Management of Achilles and patellar tendinopathy: what we know, what we can do

Review of Preclinical and Clinical Studies Supporting the Role of Polydeoxyribonucleotide in the Treatment of Tendon Disorders

Tendon disorders are among the most common musculoskeletal conditions, accounting for 30% to 50% of all sports-related injuries. Injured tendons heal slowly and often fail to regain their original structural integrity and mechanical strength, creating significant challenges for physicians. Recently, investigations have reported that polydeoxyribonucleotide (PDRN) plays a key role in promoting tendon healing. For example, preclinical studies indicate that PDRN can enhance tendon repair by inhibiting inflammation and cell apoptosis while promoting collagen production. In clinical studies, the effectiveness and safety of PDRN were also confirmed for managing several conditions, including plantar fasciitis, epicondylitis, Achilles tendinopathy, pes anserine tendinopathy, and chronic rotator cuff disease. In light of these findings, this article aims to review the preclinical and clinical studies that support the role of PDRN in the treatment of tendon disorders. A search was conducted in Medline and PubMed from January 1994 to October 2024 to find relevant research. Ultimately, the review included 3 preclinical studies and 8 clinical studies, involving a total of 318 patients. In conclusion, PDRN is a promising therapeutic option for treating tendon disorders. However, further preclinical and clinical studies are needed to better understand its effects on tendon disorders and to support future clinical applications.

The use of pain killers (NSAIDs) in athletes: How large is the risk?

Nonsteroidal anti-inflammatory drug use is prevalent in sport however the risk associated with their use in athletes is not well-understood. This review discusses the pharmacology of nonsteroidal anti-inflammatory drugs and the prevalence of their use in different sports and factors driving this. Use is very high in sports such as professional football and is sometimes by routine without indication and without medical supervision. However there is a paucity of evidence in other sports. There is good evidence for use of nonsteroidal anti-inflammatory drugs following an acute injury but they may prevent normal tissue healing and remodelling if used longer term for musculoskeletal injuries. There are well-known risks of cardiac, gastrointestinal and renal side effects but little specific data for athletes. Renal events are discussed in detail including the cumulative effect that nonsteroidal anti-inflammatory drug use, dehydration and concurrent illness can have to produce significant renal and systemic insult. We then discuss a pragmatic prescribing model enabling clinicians to utilise the beneficial effects of these medications whilst minimising risks.

Predictive utility of the machine learning algorithms in predicting tendinopathy: a meta-analysis of diagnostic test studies

BACKGROUND

Tendinopathy, a degenerative condition of tendon collagen protein, is a common sports injury among elite athletes. Despite its prevalence, the manifestation and progression of tendinopathy remain unclear, and the efficiency of diagnosis and treatment modalities is uncertain. Artificial intelligence and machine learning (ML) have shown positive results in disease diagnosis and treatment evaluation. This systematic review examined many ML methods and their diagnostic yield in predicting tendinopathy.

METHODS

A comprehensive search of electronic databases, including Ovid Medline, EMBASE, PubMed and the Web of Science, was conducted. The quality of the studies was assessed using the Newcastle-Ottawa scale. The statistical analysis was performed using mada package on R software.

RESULTS

Four studies were considered eligible for this meta-analysis, constituting outcomes from 12,611 patients. The ML methods used in the selected studies included random forest, convolutional neural networks and linear support vector machines. The results showed that all selected studies demonstrated the relevance of ML in moderately (Reviewer 2, Comment 2) predicting tendinopathy. The pooled diagnostic yield of the ML algorithms estimated an overall sensitivity of 0.74 (95% CI: 0.64 to 0.82, p =  < 0.001) and an overall specificity of 0.69 (95% CI: 0.49 to 0.85, p = 0.06). The diagnostic odds ratio was 6.01 (95% CI: 1.8 to 20.13), with substantial heterogeneity (I2 = 97.6%).

CONCLUSION

ML methods can predict tendinopathy accurately in elite and non-elite athletes. However, further research is needed to establish the specific clinical features associated with tendinopathy prevalence.

An Observational Study on the Prediction of Range of Motion in Soldiers Diagnosed with Patellar Tendinopathy Using Ultrasound Shear Wave Elastography

INTRODUCTION

This study hypothesized that changes in the elasticity of the quadriceps and patellar tendons before and after the diagnosis of patellar tendinopathy would correlate with the range of motion (ROM) following conservative treatment. We aimed to prospectively assess post-treatment ROM using multinomial logistic regression, incorporating elasticity measurements obtained via shear wave elastography (SWE).

MATERIALS AND METHODS

From March 2023 to April 2024, 95 patients (86 men; aged 20-45 years, mean 25.62 ± 5.49 years) underwent SWE preoperatively and two days post-diagnosis of patellar tendinopathy. Elasticity measurements of the rectus femoris, vastus medialis, vastus lateralis, patellar tendon, and biceps tendon were obtained during full flexion and extension. Based on ROM 56 days post-treatment, patients were categorized into two groups: Group A (ROM > 120 degrees) and Group B (ROM < 120 degrees). A multinomial logistic regression algorithm was employed to classify the groups using patient information and tendon elasticity measurements both at diagnosis and 1-week post-diagnosis.

RESULTS

The predictive accuracy using only patient information was 62%, while using only elasticity measurements yielded 68% accuracy. When combining patient information with elasticity measurements taken at diagnosis and two days post-diagnosis, the algorithm achieved an accuracy of 79%, sensitivity of 92%, and specificity of 56%.

CONCLUSIONS

The combination of patient information and tendon elasticity measurements obtained via SWE at pre-conservative treatment and early post-conservative treatment periods effectively predicts post-treatment ROM. This algorithm can guide rehabilitation strategies for soldiers with patellar tendinopathy.

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.

Effects of sensorimotor training on functional and pain outcomes in achilles tendinopathy: a systematic review

Background

Considering the neuromuscular alterations in Achilles tendinopathy (AT), sensorimotor training (SMT) might be beneficial to restore the neuromuscular capacity of the muscle-tendon complex and thereby improve patients' functions and alleviate symptoms. However, there is still a lack of knowledge concerning the effects of SMT on improving functional (e.g., strength) and pain outcomes in this population. Thus, the purpose of this study was to synthesize current evidence to analyze the efficacy of SMT in people with AT.

Methods

A systematic electronic search was performed in PubMed, Web of Science, and Cochrane Central Register of Controlled Trials from inception to December 2023. Studies applying SMT in people with AT investigating functional or clinical pain outcomes were considered. Protocols had to incorporate balance, stabilization, proprioception, or vibration training. Patients with insertional or mid-portion AT (≥18 years age) diagnosed with clinical or sonographic evaluation were included.

Results

The search yielded 823 records. A total of three randomized controlled trials were considered eligible for the analysis. Each trial used a different SMT protocol: balance training, balance with stabilization training, or whole-body vibration training (WBVT) with other co-interventions. Most functional and pain parameters improved compared to baseline. The first study reported a decrease in pain and an increase in performance (i.e., countermovement jump height) and endurance (i.e., number of heel-raises) by 12-week use of a balance training in addition to isometric, concentric/eccentric, and eccentric exercises. The second study evaluated the four weeks effect of SMT (balance and stabilization training plus eccentric exercises) in addition to passive physiotherapy (deep frictions, ice, ultrasound), resulting in an increased plantarflexion peak torque and reduced pain levels. The third study investigating WBVT reported at 12 weeks an increase in flexibility and a decrease in tendon pain.

Discussion

SMT in addition to other co-interventions (i.e., eccentric, isometric, concentric/eccentric training, physiotherapy) showed improvements in strength, performance, muscle flexibility, and alleviated clinical outcomes of pain. SMT might therefore be useful as part of a multimodal treatment strategy protocol in patients suffering from AT. However, due to the small number of studies included and the diversity of SMT protocols, the current evidence is weak; its additional effectiveness should be evaluated.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=467698, Identifier CRD42023467698.

The Efficacy of Intratissue Percutaneous Electrolysis (EPI®) and Nutritional Factors for the Treatment of Induced Tendinopathy in Wistar Rats: Hepatic Intermediary Metabolism Effects

Achilles tendinopathy (TP) is characterized as the third most common disease of the musculoskeletal system, and occurs in three phases. There is currently no evidence of effective treatment for this medical condition. In this study, the modulatory effects of the minimally invasive technique intratissue percutaneous electrolysis (EPI) and combinations of EPI with four nutritional factors included in the diet, hydroxytyrosol (HT), maslinic acid (MA), glycine, and aspartate (AA), on hepatic intermediary metabolism was examined in Wistar rats with induced tendinopathy at various stages of TP. Results obtained showed that induced tendinopathy produced alterations in the liver intermediary metabolisms of the rats. Regarding carbohydrate metabolism, a reduction in the activity of pro-inflammatory enzymes in the later stages of TP was observed following treatment with EPI alone. Among the combined treatments using nutritional factors with EPI, HT+EPI and AA+EPI had the greatest effect on reducing inflammation in the late stages of TP. In terms of lipid metabolism, the HT+EPI and AA+EPI groups showed a decrease in lipogenesis. In protein metabolism, the HT+EPI group more effectively reduced the inflammatory effects of induced TP. Treatment with EPI combined with nutritional factors might help regulate intermediary metabolism in TP disease and reduce the inflammation process.

Cross-Cultural Adaptation, Translation, and Validation of the Victorian Institute of Sport Assessment-Achilles Questionnaire (VISA-A) for Use With Arabic-Speaking Patients With Achilles Tendinopathy

Background

The Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire is a validated instrument for assessing symptoms of Achilles tendinopathy (AT). However, there is a need to validate the Arabic version of the VISA-A (VISA-A-AR) in Arabic-speaking patients with AT.

Purpose

To validate the VISA-A-AR in Arabic patients with AT and evaluate its reliability and validity.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

The translation and cultural adaptation of the VISA-A questionnaire into Arabic followed international guidelines. A total of 81 participants were recruited, including 45 patients diagnosed with AT and 36 healthy individuals. The AT group comprised male and female native Arabic speakers aged ≥18 years who were diagnosed with and had symptoms of AT. The inclusion criteria for the healthy group were the same, except that they must not have had AT at the time of the study or previously. The exclusion criteria were individuals with a partial or complete Achilles tendon rupture or prior Achilles tendon surgery. The internal consistency of the VISA-A-AR was assessed using the Cronbach α coefficient. Test-retest reliability was evaluated using the intraclass correlation coefficient (ICC[3,1]). Construct validity was assessed through correlation analysis between VISA-A-AR scores and the Arabic versions of the Short Form-36 Health Survey (SF-36-AR) and the Numeric Pain Rating Scale (ANPRS). Differences in VISA-A-AR scores between patients with AT and healthy controls were analyzed using appropriate statistical tests.

Results

The VISA-A-AR demonstrated a high level of internal consistency (Cronbach α = 0.935) and excellent test-retest reliability (ICC[3,1] = 0.985). Significant positive correlations were observed between VISA-A-AR scores and SF-36-AR (r(43) = 0.838, P < .001), indicating good construct validity. In addition, VISA-A-AR scores showed a significant negative correlation with ANPRS (rS(43) = -0.835, P < .001). Furthermore, VISA-A-AR scores exhibited a significant difference between patients with AT (mean, 45.82 ± 16.65) and healthy controls (mean, 99.94 ± 0.33) (P < .001).

Conclusion

The findings of this study validate the VISA-A-AR as a reliable and valid tool for assessing symptoms of AT in Arabic-speaking patients.

Surgical and Biological Treatment with a Platelet-Rich Fibrin Matrix for Patellar Tendinopathy: Clinical Outcomes and Return to Sport at 2-Year Follow-Up

BACKGROUND

Patellar tendinopathy (PT) involves anterior knee pain and functional. Platelet-rich fibrin matrix (PRFM) is a promising biological therapy for tendinopathies. We examined a cohort of PT patients treated with tendon debridement and autologous PRFM at the 24-month follow-up to assess whether the combined treatment facilitated return to sports and yielded satisfactory clinical and functional scores.

METHODS

Baseline and 24-month visual analogue scale (VAS), Victorian Institute of Sport Assessment Scale for Patellar Tendinopathy (VISA-P), Tegner Activity Scale (TAS), and Blazina scores were compared to evaluate treatment effectiveness. The Friedman test was used to compare repeated observations of VAS, VISA-P, TAS, and Blazina Score values. Return to sport rate, Tampa Scale of Kinesiophobia (TKS) score and patient satisfaction were collected at 24 months.

RESULTS

The postoperative clinical scores demonstrated significant improvement compared with their preoperative values (all p < 0.001). Specifically, the VISA-P score was 80.32 (±20.58), 92.10% of patients had resumed sports activities and patient satisfaction was 9.21 (±1.21) at 24 months.

CONCLUSIONS

Surgical debridement and autologous PRFM application in patients with chronic PT resulted in a higher rate of return to sports when compared to solely surgical treatment, significantly improved clinical outcomes and excellent patient satisfaction at 24 months.

Does Radial Extracorporeal Shockwave Therapy Applied to the Achilles Tendon Influence Ankle Functionality?

This study aimed to determine the effectiveness of radial extracorporeal shockwave therapy (rESWT) in enhancing ankle function in patients with Achilles tendon injuries. The choice of rESWT was based on previous success in the treatment of musculoskeletal conditions. The study involved an intervention group that received rESWT, and a control group that received sham therapy. The results revealed that rESWT led to significant improvements in single-leg vertical jump (d = 0.55, p < 0.05), indicating enhanced power generation and ankle functionality that were not observed in the control group. Additionally, the therapy resulted in increased ankle mobility, as observed by improvements in plantar flexion and heel-rise tests. Interestingly, these functional gains were not accompanied by changes in the Achilles tendon stiffness, suggesting that the benefits of rESWT may be more functional than structural. This study highlights rESWT as a promising tool for rehabilitation, particularly following Achilles tendon injuries. The study concluded that, although rESWT appears to improve certain aspects of ankle function, further studies with a larger and more diverse population over a longer period are necessary to confirm these findings and establish comprehensive treatment protocols.

The Best Current Research on Patellar Tendinopathy: A Review of Published Meta-Analyses

Patellar tendinopathy is a frequent overuse injury in sports that can cause significant pain and disability. It requires evidence-based guidelines on effective prevention and management. However, optimal treatments remain uncertain. We aimed to analyze available meta-analyses to summarize treatment recommendations, compare therapeutic modalities, examine included trials, and offer methodological suggestions to improve future systematic reviews. Meta-analyses were systematically searched for in PubMed (PROSPERO: CRD42023457963). A total of 21 meta-analyses were included. The AMSTAR-2 scale assessed study quality, which was low, with only 23.8% of the meta-analyses being of moderate quality, and none were considered to be of high quality. Heterogeneous outcomes are reported. Multiple platelet-rich plasma (PRP) injections appear superior to eccentric exercises and provide lasting improvements compared to eccentric exercises when conservative treatments fail. Extracorporeal shockwave therapy (ESWT) also seems superior to non-operative options and similar to surgery for patellar tendinopathy in the long term. However, evidence for eccentric exercise efficacy remains unclear due to inconclusive findings. Preliminary findings also emerged for genetic risk factors and diagnostic methods but require further confirmation. This review reveals a lack of high-quality evidence on optimal patellar tendinopathy treatments. While PRP and ESWT show promise, limitations persist. Further rigorous meta-analyses and trials are needed to strengthen the evidence base and guide clinical practice. Methodological enhancements are proposed to improve future meta-analyses.

Effect of Nutraceutical Factors on Hepatic Intermediary Metabolism in Wistar Rats with Induced Tendinopathy

Tendinopathy (TP) is a complex clinical syndrome characterized by local inflammation, pain in the affected area, and loss of performance, preceded by tendon injury. The disease develops in three phases: Inflammatory phase, proliferative phase, and remodeling phase. There are currently no proven treatments for early reversal of this type of injury. However, the metabolic pathways of the transition metabolism, which are necessary for the proper functioning of the organism, are known. These metabolic pathways can be modified by a number of external factors, such as nutritional supplements. In this study, the modulatory effect of four dietary supplements, maslinic acid (MA), hydroxytyrosol (HT), glycine, and aspartate (AA), on hepatic intermediary metabolism was observed in Wistar rats with induced tendinopathy at different stages of the disease. Induced tendinopathy in rats produces alterations in the liver intermediary metabolism. Nutraceutical treatments modify the intermediary metabolism in the different phases of tendinopathy, so AA treatment produced a decrease in carbohydrate metabolism. In lipid metabolism, MA and AA caused a decrease in lipogenesis at the tendinopathy and increased fatty acid oxidation. In protein metabolism, MA treatment increased GDH and AST activity; HT decreased ALT activity; and the AA treatment does not cause any alteration. Use of nutritional supplements of diet could help to regulate the intermediary metabolism in the TP.

Prevalence, diagnosis and management of musculoskeletal disorders in elite athletes: A mini-review

Musculoskeletal injuries in elite sports are ones of the most impact issue because their remarkable impact on performance caused by drastic absence of training and competition and a progressive deterioration in physical health, emotional and social athletes' dimensions. Also, the prevalence of epidemiologic research found an incidence of musculoskeletal disorders vary within sports and in elite athletes which is even higher as a consequence of higher demand physical performance. This way, the loss of physical performance due to an sport injury impacts not only the individual economic sphere of the professional but also that ofsports entities, reaching, according to some studies, a loss estimated in the range of 74.7 million pounds. Thus, the purpose of this article is to review and to provide an overview of the most common musculoskeletal injuries in elite sports precipitating factors, clinical presentation, evidence-based diagnostic evaluation, and treatment recommendations with a view to preventing medical conditions or musculoskeletal injuries that may alter performance and general health in the elite athletes.

Patellar tendinopathy: an overview of prevalence, risk factors, screening, diagnosis, treatment and prevention

Patellar tendinopathy (PT), or jumper's knee, is an overuse injury that occurs in professional, as well as recreational, athletes. This condition is a noncontact injury, typically characterized by gradually increasing pain in the patellar tendon. It is prevalent in participants of several sports, but it occurs mostly in jumping sports. The diagnosis of PT is primarily clinical; however, imaging techniques can be useful as well. Risk factors differ between sexes, playing conditions, the kind of sport, playing level and personal characteristics. Screening is an essential tool to assess PT. This condition affects athletic performance and often persists for years. The use of preventative methods is imperative because of the persistence of this condition, especially in elite athletes who sometimes end their career after long and failed treatments. There are a wide variety of treatment and rehabilitation options available, the majority of which are non-operative, such as eccentric exercises, cryotherapy, platelet-rich plasma (PRP) injections, and anti-inflammatory strategies. If conservative treatment fails, surgery is the next most preferable step. Even though there are many surgical treatment methods, there is no clear evidence on what is the most effective approach to address PT. Taking this into consideration, as well as the extent of this clinical entity, novel therapeutic techniques, as well as screening and prevention methods, are expected to emerge in the near future.

Patellar Tendon Elasticity and Temperature Following after a 448 Kilohertz Radiofrequency Intervention on Active Healthy Subjects: An Open Controlled Clinical Trial

The purpose of this study was to analyze the changes in the elasticity and temperature of the patellar tendon produced by the application of a radiofrequency at 448 kHz (CRMR) just after and 7 days after the intervention. An open controlled clinical trial was used with participants being recruited from a private clinic. The experimental group (n = 22) received a 448 kHz CRMR treatment while the control group (n = 22) did not receive any type of intervention. Quantitative ultrasound strain elastography (SEL) and thermography were used to collect data from 4 different areas of the patellar tendon. These areas were measured at the start (T0), just after (T1), and seven days after (T2) the intervention. There were thermal changes immediately after the intervention (p < 0.001). In addition, when the measurements were collected just after the intervention and seven days after they were analyzed, significant changes (p < 0.001) in temperature were observed in the tendons of both groups. Finally, a low but significant association (r = 0.434, p < 0.04) was observed between the elastic properties of the tendon at its insertion in the patella and thermal changes just after the 448 kHz intervention.

Safety and Efficacy of Bone Marrow-Derived Mesenchymal Stem Cells for Chronic Patellar Tendinopathy (With Gap >3 mm) in Patients: 12-Month Follow-up Results of a Phase 1/2 Clinical Trial

Background

In a previous study, the authors found that at 6 months after treatment with a 20 × 106 dose of bone marrow-derived mesenchymal stem cells (BM-MSCs), patients showed improved tendon structure and regeneration of the gap area when compared with treatment using leukocyte-poor platelet-rich plasma (Lp-PRP). The Lp-PRP group (n = 10), which had not seen tendon regeneration at the 6-month follow-up, was subsequently offered treatment with BM-MSCs to see if structural changes would occur. In addition, the 12-month follow-up outcomes of the original BM-MSC group (n = 10) were evaluated.

Purpose

To evaluate the outcomes of all patients (n = 20) at 12 months after BM-MSC treatment and observe if the Lp-PRP pretreated group experienced any type of advantage.

Study Design

Cohort study; Level of evidence, 2.

Methods

Both the BM-MSC and original Lp-PRP groups were assessed at 12 months after BM-MSC treatment with clinical examination, the visual analog scale (VAS) for pain during daily activities and sports activities, the Victorian Institute of Sport Assessment-Patella score for patellar tendinopathy, dynamometry, and magnetic resonance imaging (MRI). Differences between the 2 groups were compared with the Student t test.

Results

The 10 patients originally treated with BM-MSCs continued to show improvement in tendon structure in their MRI scans (P < .0001), as well as in the clinical assessment of their pain by means of scales (P < .05). Ten patients who were originally treated with Lp-PRP and then with BM-MSCs exhibited an improvement in tendon structure in their MRI scans, as well as a clinical pain improvement, but this was not significant on the VAS for sports (P = .139). Thus, applying Lp-PRP before BM-MScs did not yield any type of advantage.

Conclusion

The 12-month follow-up outcomes after both groups of patients (n = 20) received BM-MSC treatment indicated that biological treatment was safe, there were no adverse effects, and the participants showed a highly statistically significant clinical improvement (P < .0002), as well as an improvement in tendon structure on MRI (P < .0001). Preinjection of Lp-PRP yielded no advantages.

Achilles Tendinopathy Pathogenesis and Management: A Narrative Review

The Achilles tendon is the thickest and strongest tendon of the human body, and it is frequently injured during sports activity. The incidence of Achilles tendon pathologies has increased over recent decades, especially in the last few years, because of increased sports participation among the general population and due to the diffusion of competitive sports at a high level. Tendinopathies are common in athletes and in middle-aged overweight patients. The term "tendinopathy" refers to a condition characterised clinically by pain and swelling, with functional limitations of tendon and nearby structures, and consequently to chronic failure of healing response process. Tendinopathies can produce marked morbidity, and at present, scientifically validated management modalities are limited. Despite the constantly increasing interest and number of studies about Achilles tendinopathy (AT), there is still not a consensual point of view on which is the best treatment, and its management is still controversial. AT can be treated conservatively primarily, with acceptable results and clinical outcomes. When this approach fails, surgery should be considered. Several surgical procedures have been described for both conditions with a relatively high rate of success with few complications and the decision for treatment in patients with AT should be tailored on patient's needs and level of activity. The aim of this article is to give insights about the pathogenesis and most used and recent treatment options for AT.

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

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

Tectorigenin: A Review of Its Sources, Pharmacology, Toxicity, and Pharmacokinetics

Tectorigenin is a well-known natural flavonoid aglycone and an active component that exists in numerous plants. Growing evidence suggests that tectorigenin has multiple pharmacological effects, such as anticancer, antidiabetic, hepatoprotective, anti-inflammatory, antioxidative, antimicrobial, cardioprotective, and neuroprotective. These pharmacological properties provide the basis for the treatment of many kinds of illnesses, including several types of cancer, diabetes, hepatic fibrosis, osteoarthritis, Alzheimer's disease, etc. The purpose of this paper is to provide a comprehensive summary and review of the sources, extraction and synthesis, pharmacological effects, toxicity, pharmacokinetics, and delivery strategy aspects of tectorigenin. Tectorigenin may exert certain cytotoxicity, which is related to the administration time and concentration. Pharmacokinetic studies have demonstrated that the main metabolic pathways in rats for tectorigenin are glucuronidation, sulfation, demethylation and methoxylation, but that it exhibits poor bioavailability. From our perspective, further research on tectorigenin should cover: exploring the pharmacological targets and mechanisms of action; finding an appropriate concentration to balance pharmacological effects and toxicity; attempting diversified delivery strategies to improve the bioavailability; and structural modification to obtain tectorigenin derivatives with higher pharmacological activity.

Drug Delivery Approaches to Improve Tendon Healing

Tendon injuries disrupt the transmission of forces from muscle to bone, leading to chronic pain, disability, and a large socioeconomic burden. Tendon injuries are prevalent; there are over 300,000 tendon repair procedures a year in the United States to address acute trauma or chronic tendinopathy. Successful restoration of function after tendon injury remains challenging clinically. Despite improvements in surgical and physical therapy techniques, the high complication rate of tendon repair procedures motivates the use of therapeutic interventions to augment healing. While many biological and tissue engineering approaches have attempted to promote scarless tendon healing, there is currently no standard clinical treatment to improve tendon healing. Moreover, the limited efficacy of systemic delivery of several promising therapeutic candidates highlights the need for tendon-specific drug delivery approaches to facilitate translation. This review article will synthesize the current state-of-the-art methods that have been used for tendon-targeted delivery through both systemic and local treatments, highlight emerging technologies used for tissue-specific drug delivery in other tissue systems, and outline future challenges and opportunities to enhance tendon healing through targeted drug delivery.

Genetic Polymorphisms in COL1A2 gene and the Risk of Tendinopathy: Case-Control Study

Objective  To evaluate the influence of polymorphisms on genes encoding type I collagen and the genetic susceptibility of tendinopathy. Methodology  Case-control study involving 242 Brazilian athletes from different sports modalities (55 cases of tendinopathy and 187 controls). The polymorphisms COL1A1 (rs1107946) and COL1A2 (rs412777, rs42524, and rs2621215) were analyzed by the TaqMan system. Odds ratio (OR) with their 95% confidence intervals (CIs) were calculated using a nonconditional logistic regression model. Results  The mean age was 24.0 ± 5.6 years old and 65.3% were men. Of the 55 cases of tendinopathy, 25.4% had > 1 affected tendon, the most frequent being patellar (56.3%), rotator cuff (30.9%) and elbow or hand flexors (30.9%). Age and amount of time of sports practice were associated with a higher chance of presenting tendinopathy (5 and 8 times, respectively). The frequency of variant alleles in control and case patients, respectively, was: COL1A1 rs1107946 24.0 and 29.6%; COL1A2 rs412777 36.1 and 27.8%; rs42524 17.5 and 25.9%; and rs2621215 21.3 and 27.8%. After adjusting for confounding factors (age and years of sports practice), COL1A2 rs42524 and rs2621215 polymorphisms were associated with increased risk of tendinopathy (OR = 5.5; 95%CI = 1.2-24.6 and OR = 3.9; IC95% = 1.1-13.5, respectively). The haplotype COL1A2 CGT was associated with low risk for disease development (OR = 0.5; 95%CI = 0.3-0.9). Conclusion  Age (≥ 25 years old), time of sports practice (≥ 6 years) and polymorphisms in the COL1A2 gene increased the risk of developing tendinopathy.

Relationships between surrogate measures of mechanical and psychophysiological load, patellar tendon adaptations, and neuromuscular performance in NCAA division I men's volleyball athletes

Introduction

Patellar tendon adaptations occur in response to mechanical load. Appropriate loading is necessary to elicit positive adaptations with increased risk of injury and decreased performance likely if loading exceeds the capacity of the tendon. The aim of the current study was to examine intra-individual associations between workloads and patellar tendon properties and neuromuscular performance in collegiate volleyball athletes.

Methods

National Collegiate Athletics Association Division I men's volleyball athletes (n = 16, age: 20.33 ± 1.15 years, height: 193.50 ± 6.50 cm, body mass: 84.32 ± 7.99 kg, bodyfat%: 13.18 ± 4.72%) competing across 9 weeks of in-season competition participated. Daily measurements of external workloads (i.e., jump count) and internal workloads [i.e., session rating of perceived exertion (sRPE)] were recorded. Weekly measurements included neuromuscular performance assessments (i.e., countermovement jump, drop jump), and ultrasound images of the patellar tendon to evaluate structural adaptations. Repeated measures correlations (r-rm) assessed intra-individual associations among performance and patellar tendon metrics.

Results

Workload measures exhibited significant negative small to moderate (r-rm =-0.26-0.31) associations with neuromuscular performance, negative (r-rm = -0.21-0.30), and positive (r-rm = 0.20-0.32) small to moderate associations with patellar tendon properties.

Discussion

Monitoring change in tendon composition and performance adaptations alongside workloads may inform evidence-based frameworks toward managing and reducing the risk of the development of patellar tendinopathy in collegiate men's volleyball athletes.

Factors associated with lower limb tendinopathy in a large cohort of runners: a survey with a particular focus on nutrition

Objectives

Lower limb tendinopathy (LLT) is highly prevalent in runners. Treatment can be challenging, and knowledge of risk factors may be valuable to develop preventive or treatment interventions for LLT. The aims of this study were (1) to assess the prevalence of three common LLTs (Achilles tendinopathy (AT), patellar tendinopathy and plantar fasciopathy) in a large cohort of Dutch and Belgian runners and (2) to investigate its association with potential risk factors, with a particular focus on nutritional factors in the habitual diet.

Methods

A total of 1993 runners were included in the study. They completed two online questionnaires: a general questionnaire on running habits and injuries and a Food Frequency Questionnaire. Runners with and without LLT were compared regarding personal characteristics, running characteristics and nutritional factors.

Results

The point prevalence for the three LLTs was 6%; 33% of the runners reported LLT in the past and 35% had either a current or past LLT. AT was the most prevalent type of LLT, and prevalence rates for all types of LLT were higher in men than women. Positive associations with LLT were observed for age and running years (men and women), running level and running distance (men). No associations between LLT and nutritional factors were observed.

Conclusion

One-third of this population of runners had ever experienced an LLT. These tendinopathies were associated with gender, age and running load, but not with nutritional factors.

Psychosocial and individual factors affecting Quality of Life (QoL) in patients suffering from Achilles tendinopathy: a systematic review

BACKGROUND

Achilles tendinopathy (AT) is a joint condition that causes functional restrictions and pain. This condition negatively impacts patients' social connectedness and psychological well-being, reducing their quality of life (QoL). This review aims to summarise the current information on QoL in patients suffering from AT from different angles: compared to a healthy population, reported individual factors that influence it and the effects of some AT interventions on QoL.

METHODS

A systematic review was conducted at PubMed, Cochrane, Google Scholar, and PsycINFO using tendinopathy and QoL-related keywords up to November 2021. Articles were included if they compared QoL to demographic factors such as age or gender, lifestyle factors (physical activity levels), comorbidity factors (diabetes, obesity), and/or a control group.

RESULTS

Three hundred twenty-nine articles were reviewed; 23 met the inclusion criteria. SF-36, EQ-5D, and VISA-A were the most common instrument used. Patients with AT reported low QoL when compared to no AT population. When women were compared to men, women reported worse QoL. The patients who participated in different exercise programs (strengthening and stretching) showed improvements in QoL. Surgical AT intervention improved QoL, although results varied by age.

CONCLUSION

AT has a substantial impact on QoL. In AT patients, QoL is also influenced by specific individual factors, including gender and physical activity. Exercise, education, and surgical treatment improve QoL. We suggest more research on AT patients to better understand the aspects leading to poor QoL.

SS-31 as a Mitochondrial Protectant in the Treatment of Tendinopathy: Evaluation in a Murine Supraspinatus Tendinopathy Model

BACKGROUND

Prior studies have demonstrated mitochondrial dysfunction in tendinopathy. The objective of this investigation was to explore the potential of SS-31 (elamipretide), a mitochondrial protectant, to improve mitochondrial function and promote tendon healing in a murine supraspinatus tendinopathy model.

METHODS

One hundred and twenty-six mice (252 limbs) were divided into 6 groups (42 limbs/group) that received (I) 4 weeks of impingement; (II) 8 weeks of impingement; (III) 8 weeks of impingement including 4 weeks of SS-31 treatment (5 mg/kg/d) starting after 4 weeks of impingement; (IV) 4 weeks of impingement ending with clip removal, followed by harvesting 4 weeks later; and (V) 4 weeks of impingement ending with clip removal, followed by 4 weeks of SS-31 treatment and harvesting; and a control group. Specimens were prepared for biomechanical testing, histological analysis, transmission electron microscopy, measurement of superoxidative dismutase (SOD) activity, and measurement of gene expression.

RESULTS

Failure force decreased after impingement, compared with the intact tendon, and the decrease was partially reversed after clip removal, SS-31 treatment, and the 2 treatments combined. A similar pattern was observed for stiffness. Histological analysis demonstrated higher modified Bonar scores in the impingement groups; however, the changes in tendon morphology were partially reversed following all treatments, especially the combined treatment. Decreased mitochondrial number and altered organization and density of cristae were observed in the impingement groups. Mitochondrial structure and number became more normal, with improvement in morphology of the cristae, after clip removal and/or SS-31 treatment. SOD activity decreased after impingement, compared with the control group, then increased significantly again after treatment, especially in the combined treatment group. Mitochondria-related gene expression decreased in the impingement groups and increased again after treatment.

CONCLUSIONS

The mitochondrial protectant SS-31 improved mitochondrial function, promoting tendon healing, especially when combined with removal of subacromial impingement.

CLINICAL RELEVANCE

Improving mitochondrial function with agents such as SS-31 may represent an effective treatment to promote healing in the setting of supraspinatus tendinopathy.

A Population-Level Summary of Health Care Utilization for the Management of Patellar Tendinopathy in the Military Health System

Patellar tendinopathy (PT) is a common nontraumatic orthopaedic disorder of the knee suffered by many service members. Understanding the make-up of usual care for PT at the system level can better frame current clinical gaps and areas that need improvement. Exercise therapy is recommended as a core treatment for PT, but it is unclear how often it is used as a part of usual care for PT within the Military Health System (MHS). The purpose of the study was to identify interventions used in the management of PT and the timing of these interventions. A secondary purpose was to determine if exercise therapy use was associated with reduced recurrence of knee pain. In total, 4,719 individuals aged 17 to 50 years in the MHS diagnosed with PT between 2010 and 2011 were included. Pharmacological and nonpharmacological interventions, visits to specialty providers, and imaging services were captured. Descriptive statistics were used to report the findings. Interventions were further categorized as being part of initial care (within the first 7 days), the initial episode of care (within the first 60 days), or the 2-year time period after diagnosis. Linear regression assessed the relationship between the number of exercise therapy visits in the initial episode of care and recurrences of knee pain. In total, 50.6% of this cohort had no more than one medical visit total for PT. Exercise therapy (18.2%) and nonsteroidal anti-inflammatory drugs (4.3%) were the two most used interventions in the initial episode of care. Radiographs were ordered for 23.1% of the cohort in the initial episode of care. The number of exercise therapy visits a patient received during the initial episode of care was not associated with recurrences of knee pain. Half of the individuals received no further care beyond an initial visit for the diagnosis of PT. Exercise therapy was the most common intervention used during the initial episode of care, but exercise therapy did not influence the recurrence of knee pain.

The effects of orthobiologics in the treatment of tendon pathologies: a systematic review of preclinical evidence

Purpose

The aim of this systematic review is to explore the current available knowledge about tendon disorders and orthobiologics derived by preclinical experiments to evaluate their role and efficacy in the different stages and conditions related to the tendon healing processes.

Methods

The systematic review was performed according to the PRISMA guidelines. Different electronic databases (MEDLINE, Web of Science, EMBASE) were searched for studies investigating orthobiologics (PRP and cell-based products from adipose tissue or bone marrow) in animal models or veterinary clinical trials for tendon pathologies (complete/partial tendon ruptures, rotator cuff tears, tendinopathy, enthesis-related injuries). Data regarding the specific product used, the treatment site/pathology, the host and the model were collected. The results were classified into the following categories: histological, biomechanical, molecular and imaging.

Results

A large pool of preclinical studies on tendon disorders have been found on platelet-rich plasma (PRP), while data about stromal vascular fraction (SVF) and bone marrow concentrate (BMAC) are still limited and frequently focused on expanded cells, rather than orthobiologics prepared at the point of care.

The effect of PRP is related to an acceleration of the healing process, without improvements in the final structure and properties of repaired tendon. Cell-based products have been reported to produce more durable results, but the level of evidence is currently insufficient to draw clear indications.

Conclusions

The preclinical results about orthobiologics applications to tendon pathologies would support the rationale of their clinical use and encourage the performance of clinical trials aimed to confirm these data in human subjects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00468-w.

Prevalence of Achilles tendinopathy in physical exercise: A systematic review and meta-analysis

This comprehensive systematic review and meta-analysis assessed the prevalence of Achilles tendinopathy (AT) in physical exercise (PE). Specifically, we estimate the overall risk of AT in physical exercise and compare sport-specific estimates of AT risk. PubMed, Web of Science, Cochrane Library, and SPORTDiscus were searched before the 1^st of October 2021. Random-effects, subgroup analysis, sensitivity analysis and meta-regressions were conducted, involving 16 publications. This meta-analysis found that the overall prevalence of AT was 0.06 (95%CI, 0.04–0.07). The prevalence of Achilles tendon rupture was 0.03 (95%CI, 0.02–0.05). Subgroup analysis showed that the prevalence of AT increased with age, the highest among the group aged over 45 (0.08; 95%CI, 0.04–0.11), and the lowest among the group under 18 years old (0.02; 95%CI, 0.01–0.03). The gymnastics and ball games had the highest prevalence of AT, at (0.17; 95%CI, 0.14–0.20) and (0.06; 95%CI, 0.02–0.11), respectively. The prevalence of AT in athletes (0.06; 95%CI, 0.04–0.08) was higher than that of amateur exercisers (0.04; 95%CI, 0.02–0.06) and there was no difference in the prevalence of AT between males and females. There are differences in the prevalence of AT in different ages, sport events and characteristics of participants. This systematic review and meta-analysis suggested that it was necessary to pay more attention to AT in people who were older or engaged in gymnastics.

Achilles Paratenon Needle Tendoscopy in the Office Setting

Achilles tendinopathy is a common inflammatory condition of the Achilles tendon prevalent in the athletic population in which patients present with pain, swelling, and reduced performance exacerbated by physical activity. Operative intervention using either open or percutaneous approaches has traditionally been performed after failure of nonoperative treatment, but less invasive modalities that include endoscopic approaches have been increasingly used. This Technical Note highlights our technique for Achilles paratenon needle tendoscopy in the wide-awake office setting, with accompanying indications for use, advantages, and technical pearls.

Gastrocnemius release is an effective management option for Achilles tendinopathy: a systematic review

PURPOSE

This systematic review aims to summarise the outcomes of gastrocnemius release in the management of Achilles Tendinopathy.

METHODS

A systematic review was performed according to PRISMA guidelines. A computer-based search was performed in PubMed, Embase, Cinahl, Scopus and ISI Web of Science. Two independent reviewers performed both title/abstract and full-text screening according to a-priori selection criteria. English-language original research studies reporting outcomes for gastrocnemius recession in patients with Achilles tendinopathy were included. Study quality and risk of bias were assessed using the MINORS criteria.

RESULTS

Of the 229 articles identified following database searching, nine studies describing 145 cases of gastrocnemius recession were included in the review. Clinically important differences were reported across a range of validated patient reported outcome scores including VISA-A, FFI, FAAM and VAS pain score. Outcomes appear to be superior in patients with noninsertional Achilles tendinopathy, however further research is required to confirm this. Studies also reported an increase in ankle dorsiflexion range of motion and a good rate of return to sport/work. The overall complication rate was 10/123 (8.1%), with sural nerve injury being the most common complication, occurring in 5/123 (4.1%) of cases.

CONCLUSION

The results of this review suggest gastrocnemius release to be an effective treatment option in the management of patients with Achilles tendinopathy, who have gastrocnemius contracture and have previously failed to respond adequately to non-operative treatment.

LEVEL OF EVIDENCE

Level IV.

3D Biomimetic Scaffold for Growth Factor Controlled Delivery: An In-Vitro Study of Tenogenic Events on Wharton's Jelly Mesenchymal Stem Cells

The present work described a bio-functionalized 3D fibrous construct, as an interactive teno-inductive graft model to study tenogenic potential events of human mesenchymal stem cells collected from Wharton’s Jelly (hWJ-MSCs). The 3D-biomimetic and bioresorbable scaffold was functionalized with nanocarriers for the local controlled delivery of a teno-inductive factor, i.e., the human Growth Differentiation factor 5 (hGDF-5). Significant results in terms of gene expression were obtained. Namely, the up-regulation of Scleraxis (350-fold, p ≤ 0.05), type I Collagen (8-fold), Decorin (2.5-fold), and Tenascin-C (1.3-fold) was detected at day 14; on the other hand, when hGDF-5 was supplemented in the external medium only (in absence of nanocarriers), a limited effect on gene expression was evident. Teno-inductive environment also induced pro-inflammatory, (IL-6 (1.6-fold), TNF (45-fold, p ≤ 0.001), and IL-12A (1.4-fold)), and anti-inflammatory (IL-10 (120-fold) and TGF-β1 (1.8-fold)) cytokine expression upregulation at day 14. The presented 3D construct opens perspectives for the study of drug controlled delivery devices to promote teno-regenerative events.

Image-guided intervention in the management of chronic patellar tendinopathy with calcification: a three-pronged approach

Patellar tendinopathy is a common cause of knee pain and functional impairment in athletes. It is commonly managed using conservative measures such as physiotherapy, but cases that are refractory to such treatment may require a more invasive approach. Various forms of image-guided injection therapy have been described in the literature. We present a case of successful treatment of chronic patellar tendinopathy with calcification with the first reported use of a three-pronged image-guided approach, consisting of dry needling, high volume image-guided injection (but at a reduced dose) and barbotage applied in a single sitting. The patient reported resolution of symptoms persisting to 1 year postprocedure. We suggest that this management option, if supported by further positive research findings, could be used in the future in the management of certain cases of patellar tendinopathy with calcification where conservative measures have failed.

Small interfering RNAs in tendon homeostasis

BACKGROUND

Tenogenesis and tendon homeostasis are guided by genes encoding for the structural molecules of tendon fibres. Small interfering RNAs (siRNAs), acting on gene regulation, can therefore participate in the process of tendon healing.

SOURCES OF DATA

A systematic search of different databases to October 2020 identified 17 suitable studies.

AREAS OF AGREEMENT

SiRNAs can be useful to study reparative processes of tendons and identify possible therapeutic targets in tendon healing.

AREAS OF CONTROVERSY

Many genes and growth factors involved in the processes of tendinopathy and tendon healing can be regulated by siRNAs. It is however unclear which gene silencing determines the expected effect.

GROWING POINTS

Gene dysregulation of growth factors and tendon structural proteins can be influenced by siRNA.

AREAS TIMELY FOR DEVELOPING RESEARCH

It is not clear whether there is a direct action of the siRNAs that can be used to facilitate the repair processes of tendons.