Drug-Induced Tendon Disorders

Predictive ability of Achilles tendon elastography for frailty in older adults

PURPOSE

The Achilles tendon (AT) is the largest and strongest tendon in the human body, and its elasticity is known to be affected by the aging process. However, the relation between AT stiffness and frailty in older individuals remains uncertain. This study aims to explore the potential of Achilles tendon shear wave elastography (AT-SWE) as a tool for assessing physical frailty in older adults.

METHODS

A total of 148 patients aged 65 years and over were included in this cross-sectional study. Patients with heart failure, AT injury, stroke history, active malignancy, and claudication were excluded. All patients underwent a comprehensive geriatric assessment. Physical frailty assessment was performed with the fried frailty phenotype. Achilles tendon elastography was measured by ultrasound.

RESULTS

The mean age of the participants was 73.8 years and 62.2% were female. 30.4% of the participants were defined as frail. Achilles tendon shear wave elastography measurements were statistically lower in the frail group (p < 0.05). In the multivariate regression analysis, AT-SWE demonstrated a statistically significant association with frailty independent of confounding factors (OR 0.982, 95% CI 0.965-0.999, p value = 0.038). In the ROC curve analysis, the area under the curve for AT-SWE was 0.647 (95% CI, 0.564-0.724, p < 0.01) and the optimum cut-off point was 124.1 kilopascals.

CONCLUSION

These findings highlight the value of AT-SWE as a non-invasive and objective tool for predicting frailty in older adults.

Cellular and Structural Changes in Achilles and Patellar Tendinopathies: A Pilot In Vivo Study

Tendinopathies continue to be a challenge for both patients and the medical teams providing care as no universal clinical practice guidelines have been established. In general, tendinopathies are typically characterized by prolonged, localized, activity-related pain with abnormalities in tissue composition, cellularity, and microstructure that may be observed on imaging or histology. In the lower limb, tendinopathies affecting the Achilles and the patellar tendons are the most common, showing a high incidence in athletic populations. Consistent diagnosis and management have been challenged by a lack of universal consensus on the pathophysiology and clinical presentation. Current management is primarily based on symptom relief and often consists of medications such as non-steroidal anti-inflammatories, injectable therapies, and exercise regimens that typically emphasize progressive eccentric loading of the affected structures. Implementing the knowledge of tendon stem/progenitor cells (TSPCs) and assessing their potential in enhancing tendon repair could fill an important gap in this regard. In the present pilot in vivo study, we have characterized the structural and cellular alterations that occur soon after tendon insult in models of both Achilles and patellar tendinopathy. Upon injury, CD146+ TSPCs are recruited from the interfascicular tendon matrix to the vicinity of the paratenon, whereas the observed reduction in M1 macrophage polarization is related to a greater abundance of reparative CD146+ TSPCs in situ. The robust TSPCs' immunomodulatory effects on macrophages were also demonstrated in in vitro settings where TSPCs can effectively polarize M1 macrophages towards an anti-inflammatory therapeutic M2 phenotype. Although preliminary, our findings suggest CD146+ TSPCs as a key phenotype that could be explored in the development of targeted regenerative therapies for tendinopathies.

Bisphosphonates-related tendinopathies and ligament disorders: Cases analysis from the U.S. Food and Drug Administration adverse event reporting system

Fluoroquinolone antibiotics are known to induce serious tendinopathies and ligament disorders (TPLDs) on rare occasion, but it is less well-appreciated whether such adverse reactions result from the use of bisphosphonates (BPs). In this study, we assessed the correlation between TPLDs and the use of BPs via U.S. FDA Adverse Event Reporting System (FAERS) database. Bayesian and nonproportional analyses were applied to data retrieved from the FAERS database from the first quarter of 2004 to the third quarter of 2022. A total of 3202 reported cases of TPLDs were associated with five BPs (alendronate, pamidronate, ibandronate, risedronate, zoledronate), with statistically significant reporting odds ratio (ROR), proportional reporting ratio (PRR), and information component (IC). Alendronate showed the highest association with tendinopathies and ligament disorders (ROR = 16.30, PRR = 15.47, IC = 3.88), while zoledronate had the lowest association (ROR = 2.13, PRR = 2.12, IC = 1.08), which was consistent with the results of top 10 preferred terms (PTs) under the narrow standardized MedDRA queries (SMQs) sorted by frequency of reports. Excluding zoledronate, over half of patients who reported BP-related TPLDs were hospitalized, either briefly or extendedly. This was especially true for alendronate, which showed the highest rate of hospitalization (83.25 %), however, the mortality rate reported by those taking alendronate were significantly lower than those of zoledronate and pamidronate. In addition, the clinical characteristics of BP-related TPLDs was analyzed. It is more common to reported in middle-aged and elderly females, the highest proportion was in 50-69 years old. Except for osteoporosis, osteopenia, and osteoporosis prophylaxis, cancer bone metastasis was also the indication of some BPs. The most often reported concomitant/prior medicines were calcium supplements, another BPs, antitumor agents, and nonsteroidal anti-inflammatory drugs. In conclusion, we provide a comprehensive overview of the correlation and clinical characteristics, and prognosis of BP-related TPLDs deserving continued surveillance and appropriate management.

Bilateral Spontaneous Supraspinatus Tendon Rupture Under Prolonged BRAF/MEK Targeting Treatment in a Melanoma Patient

The B-Raf proto-oncogene, serine/threonine kinase (BRAF)/ mitogen-activated protein kinase kinase (MEK) targeting agents have become the treatment of choice for BRAF-mutated melanoma during the last decade. However, it is possible that some long-term adverse events of these drugs have not yet been reported. A case of bilateral spontaneous, non-traumatic, supraspinatus tendon rupture in a 65-year-old Caucasian male suffering metastatic melanoma under prolonged and successful combination treatment with dabrafenib plus trametinib is presented. These damages could not be attributed to some other probable cause. The ruptured tendons were promptly restored arthroscopically. Oncologists should remain vigilant for the early detection of potential side effects of BRAF/MEK targeting agents that have not been systematically recorded yet but may appear and affect patients in the long run.

Platelet-rich plasma in the pathologic processes of tendinopathy: a review of basic science studies

Tendinopathy is a medical condition that includes a spectrum of inflammatory and degenerative tendon changes caused by traumatic or overuse injuries. The pathological mechanism of tendinopathy has not been well defined, and no ideal treatment is currently available. Platelet-rich plasma (PRP) is an autologous whole blood derivative containing a variety of cytokines and other protein components. Various basic studies have found that PRP has the therapeutic potential to promote cell proliferation and differentiation, regulate angiogenesis, increase extracellular matrix synthesis, and modulate inflammation in degenerative tendons. Therefore, PRP has been widely used as a promising therapeutic agent for tendinopathy. However, controversies exist over the optimal treatment regimen and efficacy of PRP for tendinopathy. This review focuses on the specific molecular and cellular mechanisms by which PRP manipulates tendon healing to better understand how PRP affects tendinopathy and explore the reason for the differences in clinical trial outcomes. This article has also pointed out the future direction of basic research and clinical application of PRP in the treatment of tendinopathy, which will play a guiding role in the design of PRP treatment protocols for tendinopathy.

Tendon Disorders in Chronic Liver Disease: A Retrospective Cohort Study in Taiwan

To investigate the relationship between chronic liver disease and tendon disorder, a retrospective cohort study was conducted using the Kaohsiung Veterans General Hospital database. Patients >18 years with newly diagnosed liver disease and with at least a two-year follow-up in the hospital were included. An equal number of 20,479 cases were enrolled in both the liver-disease and non-liver-disease groups using a propensity score matching method. Disease was defined using ICD-9 or ICD-10 codes. The primary outcome was the development of tendon disorder. Demographic characteristics, comorbidities, use of tendon-toxic drugs, and status of HBV/HCV infection were included for analysis. The results showed 348 (1.7%) and 219 (1.1%) individuals developed tendon disorder in the chronic liver disease group and non-liver-disease group. Concomitant use of glucocorticoids and statins may have further raised the risk of tendon disorder in the liver disease group. The co-existence of HBV/HCV infection did not increase the risk of tendon disorder in the patients with liver disease. Considering these findings, physicians should be more aware of tendon issues in advance, and a prophylactic strategy should be adopted in patients with chronic liver disease.

Tendon pain - what are the mechanisms behind it?

OBJECTIVES

Management of chronic tendon pain is difficult and controversial. This is due to poor knowledge of the underlying pathophysiology of chronic tendon pain, priorly known as tendinitis but now termed tendinopathy. The objective of this topical review was to synthesize evolving information of mechanisms in tendon pain, using a comprehensive search of the available literature on this topic.

CONTENT

This review found no correlations between tendon degeneration, collagen separation or neovascularization and chronic tendon pain. The synthesis demonstrated that chronic tendon pain, however, is characterized by excessive nerve sprouting with ingrowth in the tendon proper, which corresponds to alterations oberserved also in other connective tissues of chronic pain conditions. Healthy, painfree tendons are devoid of nerve fibers in the tendon proper, while innervation is confined to tendon surrounding structures, such as sheaths. Chronic painful tendons exhibit elevated amounts of pain neuromediators, such as glutamate and substance p as well as up-regulated expression and excitability of pain receptors, such as the glutamate receptor NMDAR1 and the SP receptor NK1, found on ingrown nerves and immune cells. Increasing evidence indicates that mast cells serve as an important link between the peripheral nervous system and the immune systems resulting in so called neurogenic inflammation.

SUMMARY

Chronic painful tendons exhibit (1) protracted ingrowth of sensory nerves (2) elevated pain mediator levels and (3) up-regulated expression and excitability of pain receptors, participating in (4) neuro-immune pathways involved in pain regulation. Current treatments that entail the highest scientific evidence to mitigate chronic tendon pain include eccentric exercises and extracorporeal shockwave, which both target peripheral neoinnervation aiming at nerve regeneration.

OUTLOOK

Potential mechanism-based pharmacological treatment approaches could be developed by blocking promotors of nerve ingrowth, such as NGF, and promoting inhibitors of nerve ingrowth, like semaphorins, as well as blocking glutamate-NMDA-receptor pathways, which are prominent in chronic tendon pain.

Is Curcumine Useful in the Treatment and Prevention of the Tendinopathy and Myotendinous Junction Injury? A Scoping Review

Physical activity in general and sports in particular, is a mechanism that produces stress and generates great force in the tendon and in the muscle-tendon unit, which increases the risk of injury (tendinopathies). Eccentric and repetitive contraction of the muscle precipitates persistent microtraumatism in the tendon unit. In the development of tendinopathies, the cellular process includes inflammation, apoptosis, vascular, and neuronal changes. Currently, treatments with oral supplements are frequently used. Curcumin seems to preserve, and even repair, damaged tendons. In this systematic review, we focus more especially on the benefits of curcumin. The biological actions of curcumin are diverse, but act around three systems: (a) inflammatory, (b) nuclear factor B (NF-κB) related apoptosis pathways, and (c) oxidative stress systems. A bibliographic search is conducted under the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) as a basis for reporting reliable systematic reviews to perform a Scoping review. After analysing the manuscripts, we can conclude that curcumin is a product that demonstrates a significant biological antialgic, anti-inflammatory, and antioxidant power. Therefore, supplementation has a positive effect on the inflammatory and regenerative response in tendinopathies. In addition, curcumin decreases and modulates the cell infiltration, activation, and maturation of leukocytes, as well as the production of pro-inflammatory mediators at the site of inflammation.

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

OBJECTIVES

Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT).

METHODS

We recruited runners with (n = 12) and without (n = 13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using high-density surface electromyography during 10 and 20% isometric plantar flexor contractions.

RESULTS

MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24 pps (95% CI 7.08 to 9.41) to 20%, 8.52 pps (7.41 to 9.63, p = 0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39 pps (7.25-9.53) to 20%, 10.07 pps (8.89-11.25, p < 0.001). There were no between-group difference in gastrocnemius medialis (GM) or soleus (SOL) MU discharge rates. We found no between-group differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness.

CONCLUSION

Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focussing on increasing neural drive to GL would affect muscle function in runners with AT.

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

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

Dexamethasone Enhances Achilles Tendon Healing in an Animal Injury Model, and the Effects Are Dependent on Dose, Administration Time, and Mechanical Loading Stimulation

BACKGROUND

Corticosteroid treatments such as dexamethasone are commonly used to treat tendinopathy but with mixed outcomes. Although this treatment can cause tendon rupture, it can also stimulate the tendon to heal. However, the mechanisms behind corticosteroid treatment during tendon healing are yet to be understood.

PURPOSE

To comprehend when and how dexamethasone treatment can ameliorate injured tendons by using a rat model of Achilles tendon healing.

STUDY DESIGN

Controlled laboratory study.

METHODS

An overall 320 rats were used for a sequence of 6 experiments. We investigated whether the drug effect was time-, dose-, and load-dependent. Additionally, morphological data and drug administration routes were examined. Healing tendons were tested mechanically or used for histological examination 12 days after transection. Blood was collected for flow cytometry analysis in 1 experiment.

RESULTS

We found that the circadian rhythm and drug injection timing influenced the treatment outcome. Dexamethasone treatment at the right time point (days 7-11) and dose (0.1 mg/kg) significantly improved the material properties of the healing tendon, while the adverse effects were reduced. Local dexamethasone treatment did not lead to increased peak stress, but it triggered systemic granulocytosis and lymphopenia. Mechanical loading (full or moderate) is essential for the positive effects of dexamethasone, as complete unloading leads to the absence of improvements.

CONCLUSION

We conclude that dexamethasone treatment to improve Achilles tendon healing is dose- and time-dependent, and positive effects are perceived even in a partly unloaded condition.

CLINICAL RELEVANCE

These findings are promising from a clinical perspective, as the positive effect of this drug was seen even when given at lower doses and in a moderate loading condition, which better mimics the load level in patients with tendon ruptures.

Runners with mid-portion Achilles tendinopathy have greater triceps surae intracortical inhibition than healthy controls

OBJECTIVES

This study aimed to investigate short-interval intracortical inhibition (SICI) and muscle function in the triceps surae of runners with mid-portion Achilles tendinopathy (AT).

METHODS

Runners with (n = 11) and without (n = 13) AT were recruited. Plantar flexor isometric peak torque and rate of torque development (RTD) were measured using an isokinetic dynamometer. Triceps surae endurance was measured as single-leg heel raise (SLHR) to failure test. SICI was assessed using paired-pulse transcranial magnetic stimulation during a sustained contraction at 10% of plantar flexor isometric peak torque.

RESULTS

Triceps surae SICI was 14.3% (95% CI: -2.1 to 26.4) higher in AT than in the control group (57.9%, 95% CI: 36.2 to 79.6; and 43.6% 95% CI: 16.2 to 71.1, p = 0.032) irrespective of the tested muscle. AT performed 16 (95% CI: 7.9 to 23.3, p < 0.001) fewer SLHR repetitions on the symptomatic side compared with controls, and 14 (95% CI: 5.8 to 22.0, p = 0.004), fewer SLHR repetitions on the non-symptomatic compared with controls. We found no between-groups differences in isometric peak torque (p = 0.971) or RTD (p = 0.815).

PERSPECTIVE

Our data suggest greater intracortical inhibition for the triceps surae muscles for the AT group accompanied by reduced SLHR endurance, without deficits in isometric peak torque or RTD. The increased SICI observed in the AT group could be negatively influencing triceps surae endurance; thus, rehabilitation aiming to reduce intracortical inhibition should be considered to improve patient outcomes. Furthermore, SLHR is a useful clinical tool to assess plantar flexor function in AT patients.

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

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

Beirut port explosion: unusual presentation of bilateral blast-related extensor mechanism rupture

Industrial disasters related to high-order explosives result in characteristic injuries that are seldom seen among civilians. Survivors of these disasters often present with injuries of the musculoskeletal system. Awareness of explosion and blast injuries for healthcare providers who care for civilians is important considering the possibility of such events as demonstrated in the past two decades, including the Boston Marathon bombing in 2013 and the explosion of the port of Tianjin, China, in 2015. We report an unusual presentation of isolated bilateral rupture of the knee extensor mechanism in a 46-year-old healthy male, with history of anabolic androgen steroid (AAS) use. He was standing 1.5 miles from the site of the site of explosion of the port of Beirut on August 4, 2020. We discuss the imaging appearance of this injury, the different mechanisms of blast-related injuries, the role of possible underlying pathology, and the management of this patient.

Industrial Development of Standardized Fetal Progenitor Cell Therapy for Tendon Regenerative Medicine: Preliminary Safety in Xenogeneic Transplantation

Tendon defects require multimodal therapeutic management over extensive periods and incur high collateral burden with frequent functional losses. Specific cell therapies have recently been developed in parallel to surgical techniques for managing acute and degenerative tendon tissue affections, to optimally stimulate resurgence of structure and function. Cultured primary human fetal progenitor tenocytes (hFPT) have been preliminarily considered for allogeneic homologous cell therapies, and have been characterized as stable, consistent, and sustainable cell sources in vitro. Herein, optimized therapeutic cell sourcing from a single organ donation, industrial transposition of multi-tiered progenitor cell banking, and preliminary preclinical safety of an established hFPT cell source (i.e., FE002-Ten cell type) were investigated. Results underlined high robustness of FE002-Ten hFPTs and suitability for sustainable manufacturing upscaling within optimized biobanking workflows. Absence of toxicity or tumorigenicity of hFPTs was demonstrated in ovo and in vitro, respectively. Furthermore, a 6-week pilot good laboratory practice (GLP) safety study using a rabbit patellar tendon partial-thickness defect model preliminarily confirmed preclinical safety of hFPT-based standardized transplants, wherein no immune reactions, product rejection, or tumour formation were observed. Such results strengthen the rationale of the multimodal Swiss fetal progenitor cell transplantation program and prompt further investigation around such cell sources in preclinical and clinical settings for musculoskeletal regenerative medicine.

Curcuminoids and Boswellia serrata extracts combination decreases tendinopathy symptoms: findings from an open-label post-observational study

Background: To investigate the effects of 1-month treatment in addition to standard care with a food supplement containing both Curcuma longa and Boswellia serrata extracts on tendinopathy symptoms.Method: This open-label, non-controlled, post-observational study included 670 patients suffering from tendinopathy recruited at different sites by Belgian general practitioners. Patients received a medical prescription for 1-month treatment with two tablets twice a day of a pharmaceutical grade food supplement containing both C. longa and B. serrata extracts. Pain and functional limitation were evaluated using a visual analog scale at the inclusion and 1-month treatment later. Patient satisfaction, concomitant drugs intake and side effects were also recorded.Results: After 1-month treatment, pain and functional limitation were significantly improved whatever the cause of tendinopathy, its localization, and the duration of symptoms. The pain score decreased from 6.16 ± 1.53 to 2.98 ± 1.64 (p < .0001), yielding a drop of 51.6% and the functional limitation score fell after 1-month treatment from 5.96 ± 1.73 to 2.88 ± 1.67 (p < .0001) corresponding to a drop of 51.6%. The percentage of patients taking at least one concomitant treatment at the end of the treatment period had decreased from 81.3% to 61.8% (p < .0001). Only 43 (6.5%) patients reported side effects. No severe adverse effects related to the product were reported.Conclusion: The combination of C. longa and B. serrata extracts improves symptoms in patients suffering of tendinopathy and shows a good safety. Although its effect will have to be confirmed in randomized controlled trials, it can be considered as a helpful support of standard symptomatic treatments for tendinopathies. HighlightsTendinopathy is a common disease representing 30% of all consultations with a general practitioner for musculoskeletal disorders.The combination of Curcuminoids and Boswelliaserrata extracts are efficient on tendinopathy symptoms in support of standard symptomatic treatments.The combination of Curcuminoids and B. Serrata extract is safe and can be administrated for at least 1 month in addition of analgesic and non-steroidal anti-inflammatory drugs.

Suture Anchor Versus Allogenic Tendon Suture in Treatment of Haglund Syndrome

Background

Haglund’s deformity is an abnormal bony enlargement on the back of the heel. It can cause the impact of the posterior calcaneal bursa and Achilles tendon insertion, and finally result in pain. This syndrome is called Haglund syndrome. The purpose of this study was to explore the effect of the suture anchor and allogeneic tendon suture in the treatment of Haglund syndrome.

Material/Methods

We retrospectively studied 20 patients with Haglund syndrome treated from January 2015 to December 2016. The patients were randomly divided into Group 1 (the suture anchor group) and Group 2 (the allogeneic tendon group), with 10 patients in each group and an average follow-up of 32 months after surgery. The AOFAS, VAS, and Arner-Lindholm scales were used to summarize the patient follow-up results and complications.

Results

In the 2 groups of patients, the postoperative AOFAS, VAS scores, and the Arner-Lindholm scale showed good results. However, the postoperative AOFAS score and VAS of the suture anchor group were better than those of the allogeneic tendon group, with shorter operation times. No Achilles tendon rupture or wound infection occurred during the entire postoperative period in either group. These results show the superiority of suture anchors.

Conclusions

The higher AOFAS and VAS score and shorter operation time in the suture anchor group suggest it is the better alternative for treatment of Haglund syndrome.

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

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

The influence of donor and recipient characteristics on allograft tendons: a systematic review

Tendon allograft has been an important alternative graft option aside from autograft. The outcome of reconstruction surgery is determined by donor and recipient related factors. The purpose of this article was to identified all studies reporting donor and recipient characteristics, including the age and gender of donors, along with the age, gender, activity level and smoking status of recipients, that affect the biomechanical properties and post-transplantation outcomes of allograft tendons. The systematic study search was based on MEDLINE via PubMed, Embase and the Cochrane Library databases. The reference lists of the included studies were used for hand searching (snowballing). The searching process was performed by two independent investigators, using search MESH term: "tendon", "allograft", and "person". Studies evaluating the influence of donor and recipient biological characteristics on the mechanical property and transplantation outcome of allograft were included. A total of 12 studies were selected for qualitative synthesis, including 6 studies evaluated the influence of donor characteristics, including age and gender, on the mechanical strength of tendon allograft. 6 studies assessed the influence of recipient characteristics, including age, gender, smoking status, and activity level, on the clinical outcome. As a conclusion, tendon allografts from donor younger than 40 years old were expected to have a higher mechanical property. Young patients or patients with a high level of activity were not recommended to receive allograft tendon when autograft is optional. There is no strong evidence supporting that neither donor or recipient gender affects the tendon allograft transplantation outcomes. Smoking history could increase the risk of complications.

Tendinopathy: Pathophysiology, Therapeutic Options, and Role of Nutraceutics. A Narrative Literature Review

Tendinopathies are very common in general population and a huge number of tendon-related procedures take place annually worldwide, with significant socio-economic repercussions. Numerous treatment options are commonly used for tendon disorders. Besides pharmacological and physical therapy, nutrition could represent an additional tool for preventing and treating this complex pathology that deserve a multidisciplinary approach. In recent years, nutraceutical products are growing up in popularity since these seem to favor the prevention and the healing processes of tendon injuries. This narrative literature review aims to summarize current understanding and the areas of ongoing research about the management of tendinopathies with the help of oral supplementation.

Cephalexin-associated Achilles Tendonitis: Case Report and Review of Drug-induced Tendinopathy

Tendon disorders include tenosynovitis or tendonitis, tendinosis, and tendon rupture. Tendinopathy associated with drug administration has been associated with the systemic or local administration of several medications. A 90-year-old man who developed toxic tendinopathy after receiving cephalexin 500 mg twice daily has been described. Unilateral pain of his left Achilles tendon pain during walking appeared three weeks after starting the antibiotic. The drug was stopped after four weeks of treatment; within one week after discontinuing the cephalexin, all tendonitis symptoms spontaneously resolved. Drug-induced tendinopathy has most commonly been associated with fluoroquinolones, statins, glucocorticoids, and aromatase inhibitors. In addition, other systemic agents have caused tendinopathy; they include amlodipine, anabolic steroids, antiretrovirals, isotretinoin, renin-angiotensin II receptor antagonists, rituximab, and sitagliptin. Albeit less frequent, other oral antibiotics, including cephalosporins, azithromycin, and sulfonamides, have also been associated with toxic tendinopathy. Also, injections of collagenase Clostridium histolyticum, corticosteroids, and polidocanol have been followed by tendon rupture. The features of tendinopathy associated with drug treatment are summarized and their postulated mechanisms of pathogenesis are reviewed. The onset of tendon pain following the initiation of treatment with a new medication, especially if the agent has previously been associated with drug-induced tendonitis, tendinosis, or tendon rupture, should prompt the consideration of drug-associated toxic tendinopathy.

Pathogenesis and Management of Tendinopathies in Sports Medicine

Objective

Tendinopathy is a major clinical problem in sports medicine and is often difficult to treat. Traditional therapeutic approaches have focused on reducing inflammation, yet research suggests that little to no inflammation is present in the tendons that fail to heal. The purpose of this review was to evaluate the effectiveness of the available treatment options for tendinopathy and to inform best clinical practices.

Design

A narrative review.

Methods

A comprehensive search of electronic databases (PubMed, Google Scholar and Web of Science) was conducted to identify relevant studies through June 2016. Studies were deemed relevant if they were published in English and contained original research on the management of tendinopathy in humans.

Results

Studies varied in methodological quality and were often limited by small sample size and lack of sufficient control groups. Critical evaluation of the literature suggests that physical therapy with or without eccentric exercise should be considered a first-line treatment. Corticosteroids and nonsteroidal anti-inflammatory drugs provide short-term symptomatic relief, but long-term efficacy has not been demonstrated. Inconsistent results do not support the routine use of prolotherapy, platelet-rich plasma injections and topical nitric oxide patches. Operative intervention should be reserved until conservative measures fail or an obvious operative lesion is present.

Conclusions

While numerous therapeutic modalities exist for tendinopathy in the athlete, the ideal treatment protocol has not been clearly defined. The development of new targeted therapies for tendinopathy is likely to follow a greater understanding of the cellular and molecular mechanisms that underlie its pathogenesis.

Atraumatic bilateral rupture of the peroneus brevis tendon in recreational sport: A case report

Issue:

Lower extremity tendon injuries often occur in physically active individuals. Most ruptures not involving great force are diagnosed in patients presenting underlying tendon degenerations. This also applies to patients taking medications because of a disease. We have observed several cases of bilateral Achilles tendon ruptures in patients who have been taking cortisone for a long period. We treated a healthy colleague (neurologist) in our clinic who sustained ruptures of the Achilles tendon on the left side (2012) and the peroneus brevis tendon on left side (2015) and right side (2016) after minimal traumata. Aim of this report is to provide a systematic review of this case and a literature review of similar cases, as few such cases have been published.

Methods:

We reviewed and analysed this patient’s records containing the sport-specific anamnesis, pre-existing condition, anamnesis of medications and therapy. The three injuries were magnetic resonance imaging–proven. Furthermore, the tendon’s condition was examined histologically in the context of the operative treatment through lace technique of the Achilles tendon and transfer of the peroneus brevis to the peroneus longus. We also researched the literature for bilateral ruptures of the peroneal tendons.

Results and conclusion:

The anamnesis confirmed no underlying disease. The patient took a macrolide antibiotic about half a year prior to the first peroneal injury for an otitis media. He denied having taken any other antibiotics, especially no quinolone antibiotics. However, the patient reported cortisone intake for 2 days some months before the second peroneal injury to treat an allergic reaction. That involved no local cortisone infiltration in the lower extremity. He underwent surgery within the first 2 weeks after each trauma. Each time, postoperative follow-ups revealed a good healing process. Three months after each operation, the patient was free of complaints. Axibal and Anderson described a patient with bilateral peroneus longus and peroneus brevis ruptures, as well as an Achilles tendon rupture on the left side plus tendinopathy of the Achilles tendon on the right side of uncertain aetiology. We detected additional similar cases in patients who had taken medications, especially cortisone and levofloxacine. Further research should be conducted to clarify other risk factors to help prevent such injuries.

Mini-Review: Toxic Tendinopathy

Toxic tendinopathy is a rare but reproducible complication in humans, given agents of four drug classes: aromatase inhibitors, fluoroquinolone antibiotics, glucocorticoids (long-term regimens), and statins. Toxic tendinopathy in humans has been linked less consistently to treatment with anabolic steroids, antiretroviral agents (mainly protease inhibitors), metalloproteinase inhibitors (MMPI), and isotretinoin. Classic drug-induced tendinopathies appear as "tendinosis" (i.e., progressive tendon degeneration without inflammation), although cases associated with aromatase inhibitors exhibit mainly tenosynovitis. Any tendon may be affected, but fluoroquinolones, glucocorticoids, and statins most frequently affect large load-bearing tendons in the lower limb, especially the calcaneal ("Achilles") tendon-which ruptures in approximately 30 to 40% of cases. The time to symptom onset ranges from days (fluoroquinolones) to weeks, months, or even years. The pathogenesis is incompletely understood, but proposed mechanisms include apoptosis of tenoblasts and tenocytes, deficient tenocyte function (leading to abnormal extracellular matrix maintenance and repair as well as disrupted intercellular signaling), and structural disintegration (via a combination of increased expression of lytic enzymes, lessened cholesterol content in cell membranes, and neoangiogenesis within highly ordered tendon tissue). Nonclinical safety assessment of therapeutic candidates in these drug classes should incorporate tendon routinely as a protocol-specified tissue for pathology evaluation.