How do eccentric exercises work in tendinopathy?

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.

Platelet-rich plasma injection in the treatment of patellar tendinopathy: a systematic review and meta-analysis

Purpose

The objective of the study was to assess the efficacy of autologous platelet-rich plasma (PRP) injections in the treatment of patellar tendinopathy.

Methods

The PubMed, MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials databases were searched for clinical trials which compared PRP injection with other ‘active treatment’ interventions (‘Non-PRP’ injection and ‘No-injection’ treatments) or ‘No-active treatment’ interventions. Randomized and non-randomized clinical trials that had been published up to 15 November 2021, were included in the meta-analysis. The primary outcome, pain relief, was measured on a ‘visual analog scale.’ Secondary outcomes were knee functional activities and quality of life (QoL). The PRISMA guidelines were followed throughout the study.

Results

Eight comparative studies were identified for inclusion in the meta-analysis. Assessment of these studies revealed that there were no significant differences in pain relief, functional outcomes, and QoL in the short, medium, and long term between PRP injection and Non-PRP injection interventions. Similarly, comparison of PRP injection to the No-active treatment intervention showed no differences in short- and medium-term pain relief. However, when PRP injection was compared to the No-injection treatment intervention extracorporeal shock wave therapy (ECWT), the former was found to be more effective in terms of pain relief in the medium term (mean difference [MD] − 1.50; 95% confidence interval [CI] − 2.72 to − 0.28) and long term (MD − 1.70; 95% CI, − 2.90 to − 0.50) and functional outcomes in the medium term (MD 13.0; 95% CI 3.01–22.99) and long term (MD 13.70; 95% CI 4.62–22.78).

Conclusions

In terms of pain relief and functional outcomes, the PRP injection did not provide significantly greater clinical benefit than Non-PRP injections in the treatment of patellar tendinopathy. However, in comparison with ESWT, there was a significant benefit in favor of PRP injection.

Trends in hospitalization for paediatric flatfoot: an Italian nationwide study from 2001 to 2016

Background

Flatfoot is a common condition in young patients, but usually resolves by adolescence. This study aimed to estimate annual trend hospitalizations for flatfoot in Italian paediatric population from 2001 to 2016.

Methods

Data of this study were collected from the National Hospital Discharge Reports (SDO) reported at the Italian Ministry of Health regarding the years of this paper (2001–2016). The yearly number of hospital admission for flatfoot, the percentage of males and females, the average age, the average days of hospitalization, primary diagnoses and primary procedures in the whole Italian population were calculated using descriptive statistical analyses.

Results

109,300 hospitalizations for flatfoot of young patients were performed during this period. 59.3% of patients were male and 40.7% female of the 10–14 years-old age class. The average days of hospitalization stay were 1.73 ± 1.27 days. The data highlights that the burden of flatfoot surgery is growing and affecting the healthcare system. The mean rate of hospital admissions in Italy for flatfoot in the young population was 82.14 for 100,000 inhabitants of the same age class.

Conclusions

The data highlights that the cases of flatfoot surgery increased from 2001 to 2016. The most common treatment was the “Internal Fixation Of Bone Without Fracture Reduction, Tarsals And Metatarsals followed by Subtalar Fusion and Arthroereisis. Further prospective studies on this topic may be conducted to improve the evidence of the results.

Current understanding of the diagnosis and management of the tendinopathy: An update from the lab to the clinical practice

Tendinopathy is labeled by many authors as a troublesome, common pathology, present in up to 30% medical care consultations involving musculoskeletal conditions. Despite the lasting interest for addressing tendon pathology, current researchers agree that even the exact definition of the term tendinopathy is unclear. Tendinopathy is currently diagnosed as a clinical hypothesis based on the patient symptoms and physical context. One of the main goals of current clinical management is to personalize treatment approaches to adapt them to the many different needs of the population. Tendons are complex structures that unite muscles and bones with two main objectives: to transmit forces and storage and release energy. Regarding the tensile properties of the tendons, several authors argued that tendons have higher tensile strength compared with muscles, however, are considered less flexible. Tendinopathy is an accepted term which is used to indicated a variety of tissue conditions that appear in injured tendons and describes a non-rupture damage in the tendon or paratendon, which is intensified with mechanical loading Even when the pathoetiology of tendinopathy is unclear, there is a wide array of treatments available to treat and manage tendinopathy. Although tendinitis usually debuts with an inflammatory response, the majority of chronic tendinopathies do not present inflammation and so the choosing of treatment should vary depending on severity, compliance, pain and duration of symptoms. The purpose of this article is to review and provide an overview about the currently research of the tendon diagnosis, management and etiology.

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

Tendinopathies are challenging conditions frequent in athletes and in middle-aged overweight patients with no history of increased physical activity. The term “tendinopathy” refers to a clinical condition characterised by pain, swelling, and functional limitations of tendons and nearby structures, the effect of chronic failure of healing response. Tendinopathies give rise to significant morbidity, and, at present, only limited scientifically proven management modalities exist. Achilles and patellar tendons are among the most vulnerable tendons, and among the most frequent lower extremity overuse injuries. Achilles and patellar tendinopathies can be managed primarily conservatively, obtaining good results and clinical outcomes, but, when this approach fails, surgery should be considered. Several surgical procedures have been described for both conditions, and, if performed well, they lead to a relatively high rate of success with few complications. The purpose of this narrative review is to critically examine the recent available scientific literature to provide evidence-based opinions on these two common and troublesome conditions.

Achilles tendinopathy

BACKGROUND

Achilles Tendinopathy (AT) is essentially a failed healing response with haphazard proliferation of tenocytes, abnormalities in tenocytes with disruption of collagen fibers, and subsequent increase in non-collagenous matrix.

METHODS

The diagnosis of Achilles tendinopathy is clinical, and MRI and utrasound imaging can be useful in differential diagnosis. Conservative manegement, open surgery or minimally invasive techniques are available. Injections and physical therapy are also vauable options.

RESULTS

Eccentric exercises are useful tools to manage the pathology. If the condition does not ameliorate, shock wave therapy, or nitric oxide patches might be considered. Peritendinous injections or injections at the interface between the Achilles tendon and Kager's triangle could be considered if physical therapy should fail. Surgery is indicated after 6 months of non-operative management.

CONCLUSIONS

The clinical diagnosis and management of AT are not straightforward. Hence, patients should understand that symptoms may recur with either conservative or surgical approaches.

Alda-1, an activator of ALDH2, ameliorates Achilles tendinopathy in cellular and mouse models

Achilles tendinopathy has a high re-injury rate and poor prognosis. Development of effective therapy for Achilles tendinopathy is important. Excessive accumulation of ROS and resulting oxidative stress are believed to cause tendinopathy. Overproduction of hydrogen peroxide (H₂O₂), the most common ROS, could lead to the tendinopathy by causing oxidative damage, activation of endoplasmic reticulum (ER) stress and apoptotic death of tenocytes. Activation of mitochondrial aldehyde dehydrogenase 2 (ALDH2) is expected to alleviate oxidative stress and ER stress. Alda-1 is a selective and potent activator of ALDH2. In this study, we examined the cytoprotective benefit of Alda-1, an activator of ALDH2, on H₂O₂-induced Achilles tendinopathy in cellular and mouse models. We prepared cellular and mouse models of Achilles tendinopathy by treating cultured Achilles tenocytes and Achilles tendons with oxidative stressor H₂O₂. Subsequently, we studied the protective benefit of Alda-1 on H₂O₂-induced Achilles tendinopathy. Alda-1 pretreatment attenuated H₂O₂-induced cell death of cultured Achilles tenocytes. Treatment of Alda-1 prevented H₂O₂-induced oxidative stress and depolarization of mitochondrial membrane potential in tenocytes. Application of Alda-1 attenuated H₂O₂-triggered mitochondria- and ER stress-mediated apoptotic cascades in cultured tenocytes. Alda-1 treatment ameliorated the severity of H₂O₂-induced Achilles tendinopathy in vivo by preventing H₂O₂-induced pathological histological features of Achilles tendons, apoptotic death of Achilles tenocytes and upregulated expression of inflammatory cytokines IL-1β and TNF-α. Our results provide the evidence that ALDH2 activator Alda-1 ameliorates H₂O₂-induced Achilles tendinopathy. Alda-1 could be used for preventing and treating Achilles tendinopathy.

Updates in Tendinopathy Treatment Options

Tendinopathy is a common but disabling condition. The term describes a complex, multifaceted pathology of the tendon characterized by pain, decreased function, and reduced exercise tolerance. Tendinopathy accounts for up to 30% of general practice musculoskeletal consultations. Advances in understanding the disease process include inflammation as part of the early tendinopathy process. Once thought to not contribute to the early process of tendon degeneration, this hypothesis has been refuted. This allows guidance in conservative treatment. However, when conservative treatments fail, there are minimally invasive injections and ultrasonic debridement techniques that offer an intermediate treatment step with low reported morbidity.

Conservative Treatment of Chronic Achilles Tendinopathy: A Systematic Review

Achilles tendinopathy is a common musculoskeletal disorder. Athletes, runners and jumpers, and the sedentary are frequently affected. Numerous are the therapeutic choices to manage these kinds of disorders. The aim of this review is to analyze the available literature to document the up-to-date evidence on conservative management of Achilles tendinopathy. A systematic review of two medical electronic databases was performed by three independent authors, using the following inclusion criteria: conservative treatment consisted of pharmacologic, physical therapy without operative treatment, with more of 6 months symptoms and a minimum average of 6-months follow-up. Studies of any level of evidence, reporting clinical results, and dealing with Achilles tendinopathy and conservative treatment were searched for. A total of n = 1228 articles were found. At the end of the first screening, following the previously described selection criteria, we selected n = 94 articles eligible for full-text reading. Ultimately, after full-text reading and a reference list check, we selected n = 29 articles. Achilles tendinopathy is a frequent musculoskeletal disorder and several conservative treatments have been proposed, but no therapy is universally accepted, except for eccentric exercise training, which is the gold standard and a commonly used protocol.

Synergistic activity of platelet rich plasma and high volume image guided injection for patellar tendinopathy

PURPOSE

Platelet rich plasma and high volume image guided injections of saline have been used in the treatment of patellar tendinopathy with positive results. As the different mechanisms of action do not interfere each other, it can be hypothesized that they can be used in combination. Aim of this study was twofold: first, to evaluate the efficacy of these two treatments in the management of patellar tendinopathy; second, to verify whether the combination of these therapies could provide further advantages.

METHODS

Fifty-four patients suffering from patellar tendinopathy were enrolled. After clinical (VAS and VISA-P) and sonographic evaluation, two ultrasound guided injections (2 weeks apart) of platelet rich plasma, high-volume image-guided injections of saline, or both in association were performed. The VAS and VISA-P scores obtained from the three treatments groups (18 patients in each group) were compared across the different follow-up times (3 and 6 months).

RESULTS

In the short term both treatments showed comparable efficacy, whereas in the medium term the positive effects of high-volume image-guided injections gradually diminished and platelet rich plasma showed greater efficacy. Better results (reduced pain, improved function and increased number of subjects who exhibited optimal recovery [> 20 points in VISA-P score]) were observed when both procedures were associated.

CONCLUSIONS

The contemporaneous administration of platelet rich plasma and high volume image guided injections of saline treatments, which influence tendon repair by means of different mechanisms, grants a greater improvement for patellar tendinopathy. This finding has clinical relevance, given that this condition has a substantial impact on sports and work performance.

LEVEL OF EVIDENCE

III.

Achilles Tendinopathy

Achilles tendinopathy is a common cause of disability. Despite the economic and social relevance of the problem, the causes and mechanisms of Achilles tendinopathy remain unclear. Tendon vascularity, gastrocnemius-soleus dysfunction, age, sex, body weight and height, pes cavus, and lateral ankle instability are considered common intrinsic factors. The essence of Achilles tendinopathy is a failed healing response, with haphazard proliferation of tenocytes, some evidence of degeneration in tendon cells and disruption of collagen fibers, and subsequent increase in noncollagenous matrix. Tendinopathic tendons have an increased rate of matrix remodeling, leading to a mechanically less stable tendon which is more susceptible to damage. The diagnosis of Achilles tendinopathy is mainly based on a careful history and detailed clinical examination. The latter remains the best diagnostic tool. Over the past few years, various new therapeutic options have been proposed for the management of Achilles tendinopathy. Despite the morbidity associated with Achilles tendinopathy, many of the therapeutic options described and in common use are far from scientifically based. New minimally invasive techniques of stripping of neovessels from the Kager's triangle of the tendo Achillis have been described, and seem to allow faster recovery and accelerated return to sports, rather than open surgery. A genetic component has been implicated in tendinopathies of the Achilles tendon, but these studies are still at their infancy.

Immunobiological factors aggravating the fatty infiltration on tendons and muscles in rotator cuff lesions

Rotator cuff lesions (RCLs) are a common cause of shoulder pain and dysfunction. The rotator cuff tendons can degenerate and/or tear from the greater tuberosity of the humerus, which is associated with several anatomical, physiological, biochemical, and molecular changes in tendon and muscle. In this article, these pathways are critically reviewed and discussed with various management strategies of RCLs. The article also highlights the immunobiological responses following the RCL and the inherent repair mechanisms elicited by the body. The greatest difficulty in treating this pathology is that the muscle can undergo irreversible fatty infiltration in the setting of chronic tears that is associated with poor surgical outcomes. The article also investigates the key molecular pathways of the muscle homeostasis (mTOR, Rho kinase, AMPK, and Ca(2+)) with the energy metabolism to propose a possible mechanism for fatty infiltration. Future research is warranted to target the key players of these pathways in the management of fatty infiltration and thus RCL.

Physiological and Neural Adaptations to Eccentric Exercise: Mechanisms and Considerations for Training

Eccentric exercise is characterized by initial unfavorable effects such as subcellular muscle damage, pain, reduced fiber excitability, and initial muscle weakness. However, stretch combined with overload, as in eccentric contractions, is an effective stimulus for inducing physiological and neural adaptations to training. Eccentric exercise-induced adaptations include muscle hypertrophy, increased cortical activity, and changes in motor unit behavior, all of which contribute to improved muscle function. In this brief review, neuromuscular adaptations to different forms of exercise are reviewed, the positive training effects of eccentric exercise are presented, and the implications for training are considered.

Gastrocnemius shortening and heel pain

Pain and reduced function caused by disorders of either the plantar fascia or the Achilles tendon are common. Although heel pain is not a major public health problem it affects millions of people each year. For most patients, time and first-line treatments allow symptoms to resolve. A proportion of patients have resistant symptoms. Managing these recalcitrant cases is a challenge. Gastrocnemius contracture produces increased strain in both the Achilles tendon and the plantar fascia. This biomechanical feature must be properly assessed otherwise treatment is compromised.

Eccentric training as a new approach for rotator cuff tendinopathy: Review and perspectives

Excessive mechanical loading is considered the major cause of rotator cuff tendinopathy. Although tendon problems are very common, they are not always easy to treat. Eccentric training has been proposed as an effective conservative treatment for the Achilles and patellar tendinopathies, but less evidence exists about its effectiveness for the rotator cuff tendinopathy. The mechanotransduction process associated with an adequate dose of mechanical load might explain the beneficial results of applying the eccentric training to the tendons. An adequate load increases healing and an inadequate (over or underuse) load can deteriorate the tendon structure. Different eccentric training protocols have been used in the few studies conducted for people with rotator cuff tendinopathy. Further, the effects of the eccentric training for rotator cuff tendinopathy were only evaluated on pain, function and strength. Future studies should assess the effects of the eccentric training also on shoulder kinematics and muscle activity. Individualization of the exercise prescription, comprehension and motivation of the patients, and the establishment of specific goals, practice and efforts should all be considered when prescribing the eccentric training. In conclusion, eccentric training should be used aiming improvement of the tendon degeneration, but more evidence is necessary to establish the adequate dose-response and to determine long-term follow-up effects.

The role of eccentric exercise in sport injuries rehabilitation

INTRODUCTION

Sports injuries frequently involve tendons, muscles and ligaments. The variable outcome of surgery and medical treatment support early functional treatments. Eccentric exercise (EE) showed effectiveness in the management of Achilles tendinopathy (AT), patellar tendinopathy (PT) and lateral epicondyle tendinopathy (LET). Preliminary results of EE in other tendinopathies and sports injuries suggest its wide prescription in the sport rehabilitation field.

SOURCES OF DATA

A comprehensive search of PubMed, Web of Science, the Cochrane Collaboration Database, Physiotherapy Evidence Database (PEDro), Evidence Based Medicine (EBM) Search review, National Guidelines, Scopus and Google Scholar was performed using keywords such as 'eccentric exercise', 'sports injuries rehabilitation', 'tendinopathy', 'hamstrings strain' 'adductor injuries' and 'ACL reconstruction rehabilitation'.

AREAS OF AGREEMENT

EE, alone or associated with other therapies, represents a feasible, cost-effective and successful tool in the treatment of well-known targets and might be promising in shoulder tendinopathy, adductor-related groin pain, hamstring strains, and ACL rehabilitation.

AREA OF CONTROVERSY

The lack of standardization of protocols, the variable amount, quality and follow-up of studies, the different anatomy and pathophysiology of the therapeutic targets limit the evidence of applicability of EE to sports injuries.

GROWING POINTS

The role of pathology and biomechanics in the response to EE should be further investigated.

AREAS TIMELY FOR DEVELOPING RESEARCH

New randomized controlled trials should test the effectiveness of standardized EE regimens to various sites of sports injuries.

Is eccentric exercise an effective treatment for lateral epicondylitis? A systematic review

OBJECTIVE

To establish the effectiveness of eccentric exercise as a treatment intervention for lateral epicondylitis.

DATA SOURCES

ProQuest, Medline via EBSCO, AMED, Scopus, Web of Science, CINAHL.

REVIEW METHODS

A systematic review was undertaken to identify randomized and controlled clinical trials incorporating eccentric exercise as a treatment for patients diagnosed with lateral epicondylitis. Studies were included if: they incorporated eccentric exercise, either in isolation or as part of a multimodal treatment protocol; they assessed at least one functional or disability outcome measure; and the patients had undergone diagnostic testing. The methodological quality of each study was assessed using the Modified Cochrane Musculoskeletal Injuries Group score sheet.

RESULTS

Twelve studies met the inclusion criteria. Three were deemed 'high' quality, seven were 'medium' quality, and two were 'low' quality. Eight of the studies were randomized trials investigating a total of 334 subjects. Following treatment, all groups inclusive of eccentric exercise reported decreased pain and improved function and grip strength from baseline. Seven studies reported improvements in pain, function, and/or grip strength for therapy treatments inclusive of eccentric exercise when compared with those excluding eccentric exercise. Only one low-quality study investigated the isolated effects of eccentric exercise for treating lateral epicondylitis and found no significant improvements in pain when compared with other treatments.

CONCLUSION

The majority of consistent findings support the inclusion of eccentric exercise as part of a multimodal therapy programme for improved outcomes in patients with lateral epicondylitis.

High volume image guided injections for the management of chronic tendinopathy of the main body of the Achilles tendon

OBJECTIVES

Several substances are routinely injected in and around tendons. The present study evaluated the long term effects of high volume image guided injection (HVIGI) of normal saline, local anaesthetic and aprotinin in athletic patients with resistant tendinopathy of the main body of the Achilles tendon.

DESIGN

Case series.

METHODS

The study included a series of 94 athletes (69 men and 25 women; average age 37.5 years, range 22-63) with ultrasound confirmed tendinopathy of the main body of the Achilles tendon. All the patients had not improved after at least three months of conservative management. Patients were injected with 10 mL of 0.5% Bupivacaine Hydrochloride, 25 mg aprotinin, and up to 40 mL of injectable normal saline. We prospectively administered the Victorian Institute of Sport Assessment-Achilles tendon (VISA-A) to assess the short- and long-term pain and functional improvement.

RESULTS

At baseline (n = 94), the VISA-A score was 41.7 ± 23.2 (range 11-60), and had improved to 74.6 ± 21.4 (range 71-100) by 12 months (n = 87) (p = 0.003), with no significant difference between sexes.

CONCLUSION

HVIGI with aprotinin significantly reduces pain and improves function in patients with chronic Achilles tendinopathy in the short- and long-term follow up.

Do structural changes (eg, collagen/matrix) explain the response to therapeutic exercises in tendinopathy: a systematic review

BACKGROUND

Previous reviews have highlighted the benefit of loaded therapeutic exercise in the treatment of tendinopathy. Changes in observable structural outcomes have been suggested as a possible explanation for this response to therapeutic exercise. However, the mechanism for the efficacy of therapeutic exercise remains unclear.

OBJECTIVE

To systematically review the relationship between the observable structural change and clinical outcomes following therapeutic exercise.

DATA SOURCES

An electronic search of AMED, CiNAHL, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PEDro and SPORTDiscus was undertaken from their inception to June 2012.

STUDY ELIGIBILITY CRITERIA

Any study design that incorporated observable structural outcomes and clinical outcomes when assessing the effect of therapeutic exercise on participants with tendinopathy.

STUDY APPRAISAL AND SYNTHESIS METHODS

Included studies were appraised for risk of bias using the tool developed by the Cochrane Back Review Group. Due to heterogeneity of studies, a qualitative synthesis was undertaken.

RESULTS

Twenty articles describing 625 patients were included. Overall, there is a strong evidence to refute any observable structural change as an explanation for the response to therapeutic exercise when treated by eccentric exercise training. Moderate evidence does exist to support the response of heavy-slow resistance training (HSR).

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The available literature does not support observable structural change as an explanation for the response of therapeutic exercise except for some support from HSR. Future research should focus on indentifying other explanations including neural, biochemical and myogenic changes.

REGISTRATION NUMBER

Registered with PROSPERO, registration number CRD42011001638.

Ovine amniotic epithelial cells: in vitro characterization and transplantation into equine superficial digital flexor tendon spontaneous defects

In vitro expanded and frosted ovine amniotic epithelial cells (oAECs) were evaluated for their phenotype, stemness and attitude to differentiate into tenocytes. Fifteen horses with acute tendon lesions were treated with one intralesional injection of oAECs. Tendon recovery under controlled training was monitored. In vitro expanded oAECs showed a constant proliferative ability, a conserved phenotype and stable expression profile of stemness markers. Differentiation into tenocytes was also regularly documented. US controls showed the infilling of the defect and early good alignment of the fibers and 12 horses resumed their previous activity. Histological and immunohistochemical examinations in an explanted tendon demonstrated the low immunogenicity of oAECs that were able to survive in the healing site. In addition, oAECs supported the regenerative process producing ovine collagen type I amongst the equine collagen fibers. Considering our results, oAECs can be proposed as a new approach for the treatment of spontaneous equine tendon injuries.

Biological factors in the pathogenesis of rotator cuff tears

Rotator cuff tears are common, and lead to shoulder pain and functional impairment. Despite their frequency and related disability, etiology and pathogenesis are still debated. Multiple factors contribute to tears of the rotator cuff. Extrinsic factors are anatomic variables, such as acromial morphologic characteristics, os acromiale, and acromial spurs that compress the rotator cuff by bony impingement or direct pressure from the surrounding soft tissue. Intrinsic factors arise from the tendon itself, because of tensile overload, aging, microvascular supply, traumatisms, or degeneration. Little information is available from a cellular and molecular point of view. We reviewed the biological factors involved in the pathogenesis of rotator cuff tears. Understanding the mechanism of rotator cuff pathology would facilitate the rationale for therapeutic interventions, by guiding the design, selection, and implementation of treatment strategies such as biologic modulation and preventive measures.

Biological strategies to enhance healing of the avascular area of the meniscus

Meniscal injuries in the vascularized peripheral part of the meniscus have a better healing potential than tears in the central avascular zone because meniscal healing principally depends on its vascular supply. Several biological strategies have been proposed to enhance healing of the avascular area of the meniscus: abrasion therapy, fibrin clot, organ culture, cell therapy, and applications of growth factors. However, data are too heterogeneous to achieve definitive conclusions on the use of these techniques for routine management of meniscal lesions. Although most preclinical and clinical studies are very promising, they are still at an experimental stage. More prospective randomised controlled trials are needed to compare the different techniques for clinical results, applicability, and cost-effectiveness.

Scaffolds in tendon tissue engineering

Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair.

Tissue engineered strategies for skeletal muscle injury

Skeletal muscle injuries are common in athletes, occurring with direct and indirect mechanisms and marked residual effects, such as severe long-term pain and physical disability. Current therapy consists of conservative management including RICE protocol (rest, ice, compression and elevation), nonsteroidal anti-inflammatory drugs, and intramuscular corticosteroids. However, current management of muscle injuries often does not provide optimal restoration to preinjury status. New biological therapies, such as injection of platelet-rich plasma and stem-cell-based therapy, are appealing. Although some studies support PRP application in muscle-injury management, reasons for concern persist, and further research is required for a standardized and safe use of PRP in clinical practice. The role of stem cells needs to be confirmed, as studies are still limited and inconsistent. Further research is needed to identify mechanisms involved in muscle regeneration and in survival, proliferation, and differentiation of stem cells.

Tissue engineering for rotator cuff repair: an evidence-based systematic review

The purpose of this systematic review was to address the treatment of rotator cuff tears by applying tissue engineering approaches to improve tendon healing, specifically platelet rich plasma (PRP) augmentation, stem cells, and scaffolds. Our systematic search was performed using the combination of the following terms: “rotator cuff”, “shoulder”, “PRP”, “platelet rich plasma”, “stemcells”, “scaffold”, “growth factors”, and “tissue engineering”. No level I or II studies were found on the use of scaffolds and stem cells for rotator cuff repair. Three studies compared rotator cuff repair with or without PRP augmentation. All authors performed arthroscopic rotator cuff repair with different techniques of suture anchor fixation and different PRP augmentation. The three studies found no difference in clinical rating scales and functional outcomes between PRP and control groups. Only one study showed clinical statistically significant difference between the two groups at the 3-month follow up. Any statistically significant difference in the rates of tendon rerupture between the control group and the PRP group was found using the magnetic resonance imaging. The current literature on tissue engineering application for rotator cuff repair is scanty. Comparative studies included in this review suggest that PRP augmented repair of a rotator cuff does not yield improved functional and clinical outcome compared with non-augmented repair at a medium and long-term followup.

Growth factors and anticatabolic substances for prevention and management of intervertebral disc degeneration

Intervertebral disc (IVD) degeneration is frequent, appearing from the second decade of life and progressing with age. Conservative management often fails, and patients with IVD degeneration may need surgical intervention. Several treatment strategies have been proposed, although only surgical discectomy and arthrodesis have been proved to be predictably effective. Biological strategies aim to prevent and manage IVD degeneration, improving the function and anabolic and reparative capabilities of the nucleus pulposus and annulus fibrosus cells and inhibiting matrix degradation. At present, clinical applications are still in their infancy. Further studies are required to clarify the role of growth factors and anticatabolic substances for prevention and management of intervertebral disc degeneration.

Advances in meniscal tissue engineering

Meniscal tears are the most common knee injuries and have a poor ability of healing. In the last few decades, several techniques have been increasingly used to optimize meniscal healing. Current research efforts of tissue engineering try to combine cell-based therapy, growth factors, gene therapy, and reabsorbable scaffolds to promote healing of meniscal defects. Preliminary studies did not allow to draw definitive conclusions on the use of these techniques for routine management of meniscal lesions. We performed a review of the available literature on current techniques of tissue engineering for the management of meniscal tears.

Analysis of knee flexion angles during 2 clinical versions of the heel raise test to assess soleus and gastrocnemius function

STUDY DESIGN

Controlled laboratory study, using a repeated-measures, counterbalanced design.

OBJECTIVES

To provide estimates on the average knee angle maintained, absolute knee angle error, and total repetitions performed during 2 versions of the heel raise test.

BACKGROUND

The heel raise test is performed in knee extension (EHRT) to assess gastrocnemius and knee flexion (FHRT) for soleus. However, it has not yet been determined whether select knee angles are maintained or whether total repetitions differ between the clinical versions of the heel raise test.

METHODS

Seventeen healthy males and females performed maximal heel raise repetitions in 0° (EHRT) and 30° (FHRT) of desired knee flexion. The average angle maintained and absolute error at the knee during the 2 versions, and total heel raise repetitions, were measured using motion analysis. Participants' kinematic measures were fitted into a generalized estimation equation model to provide estimates on EHRT and FHRT performance applicable to the general population.

RESULTS

The model estimates that average angles of 2.2° and 30.7° will be maintained at the knee by the general population during the EHRT and the FHRT, with an absolute angle error of 3.4° and 2.5°, respectively. In both versions, 40 repetitions should be completed. However, the average angles maintained by participants ranged from -6.3° to 21.6° during the EHRT and from 22.0° to 43.0° during the FHRT, with the highest absolute errors in knee position being 25.9° and 33.5°, respectively.

CONCLUSION

On average, select knee angles will be maintained by the general population during the select heel raise test versions, but individualized performance is variable and total repetitions do not distinguish between versions. Clinicians should, therefore, interpret select heel raise test outcomes with caution when used to respectively assess and rehabilitate soleus and gastrocnemius function.

Marked pathological changes proximal and distal to the site of rupture in acute Achilles tendon ruptures

A laboratory study was performed to evaluate the histopathological features of the macroscopically intact portion of the Achilles tendon in patients undergoing surgery for an acute rupture of the Achilles tendon. Tendon samples were harvested from 29 individuals (21 men, 8 women; mean age: 46 ± 12) who underwent repair of an Achilles tendon tear tear, and from 11 male patients who died of cardiovascular events (mean age: 61). Three pieces of tendon were harvested: at the rupture site, 4 cm proximal to the site of rupture, 1 cm proximal to the insertion of the Achilles tendon on the calcaneum. Slides were assessed using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. Intra-observer reliability of the subscore readings was calculated. The pathological features were significantly more pronounced in the samples taken from the site of rupture than in the samples taken proximally and distal to it (0.008 < P < 0.01). There were no significant differences in the mean pathologic sum-scores in the samples taken proximally and distal to the site of rupture. Unruptured Achilles tendons, even at an advanced age, and ruptured Achilles tendons are clearly part of two distinct populations, with the latter demonstrating histopathological evidence of failed healing response even in areas macroscopically normal.

Current treatment options for tendinopathy

IMPORTANCE OF THE FIELD

Tendon disorders are frequent and are responsible for much morbidity, both in sport and the workplace. Although several therapeutic options are routinely used, very few well-conducted randomised prospective, placebo, controlled trials have been performed to assist in choosing the best evidence-based management.

AREAS COVERED IN THIS REVIEW

We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL, and Embase databases over the years 1966 - 2010 to review the best evidence-based options for the management of patients with tendinopathy.

WHAT THE READER WILL GAIN

The reader will obtain information on the available medical and surgical therapies used to manage tendinopathy-related symptoms. The effectiveness of therapies, the length of management and the adverse effects are examined.

TAKE-HOME MESSAGE

Management of tendinopathy is often anecdotic and lacking well-researched scientific evidence. Teaching patients to control the symptoms may be more beneficial than leading them to believe that tendinopathy is fully curable.

[Surgical treatment for pain syndromes of the Achilles tendon]

Pain syndromes of the Achilles tendon (AT) include both insertional and non-insertional tendinopathy, two distinct disorders with different underlying pathophysiologies and management options, characterized by pain, impaired performance and swelling in and around the tendon. This article gives an overview of the operative treatment of pain syndromes of the Achilles tendon, including both insertional tendinopathy of the AT and tendinopathy of the main body of the AT. New minimally invasive techniques for the management of this condition, including endoscopy are also reported.

Tissue engineered biological augmentation for tendon healing: a systematic review

INTRODUCTION

Tendon injuries give rise to significant morbidity. In the last few decades, several techniques have been increasingly used to optimize tendon healing.

SOURCES OF DATA

We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL and Embase databases using various combinations of the commercial names of each scaffold and the keywords 'tendon', 'rotator cuff', 'supraspinatus tendon', 'Achilles tendon', 'growth factors', 'cytokines', 'gene therapy', 'tissue engineering', 'mesenchymal' and 'stem cells' over the years 1966-2009. All articles relevant to the subject were retrieved, and their bibliographies were hand searched for further references in the context to tissue-engineered biological augmentation for tendon healing.

AREAS OF AGREEMENT

Several new techniques are available for tissue-engineered biological augmentation for tendon healing, growth factors, gene therapy and mesenchimal stem cells.

AREAS OF CONTROVERSY

Data are lacking to allow definitive conclusions on the use of these techniques for routine management of tendon ailments.

GROWING POINTS

The emerging field of tissue engineering holds the promise to use new techniques for tendon augmentation and repair. Preliminary studies support the idea that these techniques can provide an alternative for tendon augmentation with great therapeutic potential.

AREAS TIMELY FOR DEVELOPING RESEARCH

The optimization strategies discussed in this article are currently at an early stage of development. Although these emerging technologies may develop into substantial clinical treatment options, their full impact needs to be critically evaluated in a scientific fashion.

Achilles tendon ruptures in elite athletes

BACKGROUND

The management of Achilles tendon (AT) ruptures in elite athletes can be challenging. We performed a retrospective review of prospectively collected data study to evaluate the results of percutaneous repair of an acute AT rupture in elite athletes.

MATERIALS AND METHODS

Seventeen elite athletes with prodromal tendinous problems sustained an acute tear of the AT and underwent percutaneous surgical repair. We performed preoperative evaluations the day of surgery, and report the results of postoperative evaluation at a final followup at an average of 72 months from the procedure. Each patient was evaluated for limb dominance, trauma history, duration and type of preoperative symptoms, and postoperative AT Total Rupture Score (ATRS).

RESULTS

All patients were able to fully weightbear on the operated limb by the end of the 8th postoperative week. The average time to return to full sport participation was 4.8±0.9 months. Two of the 15 elite athletes on whom we have full data suffered from a superficial infection of the surgical wound.

CONCLUSION

Our study suggests that percutaneous repair of the AT is a good option for elite athletes, allowing a safe and prompt return to sport activities.

The cross-talk between transforming growth factor-beta1 and ultrasound stimulation during mechanotransduction of rat tenocytes

Ultrasound is an effective noninvasive treatment for various tendinopathies. However, how tenocytes convert ultrasound stimulation into cascades of cellular and molecular events is not well understood. The purpose of this study is to elucidate the signaling pathways of tenocytes during ultrasound stimulation. Primary cultures of tenocytes were harvested from Achilles tendons of Sprague-Dawley rats. The viability and proliferation of tenocytes, their genes expression, and the signaling pathways after ultrasound treatment with or without specific inhibitors were evaluated and analyzed. The results showed that ultrasound treatment (100 mW/cm(2) for 20 min) significantly enhanced matrix metalloproteinase 13 (MMP-13), c-Fos, and c-Jun gene expression, increased JNK and p38, but not extracellular signal-regulated kinase-1/2 (ERK1/2), phosphorylation at 5 min, and sustained up to 60 min. JNK inhibitor and p38 inhibitor, but not ERK1/2 inhibitor, attenuated ultrasound-dependent induction of MMP-13 expression, indicating that the JNK and p38 pathways are required for ultrasound-induced MMP-13 expression in tenocytes. We also found that SB431542 (transforming growth factor-beta (TGF-β) receptor kinases inhibitor) suppressed ultrasound-induced MMP?13 and c-Fos gene expression, and p38 phosphorylation. This study revealed that ultrasound treatment stimulates tenocytes proliferation and regulates their matrix metabolism through the cross-talk between TGF-β and ultrasound-induced mitogen-activated protein kinases (MAPKs) signaling pathways.

Minimally invasive surgery for Achilles tendon pathologies

Minimally invasive trauma and orthopedic surgery is increasingly common, though technically demanding. Its use for pathologies of the Achilles tendon (AT) hold the promise to allow faster recovery times, shorter hospital stays, and improved functional outcomes when compared to traditional open procedures, which can lead to difficulty with wound healing because of the tenuous blood supply and increased chance of wound breakdown and infection. We present the recent advances in the field of minimally invasive AT surgery for tendinopathy, acute ruptures, chronic tears, and chronic avulsions of the AT. In our hands, minimally invasive surgery has provided similar results to those obtained with open surgery, with decreased perioperative morbidity, decreased duration of hospital stay, and reduced costs. So far, the studies on minimally invasive orthopedic techniques are of moderate scientific quality with short follow-up periods. Multicenter studies with longer follow-up are needed to justify the long-term advantages of these techniques over traditional ones.

Effect of dihydrotestosterone on cultured human tenocytes from intact supraspinatus tendon

The role of hormones in the pathogenesis of tendinopathy is not well recognised, even though the use of anabolic steroids is correlated with a higher incidence of spontaneous tendon ruptures. The aim of this study was to investigate the effects of dihydrotestosterone (DHT) on human tenocyte cultures from the intact supraspinatus tendon of male subjects. Cultured human tenocytes were seeded into culture plates at a density of 5 x 10(4) cells per well and incubated for 24 h. Then, 10(-9) M-10(-7) M DHT or Dulbecco's modified Eagle's medium (DMEM) only (control) was added to the culture plate wells. Cell morphology assessment and cell proliferation tests were performed 48, 72 and 96 h after DHT treatment. DHT-treated tenocytes showed an increased proliferation rate at DHT concentration higher than 10(-8) M. Differences in cell numbers between control and DHT-treated cells were statistically significant (P < 0.05) after 48 and 72 h of treatment with DHT concentrations of 10(-8) and 10(-7) M. The tenocytes treated with DHT (10(-8) and 10(-7) M) became more flattened and polygonal compared to control cells that maintained their fibroblast-like appearance during the experiment at each observation time. In conclusion, in vitro, progressive increasing concentration of DHT at doses greater than 10(-8) M had direct effects on male human tenocytes, increasing cell number after 48 and 72 h of treatment, and leading to a dedifferentiated phenotype after 48 h of treatment. This effect can be important during tendon-healing and repair, when active proliferation is required. Our results represent preliminary evidence for a possible correlation between testosterone abuse and shoulder tendinopathy.

New options in the management of tendinopathy

Tendon injuries can be acute or chronic, and caused by intrinsic or extrinsic factors, either alone or in combination. Tendinopathies are a common cause of disability in occupational medicine and account for a substantial proportion of overuse injuries in sports. Tendinopathy is essentially a failed healing response, with haphazard proliferation of tenocytes, abnormalities in tenocytes, with disruption of collagen fibres and subsequent increase in noncollagenous matrix. The scientific evidence base for managing tendinopathies is limited. What may appear clinically as an "acute tendinopathy" is actually a well advanced failure of a chronic healing response in which there is neither histologic nor biochemical evidence of inflammation. In this review we report the new options for the management of tendinopathy, including eccentric exercises, extracorporeal shockwave therapy, injections (intratendinous injections of corticosteroids, aprotinin, polidocanol platelet-rich plasma, autologous blood injection, high-volume injections) and surgery. Open surgery aims to excise fibrotic adhesions, remove areas of failed healing and make multiple longitudinal incisions in the tendon to detect intratendinous lesions, and to restore vascularity and possibly stimulate the remaining viable cells to initiate cell matrix response and healing. New surgical techniques aim to disrupt the abnormal neoinnervation to interfere with the pain sensation caused by tendinopathy. These procedures are intrinsically different from the classical ones in present use, because they do not attempt to address directly the pathologic lesion, but act only to denervate them. They include endoscopy, electrocoagulation, and minimally invasive stripping. Further randomized controlled trials are necessary to clarify better the best therapeutic options for the management of tendinopathy.

Genetics and sports

INTRODUCTION

The limit of each individual to perform a given type of exercise depends on the nature of the task, and is influenced by a variety of factors, including psychology, environment and genetic make up. Genetics provide useful insights, as sport performances can be ultimately defined as a polygenic trait.

SOURCES OF DATA

We searched PubMed using the terms 'sports' and 'genetics' over the period 1990 to present.

AREAS OF AGREEMENT

The physical performance phenotypes for which a genetic basis can be suspected include endurance capacity, muscle performance, physiological attitude to train and ability of tendons and ligaments to withstand injury. Genetic testing in sport would permit to identify individuals with optimal physiology and morphology, and also those with a greater capacity to respond/adapt to training and a lesser chance of suffering from injuries.

AREAS OF CONTROVERSY

Ethical and practical caveats should be clearly emphasized. The translation of an advantageous genotype into a champion's phenotype is still influenced by environmental, psychological and sociological factors.

EMERGING AREAS FOR DEVELOPING RESEARCH

The current scientific evidence on the relationship between genetics and sports look promising. There is a need for additional studies to determine whether genome-wide genotyping arrays would be really useful and cost-effective. Since exercise training regulates the expression of genes encoding various enzymes in muscle and other tissues, genetic research in sports will help clarify several aspects of human biology and physiology, such as RNA and protein level regulation under specific circumstances.

Pathogenesis of tendinopathies: inflammation or degeneration?

The intrinsic pathogenetic mechanisms of tendinopathies are largely unknown and whether inflammation or degeneration has the prominent role is still a matter of debate. Assuming that there is a continuum from physiology to pathology, overuse may be considered as the initial disease factor; in this context, microruptures of tendon fibers occur and several molecules are expressed, some of which promote the healing process, while others, including inflammatory cytokines, act as disease mediators. Neural in-growth that accompanies the neovessels explains the occurrence of pain and triggers neurogenic-mediated inflammation. It is conceivable that inflammation and degeneration are not mutually exclusive, but work together in the pathogenesis of tendinopathies.