Changes In Tendon Structure Research Articles

Effects of Training Load and Leg Dominance on Achilles and Patellar Tendon Structure.

Detrimental changes in tendon structure increase the risk of tendinopathies. The aim of this study was to investigate the influence of individual internal and external training loads and leg dominance on changes in the Achilles and patellar tendon structure. The internal structure of the Achilles and patellar tendons of both limbs of 26 elite Australian footballers was assessed using ultrasound tissue characterization at the beginning and the end of an 18-wk preseason. Linear-regression analysis was used to estimate the effects of training load on changes in the proportion of aligned and intact tendon bundles for each side. Standardization and magnitude-based inferences were used to interpret the findings. Possibly to very likely small increases in the proportion of aligned and intact tendon bundles occurred in the dominant Achilles (initial value 81.1%; change, ±90% confidence limits 1.6%, ±1.0%), nondominant Achilles (80.8%; 0.9%, ±1.0%), dominant patellar (75.8%; 1.5%, ±1.5%), and nondominant patellar (76.8%; 2.7%, ±1.4%) tendons. Measures of training load had inconsistent effects on changes in tendon structure; eg, there were possibly to likely small positive effects on the structure of the nondominant Achilles tendon, likely small negative effects on the dominant Achilles tendon, and predominantly no clear effects on the patellar tendons. The small and inconsistent effects of training load are indicative of the role of recovery between tendon-overloading (training) sessions and the multivariate nature of the tendon response to load, with leg dominance a possible influencing factor.

What tendon pathology is seen on imaging in people who have taken fluoroquinolones? A systematic review.

Fluoroquinolones (FQs) are highly effective broad-spectrum antibiotics. Clinical data reveal an increased incidence of tendon pain and rupture in those taking FQs, yet little is known about tendon structural changes. This review synthesises published data on tendon structural changes in people who have taken FQs. Eight databases were searched for potentially relevant articles (Medline, CINAHL, Biological Abstracts, AMED, Web of Knowledge, SCOPUS, SportDiscus and EMBASE) using MeSH and free-text searches. Inclusion and exclusion criteria determined which articles were used for this review. Twenty-six papers met the eligibility criteria. The Achilles tendon was most commonly affected, and ciprofloxacin and levofloxacin were the most commonly implicated FQs. Mean time to onset of symptoms was 16 days following first FQ dose. Imaging modalities used included magnetic resonance imaging (MRI), B-mode ultrasound (US) and computed tomography (CT). Tendon measurements were rarely reported, and intratendinous imaging findings were not reported in a consistent manner. Few studies imaged tendons bilaterally, and only two studies were longitudinal in design. Future studies should report imaging measures such as thickness and cross-sectional area and use consistent descriptions of intratendinous changes during and post-FQ treatment.

Ultrasound assessment for grading structural tendon changes in supraspinatus tendinopathy: an inter-rater reliability study

AimTo evaluate the inter-rater reliability of measuring structural changes in the tendon of patients, clinically diagnosed with supraspinatus tendinopathy (cases) and healthy participants (controls), on ultrasound (US) images captured by...

Structural tendon changes in patients with acromegaly: assessment of Achilles tendon with sonoelastography.

To describe the sonoelastographic appearance of the Achilles tendon in acromegalic patients and to determine whether the blood concentrations of growth hormone (GH) and insulin-like growth factor (IGF-1) are associated with the various sonographic elasticity types of Achilles tendons. Eighty-four Achilles tendons of 42 acromegaly patients and 84 Achilles tendons of 42 healthy volunteers were assessed with sonoelastography. The tendons were classified into two main types according to the elasticity features: type 1 blue/green (hard tissue) and type 2 yellow/red within green (intermediate-soft tissue). Two subtypes of these types were also defined. According to the definition, the elasticity of the tissue was in a spectrum ranging from hard to soft as the type progressed from 1a to 2b. The mean thickness of Achilles tendons in patients with acromegaly was significantly higher compared with healthy Achilles tendons (5.1+/-0.7 mm vs. 4.4+/-0.5, p<0.001), and patients with active disease had thicker Achilles tendons (5.5+/-0.8 mm vs. 4.8+/-0.5 mm in inactive disease, p=0.003). A significantly higher proportion of acromegaly patients had type 2 sonoelastographic appearance of the Achilles tendon (124/252 third; 49.2% vs. 81/252 third; 32.1%, p=0.0001). Activity status of acromegaly and GH/IGF-I levels were similar in patients with different types of elasticity (p>0.05). Sonoelastography revealed structural changes in the tendinous tissue of patients with acromegaly, but it was not sensitive enough to reflect changes in the serum levels of GH/IGF-1.

Extended field of view ultrasound imaging to evaluate Achilles tendon length and thickness: a reliability and validity study.

Achilles tendon structural changes are common after injury and correlate with recovery of function. Having simple, inexpensive, yet valid and reliable measures of Achilles tendon structure are useful both in research and clinical. The purpose of this study was to perform reliability and validity measures of extended field of view (EFOV) ultrasound (US) imaging of the Achilles tendon. eight cadavers (16 tendons) were used for the validation study to compare Achilles tendon length measurements from US images with actual measured length from dissected tendons. Nine healthy subjects (18 tendons) were included in the test-retest evaluation. the correlation between the US images and cadaveric measurements was excellent (ICC=0.895) for the length between calcaneus and the gastrocnemius and good (ICC=0.744) for the length between the calcaneus and the soleus. The between-limb reliability was excellent (ICC 0.886-0.940) for the tendon length measurements with standard error of measurements (SEM) of 0.64 cm for calcaneus to soleus and 0.67 cm for calcaneus to gastrocnemius. Between-day test-retest reliability was also excellent (ICC=0.898-0.944). this study supports the use of EFOV US imaging as a reliable and valid method to determine Achilles tendon length and thickness, and using the uninjured limb for comparison.

Preventive interventions for tendinopathy: A systematic review.

Tendinopathy, the most prevalent tendon disorder which is considered as the clinical diagnosis of pain and dysfunction, is common in sports and its prevalence is ever-increasing. Despite the lack of clarity about risk factors, various preventive interventions for tendinopathy have been investigated. The main objective of this study is to review current preventive interventions for tendinopathy in the major regions: ankle, knee, hip, groin, shoulder and elbow. A systematic literature search was conducted. The PubMed and Embase databases were explored to identify articles that met the inclusion criteria. The included studies were assessed on methodological quality and data was summarized. Ten articles were included that describe a wide variety of preventive interventions. These were divided into three categories: stretch and exercise interventions, shoe adaptations and other interventions. The methodological quality of the studies was moderate to high. Three out of ten studies showed a significant beneficial result. There is limited evidence that a long-term intervention including balance training is effective in the prevention of patellar and Achilles tendinopathy. Shoe adaptations in the form of shock absorbing insoles could have a preventive effect on Achilles tendinopathy. Hormone replacement therapy seems to reduce the risk for structural Achilles tendon changes in active post-menopausal women. No evidence was found for a positive effect of stretching exercises. Prophylactic eccentric training and stretching can increase the risk of injury in asymptomatic players with patellar tendon abnormalities. A limited amount of studies was available and more research is needed on (multifactorial) etiology, risk factors and preventive interventions.

Structural integrity is decreased in both Achilles tendons in people with unilateral Achilles tendinopathy.

A high proportion of Achilles tendinopathy patients develop bilateral symptoms with human and animal studies showing bilateral histological changes associated with overuse/pathology in one tendon. The current study examined changes in tendon structure, assessed semi-quantitatively using ultrasound tissue characterisation, in both the symptomatic and asymptomatic tendon in unilateral Achilles tendinopathy patients in comparison to individuals with no history of tendinopathy. Cross-sectional case-control study. Participants with Achilles tendinopathy (n=21), with varying severity and length of clinical symptoms, and six participants with no history of tendinopathy were recruited. Tendons were scanned using ultrasound tissue characterisation, which captures contiguous transverse ultrasound images every 0.2mm and renders a 3-dimensional image. Ultrasound tissue characterisation quantifies tendon structure by measuring the stability of echopattern over contiguous transverse images. Four echo-types were discriminated and expressed as a percentage. Antero-posterior diameter of all tendons was measured. Significant differences were observed in the proportion of normal tendon structure between all three groups (p<0.01), with the symptomatic tendon containing the least amount of normal tendon structure (symptomatic - 79.5%, asymptomatic - 81.8%, control - 86.4%). The asymptomatic tendon contained significantly less normal tendon in comparison to the control tendon (p=0.008), suggesting the asymptomatic tendon is structurally compromised despite the absence of symptoms. Both Achilles tendons are structurally compromised in patients with unilateral Achilles tendinopathy. Future studies need to investigate whether these changes increase the risk of developing symptoms.

AB0708 Differences in Localization and Activity of the Entheseal Involvement between Non-Radiographic and Radiographic Axial Spondyloarthritis by the Ultrasound Assessment

BackgroundPeripheral entheseal involvement seems to be an important sign of spondyloarthritis (SpA). It may occur in patients with long-term as well as newly diagnosed disease and in those with definite...

AB0798 Association between Knee Osteoarthritis and Achilles Tendinopathy

BackgroundIn our clinical practice, we noticed that individuals with symptomatic knee osteoarthritis (OA) frequently complain on pain or swelling above Achilles tendon. We found no studies that evaluated association between...

CSM 2014 Orthopaedic Section Poster Presentations (OPO1106–OPO1165, OPO2218–OPO2298, OPO3106–OPO3183)

CSM 2014 Orthopaedic Section Poster Presentations (OPO1106–OPO1165, OPO2218–OPO2298, OPO3106–OPO3183)

The Effect of Lubricin on the Gliding Resistance of Mouse Intrasynovial Tendon

The purpose of this study was to investigate the role of lubricin on the gliding resistance of intrasynovial tendons by comparing lubricin knockout, heterozygous, and wild type mice. A total of thirty-six deep digital flexor (DDF) tendons in the third digits of each hind paw from eighteen adult mice were used, including six lubricin knockout mice (Prg4 –/–), six heterozygous mice (Prg4 +/–), and six wild type mice (Prg4 +/+). The tendon gliding resistance was measured using a custom-made device. Tendon structural changes were evaluated by scanning electron and light microscopy. The gliding resistance of intrasynovial tendons from lubricin knockout mice was significantly higher than the gliding resistance of either wild type or heterozygous mice. The surface of the lubricin knockout tendons appeared to be rougher, compared to the wild type and heterozygous tendons. Synovial hyperplasia was found in the lubricin knockout mice. Cartilage-like tissue was found in the tendon and pulley of the lubricin knockout mice. Our findings confirm the importance of lubricin in intrasynovial tendon lubrication. This knockout model may be useful in determining the effect of lubricin on tendon healing and the response to injury.

When pictures tell more than a thousand words: The clinical role of imaging for tendinopathy and emergence of UTC

This workshop will discuss the importance and relevance of imaging modalities in the diagnosis and management of lower limb tendinopathy. Included is a practical demonstration of ultrasound tissue characterisation (UTC) in imaging the Achilles and patellar tendon with detailed input from Prof Jill Cook and Ebonie Rio on the conservative and intervention management directed by findings on UTC. UTC utilises conventional ultrasound to render a 3-dimensional image of the tendon and allows semi-quantitative analysis of tendon structure and detection of subtle changes in tendon structure in response to load.

Football for health – A global health initiative of FIFA

Department of Physiotherapy, Monash University, Australia This workshop will discuss the importance and relevance of imaging modalities in the diagnosis and management of lower limb tendinopathy. Included is a practical demonstration of ultrasound tissue characterisation (UTC) in imaging the Achilles and patellar tendon with detailed input from Prof Jill Cook and Ebonie Rio on the conservative and intervention management directed by findings on UTC. UTC utilises conventional ultrasound to render a 3-dimensional image of the tendon and allows semi-quantitative analysis of tendon structure and detection of subtle changes in tendon structure in response to load. Previous research utilising conventional ultrasound and MRI will be discussed as well as the emergence of UTC in the clinical setting.

Tendon structural adaptations to load exercise are inhibited by anabolic androgenic steroids

The present study investigated the structural changes in the rat calcaneal tendon (CT), superficial flexor tendon (SFT), and deep flexor tendon (DFT) in response to jump exercises and anabolic androgenic steroids (AAS). Animals were divided into four groups: sedentary, trained, AAS-treated sedentary rats, and AAS-treated trained animals. Training increased the volume density (Vv%) of blood vessels in all regions of the CT and DFT, cell Vv% in the peritendinous sheath of the proximal and distal regions of the SFT and proximal region of DFT, and cell Vv% in the tendon proper of the proximal and distal regions of the SFT and DFT. The combination of AAS and load exercises showed little increased blood vessel Vv% at the proximal region of the CT, intermediate region of the SFT, and all regions of the DFT as opposed to an increase in adipose cell Vv% in the CT proximal region. The AAS reduced the levels of hydroxyproline in the proximal region of the DFT and in the distal region of the STF. In conclusion, exercise promoted benefits to the adaptation of the tendons to overload. These effects were absent when load exercise was combined with AAS. The abusive consumption of AAS contributes to tendon inertness and rigidity, and increases the potential risk of injury.

BILATERAL CHANGES IN UNILATERAL ACHILLES TENDINOPATHY QUANTIFIED USING ULTRASOUND TISSUE CHARACTERISATION

IntroductionAchilles tendinopathy is a prevalent musculoskeletal injury in the young athletic population as well as older individuals. A high proportion of individuals develop symptoms within both Achilles tendons as well...

TENDON RESPONSE IN ACHILLES TENDON OF AUSTRALIAN FOOTBALL PLAYERS USING ULTRASOUND TISSUE CHARACTERISATION

IntroductionThe Achilles tendon is an elastic storage tendon that converts kinetic energy into mechanical energy and reduces the metabolic cost of high-speed locomotion. Numerous studies have shown that the tendon...

Sonographic examination of the common extensor tendon of the forearm at three different locations in the normal asymptomatic population

The aim is to examine the common extensor tendon (CET) thicknesses at three locations in the normal population with ultrasound (US), to determine changes related to dominancy, age, gender, body mass index and to evaluate structural changes in normal tendons. The study included 100 normal volunteers (200 elbows). CET was examined at three landmark locations bilaterally (humeral, articular and radial) and if present, other structural abnormalities such as tendinosis (focal or diffuse tendon echogenicity changes), tears, bone changes (enthesophytes, spurs, irregularities), tendon calcification, effusion and neovascularization were noted. Common extensor tendon was thicker on the dominant side at all three locations (humeral 4.60 versus 4.22 mm, articular 3.55 versus 3.23 mm, radial 3.17 versus 2.88 mm, p < 0.001) and gradually tapered from proximal to distal, moderate relation with age and BMI was present, most pronounced at the humeral location. Bone changes (spurs, irregularities) correlated positively with age and CET thickened in the dominant arm after 42.5 years of age which was also a cut-off age for bone changes (p < 0.05). Asymptomatic tendinosis (12%) within the normal population was significantly related to the dominancy (p = 0.032) but was not influenced by age, gender, BMI, bone degeneration or tendon thickening. When interpreting CET thickness, caution should be placed on tendon measurement points in addition to variables such as age, gender, BMI, dominancy and bone changes. Structural tendon changes (tendinosis) may be encountered in the symptom free (healthy), normal population and, not tendon thickening but dominancy is a feature of this asymptomatic tendinosis.

Overweight and obesity alters the cumulative transverse strain in the Achilles tendon immediately following exercise

This research evaluated the effect of obesity on the acute cumulative transverse strain of the Achilles tendon in response to exercise. Twenty healthy adult males were categorized into 'low normal-weight' (BMI <23kgm(-2)) and 'overweight' (BMI >27.5kgm(-2)) groups based on intermediate cut-off points recommended by the World Health Organization. Longitudinal sonograms of the right Achilles tendon were acquired immediately prior and following weight-bearing ankle exercises. Achilles tendon thickness was measured 20-mm proximal to the calcaneal insertion and transverse tendon strain was calculated as the natural log of the ratio of post- to pre-exercise tendon thickness. The Achilles tendon was thicker in the overweight group both prior to (t18=-2.91, P=0.009) and following (t18=-4.87, P<0.001) exercise. The acute transverse strain response of the Achilles tendon in the overweight group (-10.7±2.5%), however, was almost half that of the 'low normal-weight' (-19.5±7.4%) group (t18=-3.56, P=0.004). These findings suggest that obesity is associated with structural changes in tendon that impairs intra-tendinous fluid movement in response to load and provides new insights into the link between tendon pathology and overweight and obesity.

Normal aging alters in vivo passive biomechanical response of the rat gastrocnemius-Achilles muscle–tendon unit

Predisposition to Achilles tendon (AT) ruptures in middle-aged individuals may be associated with age-related changes to inherent passive biomechanical properties of the gastrocnemius-Achilles (GC-AT) muscle–tendon unit, due to known muscle–tendon structural changes in normal aging. The goal of this study was to determine whether the passive biomechanical response of the GC-AT muscle–tendon unit was altered with age in 6 young (8 months) and 6 middle-aged (24 months) F344xBN hybrid rats from the National Institute on Aging colony. Fung's quasilinear viscoelastic (QLV) model was used to determine in vivo history and time-dependent load-relaxation response of the GC-AT. Effective stiffness and modulus were also estimated using linear regression analysis. Fung's QLV revealed a significantly decreased magnitude of the relaxation response (parameter C, p=0.026) in middle-aged animals compared to young animals (0.108±0.007 vs. 0.144±0.015), with similar time-dependent viscous GC-AT properties (τ1, τ2). The product of elastic parameters (A⁎B), which represents the initial slope of the elastic response, was significantly increased by 50% in middle-aged rats (p=0.014). Estimated GC-AT stiffness increased 28% at peak tensions in middle-aged rats (2.7±0.2N/mm) compared to young rats (1.9±0.2N/mm; p=0.036). While the limitations of this animal model must be considered, the changes we describe could be associated with the observation that GC-AT pathology and injury is more common in middle-aged individuals. Further studies are necessary to characterize the load-to-failure behavior of AT in middle-aged compared to young animals.

Decorin expression is important for age-related changes in tendon structure and mechanical properties

The aging population is at an increased risk of tendon injury and tendinopathy. Elucidating the molecular basis of tendon aging is crucial to understanding the age-related changes in structure and function in this vulnerable tissue. In this study, the structural and functional features of tendon aging are investigated. In addition, the roles of decorin and biglycan in the aging process were analyzed using transgenic mice at both mature and aged time points. Our hypothesis is that the increase in tendon injuries in the aging population is the result of altered structural properties that reduce the biomechanical function of the tendon and consequently increase susceptibility to injury. Decorin and biglycan are important regulators of tendon structure and therefore, we further hypothesized that decreased function in aged tendons is partly the result of altered decorin and biglycan expression. Biomechanical analyses of mature (day 150) and aged (day 570) patellar tendons revealed deteriorating viscoelastic properties with age. Histology and polarized light microscopy demonstrated decreased cellularity, alterations in tenocyte shape, and reduced collagen fiber alignment in the aged tendons. Ultrastructural analysis of fibril diameter distributions indicated an altered distribution in aged tendons with an increase of large diameter fibrils. Aged wild type tendons maintained expression of decorin which was associated with the structural and functional changes seen in aged tendons. Aged patellar tendons exhibited altered and generally inferior properties across multiple assays. However, decorin-null tendons exhibited significantly decreased effects of aging compared to the other genotypes. The amelioration of the functional deficits seen in the absence of decorin in aged tendons was associated with altered tendon fibril structure. Fibril diameter distributions in the decorin-null aged tendons were comparable to those observed in the mature wild type tendon with the absence of the subpopulation containing large diameter fibrils. Collectively, our findings provide evidence for age-dependent alterations in tendon architecture and functional activity, and further show that lack of stromal decorin attenuates these changes.