, cleaved caspase 3, or p53 (p = 0.4216, p = 0.5449, p = 0.5613, respectively). However, the cleaved caspase 3 expression index showed a negative correlation with the severity of rotator cuff lesions in the total population (p = 0.0193, rho = -0.4651).

CONCLUSIONS

While apoptotic processes in the LHB tendon were observed, no significant association was found between tobacco smoking, the extent of apoptosis, and clinical outcomes. However, the expression of the apoptotic marker cleaved caspase 3 correlated with the severity of rotator cuff pathology. Furthermore, active smoker status was associated with worse clinical outcomes in terms of pain following LHB tenodesis or tenotomy.

Hypoxia-Inducible Factor and Oxidative Stress in Tendon Degeneration: A Molecular Perspective

Tendinopathy is a debilitating condition marked by degenerative changes in the tendons. Its complex pathophysiology involves intrinsic, extrinsic, and physiological factors. While its intrinsic and extrinsic factors have been extensively studied, the role of physiological factors, such as hypoxia and oxidative stress, remains largely unexplored. This review article delves into the contribution of hypoxia-associated genes and oxidative-stress-related factors to tendon degeneration, offering insights into potential therapeutic strategies. The unique aspect of this study lies in its pathway-based evidence, which sheds light on how these factors can be targeted to enhance overall tendon health.

Patellar height: an important parameter in knee MRI associated with tendinopathy, quadriceps fat pad edema (QFPE), anterior cruciate ligament mucoid degeneration (ACL-MD), and lateral cartilage damage

BACKGROUND

Some pathologies associated with abnormal patellar height have been reported in the literature. However, its relationship with some pathologies, such as anterior cruciate ligament mucoid degeneration (ACL-MD) and focal cartilage defect, has not been investigated.

PURPOSE

To investigate the relationship between patellar height with patellar-quadriceps tendinopathy, quadriceps fat pad edema, ACL-MD, and focal cartilage defect.

MATERIAL AND METHODS

Magnetic resonance imaging of the knees of 261 patients were classified into three groups as normal, patella alta, and patella baja, and evaluated in terms of patellar-quadriceps tendinopathy, quadriceps fat pad edema, ACL-MD, and focal cartilage defect.

RESULTS

There were 261 patients (140 men, 121 women; age range = 18-60 years; mean age = 30 ± 4.7 years). Of the 261 patients, 181 (69.3%) were normal, 56 (21.4%) were patella alta, and 24 were patella baja (9.1%). Patellar-quadriceps tendinopathy, quadriceps fat pad edema, and ACL-MD rates were significantly higher compared to the normal group (P <0.05). While a moderate positive correlation was found between patellar height shift and patellar-quadriceps tendinopathy and ACL-MD, there was a small correlation between patellar height shift and quadriceps fat pad edema. The rate of focal cartilage defect was significantly higher in the middle part of the lateral femoral condyle and lateral knee joint only in patella alta.

CONCLUSION

The risk of patellar-quadriceps tendinopathy, quadriceps fat pad edema, ACL-MD, and lateral focal cartilage defect is higher in patients with alta-baja. The radiologist should evaluate these pathologies more carefully, especially subtle ones, in patients with abnormal patellar height.

Effects of adipose-derived mesenchymal stem cell conditioned medium on human tenocytes exposed to high glucose

Introduction

Diabetic tendinopathy is a common invalidating and challenging disease that may be treated using stem cells. However, the effects of adipose-derived mesenchymal stem cell conditioned medium (ASC-CM) in diabetic tendinopathy have never been explored.

Objectives

The present study evaluated the effects of ASC-CM on morphology, cell viability, structure, and scratch wound closure of human tenocytes (HTNC) exposed to high glucose (HG).

Design

Experimental study.

Methods

HTNC were exposed to HG (25 mM) for 7, 14 and 21 days with or without ASC-CM for the last 24 h. CM was collected from 4 × 105 ASCs, centrifuged for 10 min at 200 g and sterilized with 0.22 μm syringe filter.

Results

At 7 days, HG-HTNC had decreased cell viability [72 ± 2%, p < 0.01 versus normal glucose (NG)] compared to NG-HTNC (90 ± 5%). A further decrement was detected after 14 and 21 days (60 ± 4% and 60 ± 5%, both, p < 0.01 versus NG and p < 0.01 versus HG7). While NG-HTNC evidenced a normal fibroblast cell-like elongated morphology, HG-HTNC showed increased cell roundness. In contrast, HG-HTNC exposed to ASC-CM showed a significant increase in cell viability, an improved cell morphology and higher scratch wound closure at all HG time points. Moreover, the exposure to ASC-CM significantly increased thrombospondin 1 and transforming growth factor beta 1 (TGF-β1) content in HG-HTNC. The TGF-β1 elevation was paralleled by higher Collagen I and Vascular Endothelial Growth Factor in HG-HTNC.

Conclusion

ASC-CM may restore the natural morphology, cell viability and structure of HTNC, promoting their scratch wound closure through TGF-β1 increase.

Minimally Invasive Peroneal Tenodesis Assisted by Peroneal Tendoscopy: Technique and Preliminary Results

Introduction: Peroneal disorders are a common cause of ankle pain and lateral instability and have been described in as much as 77% of patients with lateral ankle instability. Clicking, swelling, pain, and tenderness in the peroneal tendons track are frequent symptoms, but they can be confused with other causes of lateral ankle pain. The management of peroneal disorders can be conservative or surgical. When the conservative treatment fails, surgery is indicated, and open or tendoscopic synovectomy, tubularization, tenodesis or tendon transfers can be performed. The authors present a surgical technique of tendoscopy associated to minimally invasive tenodesis for the treatment of peroneal tendon tears, as well as the preliminary results of patients submitted to this procedure. Methods: Four patients with chronic lateral ankle pain who were diagnosed with peroneal brevis pathology were treated between 2020 and 2022 with tendoscopic-assisted minimally invasive synovectomy and tenodesis. Using a 2.7 mm 30° arthroscope and a 3.0 mm shaver blade, the entire length of the peroneus brevis tendon and most parts of the peroneus longus tendon can be assessed within Sammarco's zones 1 and 2. After the inspection and synovectomy, a minimally invasive tenodesis is performed. Results: All patients were evaluated at least six months after surgery. All of them reported improvement in daily activities and in the Foot Function Index (FFI) questionnaire (pre-surgery mean FFI = 23.86%; post-surgery mean FFI = 6.15%), with no soft tissue complications or sural nerve complaints. Conclusion: The tendoscopy of the peroneal tendons allows the surgeon to assess their integrity, confirm the extent of the lesion, perform synovectomy, prepare the tendon for tenodesis, and perform it in a safe and minimally invasive way, reducing the risks inherent to the open procedure.

Validation of a novel clinical tool for monitoring distal limb stiffness

Objective

To validate a novel technique to measure limb stiffness in a clinical setting.

Animals

Three horses and three ponies owned by the Royal Veterinary College.

Procedures

Limb stiffness indices for both forelimbs were first derived using the gold standard of kinematic analysis. Using the same animals, limb stiffness indices were then calculated using portable floor scales to record weight and an electrogoniometer to record changes in metacarpophalangeal joint angle. The two techniques were then assessed for correlation and repeatability.

Results

The repeatability of limb stiffness measurement using the novel clinical tool was considered to be good based on a small coefficient of variation (5.70%). The correlation of limb stiffness as derived by both methods was high (r = 0.78, p < 0.01). Limb stiffness was positively correlated with the mass of the subject (r = 0.85, p < 0.01), with heavier horses having greater limb stiffness.

Clinical relevance

This study has compared a novel method to measure distal forelimb stiffness non-invasively in a clinical setting to kinematic analysis in six equids. It has demonstrated that limb stiffness increases in a linear fashion with body mass consistent with the role of forelimbs providing energy storage. Because in vivo limb stiffness has been shown previously to alter with injury to the superficial digital flexor tendon, it is hypothesized that this technique will offer a practical technique for the clinician to assess limb stiffness in clinical cases. Further study will be necessary to determine its clinical usefulness in such cases.

Photobiomodulation Therapy Plus Usual Care Is Better than Usual Care Alone for Plantar Fasciitis: A Randomized Controlled Trial

Background

Plantar fasciitis (PF) results in pain-related disability and excessive healthcare costs. Photobiomodulation therapy (PBMT) has shown promise for decreasing both pain and disability related to PF.

Purpose

The purpose was to assess the clinical impact of PBMT on pain and function in people with PF.

Study Design

Prospective, randomized controlled clinical trial.

Methods

A convenience sample of adults with PF were randomly assigned to one of three groups: (1) usual care, (2) usual care plus nine doses of PBMT with 25W output power over three weeks, or (3) usual care plus nine doses of PBMT with 10W output power over three weeks. Both 10W and 25W PBMT participants received the same total dose (10J/cm2) by utilizing a simple area equation. Pain (with Defense and Veterans Pain Rating Scale) and function (by Foot and Ankle Ability Measure) were measured at baseline, weeks 3, and 6 for all groups, and at 13 and 26 weeks for PBMT groups.

Results

PBMT groups experienced a reduction in pain over the first three weeks (from an average of 4.5 to 2.8) after which their pain levels remained mostly constant, while the UC group experienced a smaller reduction in pain (from an average of 4 to 3.8). The effects on pain were not different between PBMT groups. PBMT in both treatment groups also improved function more than the UC group, again with the improvement occurring within the first three weeks.

Conclusions

Pain and function improved during the three weeks of PBMT plus UC and remained stable over the following three weeks. Improvements sustained through six months in the PBMT plus UC groups.

Level of Evidence

Level II- RCT or Prospective Comparative Study.

Where is Your Pain? Achilles Tendinopathy Pain Location on Loading Is Different to Palpation, Imaging and Recall Location

OBJECTIVE: To describe and compare pain maps reported during Achilles tendon loading exercises with recall pain location, in people with pain on palpation in their Achilles tendon and tendon pathology on imaging. DESIGN: Cross-sectional analysis of baseline RCT. METHOD: Participants were recruited from a larger Achilles tendinopathy clinical trial. Inclusion criteria were at least 2-month self-reported history of Achilles tendinopathy, midtendon palpation pain, and pathology on ultrasound tissue characterization. Participants were asked to identify their Achilles tendon pain location on a pain map with 8 prespecified locations while at rest prior to loading (recall pain), and subsequently during tendon loading exercises (loading pain). Participants could select multiple locations or select "other" if the locations did not represent their pain. RESULTS: Ninety-three participants were included (93% of participants from a clinical trial). The locations of pain on loading were diverse; all 8 pain locations (and an "other" option) were represented within this sample. Twenty-five percent of participants did not report pain with loading (n = 23 of 93). Of the 70 participants with loading pain, recall pain location differed to loading pain location in 40% (n = 28 of 70) of the participants. CONCLUSION: Palpation pain location, recall pain location, or location of pathology on imaging were not valid proxies for load-related pain in the Achilles tendon. How different pain locations respond to treatment is unknown. Some pathologies (eg, plantaris) have clear pain locations (eg, medial tendon), and assessing pain location may assist differential diagnosis. J Orthop Sports Phys Ther 2024;54(1):1-9. Epub 7 December 2023. doi:10.2519/jospt.2023.12131.

There is a Lack of Clinical Homogeneity in Lower-Limb Tendinopathy Trials: A Scoping Review

OBJECTIVE: It is unclear if clinical trials of treatments for lower-limb tendinopathies include clinically homogeneous participant populations (an assumption for pooling in meta-analyses). We assessed the recruitment setting and participant characteristics used in randomized controlled trials (RCTs) that were investigating any treatment for lower-limb tendinopathies. DESIGN: Scoping review. METHODS: We conducted a systematic literature search in the PubMed, Embase, Cochrane CENTRAL, and Web of Science databases. All RCTs that were investigating treatments for lower-limb tendinopathies in an adult population (≥18 years) were eligible for inclusion. At least 2 authors conducted independent screening and selection of full-text papers, and extracted data from included studies. RESULTS: Of 18 341 records, 342 RCTs (21 897 participants) were eligible for inclusion and data extraction. The most common diagnoses were plantar fasciopathy (n = 195, 57%), Achilles tendinopathy (n = 82, 24%), and patellar tendinopathy (n = 41, 12%). Secondary care (n = 144, 42%) was the most reported recruitment setting, followed by an open setting (n = 44, 13%). In 93 (27%) RCTs, the recruitment setting was not described. We found high heterogeneity in participant characteristics (eg, symptom duration, age, body mass index, and the Victorian Institute of Sport Assessment [VISA] questionnaire score) within and between recruitment settings. CONCLUSION: Our results question whether clinical homogeneity can be adequately assumed in clinical trials of lower-limb tendinopathies due to the lack of clear reporting of the recruitment setting and the variability within and between recruitment settings of key participant characteristics. These findings threaten assumptions for meta-analyses in lower-limb tendinopathies. J Orthop Sports Phys Ther 2024;54(1):1-10. Epub 5 December 2023. doi:10.2519/jospt.2023.11722.

Pristimerin suppresses AIM2 inflammasome by modulating AIM2-PYCARD/ASC stability via selective autophagy to alleviate tendinopathy

Macroautophagy/autophagy plays an important role in regulating cellular homeostasis and influences the pathogenesis of degenerative diseases. Tendinopathy is characterized by tendon degeneration and inflammation. However, little is known about the role of selective autophagy in tendinopathy. Here, we find that pristimerin (PM), a quinone methide triterpenoid, is more effective in treating tendinopathy than the first-line drug indomethacin. PM inhibits the AIM2 inflammasome and alleviates inflammation during tendinopathy by promoting the autophagic degradation of AIM2 through a PYCARD/ASC-dependent manner. A mechanistic study shows that PM enhances the K63-linked ubiquitin chains of PYCARD/ASC at K158/161, which serves as a recognition signal for SQSTM1/p62-mediated autophagic degradation of the AIM2-PYCARD/ASC complex. We further identify that PM binds the Cys53 site of deubiquitinase USP50 through the Michael-acceptor and blocks the binding of USP50 to PYCARD/ASC, thereby reducing USP50-mediated cleavage of K63-linked ubiquitin chains of PYCARD/ASC. Finally, PM treatment in vivo generates an effect comparable to inflammasome deficiency in alleviating tendinopathy. Taken together, these findings demonstrate that PM alleviates the progression of tendinopathy by modulating AIM2-PYCARD/ASC stability via SQSTM1/p62-mediated selective autophagic degradation, thus providing a promising autophagy-based therapeutic for tendinopathy.Abbreviations: 3-MA: 3-methyladenine; AIM2: absent in melanoma 2; AT: Achilles tenotomy; ATP: adenosine triphosphate; BMDMs: bone marrow-derived macrophages; CHX: cycloheximide; Col3a1: collagen, type III, alpha 1; CQ: chloroquine; Cys: cysteine; DARTS: drug affinity responsive target stability; DTT: dithiothreitol; DUB: deubiquitinase; gDNA: genomic DNA; GSH: glutathione; His: histidine; IL1B/IL-1β: interleukin 1 beta; IND: indomethacin; IP: immunoprecipitation; LPS: lipopolysaccharide; MMP: mitochondrial membrane potential; NLRP3: NLR family, pyrin domain containing 3; PM: pristimerin; PYCARD/ASC: PYD and CARD domain containing; SN: supernatants; SOX9: SRY (sex determining region Y)-box 9; SQSTM1: sequestosome 1; Tgfb: transforming growth factor, beta; TIMP3: tissue inhibitor of metalloproteinase 3; TNMD: tenomodulin; TRAF6: TNF receptor-associated factor 6; Ub: ubiquitin; USP50: ubiquitin specific peptidase 50; WCL: whole cell lysates.

Personalized tendon loading reduces muscle-tendon imbalances in male adolescent elite athletes

An imbalanced adaptation of muscle strength and tendon stiffness in response to training may increase tendon strain (i.e., the mechanical demand on the tendon) and consequently tendon injury risk. This study investigated if personalized tendon loading inducing tendon strain within the effective range for adaptation (4.5%-6.5%) can reduce musculotendinous imbalances in male adolescent handball athletes (15-16 years). At four measurement time points during a competitive season, we assessed knee extensor muscle strength and patellar tendon mechanical properties using dynamometry and ultrasonography and estimated the tendon's structural integrity with a peak spatial frequency (PSF) analysis of proximal tendon ultrasound scans. A control group (n = 13) followed their usual training routine, an intervention group (n = 13) integrated tendon exercises into their training (3x/week for ~31 weeks) with a personalized intensity corresponding to an average of ~6.2% tendon strain. We found a significant time by group interaction (p < 0.005) for knee extensor muscle strength and normalized patellar tendon stiffness with significant increases over time only in the intervention group (p < 0.001). There were no group differences or time-dependent changes in patellar tendon strain during maximum voluntary contractions or PSF. At the individual level, the intervention group demonstrated lower fluctuations of maximum patellar tendon strain during the season (p = 0.005) and a descriptively lower frequency of athletes with high-level tendon strain (≥9%). The findings suggest that the personalized tendon loading program reduced muscle-tendon imbalances in male adolescent athletes, which may provide new opportunities for tendon injury prevention.

The Tendinopathy Game Changers: Five Papers From the Last 5 Years That Might Change How You Manage Tendons

SYNOPSIS: The clinical and scientific understanding of tendinopathy has substantially advanced since the Fifth International Scientific Tendinopathy Symposium in 2019. This editorial aims to highlight some of the fantastic tendinopathy research from the past 5 years. We have selected what we consider the "best paper" for each year from 2019 to 2023, which might change how you treat tendons. Selecting only 5 papers was not easy. Did your favorite papers make the cut? Or do you think we missed some key studies? We encourage you to tell us what you think using the social media hashtag #JOSPTtendon. J Orthop Sports Phys Ther 2024;54(1):1-3. Epub 16 November 2023. doi:10.2519/jospt.2023.12372.

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.

Shear wave elastography correlates to degeneration and stiffness of the long head of the biceps tendon in patients undergoing tenodesis with arthroscopic shoulder surgery

BACKGROUND

Tendinopathy of the long head of the biceps (LHB) tendon causes degeneration and changes its stiffness. However, a reliable means of diagnosis has not been established. Shear wave elastography (SWE) provides quantitative tissue elasticity measurements. In this study, the relationship of preoperative SWE values with biomechanically measured stiffness and degeneration of the LHB tendon tissue was investigated.

METHODS

LHB tendons were obtained from 18 patients who underwent arthroscopic tenodesis. SWE values were measured preoperatively at 2 sites, proximal to and within the bicipital groove of the LHB tendon. The LHB tendons were detached immediately proximal to the fixed sites and at their superior labrum insertion. Tissue degeneration was histologically quantified using the modified Bonar score. Tendon stiffness was determined using a tensile testing machine.

RESULTS

The SWE values of the LHB tendon were 502.1 ± 113.6 kPa proximal to the groove and 439.4 ± 123.3 kPa within the groove. The stiffness was 39.3 ± 19.2 N/mm. The SWE values displayed a moderate positive correlation with the stiffness proximal to the groove (r = 0.80) and within it (r = 0.72). The SWE value of the LHB tendon within the groove showed a moderate negative correlation with the modified Bonar score (r = -0.74).

CONCLUSIONS

These findings suggest that preoperative SWE values of the LHB tendon correlate moderately positively with stiffness and moderately negatively with tissue degeneration. Therefore, SWE may predict LHB tendon tissue degeneration and changes in stiffness caused by tendinopathy.

Effectiveness of extracorporeal shockwave therapy in treatment of upper and lower limb tendinopathies: A systematic review and meta-analysis

BACKGROUND

Tendinopathy is caused by repetitive motion, excessive stress on the tendon, overstretch, and motion past the critical angle of rotation or translation. There are various treatment options available for tendinitis, including those affecting both the upper and lower limbs and those of calcific and non-calcific types.

HYPOTHESIS/PURPOSE

Few reviews have analyzed the efficacy of Extracorporeal Shockwave Therapy (ESWT) in treating upper and lower limb tendinopathies while considering calcific and non-calcific-type tendinitis. This paper provides a review and meta-analysis on Randomized Controlled Trials (RCTs), which compared results from a group undergoing ESWT treatment to another group under different treatments.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic search was conducted on PubMed, Web of Science, Embase, the Cochrane Central Register of Control Trials (CENTRAL), and Physiotherapy Evidence Database (PEDro) databases for articles published up to January 2022. The reference lists of identified articles were further scanned. Twenty-two studies were included in the meta-analysis.

RESULTS

Meta-analysis showed no difference in pain reduction in ESWT when compared with a comparison group at 4 (p = 0.26) and 12 weeks (p = 0.33). There were no differences in DASH scores at 12 months between the two groups (p = 0.32).

CONCLUSION

Extracorporeal Shockwave Therapy (ESWT) is effective when used to treat lower limb and calcific tendinitis. It does not yield any better results than other treatment options in managing upper limb tendinopathies and non-calcific tendinopathies.

Calcific Tendinopathy Atypically Located Outside the Rotator Cuff: A Systematic Review

BACKGROUND AND PURPOSE

Calcific tendinopathy is a common cause of painful shoulder easily identified with ultrasound or conventional radiography. Although the rotator cuff is by far the most common location of the disease and diagnostic or treatment strategies are well known in clinical practice, a lack of awareness characterizes the assessment of the other sites affected by this condition; consequently, the risk of underestimating the prevalence of atypical non-rotator cuff calcific tendinopathy is high. This may lead to expensive or invasive diagnostic exams and/or inappropriate treatment, whereas the condition is usually self-limited. The present study aims at analysing the frequency of calcific tendinitis in uncommon sites, in order to fill a gap in knowledge and awareness regarding non-rotator cuff calcific tendinopathy, thus avoiding improper clinical choices and helping to identify this condition.

METHODS

This systematic review was conducted following the PRISMA guidelines. We performed a search on Pubmed and Scopus databases concerning atypically sited extra-rotator cuff calcific tendinopathy published since 1950.

RESULTS

The research found a total of 267 articles and 793 non-rotator cuff cases of calcific tendinopathy registered. The spine (213 – 26.86%), foot and ankle (191 – 23.95%), and hip (175 – 22.06%) appeared to be the most common sites of calcific tendinopathy after the rotator cuff, whereas the longus colli C1-C2 (204 – 25.72%), Achilles (173 – 21.81%), and rectus femori (61 – 7.69%) were the most commonly affected tendons.

CONCLUSION

A better awareness of this condition in several different sites of the body than the rotator cuff could avoid unnecessary choices both in assessment and treatment.

Diagnostic Imaging for Achilles Tendinopathy: Unnecessary Scans? Valuable Insights? Multidisciplinary Clinician-Scientists Present a Nuanced View

SYNOPSIS: Clinical practice guidelines for Achilles tendinopathy do not recommend imaging to inform diagnosis. However, there is considerable variation in how imaging is used, particularly in research and sports. Early imaging risks that people who see the images presume that what they "see" as pathology is the primary cause of pain; patients might end up receiving invasive treatments on the basis of the image when rehabilitation may suffice. On the other hand, imaging can help rule out Achilles tendinopathy and identify differential diagnoses. As more rehabilitation clinicians are direct access practitioners and take on expanded roles as primary health practitioners, ultrasound imaging might serve as a valuable point-of-care tool for diagnosis, identifying conditions that warrant referral and managing conditions like Achilles tendinopathy. We argue that the value of ultrasound imaging to diagnose tendinopathy outweighs the potential limitations. J Orthop Sports Phys Ther 2024;54(1):1-4. Epub 16 November 2023. doi:10.2519/jospt.2023.12255.

Efficacy of ozone injections for reducing musculoskeletal pain in comparison with corticosteroid injections: A systematic review and meta-analysis

BACKGROUND

Corticosteroid injections are frequently used in the short-term treatment of musculoskeletal pain, but their use is controversial as repeated exposures to corticosteroids can lead to deleterious effects on musculoskeletal tissue. Ozone injections have been proposed as a possible treatment for musculoskeletal pain; however, their effectiveness has not been compared with corticosteroids.

OBJECTIVE

To evaluate the effectiveness of ozone injections for reducing pain in individuals with musculoskeletal pain in comparison with corticosteroid injections through a meta-analysis.

METHODS

An online systematic search was performed using electronic databases up to September 2023. We searched for studies that compared corticosteroid injections with ozone injections in the treatment of musculoskeletal pain of diverse origins.

RESULTS

Eleven studies were included comprising a total of 534 individuals. In the overall pooled analysis, a pain reduction in favor of corticosteroid injections was found in the short term (d= 0.31, 95% CI 0.01 to 0.60, p (z) 0.04, I2 = 32%). In the medium term, no significant differences were found in reducing pain between groups (d=-0.17, 95% CI -0.42 to 0.07, p (z) 0.15, I2 = 0%).

CONCLUSIONS

Our results suggest that corticosteroids injections are more effective in reducing musculoskeletal pain in the short term, but equally effective in the medium term when compared with ozone injections. Nonetheless, better-quality clinical trials are necessary to corroborate these results.

Genetic Variability in VEGFA Gene Influences the Effectiveness of Tennis Elbow Therapy with PRP: A Two-Year Prospective Cohort Study

Vascular endothelial growth factor (VEGF) is implicated in both the etiology of tendinopathy and its healing process. Polymorphic variants of the VEGFA gene exhibit varied expression, which can influence the phenotype and treatment effectiveness. The aim of the present study was to analyze the influence of VEGFA gene variants on the effectiveness of tennis elbow therapy using platelet-rich plasma (PRP), measured through common patient-reported outcome measures (PROMs). A cohort of 107 patients (132 elbows) with tennis elbow was prospectively analyzed, with a two-year follow-up (at weeks 2, 4, 8, 12, 24, 52, and 104 after PRP injection). PROMs values were compared between variants of five VEGFA gene polymorphisms (rs699947 A>C, rs2010963 C>G, rs1413711 C>T, rs3024998 C>T and rs3025021 C>T) at each follow-up point. Patients with genotypes GG (rs2010963) and CC (rs3024998) had better response to PRP therapy (significantly fewer symptoms and limitations in the upper limb compared to carriers of alleles C and T, respectively). Polymorphisms influenced also selected hematological parameters. VEGFA gene polymorphisms (rs2010963 and rs3024998) appear to be significant treatment modifiers for tendinopathy, and their genotyping may serve as an effective tool for personalized patient selection for PRP therapy.

Bibliometric analysis of extracorporeal shock wave therapy for tendinopathy

BACKGROUND

Extracorporeal shock wave therapy (ESWT) is a mature, conservative treatment modality for tendinopathy. Although many relevant studies have been conducted, systematic bibliometric studies are lacking. This study aimed to identify trends and hotspots in the treatment of tendinopathy using ESWT.

METHODS

A literature search was conducted on ESWT for tendinopathy using the Web of Science Core Collection with a search period of 2002 to 2022. Of 559 identified studies, 276 met the inclusion criteria and were analyzed using CiteSpace software.

RESULTS

The results showed that from 2002 to 2022, the publication rate of literature on ESWT for tendinopathy was generally increasing. Research hotspots, such as tendinopathy and calcific rotator cuff deposits, began earlier but continued to receive scholarly attention. Research on animal models and molecular mechanisms has progressed slowly in this field. The combined or comparative effectiveness of injectable and supplement-based treatments with ESWT is a popular research topic.

CONCLUSION

Pain management in patients with tendinopathy has received considerable attention. Simultaneously, more clinical indicators of energy levels and pulse parameters during ESWT are needed to provide more scientific and accurate treatment for patients.

The Basas Spanish Squat: Superimposition of Electrical Stimulation to Optimize Patellar Tendon Strain: A Case Series

Background

The Basas Spanish Squat with electrical stimulation (E-stim) has shown promising results as a potential key exercise in treatment of athletes with patellar tendinopathy. Gold standard exercise therapy for tendon injuries consists of tendon loading exercises, or exercises that appropriately applies high levels of mechanical strain to the tendon. The theoretical pathway in which the Basas Spanish Squat with E-stim improves tendinopathy has been speculated to be the additional strain applied through the patellar tendon during superimposition of E-stim. This theory, however, has yet to be confirmed.

Purpose

The purpose of this case series was to compare patellar tendon strain, during the Basas Spanish Squat with, and without E-stim, and open kinetic chain knee extension.

Methods

Four healthy participants performed the three exercises while a physical therapist collected simultaneous unilateral ultrasound images from the patellar tendon. Strain was calculated as the change in patellar tendon length during contraction divided by the resting length.

Results

Amongst all participants, patellar tendon strain was smallest during the Basas Spanish Squat without E-stim, followed by the open kinetic chain knee extension at 60% maximum voluntary isometric contraction. The Basas Spanish Squat with E-stim yielded approximately double or more strain compared to the without E-stim condition and demonstrated higher level of strain compared to open kinetic chain knee extension in all participants.

Conclusion

The findings reflect a clear trend of increased strain through the patellar tendon when E-stim was superimposed. The results support the theory that the Basas Spanish Squat with E-stim increases patellar tendon strain and could explain the reported clinical benefits in individuals with patellar tendinopathy.

Level of Evidence

4, Case series.

Effect of sex on muscle-tendon imbalances and tendon micromorphology in adolescent athletes-A longitudinal consideration

Imbalances between muscle strength and tendon stiffness may cause high-level tendon strain during maximum effort muscle contractions and lead to tendon structural impairments and an increased risk for tendinopathy in adolescent athletes. However, it remains unclear whether the development of musculotendinous imbalances is influenced by sex. At four measurement time points during a competitive season, we measured quadriceps femoris muscle strength and patellar tendon mechanical properties in 15 female (14.3 ± 0.7 years) and 13 male (16.0 ± 0.6 years) elite handball players of similar maturity using dynamometry and ultrasonography. To estimate the tendon's structural integrity, the peak spatial frequency (PSF) of proximal tendon ultrasound scans was determined. Females demonstrated significantly lower muscle strength (p < 0.001) and patellar tendon stiffness (p < 0.001) than males with no significant changes over time (p > 0.05). Tendon strain during isometric maximum voluntary contractions and PSF neither differed between sexes nor changed significantly over time (p > 0.05). We found lower fluctuations in muscle strength (p < 0.001) in females during the season but no differences in the fluctuations of tendon strain, stiffness, and PSF (p > 0.05). Descriptively, there was a similar frequency (~40%) of athletes with high-level tendon strain (>9%) in both sexes. These findings suggest that the lower strength capacity of female athletes is paralleled by lower tendon stiffness. Thereby, muscle-tendon imbalances occur to a similar extent in both sexes leading to increased strain levels during the season, which indicates the need for specific tendon training.

Letrozole-induced inflammatory arthritis and tendinopathy in pediatric rheumatology setting

Musculoskeletal symptoms associated with the use of aromatase inhibitors are a well-known side effect of these drugs and are more prevalent in postmenopausal women. Aromatase inhibitor-associated symptoms are not overt inflammatory processes so are described as arthralgia syndrome. In contrast, aromatase inhibitor-associated inflammatory conditions such as myopathies, vasculitis, and rheumatoid arthritis were also reported. To our knowledge, inflammatory arthritis or tendinopathy associated with aromatase inhibitors were not reported in children despite their increased off-label use in the pediatric setting. Herein, we report a girl with inflammatory arthritis and tendinopathy associated with letrozole treatment.

Rupture of the bilateral and simultaneous tendon of the pectoralis major muscle. Description of three cases

Pectoralis major muscle tendon ruptures associated with physical activity or effort are no longer uncommon in the medical literature. Treatment has also evolved significantly in the last 20 years. However, simultaneous bilateral rupture has only been described in a few cases. This article reports three cases with simultaneous bilateral rupture and describes the examinations and treatment performed. Bilateral lesions, although infrequent, also require early diagnosis and treatment in the acute phase. The chronic phase requires tendon grafting for full correction and a slow rehabilitation process.

Three-Month Complication Rate of Ultrasound-Guided Soft Tissue Surgical Procedures Across Six Sports Medicine Clinics

OBJECTIVES

To 1) determine the types and frequency of complications within 3 months following ultrasound-guided surgical procedures, and 2) identify any patient demographics, co-morbidities, or procedural characteristics that were associated with an increased risk of complications.

METHODS

A retrospective chart review was performed at six Sports Medicine clinics across the United States. The Clavien-Dindo classification was used to categorize procedural complications on a 5-point scale from 1, representing any deviation in post-procedure care without requiring pharmacological or invasive treatment to 5, representing death. Generalized Estimating Equations for binomial outcomes with a logit link were used to estimate the overall and procedure-specific 3-month complication rates.

RESULTS

Among 1902 patients, 8.1% (n = 154) had diabetes and 6.3% (n = 119) were current smokers. The analysis included 2,369 procedures, which were performed in either the upper extremity (44.1%, n = 1045) or lower extremity (55.2%, n = 1308) regions. The most common procedure was ultrasound-guided tenotomy (69.9%, n = 1655). Additional procedures included, trigger finger release (13.1%, n = 310), tendon scraping (8.0%, n = 189), carpal tunnel release (5.4%, n = 128), soft tissue release (2.1%, n = 50), and compartment fasciotomy (1.6%, n = 37). Overall, there was a complication rate of 1.2% (n = 29 complications; 95% CI: 0.8-1.7%). Individual procedures had complication rates that ranged from 0 to 2.7%. There were 13 Grade I complications in 13 patients, 12 Grade II complications in 10 patients, 4 Grade III complications in 4 patients, and 0 Grade IV or V complications. No associations between complication risk and any patient demographics (age, sex, BMI), co-morbidities (diabetes, smoker), or procedure characteristics (type, region) were identified.

CONCLUSION

This retrospective review provides an evidence-based estimate supporting the low level of risk associated with ultrasound-guided surgical procedures for patients from a variety of geographical settings who are seeking care at private and academic-affiliated clinics.

Treatment of Naturally Occurring Tendon Disease with Allogeneic Multipotent Mesenchymal Stromal Cells: A Randomized, Controlled, Triple-Blinded Pilot Study in Horses

The treatment of tendinopathies with multipotent mesenchymal stromal cells (MSCs) is a promising option in equine and human medicine. However, conclusive clinical evidence is lacking. The purpose of this study was to gain insight into clinical treatment efficacy and to identify suitable outcome measures for larger clinical studies. Fifteen horses with early naturally occurring tendon disease were assigned to intralesional treatment with allogeneic adipose-derived MSCs suspended in serum or with serum alone through block randomization (dosage adapted to lesion size). Clinicians and horse owners remained blinded to the treatment during 12 months (seven horses per group) and 18 months (seven MSC-group and five control-group horses) of follow-up including clinical examinations and diagnostic imaging. Clinical inflammation, lameness, and ultrasonography scores improved more over time in the MSC group. The lameness score difference significantly improved in the MSC group compared with the control group after 6 months. In the MSC group, five out of the seven horses were free of re-injuries and back to training until 12 and 18 months. In the control group, three out of the seven horses were free of re-injuries until 12 months. These results suggest that MSCs are effective for the treatment of early-phase tendon disease and provide a basis for a larger controlled study.

Effect of Aging on Tendon Biology, Biomechanics and Implications for Treatment Approaches

Tendon aging is associated with an increasing prevalence of tendon injuries and/or chronic tendon diseases, such as tendinopathy, which affects approximately 25% of the adult population. Aged tendons are often characterized by a reduction in the number and functionality of tendon stem/progenitor cells (TSPCs), fragmented or disorganized collagen bundles, and an increased deposition of glycosaminoglycans (GAGs), leading to pain, inflammation, and impaired mobility. Although the exact pathology is unknown, overuse and microtrauma from aging are thought to be major causative factors. Due to the hypovascular and hypocellular nature of the tendon microenvironment, healing of aged tendons and related injuries is difficult using current pain/inflammation and surgical management techniques. Therefore, there is a need for novel therapies, specifically cellular therapy such as cell rejuvenation, due to the decreased regenerative capacity during aging. To augment the therapeutic strategies for treating tendon-aging-associated diseases and injuries, a comprehensive understanding of tendon aging pathology is needed. This review summarizes age-related tendon changes, including cell behaviors, extracellular matrix (ECM) composition, biomechanical properties and healing capacity. Additionally, the impact of conventional treatments (diet, exercise, and surgery) is discussed, and recent advanced strategies (cell rejuvenation) are highlighted to address aged tendon healing. This review underscores the molecular and cellular linkages between aged tendon biomechanical properties and the healing response, and provides an overview of current and novel strategies for treating aged tendons. Understanding the underlying rationale for future basic and translational studies of tendon aging is crucial to the development of advanced therapeutics for tendon regeneration.

Total rupture of Achilles tendon induces inflammatory response and glial activation on the spinal cord of mice

Rupture of Achilles tendon is a common accident affecting professional and recreational athletes. Acute and chronic pain are symptoms commonly observed in patients with rupture. However, few studies have investigated whether Achilles tendon rupture is able to promote disorders in the central nervous system (CNS). Therefore, the current study aimed to evaluate nociceptive alterations and inflammatory response in the L5 lumbar segment of Balb/c mice spinal cord after Achilles tendon rupture. We found increased algesia in the paw of the ruptured group on the 7th and 14th days post-tenotomy compared with the control group. This phenomenon was accompanied by overexpression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase-2 (NOS-2) as well as hyperactivation of astrocytes and microglia in nociceptive areas of L5 spinal cord as evidenced by intense GFAP and IBA-1 immunostaining, respectively. Biochemical studies also demonstrated increased levels of nitrite in the L5 spinal cord of tenotomized animals compared with the control group. Thus, we have demonstrated for the first time that total rupture of the Achilles tendon induced inflammatory response and nitrergic and glial activation in the CNS in the L5 spinal cord region.

Ultrasound-Guided Electroacupuncture Treatment for Rotator Cuff Tendinopathy: Proposing an Effective Alternative to Nonoperative Medical Treatments

Background

Rotator cuff (RTC) tendinopathy is a common painful condition of the shoulder that impairs function and quality of life. Nonoperative treatments when physical therapy and oral medications have not resolved the issue often consist of different strategies to improve blood flow and promote growth factors, thereby creating regeneration and healing of injured tissue in the RTC tendons. Acupuncture could serve in a similar role when needles are strategically targeted into injured tissue utilizing ultrasound visualization.

Case

A 58-year-old male presented with over 1 year of symptomatic RTC tendinopathy involving the supraspinatus and infraspinatus tendons. He had not gotten sustained pain relief with physical therapy or a corticosteroid injection to the subacromial bursa and was not a surgical candidate for RTC repair due to only having small partial tearing of the tendons. He wanted to consider alternative treatment options and it was decided that he could pursue ultrasound-guided electroacupuncture.

Results

Treatment was successful and completed within 4 weekly sessions. He reported 85% improvement in symptoms two months after starting treatment and is now over 1 year out from treatment, with what the patient states as "minimal" residual discomfort with one stretching movement.

Conclusions

Ultrasound guidance of acupuncture needles into areas of RTC tendon injury simulates many of the current nonoperative treatment modalities sports medicine has to offer for RTC tendinopathy. This short- and long-term successful case report provides a steppingstone for future research into this area.

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.