Achilles tendon lesions in sport

Investigation of the effects of pentoxifylline and alpha tocopherol treatment on recovery in rats with Achilles tendon rupture

Although the Achilles tendon is the largest and strongest tendon in the body, healing of the Achilles tendon is the most common injury, and this process is difficult due to poor tendon circulation; moreover, the underlying mechanism has not been fully elucidated. In our study, we aimed to investigate the effects of pentoxifylline and alpha-tocopherol administered separately or in combination on rats with Achilles tendon injury. Forty-eight male Wistar rats weighing 230 ± 30 g were used in the study. The rats were randomly divided into eight groups of six animals each. Tendons were evaluated histopathologically and biomechanically. According to the statistical analysis, the vascularity density in the pentoxifylline group on day 14 was significantly greater than that in the other groups (p < 0.05). The collagen arrangement in the pentoxifylline and alpha-tocopherol groups on day 14 was found to be firmer and smoother than that in the control group (p < 0.05). The collagen arrangement in the pentoxifylline group on day 28 was greater than that in the other groups (p < 0.05). The biomechanical results were significantly greater in all groups (p < 0.05). Pentoxifylline contributed to tendon healing both through neovascularization in the early period and by improving collagen orientation in the late period, while alpha-tocopherol had a positive effect on collagen orientation in the early period. No beneficial effects were observed when pentoxifylline and alpha-tocopherol were used together. We believe that further research is needed to understand the effects of this combination therapy on tendon healing.

Application of Nondegradable Synthetic Materials for Tendon and Ligament Injury

Tendon and ligament injuries, prevalent requiring surgical intervention, significantly impact joint stability and function. Owing to excellent mechanical properties and biochemical stability, Nondegradable synthetic materials, including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE), have demonstrated significant potential in the treatment of tendon and ligament injuries. These above materials offer substantial mechanical support, joint mobility, and tissue healing promotion of the shoulder, knee, and ankle joint. This review conclude the latest development and application of nondegradable materials such as artificial patches and ligaments in tendon and ligament injuries including rotator cuff tears (RCTs), anterior cruciate ligament (ACL) injuries, and Achilles tendon ruptures.

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.

Biomechanical comparison of new Achilles tendon rupture repair technique the "Giftbox" versus the Krackow technique in New Zealand white rabbits: An experimental animal study

INTRODUCTION

To compare the strength between the Achilles tendons repaired with the "Giftbox" and the Krackow techniques in New Zealand white rabbits post six weeks of tendon healing.

MATERIALS AND METHODS

Eight rabbits were randomized into Giftbox and Krackow groups. Tenotomy was performed on the Achilles tendon of one side of the lower limb and repaired with the respective techniques. The contralateral limb served as control. Subjects were euthanized six weeks post-operative, and both repaired and control Achilles tendons were harvested for biomechanical tensile test.

RESULTS

The means of maximum load to rupture and tenacity in the Giftbox group (156.89 ± 38.49 N and 159.98 ± 39.25 gf/tex) were significantly different than Krackow's (103.55 ± 27.48 N and 104.91 ± 26.96 gf/tex, both p = 0.043).

CONCLUSION

The tendons repaired with Giftbox technique were biomechanically stronger than those repaired with Krackow technique after six weeks of tendon healing.

Is the human sclera a tendon-like tissue? A structural and functional comparison

Collagen rich connective tissues fulfill a variety of important functions throughout the human body, most of which having to resist mechanical challenges. This review aims to compare structural and functional aspects of tendons and sclera, two tissues with distinct location and function, but with striking similarities regarding their cellular content, their extracellular matrix and their low degree of vascularization. The description of these similarities meant to provide potential novel insight for both the fields of orthopedic research and ophthalmology.

Characterization of the structure, vascularity, and stem/progenitor cell populations in porcine Achilles tendon (PAT)

This study aimed to characterize porcine Achilles tendon (PAT) in terms of its structural components, vascularity, and resident tendon cells. We found that PAT is composed of a paratenon sheath, a core of fascicles, and an endotenon/interfascicular matrix (IFM) that encases the fascicle bundles. We analyzed each of these three tendon components structurally using tissue sections and by isolating cells from each component and analyzing in vitro. Many blood vessel-like tissues were present in the paratenon and IFM but not in fascicles, and the vessels in the paratenon and IFM appeared to be inter-connected. Cells isolated from the paratenon and IFM displayed characteristics of vascular stem/progenitor cells expressing the markers CD105, CD31, with α-smooth muscle actin (α-SMA) localized surrounding blood vessels. The isolated cells from paratenon and IFM also harbored abundant stem/progenitor cells as evidenced by their ability to form colonies and express stem cell markers including CD73 and CD146. Furthermore, we demonstrate that both paratenon and IFM-isolated cells were capable of undergoing multi-differentiation. In addition, both paratenon and IFM cells expressed elastin, osteocalcin, tubulin polymerization promoting protein (TPPP), and collagen IV, whereas fascicle cells expressed none of these markers, except collagen I. The neurotransmitter substance P (SP) was also found in the paratenon and IFM-localized surrounding blood vessels. The findings of this study will help us to better understand the vascular and cellular mechanisms of tendon homeostasis, injury, healing, and regeneration.

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 Tendon Reconstruction with Semitendinous Tendon Grafts Is Associated with a High Complication Rate

BACKGROUND

In the presence of a large gap where end-to-end repair of the torn Achilles tendon is difficult and V-Y advancement would likely be insufficient, augmentation is sometimes required. At our institute we have used primarily the hamstring autograft augmentation technique for the past two decades. The aim of this study was to analyze the complications after surgical treatment of Achilles tendon rupture with semitendinous tendon augmentation.

METHODS

We retrospectively analyzed 58 consecutive patients treated with semitendinous tendon autograft augmentation at the Helsinki University Hospital between January 1, 2006, and January 1, 2016.

RESULTS

During the study period, 58 patients were operated on by six different surgeons. Of 14 observed complications (24%), seven were major and seven were minor. Most of the complications were infections (n = 10 [71%]) The infections were noted within a mean of 62 days postoperatively (range, 22-180 days). Seven patients with a complication underwent repeated operation because of skin edge necrosis and deep infection (five patients), hematoma formation (one patient), and a repeated rupture (one patient).

CONCLUSIONS

In light of the experience we have had with autologous semitendinous tendon graft augmentation, we cannot recommend this technique, and, hence, we should abandon reconstruction of Achilles tendon ruptures with autologous semitendinous tendon grafts at our institute. Instead, other augmentation techniques, such as flexor hallucis longus tendon transfer, should be used.

Mechanical Roles in Formation of Oriented Collagen Fibers

Collagen is a structural protein that is widely present in vertebrates, being usually distributed in tissues in the form of fibers. In living organisms, fibers are organized in different orientations in various tissues. As the structural base in connective tissue and load-bearing tissue, the orientation of collagen fibers plays an extremely important role in the mechanical properties and physiological and biochemical functions. The study on mechanics role in formation of oriented collagen fibers enables us to understand how discrete cells use limited molecular materials to create tissues with different structures, thereby promoting our understanding of the mechanism of tissue formation from scratch, from invisible to tangible. However, the current understanding of the mechanism of fiber orientation is still insufficient. In addition, existing fabrication methods of oriented fibers are varied and involve interdisciplinary study, and the achievements of each experiment are favorable to the construction and improvement of the fiber orientation theory. To this end, this review focuses on the preparation methods of oriented fibers and proposes a model explaining the formation process of oriented fibers in tendons based on the existing fiber theory. Impact statement As the structural base in connective tissue and load-bearing tissue, the orientation of collagen fibers plays an extremely important role in the mechanical properties and physiological and biochemical functions. However, the current understanding of the mechanism of fiber orientation is still insufficient, which is greatly responsible for the challenge of functional tissue repair and regeneration. Understanding the mechanism of fiber orientation can promote the successful application of fiber orientation scaffolds in tissue repair and regeneration, as well as providing an insight for the mechanism of tissue histomorphology.

Revolving doors of tendinopathy: definition, pathogenesis and treatment

The ultimate cure for the tendon pathology continues to elude current science. Despite great steps in technology, the causation and treatment is still not clear. The number of different theories and treatment modalities in the literature may confuse clinicians and patients. In this paper we outline the definitions, evolution of pathogenesis and treatment for tendinopathy. By highlighting these, the aim of this paper is to guide the practitioner in counselling and treating their patients.

Differential pattern of Doppler signals at lower-extremity entheses of healthy children

BACKGROUND

Ultrasonography might be an important imaging method for assessing the pediatric enthesis. To diagnose pathology, knowledge of physiological findings is essential but limited.

OBJECTIVE

To provide a detailed ultrasonographic assessment of four lower-extremity entheses in healthy adolescents as a reference for the correct interpretation of findings in children with rheumatic diseases.

MATERIALS AND METHODS

The quadriceps tendon, proximal and distal patella tendon, and Achilles enthesis were examined in B-mode, Power and color Doppler in 41 boys and girls ages 11-14 years in neutral position and 30° flexion. We assessed Doppler signals at various distances from the enthesis and analyzed the data using a marginal logistic regression model with generalized estimating equation. We assessed agreement between observers using weighted kappa and we determined agreement on repeat scans using prevalence- and bias-adjusted kappa.

RESULTS

Doppler signals were predominantly in the quadriceps and distal patella tendon with odds ratios of 50.85 and 21.35 (P<0.001) compared to the Achilles tendon. They were within 2 mm or 5 mm of the enthesis (odds ratios [ORs] of 4.58 and 4.24, P<0.001), without significant difference between flexion and neutral position and between the right and the left legs. Agreement between first and second assessment was good, with aggregate kappas from 0.79 to 0.90. The inter-reader agreement was also good, with aggregate kappas ranging from 0.75 to 0.95.

CONCLUSION

We found a differential Doppler pattern in lower-extremity entheses, with signals present mostly in the quadriceps and distal patella entheses.

Power Doppler Ultrasound Findings before and after Focused Extracorporeal Shock Wave Therapy for Achilles Tendinopathy: A Pilot Study on Pain Reduction and Neovascularization Effect

Extracorporeal shock wave therapy (ESWT) has been found to have a positive effect in the treatment of pain in Achilles tendinopathy, although the exact mechanism is not yet completely understood. Among the mechanisms suggested to underlie ESWT effects are direct stimulation of healing, neovascularization and direct suppressive effects on nociceptors and hyperstimulation, which would block the gate-control system. The neovascularization observed in flogistic tissue is associated with stimulated nerve fibers around tendons and induces a painful condition. The objectives of the present study were to evaluate the effect of ESWT on pain and function in patients with non-insertional Achilles tendinopathy (NIAT) and to assess the neovascularization phenomenon using power Doppler ultrasound (PDU). Twelve patients with NIAT underwent five sessions of focused ESWT over 5 wk. Outcome measures were the visual analogue scale, the Victorian Institute of Sport Assessment-Achilles questionnaire and active dorsiflexion and plantar flexion ankle articular range of motion. Moreover, the patients' clinical impressions of treatment results after ESWT were investigated using the Roles and Maudsley score. Patients were assessed at baseline and 1 and 3 mo after treatment. They had a significant reduction in pain with improvement of arthrokinematic motion and functionality and a positive clinical impression of treatment outcome (50% of patients considered their clinical picture as good/excellent after 3 mo). However, the pulse Doppler ultrasound exam did not reveal neovascularization in 91.7% of the patients 1 and 2 mo after focused ESWT, and in some patients there was a reduction in blood vessels related to flogistic processes. The present observational study confirmed the efficacy of ESWT in pain reduction in NIAT, with a higher degree of patient satisfaction, although doubt persists over the neovascularization effect on the Achilles tendons treated.

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.

Fabrication of novel tubular scaffold for tendon repair from chitosan in combination with zinc oxide nanoparticles

Chitosan bears numerous properties, such as biocompatibility, biodegradability and non-toxicity making it suitable for use in different biomedical fields. Zinc (Zn) is required for fibroblasts proliferation and collagen synthesis as essential elements of wound healing. Its nanoparticles are well known for their capability to enhance wound healing by cell adhesion and migration improvement through growth factors-mediated mechanisms. Poor blood supply and unique histological characteristics of tendon make its regeneration always slow. Also, adhesion formation between tendon and its surrounding tissues is another problem for neotendon to return to its normal structure and functional activities. In this study, a novel tubular scaffold of zinc oxide (ZnO) nanoparticles loaded chitosan has been fabricated for tendon repair. Experimental complete tenotomy of deep digital flexor tendon in a rabbit model was done and scaffolds were placed in the transected area after two ends suturing. After four and eight weeks, adhesion formation around the tendons and tissue reaction to the scaffolds were evaluated macroscopically. Inflammation, angiogenesis and collagen fibers arrangement were also analyzed in histopathological evaluations. After eight weeks, the scaffolds were absorbed completely, adhesions around the tendon were decreased and there was no sign of significant tissue reaction and/or infection in histopathological analyses. The reduced adhesion formation, improved gliding function and better histopathological characteristics suggest this scaffold application as a potential therapy in treatment of tendon acute injuries.

Mechanical Considerations for Electrospun Nanofibers in Tendon and Ligament Repair

Electrospun nanofibers possess unique qualities such as nanodiameter, high surface area to volume ratio, biomimetic architecture, and tunable chemical and electrical properties. Numerous studies have demonstrated the potential of nanofibrous architecture to direct cell morphology, migration, and more complex biological processes such as differentiation and extracellular matrix (ECM) deposition through topographical guidance cues. These advantages have created great interest in electrospun fibers for biomedical applications, including tendon and ligament repair. Electrospun nanofibers, despite their nanoscale size, generally exhibit poor mechanical properties compared to larger conventionally manufactured polymer fiber materials. This invites the question of what role electrospun polymer nanofibers can play in tendon and ligament repair applications that have both biological and mechanical requirements. At first glance, the strength and stiffness of electrospun nanofiber grafts appear to be too low to fill the rigorous loading conditions of these tissues. However, there are a number of strategies to enhance and tune the mechanical properties of electrospun nanofiber grafts. As researchers design the next-generation electrospun tendon and ligament grafts, it is critical to consider numerous physiologically relevant mechanical criteria and to evaluate graft mechanical performance in conditions and loading environments that reflect in vivo conditions and surgical fixation methods.

Imaging in Juvenile Spondyloarthritis

PURPOSE OF REVIEW

This review aims to provide an update on the use of imaging in the assessment of juvenile spondyloarthritis (JSpA) disease manifestations.

RECENT FINDINGS

Recent studies have demonstrated superior reliability and specificity of MRI for assessment of sacroiliac joint inflammation compared with radiography. The use of gadolinium contrast may not add incremental value to the assessment of inflammatory sacroiliitis. Sacroiliitis is common at diagnosis of spondyloarthritis. Inflammatory changes of the lumbar spine are not uncommon, and changes over time in the sacroiliac and apophyseal joints may not be concordant. Ultrasonography (US) in turn has been recognized as an excellent imaging technique to visualize the peripheral manifestations of JSpA. US does not only add important information to the clinical assessment but also helps to understand the complexity of the enthesis. Recognition of specific aspects in children is important though. The standardization of image acquisition as well as the establishment of the evidence base are underway. MRI and ultrasonography are recognized as increasingly important tools in the diagnosis and management of juvenile spondyloarthritis.

A high-glucose diet affects Achilles tendon healing in rats

Chronic and acute tendinopathies are difficult to treat and tendon healing is generally a very slow and incomplete process and our general understanding of tendon biology and regeneration lags behind that of muscle or bone. Although still largely unexplored, several studies suggest a positive effect of nutritional interventions on tendon health and repair. With this study, we aim to reveal effects of a high-glucose diet on tendon neoformation in a non-diabetic rat model of Achilles tenotomy. After surgery animals received either a high-glucose diet or a control diet for 2 and 4 weeks, respectively. Compared to the control group, tendon repair tissue thickness and stiffness were increased in the high-glucose group after 2 weeks and gait pattern was altered after 1 and 2 weeks. Cell proliferation was up to 3-fold higher and the expression of the chondrogenic marker genes Sox9, Col2a1, Acan and Comp was significantly increased 2 and 4 weeks post-surgery. Further, a moderate increase in cartilage-like areas within the repair tissue was evident after 4 weeks of a high-glucose diet regimen. In summary, we propose that a high-glucose diet significantly affects tendon healing after injury in non-diabetic rats, potentially driving chondrogenic degeneration.

Rehabilitation of Achilles tendon ruptures: is early functional rehabilitation daily routine?

INTRODUCTION

Ruptures of the Achilles tendon are the most common tendon injuries of the lower extremities. Besides the initial operative or non-operative treatment, rehabilitation of patients plays a crucial role for tendon healing and long-term outcome. As only limited evidence is available for optimized rehabilitation regimen and guidelines for the initial (e.g., first 6 weeks) rehabilitation are limited, this study investigated the current rehabilitation concepts after Achilles tendon rupture.

MATERIALS AND METHODS

We analyzed 213 written rehabilitation protocols that are provided by orthopedic and trauma surgery institutions throughout Germany in terms of recommendations for weight-bearing, range of motion (ROM), physiotherapy, and choice of orthosis. All protocols for operatively and non-operatively treated Achilles tendon ruptures were included. Descriptive analysis was carried out and statistical analysis applied where appropriate.

RESULTS

Of 213 institutions, 204 offered rehabilitation protocols for Achilles tendon rupture and, therefore, 243 protocols for operative and non-operative treatment could be analyzed. While the majority of protocols allowed increased weight-bearing over time, significant differences were found for durations of fixed plantar flexion between operative (o) and non-operative (n) treatments [fixed 30° (or 20)° to 15° (or 10)°: 3.6 weeks (±0.1; o) vs 4.7 weeks (±0.3; n) (p ≤ 0.0001) and fixed 15° (or 10)° to 0°: 5.8 weeks (±0.1; o) vs 6.6 weeks (±0.2; n) (p ≤ 0.001)]. The mean time of the recommended start of physiotherapy is at 2.9 weeks (±0.2; o) vs 3.3 weeks (±0.4; n), respectively.

CONCLUSION

Our study shows that a huge variability in rehabilitation after Achilles tendon rupture exists. This study shows different strategies in rehabilitation of Achilles tendon ruptures using a convertible vacuum brace system. To improve patient care, further clinical as well as biomechanical studies need to be conducted. This study might serve as basis for prospective randomized controlled trials to optimize rehabilitation for Achilles tendon ruptures.

Therapeutic effectiveness of instrument-assisted soft tissue mobilization for soft tissue injury: mechanisms and practical application

This article reviews the mechanism and effects of instrument-assisted soft tissue mobilization (IASTM), along with guidelines for its practical application. IASTM refers to a technique that uses instruments to remove scar tissues from injured soft tissues and facilitate healing process through formation of new extracellular matrix proteins such as collagen. Recently, frequent use of this instrument has increased in the fields of sports rehabilitation and athlete training. Some experimental studies and case reports have reported that IASTM can significantly improve soft tissue function and range of motion following sports injury, while also reducing pain. Based on the previous studies, it is thought that IASTM can help shorten the rehabilitation period and time to return to sports among athletes and ordinary people who have suffered sports injuries. However, few experimental studies of the mechanisms and effects of IASTM have examined, while case reports have accounted for the majority of articles. In the future, the scientific basis of IASTM and its reliability should be provided through well-designed experimental studies on humans. Moreover, IASTM studies that have mostly focused on tendons need to broaden their scope toward other soft tissues such as muscles and ligaments.

Moderate treadmill running exercise prior to tendon injury enhances wound healing in aging rats

The effect of exercise on wound healing in aging tendon was tested using a rat moderate treadmill running (MTR) model. The rats were divided into an MTR group that ran on a treadmill for 4 weeks and a control group that remained in cages. After MTR, a window defect was created in the patellar tendons of all rats and wound healing was analyzed. We found that MTR accelerated wound healing by promoting quicker closure of wounds, improving the organization of collagen fibers, and decreasing senescent cells in the wounded tendons when compared to the cage control. MTR also lowered vascularization, increased the numbers of tendon stem/progenitor cells (TSCs) and TSC proliferation than the control. Besides, MTR significantly increased the expression of stem cell markers, OCT-4 and Nanog, and tenocyte genes, Collagen I, Collagen III and tenomodulin, and down-regulated PPAR-γ, Collagen II and Runx-2 (non-tenocyte genes). These findings indicated that moderate exercise enhances healing of injuries in aging tendons through TSC based mechanisms, through which exercise regulates beneficial effects in tendons. This study reveals that appropriate exercise may be used in clinics to enhance tendon healing in aging patients.

Achilles tendinopathy

Achilles tendinopathy is a common clinical condition. The aetiology of Achilles tendinopathy remains unclear, but is probably multifactorial resulting from a combination of intrinsic and extrinsic factors. Excessive loading of the tendon during vigorous training activities is regarded as the main pathological stimulus. The Achilles tendon may respond to repetitive overload beyond physiological threshold by either inflammation of its sheath, degeneration of its body, or a combination of both. Conservative management, including relative rest, anti-inflammatory drugs, physiotherapy and orthoses may be beneficial. Surgery is generally recommended after exhausting conservative management, usually after at least three to six months. Long-standing Achilles tendinopathy is associated with poor postoperative results, with a greater rate of reoperation before reaching an acceptable outcome.

Soft-Tissue Radiography, Computed Tomography, and Ultrasonography of Partial Achilles Tendon Ruptures

Ultrasonography (US) was compared with soft-tissue radiography (STR) and computed tomography (CT) for demonstration of partial Achilles tendon ruptures. Thirty-nine patients suffering from chronic localized painful Achilles tendon swelling were examined. The patients had all undergone a previous clinical examination, resulting in a suspicion of a non-healed partial tear in 62 out of the 78 tendons. STR showed unspecific tendon pathology such as thickening and diffuse tendon margins. CT resulted in a better delineation of intra- as well as extratendinous abnormalities compared to STR. Various pathologic changes were seen on CT in 54 tendons and in 29 of these, localized intratendinous hypodensities indicated partial ruptures. At US, abnormal changes were observed in 69 tendons, of which 54 had discontinuity of tendon fibers, focal hypoechoic areas, and localized swelling indicating partial ruptures. In 9 cases with surgically proven partial ruptures, US was correct in all cases, while CT was false-negative in 3. STR only showed localized swelling. It was concluded that US was a better method than STR and CT for the detection of partial ruptures and the US findings correlated well with the surgical findings.

A study of wrist pain in industry — theories of causation

Arm pain has been reported in industry as a major reason for absence, particu larly amongst those whose jobs are heavy or repetitive. The purpose of this study was to identify the precise anatomical sites and nature of the conditions affecting industrial subjects. A modular physical examination was devised with an introductory module performed 'blind' to minimize bias, and a series of optional sub-modules to cope with the great variety of conditions.

The results of the examination of 332 subjects (220 with arm pain and 112 with none) demonstrated joint dysfunctions in 60% of 70 subjects reporting wrist pain. Some 20% of the wrist joint dysfunctions were 'hidden', which may explain the reports of 'nil findings'. In contrast to this there were lower than expected frequencies of tendinitis, tenosynovitis and carpal tunnel syndrome.

Theories of causation are discussed together with the implications for industry, and suggestions are made for assessment procedures.

Sonoelastography of the distal third of the Achilles tendon in asymptomatic volunteers: correlation with anthropometric data, ultrasound findings and reproducibility of the method

OBJECTIVE

Evaluating prospectively elastosonographyc (EUS) findings of distal third of Achilles tendon in asymptomatic volunteers and correlating with subject characteristics and ultrasound (US) findings and, subsequently, calculating reproducibility of method.

MATERIALS AND METHODS

70 consecutives Achilles tendons were examined with US and EUS in 35 asymptomatic volunteers. Mean age 42.3 years (±7.6), 22 were female (mean age 41 ± 8.7) and 13 were male (mean age 42.5 ± 11.4). Information about population was collected (anthropometric data, sport activity, taken therapy and associated conditions/pathologies).

RESULTS

Statistically significant correlation was found between BMI and EUS findings (p = 0.007) and between EUS aspect and US diagnosis (p = 0.039) both to the right tendon. Possible influence of smoking (p = 0.063 to right) and associated conditions (p = 0. 059 to left), has been found. The multivariate analysis showed that EUS results are correlated only with BMI (high BMI corresponds to the best EUS results), independently from smoke and associated conditions on right side. No correlations have emerged for the left tendon. The 22.8 % of the volunteers took on chronic therapies, none statistically significant correlation. In the past, 80 % of subjects played sports (7.4 % agonistic and 92.6 % non-agonistic). The 22.9 % of volunteers played sporadic or no activity. The 60 % of volunteers has played sports that may lead overload of the Achilles tendon. The 61.5 % of subjects with BMI ≥ 25 was active little or nothing; 63.6 % of the subjects with BMI < 25 is playing sports. US examination showed 57.1 % normal tendons and 42.9 % tendinosic. Rate of tendinosic tendons was similar in both left and right (40 and 45.7 %, respectively). Statistically significant correlation was found between EUS aspect and US diagnosis on the right tendon but not on the left Correlation between thickness and EUS aspect was calculated: no correlation was found. Interoperator correlation was excellent (k = 0.89 for left tendon and k = 0.91 for right tendon).

CONCLUSIONS

The EUS is an interesting and useful technique, characterised by a high reproducibility. Its results are related to BMI and US appearance of the tendon, and they are probably influenced by the smoke and associated conditions. However, the flexed ankle position, needed to properly examine the distal third by US, alters the elasticity of the tendon and causes false negative results to EUS. Then, for the EUS study of the distal third, it would be appropriate the relaxed position, with a gel pad to optimise the probe adhesion.

High Power Laser for Treatment of Achilles Tendinosis - a Single Blind Randomized Placebo Controlled Clinical Study

INTRODUCTION

Pain in the Achilles tendon during loading is a very common condition. Conservative treatments, such as low level laser therapy (LLLT) have been reported to give varying results. Recently, a new laser treatment technique, high power laser treatment (HPLT) (Swiss DynaLaser®), was introduced in Scandinavia, but has not, to our knowledge, been systematically tested before. The objective of this study was to evaluate the effects of HPLT compared to placebo HPLT in rated pain and assessed pain threshold in patients with chronic Achilles tendinosis.

METHODS

The study was a randomized, single blind, placebo controlled trial. Patients were randomized to receive 6 treatments of either HPLT or placebo HPLT during a period of 3-4 weeks with a follow up period of 8-12 weeks. Outcome measures were rated pain according to questions of the Foot and Ankle Outcome Score (FAOS, Swedish version LK1.0) and assessment of electro-cutaneous stimulated pain threshold and matched pain (PainMatcher).

RESULTS

The results of the study demonstrated significant changes of assessments within groups, that were more pronounced towards lower levels of rated pain in the HPLT group than in the placebo HPLT group. The between group difference were significant in four of nine questions regarding loading activities of the FAOS subscale. Assessed pain thresholds were found increased in the HPLT group, as compared to the placebo HPLT group. At individual level, the results varied.

CONCLUSION

The results indicate that HPLT may provide a future option for treatment of Achilles tendinosis related pain, but further studies are warranted.

Microarray profiling analysis of long non-coding RNAs expression in tendinopathy: identification for potential biomarkers and mechanisms

The role of lncRNAs in pathologies of tendinopathy has not been researched so far, this study aims to identify the role and potent mechanism of lncRNAs in tendinopathy with a bioinformatic analysis. The gene profile of GSE26051 based on the platform of Affymetrix Human Genome U133B Array condensed was downloaded from Gene Expression Omnibus. A total of 46 specimens (including 23 normal samples and 23 tendinopathy specimens) were available. Compared with the control samples, differentially expressed genes (DEGs) of tendinopathy was identified the by packages in R. The selected DEGs were further analysed using bioinformatics methods including co-expression and enrichment analysis to detect the potential role of lncRNAs. A total of 40 different expressed lncRNAs were identified. However, most of the identified lncRNAs have not been researched before. And this study only annotate one of the identified lncRNAs successfully, the LOC100507027 (myoregulin), with the potential role in regulating skeletal muscle tissue development and skeletal muscle organ development.

Percutaneous ultrasonic debridement of tendinopathy-a pilot Achilles rabbit model

Background

Tendinopathy is a common clinical pathology, with mixed treatment results, especially when chronic. In this study, we examine the effects of an ultrasonic debridement modality in a rabbit tendinopathy model.

We asked four questions: 1) Was it possible to create and visualize with ultrasound a tendinopathy lesion in a rabbit Achilles tendon? 2) Was it possible to guide a 19-gauge ultrasonic probe into the tendinopathy lesion? 3) Following ultrasonic treatment, was tendinopathy debris histologically present? and 4) Was the collagen profile qualitatively and quantitatively normalized following treatment?

Methods

Skeletally mature female New Zealand white rabbits (n = 12) were injected with, ultrasonography localization, 0.150 ml of collagenase into the Achilles tendon. The collagenase-induced Achilles tendinopathy (3 weeks) was treated with percutaneous ultrasonic debridement. The tendons were harvested, at 3 weeks after treatment, and were subjected to histological assessment (modified Movin score) and biochemical analysis (collagen isoform content).

Results

Histopathological examination revealed that all tendons injected with collagenase showed areas of hypercellularity and focal areas of tendon disorganization and degeneration. The treated tendons had lower (improved) histopathological scores than injured tendons (P < 0.001). Western blot analysis showed that ultrasonic therapy restored, within statistical limits, collagen type I, III, and X expressions in a treated tendon, to qualitative and semi-quantitative levels of a normal tendon.

Conclusions

We were successfully able to create a collagenase-injected tendinopathy lesion in a rabbit Achilles tendon and visualize the lesion with an ultrasound probe. A 19-gauge ultrasonic probe was inserted into the tendinopathic lesion under direct ultrasound guidance, and minimal tendinopathic debris remained after treatment. The treated tendon demonstrated a normalized qualitative and semi-quantitative collagen profile and improved histological appearance in the short term. This technique demonstrates scientific merit with respect to the minimally invasive treatment of tendinopathy and warrants further studies.

Clinical relevance

Recalcitrant tendinopathy has evaded consistent non-operative treatment since the tendinopathic debris remains in situ, to some extent, with non-operative approaches. This percutaneous emulsification/evacuation approach, under direct ultrasound visualization, has the potential to cure recalcitrant tendinopathies without open surgery, which would benefit the patient and result in significant healthcare cost reductions.

Macroscopic Anomalies and Pathological Findings in and Around the Achilles Tendon: Observations From 1661 Operations During a 40-Year Period

BACKGROUND

Nonsurgical treatments for chronic Achilles tendinopathy (AT) results in unpredictable success rates. Surgical treatment may be chosen as reports show mostly encouraging but variable success rates depending on the pathology. The distribution of surgically confirmed pathologies in AT is largely unknown.

PURPOSE

To ascertain the distributions of macroscopically observed anomalies in participants undergoing surgical treatment for chronic AT.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The main macroscopic pathologies of 1661 chronic Achilles tendon overuse injuries, which were diagnosed and surgically treated by a single surgeon, were reviewed. The surgeries were performed on professional and recreational athletes during the years 1976-1980, 1986-1990, 1996-2000, and 2006-2010. Surgical diagnoses, along with age- and sport-specific characteristics, were collected retrospectively from patient records.

RESULTS

The relative proportion of tendinosis increased during the study period from 4.2% to 21%, and paratenonitis decreased from 50% to 26%. Retrocalcaneal pathologies were the most common surgically confirmed lesions at 30%, while the mean age at surgery increased by 11 years over the entire study period.

CONCLUSION

Surgically confirmed pathologies in and around the Achilles tendon showed coherent changes, chronic paratenonitis, and retrocalcaneal problems as the most prevalent findings. The classification of midportion and insertional tendinopathy and retrocalcaneal bursitis in AT should strictly be used as a clinical diagnosis. During surgical evaluations, the diagnosis is further clarified as more specific pathologies may be identified.

Treatment of tendinopathies with platelet-rich plasma

Pain and dysfunction related to tendinopathy are often refractory to traditional treatments and offer a unique challenge to physicians, because no gold standard treatment exists. Injectable biologics may represent a new modality in conjunction with a multifaceted treatment approach. Platelet-rich plasma (PRP) injections are not associated with the systemic or tendon degradation risks of corticosteroids or the inherent risks of surgery. Studies are promising but have not been replicated with high-powered evidence at the clinical level. Further evidence to expand understanding of the role of PRP in the treatment of tendinopathy is needed.

The effect of tenocyte/hyaluronic acid therapy on the early recovery of healing Achilles tendon in rats

The aim of this study was to explore the potential for a better recovery outcome for the Achilles tendon at an early healing stage when a mixed biomaterial-tenocyte injection is used. The experimental animals underwent single limb Achilles tendon transection followed by suturing repair. A solution of either hyaluronic acid with or without tenocytes or normal saline was randomly chosen to be injected around the injury site after surgery. To obtain the comprehensive recovery condition of the rats on different management protocols, the animals were evaluated histologically, mechanically, and functionally. A significant difference in the recovery condition was found in the injured tendon injected with the hyaluronic acid solution with tenocytes compared with the other groups. Tendon stiffness and the locomotion abilities of the rats with healing Achilles tendons were improved in the hyaluronic acid with tenocyte transplantation group. The acceleration of the inflammatory phase in rats with the hyaluronic acid with tenocyte injections might be the major reason for the better functional outcomes.

CHELT therapy in the treatment of chronic insertional Achilles tendinopathy

The application of laser therapy on soft tissue is used for pain relief, anti-inflammation action and biostimulation. The efficiency of High Energy Laser Therapy has not yet been studied on Achilles tendinopathy. The aim of the study is to evaluate the effectiveness of a flow of Cold air and High Energy Laser Therapy (CHELT) versus Extracorporeal Shock Waves Therapy (ESWT) in the treatment of Achilles tendinopathy. In this prospective, clinical trial, 60 subjects affected by insertional Achilles tendinopathy were enrolled and randomized to CHELT (30 subjects) or to ESWT (30 subjects). In CHELT group the patients received ten daily sessions of 1,200 J and 12 W of laser therapy (wavelength of 1,084, 810 and 980 nm) added to a flow of cold air at -30 °C. In the ESWT group, the patients received three sessions at 3- to 4-day intervals of 1,600 impulses with an energy flux density (EFD) of 0.05-0.07 mJ/mm(2). Both groups of participants performed stretching and eccentric exercises over a 2-month period. The visual analogue scale (VAS), the Ankle-Hindfoot Scale, and the Roles and Maudsley Score were measured before treatment (T0), and at end of the treatment session (T1) and 2 (T2) and 6 months (T3) after treatment during the follow-up examinations. In both groups, we found a statistically significant improvement of the VAS at T1, T2 and T3 (p < 0.01). The difference between the two groups was statistically significant in favour of the CHELT group (p < 0.001). At 2 months, the CHELT group was statistically better for Ankle-Hindfoot Scale and the Roles and Maudsley Score (p < 0.05) and at 6 months only for the Roles and Maudsley Score (p < 0.001). High Energy Laser Therapy gave quicker and better pain relief. It also gave the patient a full functional recovery and greater satisfaction.

Multiple percutaneous longitudinal tenotomies for chronic Achilles tendinopathy in runners: a long-term study

BACKGROUND

Multiple percutaneous longitudinal tenotomies have been successfully undertaken in runners with isolated midportion Achilles tendinopathy (nodular lesions <2.5 cm) without any sign of paratendinopathy.

HYPOTHESIS

In the long term, minimally invasive multiple tenotomies allow the patient to remain involved in middle- and long-distance running. Clinical and ultrasound (US) evidence of paratendinopathy is a negative prognostic factor.

STUDY DESIGN

Case series study; Level of evidence, 4.

METHODS

A total of 39 patients were reviewed at an average follow-up of 17 years (range, 15-22 years) after US-guided multiple percutaneous longitudinal tenotomies for chronic Achilles tendinopathy. The Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire was completed by each patient, maximum calf circumference and isometric plantarflexion strength of the gastrocsoleus complex were measured in both the affected and contralateral legs, and functional assessment was scored by the 4-point Boyden scale. Achilles tendon changes were also assessed according to the grayscale US grading system.

RESULTS

At the final follow-up, the maximum calf circumference and the strength in the operated leg were not significantly different than those measured preoperatively, but they were significantly lower than those on the contralateral side. This did not affect patients' daily or sports activities. All patients had returned to their preinjury working occupation; 20 patients were still active in middle- and long-distance running, with an average current level of sport and function that was 60% ± 13% compared with baseline status (before onset of symptoms). Thirty of 39 patients (77%) reported good or excellent outcomes according to the Boyden assessment. On US assessment, the tendon was generally thicker than the contralateral asymptomatic tendon (average, 7.0 vs 8.7 mm, respectively; P = .003). There was no significant difference (P > .05) when comparing patients with good or excellent Boyden results versus those with fair or poor outcomes. The mean VISA-A score was 78.5, with no significant difference between patients with and without paratendinopathy on US assessment (P > .05). All of the patients who did not return to running or who gave up sports activities had signs of paratendinopathy.

CONCLUSION

This approach to the management of midportion Achilles tendinopathy is safe, has a low cost, and is effective in the long term.

What is the best clinical test for Achilles tendinopathy?

BACKGROUND

Differential diagnosis of Achilles pathology is demanding. This study evaluates the diagnostic accuracy of clinical tests identified for a chronic mid body Achilles tendinopathy. Ultrasound scanning provides the reference standard.

METHODS

Twenty-one participants with, and without, an Achilles tendinopathy, had an ultrasound scan followed immediately by the application of ten clinical tests. The accuracy and reproducibility of each test was determined.

RESULTS

The most valid tests are; pain on palpation of the tendon (sensitivity 84%, specificity 73%, kappa 0.74-0.96) and the subjective reporting of pain 2-6 cm above the insertion into the calcaneum (sensitivity 78%, specificity 77%, kappa 0.75-0.81).

CONCLUSION

Only location of pain and pain on palpation were found to be sufficiently reliable and accurate, to be recommended for use.

Surgical treatment of chronic achilles tendinopathy: long-term results of the endoscopic technique

Surgery has long been established as a valid alternative for chronic Achilles tendinopathies that have failed conservative treatment. Endoscopic procedures have shown satisfactory preliminary results for managing such injuries. The aim of the present study was to evaluate the long-term clinical outcomes of endoscopic surgery in patients with chronic midportion Achilles tendinopathy. We evaluated 27 endoscopic procedures in 24 patients (mean age 45.5 ± 8.9 years; 12 males and 12 females) with chronic Achilles tendinopathy and at least 5 (mean 7.7, range 5 to 14) years of follow-up. All ambulatory procedures consisted of paratenon debridement and longitudinal tenotomies. The clinical evaluation included 2 specific functional rating systems (the Achilles Tendon Scoring System and the Victorian Institute Sport Assessment-Achilles questionnaire) and a pain visual analog scale. Patient satisfaction with the procedure was assessed using a patient global assessment response to therapy Likert scale score. All patients had an improved clinical outcome at the final follow-up visit. Both scoring systems showed significant improvement in all clinical outcomes at the last follow-up visit. The Victorian Institute Sport Assessment-Achilles questionnaire score had improved from 37.0 ± 4.9 points preoperatively to 97.5 ± 12.1 points postoperatively (p = .0006). The Achilles Tendon Scoring System score had improved from 32.6 ± 13.1 points preoperatively to 97.2 ± 12.3 points postoperatively (p = .000006). The pain visual analog scale score averaged 0.2 ± 1.1, and the patient global assessment response to therapy score was 0.25 ± 0.71. The percentage of patients with an excellent patient global assessment response to therapy score was 85.1%. Two postoperative problems were reported (7.4%): a delayed keloid lesion and a seroma with chronic fistula. The infection rate and systemic complication rate were 0%. In conclusion, endoscopic surgery provided a high rate of excellent long-term results in patients with chronic midportion Achilles tendinopathy. Debridement of the paratenon and crural fascia, along with longitudinal tenotomies, using a minimally invasive procedure provided completely resolution of symptoms at 7 years postoperatively in 96% of patients in the present consecutive series.

Utility of an optically-based, micromechanical system for printing collagen fibers

Collagen's success as the principal structural element in load-bearing, connective tissue has motivated the development of numerous engineering approaches designed to recapitulate native fibril morphology and strength. It has been shown recently that collagen fibers can be drawn from monomeric solution through a fiber forming buffer (FFB), followed by numerous additional treatments in a complex serial process. However, internal fibril alignment, packing and resultant mechanical behavior of the fibers have not been optimized and remain inferior to native tissue. Further, no system has been developed which permits simultaneous application of molecular crowding, measurement of applied load, and direct observation of polymerization dynamics during fiber printing. The ability to perform well-controlled investigations early in the process of fiber formation, which vary single input parameters (i.e. collagen concentration, crowding agent concentration, draw rate, flow rate, temperature, pH, etc.) should substantially improve fiber morphology and strength. We have thus designed, built, and tested a versatile, in situ, optically-based, micromechanical assay and fiber printing system which permits the correlation of parameter changes with mechanical properties of fibers immediately after deposition into an FFB. We demonstrate the sensitivity of the assay by detecting changes in the fiber mechanics in response to draw rate, collagen type, small changes in the molecular crowding agent concentration and to variations in pH. In addition we found the ability to observe fiber polymerization dynamics leads to intriguing new insights into collagen assembly behavior.

Stem cell therapy for tendon injury

Tendon injury may occur suddenly or progressively, and can be divided into tendon rupture or tendinopathy based on the severity of injury. It is frequently found in professional or nonprofessional people who are making repetitive movements. In aged people, tendon degeneration becomes obvious; their tendon injuries are then frequently evident. No effective therapies for tendon injury are currently available. In this article, we review the tendon structure, mechanisms of tendon injury, and tendon healing process. More importantly, cell-based therapies for tendon injury are fully addressed, which will play an important role for tendon therapy in the near future.

SWAAT study: extracorporeal shock wave therapy and arginine supplementation and other nutraceuticals for insertional Achilles tendinopathy

INTRODUCTION

Extracorporeal shockwave therapy (ESWT) produces good results in the treatment of insertional Achilles tendinopathy. The efficacy of combined administration of dietary supplements with ESWT has not yet been studied.

METHODS

In this prospective, randomized clinical trial, Shock Waves therapy and Arginine for Achilles Tendinopathy (SWAAT), subjects affected by insertional Achilles tendinopathy were enrolled. Between January and October 2011, all participants underwent three sessions of ESWT. In addition, the patients in the experimental group received a daily dietary supplement containing arginine, Vinitrox (Bio Serae Laboratories SAS, Bram, France), collagen, methyl-sulfonyl-methane, vitamin C, and bromelain, while the control group patients received placebo.

RESULTS

There was no statistically significant difference in the visual analog scale (VAS) score between the two groups at 2 months (3.9 vs. 5.1; P=0.07), whereas at 6 months the value was significantly lower in the experimental group (2.0 vs. 2.9; P=0.04). The difference in the Ankle-Hindfoot Scale score at 2 and 6 months of follow-up (FU) was significantly in favor of the experimental group (2 months: 85.4 vs. 72.1; P=0.0035; 6 months: 92.4 vs. 76.5; P=0.0002). The Roles and Maudsley score also showed a statistically significant difference between the two groups in favor of the experimental arm as regards patient satisfaction (at 2 months: 1.7 vs. 2.8; P<0.0001; at 6 months: 1.5 vs. 2.3; P<0.001). There was a statistically significant reduction in tissue oximetry values compared to baseline in both treatment groups at 2 and 6 months of FU. Comparing the groups, only at the last FU, at 6 months, was a significantly lower oximetry value observed in the experimental group versus controls (60.2 vs. 66.0; P=0.007).

CONCLUSION

On the basis of the results obtained in this study, the authors conclude that in the treatment of insertional Achilles tendinopathy, ESWT induces a hemodynamic re-equilibrium with an amelioration in tendon trophism [corrected]. The addition of specific dietary supplements could improve the therapeutic response.

Histopathology of rotator cuff tears

The pathogenesis of rotator cuff tears is multifactorial. Tendon abnormalities of the rotator cuff include alteration of collagen fiber structure, tenocytes, cellularity, and vascularity. Ruptured tendons show marked collagen degeneration and disordered arrangement of collagen fibers. Fibroblast population decreases as the size of the tear in the rotator cuff increases. The larger fibroblast population seen in the smaller tears is also actively proliferating and is part of an active reparative process. Inflammatory cell infiltrate correlates inversely to rotator cuff tear size in the torn supraspinatus tendon samples, with larger tears showing a marked reduction in all cell types. As tear size increase, there is also a progressive decrease in the number of blood vessels. Whether rotator cuff tear heals spontaneously is an important pathologic and clinical question. Histologic changes indicative of repair and inflammation lead to consider biological options in addition to biomechanical treatment of the rotator cuff tears.

The role of pro-inflammatory and immunoregulatory cytokines in tendon healing and rupture: new insights

Owing to limited self-healing capacity, tendon ruptures and healing remain major orthopedic challenges. Increasing evidence suggests that post-traumatic inflammatory responses, and hence, cytokines are involved in both cases, and also in tendon exercise and homeostasis. This review summarizes interrelations known between the cytokines interleukin (IL)-1β, tumor necrosis factor (TNF)α, IL-6 and vascular endothelial growth factor (VEGF) in tendon to assess their role in tendon damage and healing. Exogenic cytokine sources are blood-derived leukocytes that immigrate in damaged tendon. Endogenous expression of IL-1β, TNFα, IL-6, IL-10 and VEGF was demonstrated in tendon-derived cells. As tendon is a highly mechanosensitive tissue, cytokine homeostasis and cell survival underlie an intimate balance between adequate biomechanical stimuli and disturbance through load deprivation and overload. Multiple interrelations between cytokines and tendon extracellular matrix (ECM) synthesis, catabolic mediators e.g. matrix-degrading enzymes, inflammatory and angiogenic factors (COX-2, PGE2, VEGF, NO) and cytoskeleton assembly are evident. Pro-inflammatory cytokines affect ECM homeostasis, accelerate remodeling, amplify biomechanical adaptiveness and promote tenocyte apoptosis. This multifaceted interplay might both contribute to and interfere with healing. Much work must be undertaken to understand the particular interrelation of these inflammatory and regulatory mediators in ruptured tendon and healing, which has relevance for the development of novel immunoregulatory therapeutic strategies.

Mid-portion Achilles tendinopathy: why painful? An evidence-based philosophy

Chronic mid-portion Achilles tendinopathy is generally difficult to treat as the background to the pain mechanisms has not yet been clarified. A wide range of conservative and surgical treatment options are available. Most address intratendinous degenerative changes when present, as it is believed that these changes are responsible for the symptoms. Since up to 34% of asymptomatic tendons show histopathological changes, we believe that the tendon proper is not the cause of pain in the majority of patients. Chronic painful tendons show the ingrowth of sensory and sympathetic nerves from the paratenon with release of nociceptive substances. Denervating the Achilles tendon by release of the paratenon is sufficient to cause pain relief in the majority of patients. This type of treatment has the additional advantage that it is associated with a shorter recovery time when compared with treatment options that address the tendon itself. An evidence-based philosophy on the cause of pain in chronic mid-portion Achilles tendinopathy is presented. Level of evidence V.

Cycle-dependent matrix remodeling gene expression response in fatigue-loaded rat patellar tendons

Expression profiling of selected matrix remodeling genes was conducted to evaluate differences in molecular response to low-cycle (100) and high-cycle (7,200) sub-failure-fatigue loading of patellar tendons. Using our previously developed in vivo patellar tendon model, tendons were loaded for 100 or 7,200 cycles and expression of selected metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and collagens were quantified by real-time RT-PCR at 1- and 7-day post-loading. Expression profiles were also obtained from lacerated tendons as an acute injury model. The high-cycle group showed upregulation of TIMP-1, -2, Col3a1, and Col5a1, and downregulation TIMP-4 at both time points, upregulation of MMP-2 at 7-day post-loading and downregulation of MMP-13 and -14 at 1-day post-loading, suggesting overall repair/remodeling. In contrast, the low-cycle loaded group showed upregulation of MMP-2, -3, -13, and Col12a1 at both time points, upregulation of TIMP-1, -2, -3, Col3a1, and integrin β1 and downregulation of integrin α11 at 1-day post-loading and upregulation of Col1a1 at 7-day post-loading, consistent with a hypertrophic (adaptive) pattern. Lacerated tendons showed a typical acute wound response with upregulation of all examined remodeling genes. Differences found in tendon response to high- and low-cycle loading are suggestive of the underlying mechanisms associated with a healthy or damaging response.

Anatomy and biomechanical aspects of the gastrocsoleus complex

The complexity of its anatomy coupled with the biomechanics of the Achilles tendon may explain the frequency of injury to this structure. Its unique characteristic of the muscle crossing three joints (knee, ankle, and subtalar joints) makes it more susceptible to injury than muscles that span a single joint. A better understanding of the contributing pathologic conditions associated with functional shortening of the gastroc-soleus complex and its effects on the normal biomechanics of the foot and ankle may improve the treatment of the many and varied pathologies that occur within the tendon itself and the associated abnormalities that occur with a tight Achilles tendon.