Degenerative Achilles tendon disease: assessment by magnetic resonance and ultrasonography

Exercise Effects on the Biomechanical Properties of the Achilles Tendon—A Narrative Review

Simple Summary

The Achilles tendon influences the running economy because of its ability to store and release strain energy, and it remains one of the most vulnerable tendons among athletes and recreational runners. Exercised-related mechanical loading appears to induce changes in the Achilles tendon morphology and mechanical material properties. Both acute and relatively long-term exercise induces tendon adaptation, although biomechanical changes, e.g., cross-sectional area, plantarflexion moment, Young’s modulus, and stiffness, in response to exercise duration, type, and loading-regimes differ widely. Furthermore, a strong Achilles tendon can be developed by chronic exposure to habitual mechanical loading from daily exercise, which is associated with greater energy storage, release and overall health.

Abstract

The morphological and mechanical properties (e.g., stiffness, stress, and force) of the Achilles tendon (AT) are generally associated with its tendinosis and ruptures, particularly amongst runners. Interest in potential approaches to reduce or prevent the risk of AT injuries has grown exponentially as tendon mechanics have been efficiently improving. The following review aims to discuss the effect of different types of exercise on the AT properties. In this review article, we review literature showing the possibility to influence the mechanical properties of the AT from the perspective of acute exercise and long-term training interventions, and we discuss the reasons for inconsistent results. Finally, we review the role of the habitual state in the AT properties. The findings of the included studies suggest that physical exercise could efficiently improve the AT mechanical properties. In particular, relatively long-term and low-intensity eccentric training may be a useful adjunct to enhance the mechanical loading of the AT.

Diagnosing Achilles Tendon Rupture with Ultrasound in Patients Treated Surgically: A Systematic Review and Meta-Analysis

BACKGROUND

Achilles tendon rupture is a common injury with increasing incidence due to the rising popularity of high-velocity sports, continued physical activity of the aging American population, and use of fluoroquinolones and steroid injections. The diagnosis can often be missed or delayed, with up to 20% misdiagnosed, most commonly as an ankle sprain.

OBJECTIVE

The aim of our study was to systematically evaluate the reported sensitivity, specificity, and likelihood ratios of ultrasound for detecting Achilles tendon rupture in patients who were treated surgically.

METHODS

In January 2020, we performed a literature search of MEDLINE and EMBASE databases to identify eligible articles according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria were original studies with at least five patients, which reported data on the sonographic diagnosis of Achilles tendon rupture (complete or partial) compared to surgery as the reference standard.

RESULTS

A total of 15 studies with 808 patients were included in the primary analysis. The sensitivity of ultrasound for detecting complete Achilles tendon ruptures was 94.8% (95% confidence interval [CI] 91.3-97.2%), specificity was 98.7% (95% CI 97.0-99.6%), positive likelihood ratio was 74.0 (95% CI 31.0-176.8), and negative likelihood ratio was 0.05 (95% CI 0.03-0.09), in patients who underwent surgical treatment.

CONCLUSIONS

The results from our study suggested that a negative ultrasound result may have the potential to rule out a complete, as well as a partial, Achilles tendon rupture.

The correlations between dimensions of the normal tendon and tendinopathy changed Achilles tendon in routine magnetic resonance imaging

This comparative study aimed to investigate how tendinopathy-related lesions change correlations in the dimensions of the Achilles tendon. Our experimental group included 74 patients. The mean age was 52.9 ± 10.4 years. The control group included 81 patients with a mean age was 35.2 ± 13.6 years, p < .001. The most significant difference in correlation was the thickness of the tendon and the midportion's width, which was more significant in the tendinopathy (r = .49 vs. r = .01, p < .001). The correlation was positive between width and length of the insertion but negative in normal tendons (r = .21 vs. r = − .23, p < .001). The correlation was between the midportions width in tendinopathy and the tendon's length but negative in the normal tendon (r = .16 vs. r = − .23, p < .001). The average thickness of the midportion in tendinopathy was 11.2 ± 3.3 mm, and 4.9 ± 0.5 mm in the control group, p < .001. The average width of the midportion and insertion was more extensive in the experimental group, 17.2 ± 3.1 mm vs. 14.7 ± 1.8 mm for the midportion and 31.0 ± 3.9 mm vs. 25.7 ± 3.0 mm for insertion, respectively, p < .001. The tendon's average length was longer in tendinopathy (83.5 ± 19.3 mm vs. 61.5 ± 14.4 mm, p < .001). The dimensions correlations in normal Achilles tendon and tendinopathic tendon differ significantly.

Using Ultrasound Measurement of the Achilles Tendon in Asymptomatic Runners to Assist in Predicting Tendinopathy

OBJECTIVES

The Achilles tendon is the strongest tendon in the human body, and Achilles tendinopathy is common in athletes due to the stress imparted by repetitive forces. The prevalence of Achilles tendon abnormalities in asymptomatic elite runners is unknown. Since there is a substantial risk of developing symptomatic tendinopathy in those with abnormal tendons, identifying those asymptomatic athletes with abnormal tendons and characterizing baseline characteristics of elite runners using ultrasound (US) are valuable injury prevention tools.

METHODS

This study used US to evaluate the Achilles tendons of 27 asymptomatic National Collegiate Athletic Association Division I cross-country athletes and performed correlations between dominant and nondominant side tendon size (cross-sectional area [CSA] and thickness) and athlete characteristics. Tendons were also assessed for signs of abnormalities that were suggestive of Achilles tendinopathy.

RESULTS

The prevalence of tendon abnormalities in asymptomatic collegiate runners was 11%. Among the participants included in this study, dominant and nondominant Achilles tendons did not vary significantly in thickness or CSA (P > .05). The CSA was found to correlate with height, weight, sex, body mass index, and miles run per week (P < .05). Thickness was found to correlate best with miles run per week (P < .05).

CONCLUSIONS

A US evaluation of the Achilles tendon has potential to identify changes in tendon size in addition to abnormalities consistent with tendinopathy. As more normative values are identified among various populations, tendon size may have prognostic value for collegiate athletes in the evaluation of Achilles tendinopathy.

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.

Non-insertional Achilles tendinopathy

Non-insertional Achilles tendinopathy is a degenerative condition characterised by pain on activity.Eccentric stretching is the most effective treatment.Surgical treatment is reserved for recalcitrant cases.Minimally-invasive and tendinoscopic treatments are showing promising results. Cite this article: Pearce CJ, Tan A. Non-insertional Achilles tendinopathy. EFORT Open Rev 2016;1:383-390. DOI: 10.1302/2058-5241.1.160024.

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.

Lower limb tendinopathy in athletes

Tendinopathy is a common and debilitating problem especially affecting athletes. Understanding of the disease has increased over the past two decades with the most notable change being in the perception that the pathology of tendinopathy is of a noninflammatory origin. The most prevalent aetiological factors implicated in the development of tendinopathy in athletes are overuse and training errors. The commonest lower limb tendinopathy affects the achilles tendon closely followed by patella tendinosis. Achilles tendinopathy is usually seen in running sports whereas patella tendinopathy is commoner in sports that involve jumping. The diagnosis can be confirmed by taking a good history and clinical examination and supported by appropriate radiological imaging. The investigations of choice are ultrasonography and magnetic resonance imaging with each of the investigations having some benefit over the other depending on the questions needing to be answered for the clinician. Treatment of lower limb tendinopathy is mainly conservative and includes activity modification, correction of training errors and eccentric exercises. To date, there have not been any conclusive studies to prove the benefits of nonsteroidal anti-inflammatory drugs (NSAIDs) and steroids which are currently used to help in the management of pain. Surgical treatment has a variable success rate (45—100%) and is normally reserved as the last option if conservative modalities fail. Novel therapies like infection of sclerosing agent, Traumeel®, platelet-derived growth factors (PDGF) or autologous blood injections into diseased tendons are showing promising results but need more multicentre clinical trials to evaluate their efficacy.

Real-time sonoelastography in the diagnosis of rotator cuff tendinopathy

BACKGROUND

Real-time sonoelastography can be used to assess tissue elasticity. The present study evaluated the relationship between tendon stiffness on sonoelastography and the magnetic resonance imaging (MRI) tendinosis grade in patients with rotator cuff tendinopathy.

METHODS

The study included 39 patients with chronic pain and no history of trauma or rotator cuff tear. The supraspinatus tendons were graded according to MRI findings (grade 0, normal; grade 1, mild tendinosis; grade 2, moderate tendinosis; grade 3, marked tendinosis), and the subcutaneous fat-to-tendon (Fat/T) and gel pad-to-tendon (Pad/T) strain ratios were assessed. We used the trend test to analyze the relationship of the MRI grade with the Fat/T strain ratio and the Pad/T strain ratio.

RESULTS

Of the 39 patients, 9 had grade 0, 17 had grade 1, 12 had grade 2, and 1 had grade 3 tendinosis. The mean real-time elastography Fat/T and Pad/T strain ratios were 2.92 ± 2.13 and 20.77 ± 21.78 in patients with grade 0 tendinosis, 4.08 ± 4.09 and 21.78 ± 17.16 in patients with grade 1 tendinosis, 13.48 ± 10.19 and 83.00 ± 48.26 in patients with grade 2 tendinosis, and 12.3 ± 0.00 and 16.58 ± 0.00 in patients with grade 3 tendinosis, respectively. The Fat/T and Pad/T strain ratios were positively associated with the MRI grade (P <.001).

CONCLUSION

The MRI tendinosis grade is associated with stiffness assessed using sonoelastography in patients with rotator cuff tendinopathy. Therefore, sonoelastography might be a useful diagnostic tool for supraspinatus tendinopathy.

LEVEL OF EVIDENCE

Level III; Diagnostic Study.

Tendinopathy: Is Imaging Telling Us the Entire Story?

Synopsis Tendinopathy is frequently associated with structural disorganization within the tendon. As such, the clinical use of ultrasound and magnetic resonance imaging for tendinopathy has been the focus of numerous academic studies and clinical discussions. However, similar to other musculoskeletal conditions (osteoarthritis and intervertebral disc degeneration), there is no direct link between tendon structural disorganization and clinical symptoms, with findings on imaging potentially creating a confusing clinical picture. While imaging shows the presence and extent of structural changes within the tendon, the clinical interpretation of the images requires context in regard to the features of pain and the aggravating loads. This review will critically evaluate studies that have investigated the accuracy and sensitivity of imaging in the detection of clinical tendinopathy and the methodological issues associated with these studies (subject selection, lack of a robust gold standard, reliance on subjective measures). The advent of new imaging modalities allowing for the quantification of tendon structure or mechanical properties has allowed new critical insight into tendon pathology. A strength of these novel modalities is the ability to quantify properties of the tendon. Research utilizing ultrasound tissue characterization and sonoelastography will be discussed. This narrative review will also attempt to synthesize current research on whether imaging can predict the onset of pain or clinical outcome, the role of monitoring tendon structure during rehabilitation (ie, does tendon structure need to improve to get a positive clinical outcome?), and future directions for research, and to propose the clinical role of imaging in tendinopathy. J Orthop Sports Phys Ther 2015;45(11):842-852. Epub 21 Sep 2015. doi:10.2519/jospt.2015.5880.

Tendinopathy of the achilles tendon: volume assessed by automated contour detection in submillimeter isotropic 3-dimensional magnetic resonance imaging data sets recorded at a field strength of 3 T

OBJECTIVE

This prospective study assesses volume changes of the Achilles tendon in case of chronic tendinopathy (TEN), using an automated contour detection algorithm in submillimeter isotropic 3-dimensional magnetic resonance imaging data sets, recorded at 3 T.

METHODS

Forty-one subjects (median age, 40 years; range, 19-68 years) were included in this prospective study and underwent nonenhanced magnetic resonance imaging of both Achilles tendons at 3 T, deploying a T2-weighted 3-dimensional Fast-Spin-Echo sequence with submillimeter resolution of 0.8 mm. Of the 41 subjects, 13 were classified as patients with TEN and 28 were healthy volunteers and served as control group. Of the 13 patients, 10 had unilateral TEN and 3 had bilateral TEN. Achilles tendons were automatically segmented in the T2-weighted magnetic resonance data sets for the evaluation of the tendon volume (0-3 cm proximal to the cranial border of the calcaneal bone). The total volume (length, 3 cm) was divided in 3 subvolumes of 1 cm length, named volume (0-1 cm), volume (1-2 cm), and volume (2-3 cm). Minimum and maximum tendon cross-sectional area within the total volume was processed. A standardized pain questionnaire was obtained from all patients.

RESULTS

The automated contour detection algorithm worked reliably in all cases. The TEN group showed a significantly increased tendon volume compared to the control group (mean volume, 2.94 vs 2.43 mm; P < 0.05). The difference was most obvious concerning volume (2-3 cm) (P < 0.0001). Evaluation of clinical severity revealed a moderate correlation between VISA-score and tendon volume (2-3 cm) as well as the maximum/minimum tendon area (ρ = -0.44, ρ = -0.48, and ρ = -0.41). In case of unilateral TEN, the symptomatic side showed an increased tendon volume (2-3 cm) and increased minimum area (P < 0.05).

CONCLUSIONS

Tendon volume and size are adequate surrogate parameters to differentiate patients with chronic TEN from healthy subjects, and may discriminate symptomatic TEN from asymptomatic "silent" TEN in patients with unilateral symptoms.

Dynamic contrast enhanced magnetic resonance imaging in chronic Achilles tendinosis

Background

Chronic Achilles tendinosis is a common problem. When evaluating and comparing different therapies there is a need for reliable imaging methods. Our aim was to evaluate if chronic Achilles tendinosis affects the dynamic contrast-enhancement in the tendon and its surroundings and if short-term eccentric calf-muscle training normalizes the dynamic contrast-enhancement.

Methods

20 patients with chronic Achilles tendinopathy were included. Median duration of symptoms was 31 months (range 6 to 120 months). Both Achilles tendons were examined with dynamic contrast enhanced MRI before and after a 12- week exercise programme of eccentric calf-muscle training. The dynamic MRI was evaluated in tendon, vessel and in fat ventrally of tendon. Area under the curve (AUC), time to peak of signal, signal increase per second (SI/s) and increase in signal between start and peak as a percentage (SI%) was calculated. Pain and performance were evaluated using a questionnaire.

Results

In the fat ventrally of the tendon, dynamic contrast enhancement was significantly higher in the symptomatic leg compared to the contralateral non-symptomatic leg before but not after treatment. Despite decreased pain and improved performance there was no significant change of dynamic contrast enhancement in symptomatic tendons after treatment.

Conclusion

In Achilles tendinosis there is an increased contrast enhancement in the fat ventrally of the tendon. The lack of correlation with symptoms and the lack of significant changes in tendon contrast enhancement parameters do however indicate that dynamic enhanced MRI is currently not a useful method to evaluate chronic Achilles tendinosis.

Longitudinal microvascularity in Achilles tendinopathy (power Doppler ultrasound, magnetic resonance imaging time-intensity curves and the Victorian Institute of Sport Assessment-Achilles questionnaire): a pilot study

AIM

To evaluate the imaging of the natural history of Achilles tendinopathy microvascularisation in comparison with symptoms, using a validated disease-specific questionnaire [the Victorian Institute of Sport Assessment-Achilles (VISA-A)].

METHOD

A longitudinal prospective pilot study of nine patients with post-contrast magnetic resonance imaging (MRI), time-intensity curve (TIC) enhancement, ultrasound (US) and power Doppler (PD) evaluation of tendinopathy of the mid-Achilles tendon undergoing conservative management (eccentric exercise) over 1 year.

RESULTS

There were five men and four women [mean age 47 (range 30-62) years]. Six asymptomatic tendons with normal US and MRI appearance showed less enhancement than the tibial metaphysis did and showed a flat, constant, but very low rate of enhancement in the bone and Achilles tendon (9-73 arbitrary TIC units). These normal Achilles tendons on imaging showed a constant size throughout the year (mean 4.9 mm). At baseline the TIC enhancement in those with tendinopathy ranged from 90 arbitrary units to 509 arbitrary units. Over time, 11 abnormal Achilles tendons, whose symptoms settled, were associated with a reduction in MRI enhancement mirrored by a reduction in the number of vessels on power Doppler (8.0 to 2.7), with an improvement in morphology and a reduction in tendon size (mean 15-10.6 mm). One tendon did not change its abnormal imaging features, despite improving symptoms. Two patients developed contralateral symptoms and tendinopathy, and one had more abnormal vascularity on power Doppler and higher MRI TIC peaks in the asymptomatic side.

CONCLUSIONS

In patient with conservatively managed tendinopathy of the mid-Achilles tendon over 1 year there was a reduction of MRI enhancement and number of vessels on power Doppler, followed by morphological improvements and a reduction in size. Vessels per se related to the abnormal morphology and size of the tendon rather than symptoms. Symptoms improve before the Achilles size reduces and the restoration of normal imaging over time.

Restoration of strength despite low stress and abnormal imaging after Achilles injury

PURPOSE

To determine the usefulness of clinical imaging in predicting the mechanical properties of rabbit Achilles tendons after acute injury.

METHODS

We created a 2 x 7-mm full-thickness central tendon defect in one Achilles tendon of healthy rabbits. Rabbits in groups of 10 were killed immediately and 4 and 8 wk after surgery (n = 30). We then performed magnetic resonance (MR) imaging, ultrasonography (US), bone mineral densitometry (BMD), and mechanical testing to failure using a dual-cryofixation assembly on experimental and contralateral tendons. The main outcome measures included tendon dimensions, optical density (OD) of T1-weighted, proton density (PD), and T2-weighted MR sequences, US focal abnormalities, BMD of the calcaneus, and stress and peak load to failure.

RESULTS

On MR imaging and US, all dimensions of the injured tendons after 2 wk and more were greater than those of the contralateral tendons (P < 0.05). The mean T1-weighted OD was greater at 4 wk (256 +/- 53) and 8 wk (184 +/- 24) than immediately after surgery (149 +/- 15). Mechanical stress was markedly lower in the experimental than in the contralateral tendons at both 4 wk (39 +/- 9 vs 77 +/- 16 N x mm(-2)) and 8 wk (58 +/- 6 vs 94 +/- 26 N x mm(-2); P < 0.05). Mean peak load to failure was significantly lower immediately after surgery (332 +/- 128 N) than at 4 and 8 wk (712 +/- 106 and 836 +/- 90 N, respectively). Both high T1-weighted OD (r = -0.73) and PD OD (r = -0.69) correlated with lower mechanical stress (P < 0.05). In the experimental tendons, higher T1-weighted OD correlated with lower peak load (r = -0.46; P < 0.05).

CONCLUSIONS

Normal peak loads 4 wk after injury were withstood by an enlarged tendon of lower stress. These findings support progressive physical loading 4 wk after an Achilles tendon injury. T1-weighted OD constituted a marker of tendon mechanical recovery.

Conservative treatment of Achilles tendinopathy: emerging techniques

Achilles tendinopathy is a painful condition that occurs commonly in both active and inactive individuals. It seems that this condition is painful as a result of ingrowth of neural structures and neovessels leading to poor healing, rather than from inflammatory mediators. Traditional conservative measures are often successful. There is a subset of patients who fail to respond to these measures, however, and this has led to the investigation of newer conservative techniques. This article provides a review of many of the emerging techniques in the treatment of Achilles tendinopathy.

Achilles tendon pain intensity and level of neovascularization in athletes as determined by color Doppler ultrasound

The cause of pain in Achilles tendinopathy is thought to be related to the presence of neovascularization in the tendon as seen on color Doppler ultrasound. Asymptomatic pathology has been observed in patellar tendons of elite athletes. The purpose of this study was to examine the prevalence of Achilles tendon pain and the characteristics of Achilles tendons in a young athletic population. Sixty-four varsity athletes underwent color Doppler ultrasound imaging to determine tendon thickness, presence of degeneration and neovascularization. The presence of swelling and tenderness was determined, and Achilles tendon pain was rated on three visual analogue scales (VAS) (pain during exercise, pain at rest, pain during daily activities) as well as on the VISA-A scale. Tendon symptoms were not related to the presence of neovascularization. There was a low prevalence of Achilles tendinopathy, tenderness, and neovascularization in this population. Neovascularization was seen in both a painful and a non-painful tendon.

Mechanical alterations of rabbit Achilles' tendon after immobilization correlate with bone mineral density but not with magnetic resonance or ultrasound imaging

OBJECTIVE

To assess the usefulness of magnetic resonance imaging (MRI), ultrasound (US) imaging, or bone mineral density (BMD) in predicting the mechanical properties of immobilized rabbit Achilles' tendons.

DESIGN

Experimental study.

SETTING

Basic university laboratory.

ANIMALS

Twenty-eight rabbits.

INTERVENTIONS

Twelve rabbits had 1 hindlimb casted for 4 weeks and 10 rabbits were casted for 8 weeks. Contralateral legs and 12 normal hindlimbs served as controls.

MAIN OUTCOME MEASURES

Achilles' tendon dimensions on MRI and US, T1- and T2-signal intensities on MRI, classification of abnormalities on MRI and US; BMD of the calcaneus with dual-energy x-ray absorptiometry. Biomechanic measures consisted of peak load, stiffness, and stress. Imaging variables were correlated with biomechanic alterations.

RESULTS

Immobilized Achilles' tendons were weaker and showed decreased mechanical stress compared with their contralateral legs and controls (all P<.05). MRI and US revealed larger Achilles' tendons after immobilization. However, neither increased MRI nor US signal abnormality was found. BMD was lower in immobilized calcanei and larger in contralateral legs than controls. Only BMD correlated with both the decreased peak load (R2=.42, P<.05) and stress (R2=.54, P<.05) of immobilized Achilles' tendon.

CONCLUSIONS

This study established weakened mechanical properties of immobilized Achilles' tendons. BMD of the calcaneus, but not MRI and US, was predictive of the mechanical alterations in immobilized Achilles' tendons. BMD may be a useful biomarker to monitor disease and recovery in Achilles' tendons.

Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis

It has been shown that 12 weeks of eccentric heavy resistance training can reduce pain in runners suffering from chronic Achilles tendinosis, but the mechanism behind the effectiveness of this treatment is unknown. The present study investigates the local effect of an eccentric training regime on elite soccer players suffering from chronic Achilles tendinosis on the turnover of the peritendinous connective tissue. Twelve elite male soccer players, of whom six suffered from unilateral tendinosis and six were healthy controls, participated in this study. All participants performed 12 weeks of heavy-resistance eccentric training apart from their regular training and soccer activity. Before and after the training period the tissue concentration of indicators of collagen turnover was measured by the use of the microdialysis technique. After training, collagen synthesis was increased in the initially injured tendon (n=6; carboxyterminal propeptide of type I collagen (PICP): pre 3.9+/-2.5 microg/L to post 19.7+/-5.4 microg/L, P<0.05). The collagen synthesis was unchanged in healthy tendons in response to training (n=6; PICP: pre 8.3+/-5.2 microg/L to post 11.5+/-5.0 microg/L, P>0.05). Collagen degradation, measured as carboxyterminal telopeptide region of type I collagen (ICTP), was not affected by training neither in the injured nor in the healthy tendons. The clinical effect of the 12 weeks of eccentric training was determined by using a standardized loading procedure of the Achilles tendons showing a decrease in pain in all the chronic injured tendons (VAS before 44+/-9, after 13+/-9; P<0.05), and all subjects were back playing soccer following the eccentric training regime. The present study demonstrates that chronically injured Achilles tendons respond to 12 weeks of eccentric training by increasing collagen synthesis rate. In contrast, the collagen metabolism in healthy control tendons seems not to be affected by eccentric training. These findings could indicate a relation between collagen metabolism and recovery from injury in human tendons.

Avaliação morfométrica do tendão de Aquiles por ultra-sonografia

OBJETIVO: Determinar os valores normais dos diâmetros ântero-posterior e transversal do tendão de Aquiles na nossa população e correlacioná-los com sexo, faixa etária, cor da pele, grupo sanguíneo ABO e índice de massa corporal. MATERIAIS E MÉTODOS: Foi feita análise ultra-sonográfica de 100 tendões de Aquiles de 50 voluntários sadios, visando à mensuração dos diâmetros ântero-posterior e transversal desses tendões. Todos os exames foram realizados pelo mesmo examinador, em aparelho de ultra-sonografia com transdutor linear com freqüência de 10 MHz. RESULTADOS: Dos 50 voluntários estudados, 25 eram do sexo masculino e 25, do sexo feminino, com a faixa etária variando de 20 a 52 anos (média de 33,9 anos). O valor médio do diâmetro transversal do tendão de Aquiles foi de 13,3 ± 1,0 mm para o sexo feminino e 14,4 ± 1,4 mm para o sexo masculino; em relação ao diâmetro ântero-posterior, foi de 5,4 ± 0,5 mm para o sexo feminino e 5,6 ± 0,6 mm para o sexo masculino. Os diâmetros do tendão de Aquiles foram significativamente menores no sexo feminino (p < 0,05). Não houve diferença estatisticamente significativa entre os diâmetros ântero-posterior e transversal em relação a faixa etária, grupo sanguíneo e cor da pele. O grupo com índice de massa corporal de sobrepeso apresentou diâmetro transversal do tendão de Aquiles significativamente maior que do grupo com índice de massa corporal normal. CONCLUSÃO: Os valores médios encontrados na nossa casuística foram discordantes em relação à maioria dos estudos da literatura, demonstrando ser de grande importância a padronização e o emprego de tabelas próprias da nossa população na prática clínica diária.

Reliability in the assessment of tendon volume and intratendinous signal of the Achilles tendon on MRI: a methodological description

The purpose is to introduce a method for accurately and objectively evaluating volume and mean intratendinous signal within the Achilles tendon using MRI. We prospectively studied MRI from 33 patients with chronic Achilles tendinosis (20 males and 13 females) with a median age of 52 years (range 29-70). In all patients, both Achilles tendons were investigated with T1-WI as well as PD-WI MRI. Thus, 66 Achilles tendons were evaluated in the study. Tendon volume and mean intratendinous signal were evaluated using a computerized 3-D seed-growing technique. In general, the computerized 3-D seed-growing technique resulted in an excellent overall observer reliability of the MRI-measurements. The reliability (R) for tendon volume measurements was highest for the T1-WI sequence (R=97.9%). For the mean intratendinous signal, the PD-WI sequence showed the highest reliability (R=88.1%). The same pattern was present when we studied the coefficient of variation (CV). For the CV, lower figures indicate more reliable estimates. CV was 4.9% for tendon volume and 8.9% for mean intratendinous signal. In conclusion, it could be said that a computerized 3-D seed-growing technique to monitor and evaluate the volume of the Achilles tendon and mean intratendinous signal, using MRI, shows an overall excellent reliability regarding inter- as well as intra-observer reliability.

The chronic painful Achilles and patellar tendon: research on basic biology and treatment

The etiology and pathogenesis of chronic tendon pain are unknown. Even though tendon biopsies having shown an absence of inflammatory cell infiltration, anti-inflammatory agents (non-steroidal anti-inflammatory drugs, corticosteroidal injections) are commonly used. We have demonstrated that it is possible to use intratendinous microdialysis to investigate human tendons, and found normal prostaglandin E2 (PGE2) levels in chronic painful tendinosis (Achilles and patellar) tendons. Furthermore, gene technological analyses of biopsies showed no upregulation of pro-inflammatory cytokines. These findings show that there is no PGE2-mediated intratendinous inflammation in the chronic stage of these conditions. The neurotransmitter glutamate (a potent modulator of pain in the central nervous system) was, for the first time, found in human tendons. Microdialysis showed significantly higher glutamate levels in chronic painful tendinosis (Achilles and patellar) tendons, compared with pain-free normal control tendons. The importance of this finding is under evaluation. Treatment is considered to be difficult, and not seldom, surgery is needed. However, recent researches on non-surgical methods have shown promising clinical results. Painful eccentric calf-muscle training has been demonstrated to give good clinical short- and mid-term results on patients with chronic painful mid-portion Achilles tendinosis. Good clinical results were associated with decreased tendon thickness and a structurally more normal tendon with no remaining neovessels. Using ultrasonography (US)+color Doppler (CD), and immunhistochemical analyses of biopsies, we have recently demonstrated a vasculo/neural (Substance-P and Calcitonin Gene-Related Peptide nerves) ingrowth in the chronic painful tendinosis tendon, but not in the pain-free normal tendon. A specially designed treatment, using US- and CD-guided injections of the sclerosing agent Polidocanol, targeting the neovessels outside the tendon, has been shown to cure tendon pain in pilot studies, in a majority of the patients. A recent, randomized, double-blind study verified the importance of injecting the sclerosing substance Polidocanol.

The distribution of microvascular response in Achilles tendonopathy assessed by colour and power Doppler

OBJECTIVES

To assess the distribution of microvascular response on colour Doppler (CD) and power Doppler (PD) ultrasound (US) of the tendo Achilles (TA) in tendonopathy, and to look for any relationship between tendon morphology and symptoms.

DESIGN AND PATIENTS

A retrospective, observational study was carried out on consecutive ambulant US patients with suspected tendonopathy, presenting with pain or an Achilles mass. Exclusion criteria were: use of steroids, and previous or possible rupture or surgery in either tendon or arthropathy. Using a 5-12 MHz linear array probe (ATL HDI 3000) both TAs were scanned. Tendonopathy was defined as tendon swelling and/or hypoechogenicity of the TA. The site, number and distribution of microvascularity, on CD and PD, and the anteroposterior size were recorded, with the analysis masked.

RESULTS

Fifty-two patients presented with TA pain and six also with swelling. There were 34 males and 18 females, aged from 11 to 78 years (mean 45 years). Fifty-five TAs that showed tendonopathy with hypoechogenic areas were all observed to be over 5.9 mm (mean 11.1 mm, range 5.9-20 mm), of which 45 were symptomatic with abnormal PD and 24 with abnormal CD flow. It was observed that the extent and completeness of vessel branching was more extensive on PD than CD. All TAs demonstrating tendonopathy were over 5.9 mm in adults and all TAs that showed PD flow were over 6.5 mm. All microvessels originated towards the TA from the ventral surface usually into tendonopathy, and were 16-fold more frequent around the margins. There were 49 TAs with normal spectral US, and with no PD flow, with a mean size of 4.5 mm (range 3.0-7.4 mm). For the right and left TAs independently analysed and taking the 40 patients with a paired asymptomatic and symptomatic tendon: (1) There was a highly significant difference in size (P<0.00001) using the paired t-test (parametric) between the asymptomatic tendon (mean 5.2+/-1.4 mm (1 SD)), and the contralateral morphologically abnormal and symptomatic side (mean 9.7+/-1.4 mm). (2) There was no linear Pearson correlation (0.25) between TA size and duration of symptoms (P=0.11) for symptomatic tendons. (3) There was a positive Spearman correlation (0.84) between the number of vessels and TA size (P<0.00001). (4) There was a significant difference in the number of PD vessels using the non-parametric Wilcoxon signed test (P<0.00001) between the symptomatic and asymptomatic groups.

CONCLUSIONS

(1) PD shows more tendon microvascularity than CD in TA tendonopathy. (2) All microvessels arise on the ventral side of the TA. (3) There is a non-linear relationship between tendonopathy, TA size and the amount of microvascularity, but not between PD and duration of symptoms. (4) Morphologically abnormal adult TAs were larger than 5.9 mm, and PD flow was only seen in TAs above 6.5 mm.

Tendinopathy of the main body of the Achilles tendon

Although Achilles tendinopathy has been extensively studied, there is a clear lack of properly conducted scientific research to clarify its etiology, pathology and optimal management. Emerging non-operative management and heavy load eccentric strengthening protocols based on these theories have yielded encouraging early results. Operative management traditionally produced good to excellent results, but randomized controlled studies comparing different surgical procedures and prospective evaluation of patient outcomes are necessary to truly establish the efficacy of these procedures. As the biology of tendinopathy is being clarified, more effective management regimens may come to light, improving the success rate of both conservative and operative management.

Conservative management of Achilles tendinopathy: new ideas

Chronic Achilles tendinopathy is difficult to treat, and results, even after surgical management, are variable. The few studies that reported long-term results indicated a poor outcome. Also, surgery requires prolonged rehabilitation, and, depending on the patient's occupation, a varying period of sick leave from work. This article gives an update on recently developed conservative treatment methods for the management of chronic Achilles tendinopathy.

Motion-based tendon diagnosis using sequence processing of ultrasound images

Degenerative or pre-degenerative processes in the tendon, which could lead to a spontaneous rupture, are well known problems, especially among athletes. Existing non-invasive diagnostic methods are mainly based on subjective analysis of static images of the tendon, but in many cases the degeneration cannot be diagnosed in time. Combining a set of existing image processing techniques, a tool for tracking the in vivo motion of a tendon imaged with dynamic ultrasound was implemented. A group of subjects that had undergone a degenerative rupture of their Achilles tendon, one subject with a traumatic rupture, and a group of control subjects were all tested. Using the motion information that was obtained from both tendons of all subjects, we developed an automatic test that examines the symmetrical properties of the tendon's motion, and defined a negative asymmetry property that could be quantified as a score. This score was found to be significantly more enhanced in the post-operative tendons (18.0 +/- 9.0) than in the contra-lateral healthy tendons of the same subjects (3.9 +/- 4.6). In the single traumatic rupture subject, this effect was not found (0.0). This leads us to believe that the negative asymmetry of tendon motion may be associated with degenerative or pre-degenerative processes in the tendon. Also, the mean degree of negative asymmetry in the healthy tendons of post-operative subjects (3.9 +/- 4.6) was found to be higher than that of healthy tendons of the control group (1.5 +/- 1.8). This finding may be associated with the fact that tendons that are contra-lateral to spontaneously ruptured tendons have a higher risk of developing degenerative processes. The method presented here is objective, low-cost, non-invasive and possibly more sensitive than existing non-invasive techniques.

Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up

OBJECTIVE

To prospectively investigate tendon thickness and tendon structure by ultrasonography in patients treated with eccentric calf muscle training for painful chronic Achilles tendinosis located at the 2-6 cm level in the tendon.

METHODS

The patients were examined with grey scale ultrasonography before and 3.8 years (mean) after the 12 week eccentric training regimen. At follow up, a questionnaire assessed present activity level and satisfaction with treatment.

RESULTS

Twenty six tendons in twenty five patients (19 men and six women) with a mean age of 50 years were followed for a mean of 3.8 years (range 1.6-7.75). All patients had a long duration of painful symptoms (mean 17.1 months) from chronic Achilles tendinosis before treatment. At follow up, 22 of 25 patients were satisfied with treatment and active in Achilles tendon loading activities at the desired level. Ultrasonography showed that tendon thickness (at the widest part) had decreased significantly (p<0.005) after treatment (7.6 (2.3) v 8.8 (3) mm; mean (SD)). In untreated normal tendons, there was no significant difference in thickness after treatment (5.3 (1.3) mm before and 5.9 (0.8) mm after). All tendons with tendinosis had structural abnormalities (hypoechoic areas and irregular structure) before the start of treatment. After treatment, the structure was normal in 19 of the 26 tendons. Six of the seven patients with remaining structural abnormalities experienced pain in the tendon during loading.

CONCLUSIONS

Ultrasonographic follow up of patients with mid-portion painful chronic Achilles tendinosis treated with eccentric calf muscle training showed a localised decrease in tendon thickness and a normalised tendon structure in most patients. Remaining structural tendon abnormalities seemed to be associated with residual pain in the tendon.

Chronic midportion Achilles tendinopathy: an update on research and treatment

Chronic painful midportion Achilles tendinosis has been known as a difficult condition to treat, and surgical treatment was often needed. In recent scientific studies, however, treatment with painful eccentric calf muscle training has shown very good short-term clinical results and significantly reduced the need for surgical treatment. Also, very recently, a new method consisting of sclerosing of neovessels in the area with painful tendinosis showed promising short-term results. Ongoing and future research will evaluate the potential of these treatment models.

Achilles tendinopathy: some aspects of basic science and clinical management

Achilles tendinopathy is prevalent and potentially incapacitating in athletes involved in running sports. It is a degenerative, not an inflammatory, condition. Most patients respond to conservative measures if the condition is recognised early. Surgery usually involves removal of adhesions and degenerated areas and decompression of the tendon by tenotomy or measures that influence the local circulation.

Achilles tendon (TA) size and power Doppler ultrasound (PD) changes compared to MRI: a preliminary observational study

AIM

To assess whether abnormal Achilles tendon (TA) magnetic resonance imaging (MRI) and spectral ultrasound (US) features have associated development of microvascular power Doppler (PD) flow.

MATERIALS AND METHODS

In a prospective, controlled and blinded study six patients with TA symptoms were compared to five with other ankle abnormalities. Two radiologists independently measured the mean maximal anteroposterior diameter on MRI and conventional US (categorized as normal <6 mm, mild 6.1-10 mm, moderate 1.1-1.5 cm and severely enlarged > 1.6 cm), assessed morphology and studied the vessels using power Doppler. They formed a consensus over discrepancies. Sonography of the contralateral side within 24 h was used as a control.

RESULTS

Twenty-one tendons in six women and five men, aged 45-77 years (mean 57.6 years), were examined, 12 tendons were of normal US morphology and size (< 6 mm), and did not exhibit PD's flow (interobserver agreement K > 0.74). Of the 12 tendons studied by MRI five were normal, seven tendons were enlarged, five of which had a proportionate increase in PD flow at the margin on the deep surface and four also had vessels in the centre of the tendon. All five of these tendons had high signal on T2-weighting (T2W). Of the two mildly enlarged tendons of intermediate signal on T1 and T2W, one showed PD flow and the other did not.

CONCLUSIONS

In patients with TA disease power Doppler ultrasound shows proliferation of vessels in enlarged, abnormal tendons demonstrated on MRI and standard ultrasound, in the absence of definite tears.

MR imaging of overuse injuries of the Achilles tendon

OBJECTIVE

This study was conducted to illustrate and classify the abnormalities found on high-resolution MR imaging of symptomatic Achilles tendons in athletic adult patients.

SUBJECTS AND METHODS

One hundred patients with 118 painful Achilles tendons were imaged with a 1.5-T magnet. The tendon, peritendinous tissues, tendon insertion, and musculotendinous junction were examined on MR imaging. Twenty-eight patients underwent surgery, and histopathologic samples were taken in 13. Long-term follow-up was performed, on average, 3.4 years after MR imaging.

RESULTS

Of 118 painful Achilles tendons, abnormalities were detected in 111. These were in the tendon (n = 90), surrounding structures, or both. Fifty-four tendons had a focal area of increased intratendinous signal, best detected on axial high-resolution T1-weighted gradient-echo MR imaging. Histopathology confirmed abnormal tendon structure. Of the 21 surgically proven foci of tendinosis, 20 were revealed on MR imaging. At the level of the insertion, changes were found in the tendon in 15%, in the retrocalcaneal bursa in 19%, and in the calcaneal bone marrow in 8% of the studies. Abnormalities in peritendinous soft tissues were detected in 67%. More than one type of abnormality was found in 64% of the studies.

CONCLUSION

Lesions in the Achilles tendon and in the peritendinous structures can have similar clinical presentation. MR imaging detects and characterizes these changes. A more specific diagnosis and prognosis can be made with the use of MR imaging than with clinical examination alone.

Chronic Achilles tendinosis: recommendations for treatment and prevention

Chronic Achilles tendinosis is a condition with an unknown aetiology and pathogenesis that is often, but not always, associated with pain during loading of the Achilles tendon. Histologically, there are no inflammatory cells, but increased amounts of interfibrillar glycosaminoglycans and changes in the collagen fibre structure and arrangement are seen. In situ microdialysis has confirmed the absence of inflammation. It is a condition that is most often seen among recreational male runners aged between 35 and 45 years, and it is most often considered to be associated with overuse. However, this condition is also seen in patients with a sedentary lifestyle. Chronic Achilles tendinosis is considered a troublesome injury to treat. Nonsurgical treatment most often includes a combination of rest, NSAIDs, correction of malalignments, and stretching and strengthening exercises, but there is sparse scientific evidence supporting the use of most proposed treatment regimens. It has been stated that, in general, nonsurgical treatment is not successful and surgical treatment is required in about 25% of patients. However, in a recent prospective study, treatment with heavy load eccentric calf muscle training showed very promising results and may possibly reduce the need for surgical treatment of tendinosis located in the midportion of the Achilles tendon. The short term results after surgical treatment are frequently very good, but in the few studies with long term follow-up there are signs of a possible deterioration with time. Calf muscle strength takes a long time to recover and, furthermore, a prolonged progressive calcaneal bone loss has been shown on the operated side up to 1 year after surgical treatment.

Tendon and nerve sonography

The refinement of high frequency transducers has improved the ability of ultrasound (US) to detect fine textural abnormalities of tendons and nerves and to identify a variety of pathologic conditions. Characteristic echotextural patterns, closely resembling the histologic ones, are typically depicted in these structures using high US frequencies. In tendon imaging, US can identify tendon dislocations, degenerative changes, differentiate partial from complete tears and determine whether the patient has to be treated surgically or conservatively. A spectrum of findings in inflammatory conditions, including paratendonitis and tenosynovitis, and tendon tumors also can be detected. In nerve imaging, US can support clinical and electrophysiologic testing for detection of compressing lesions caused by nerve entrapment in a variety of osteofibrous tunnels of the limbs and extremities. Nerve tears and tumors also can be diagnosed. Overall, US is an effective technique for imaging tendons and nerves.

Applications of musculoskeletal sonography

To successfully examine the musculoskeletal system sonographically, one must understand the normal musculoskeletal anatomy and function and be aware of the abnormal processes that affect the musculoskeletal structures. The goal of this review article is to provide a systematic approach to sonographic examination of the musculoskeletal system. The general sonographic appearances of normal and abnormal muscles, tendons, ligaments, bursae, and nerves are reviewed. The article then applies this general information to specific clinical applications by reviewing the normal anatomy of and specific pathologic conditions that affect the shoulder, elbow, hand, wrist, hip, knee, ankle, and foot.

Achilles tendon injuries

As the number of persons who participate in athletic activity into their later years has increased, so has the incidence of overuse injuries to the Achilles tendon. The etiology of these problems is multifactorial and includes biomechanical factors and training errors. Use of a histopathologic scheme for classification of these injuries facilitates a logical approach to treatment. Conservative care is a mainstay of treatment for inflammatory conditions. Satisfactory outcomes may be obtained with either nonoperative or operative treatment of acute ruptures, although surgically treated patients appear to recover better functional capacity. Treatment of neglected injuries to the Achilles tendon continues to be a challenging problem.

Low-field magnetic resonance imaging (0.2 T) of tendons with sonographic and histologic correlation. Cadaveric study

RATIONALE AND OBJECTIVES

The authors evaluate the role of low-field strength magnetic resonance imaging (MRI) compared with sonography in the evaluation of degenerative changes of tendons, with histologic correlation, based on investigations of horse cadavers.

METHODS

Low-field MRI and sonography was performed in 42 hours specimens for the evaluation of tendons and ligaments. Magnetic resonance imaging included sagittal and axial T1-weighted, T2-weighted, and gradient echo images. Sonography and MR images were evaluated for degenerative changes or tears and the findings were correlated with the histologic results.

RESULTS

Using histologic findings as a gold standard, the accuracy for the sonographic evaluation was 65.9%, sensitivity was 16.7%, and specificity was 100%. The corresponding data for low-field MR imaging were 70.5% accuracy, 44.4% sensitivity, and 88.5% specificity.

CONCLUSIONS

Low-field MRI investigation allows more accurate staging of tendinous changes than sonography. It is more reproducible and potentially includes the advantages of the combined evaluation of bones, ligaments, and soft tissue.

Imaging of tendons--adaptation, degeneration, rupture

Tendon imaging is mainly performed with ultrasonography (US) and magnetic resonance imaging (MRI) and has been improved within the last years because of technical advancements and a better understanding of tendon pathology. Several concepts concerning the etiology and the course of tendon diseases have influenced image interpretation and vice versa. Adaptive mechanisms within the tendon tissue against stress can be observed mainly on histologic specimens and not macroscopically or with in-vivo imaging. Degeneration may occur in the form of tendinitis, peritendinitis, enthesitis, or myotendinal junction abnormality. Distinct imaging findings exist for most of these forms. Many concepts that have been developed to explain tendon degeneration have been applied on virtually all tendons in the human body. They can be grouped into those which focus on hypovascularization, on biomechanical overload, and on degeneration secondary to other underlying disease. Tendon rupture seems, in many cases, to be the final stage of tendinitis. From this point of view, imaging may be used to predict the risk of tendon rupture together with other intrinsic and with extrinsic parameters. These considerations result in the concept of the "vulnerable zone" and of the "critical phase" in which tendon ruptures may predominantly occur.

Clinical and sonographic evaluation of the risk of rupture in the Achilles tendon

Chronic pain in the region of the Achilles tendon is a common problem and often a sign of progressive degeneration of the tendon which may lead to its rupture. We studied the clinical course and sonograms in 36 patients with achillodynia to find a prognostic parameter enabling us to estimate the risk of rupture. The patients were evaluated clinically for swelling and tenderness and by high-resolution real-time sonography. The sonograms were graded according to the tendon thickness as normal (< 6 mm), minimal (6-8 mm), moderate (8-10 mm) to high-grade (> 10 mm) in the sagittal diameter of the transverse section, and alterations of echotexture were described as diffuse, circumscribed, or inhomogenous. At the time of the primary investigation, we found thickening and alterations of the echotexture in 33 of 72 tendons. In 48 tendons we found pain and local or diffuse swelling in the Achilles tendon region (sensitivity 0.58, specificity 0.79). After a follow-up of 48 +/- 8 months, 7 tendons had ruptured spontaneously. Analysis of the sonograms of the patients taken prior to the rupture showed a high-grade thickening in 4 cases, moderate thickening in 2 cases, and a diameter between 6 and 8 nm in one patient. In no case did we find a rupture of a tendon primarily classified as normal. Patients without sonographic changes exhibited a significantly better clinical outcome following conservative treatment. Sonography was found to be a valuable tool for determination of the tendon's thickness and echotexture. In 28% of our patients with thickening, circumscribed lesions of the echotexture, and chronic pain, a spontaneous rupture occurred.

Postoperative MR imaging and ultrasonography of surgically repaired Achilles tendon ruptures

PURPOSE

To evaluate and compare MR and US findings in an unselected group of patients with 1-3-year-old surgically repaired complete ruptures of the Achilles tendon.

MATERIAL AND METHODS

Thirteen patients with complete Achilles tendon rupture underwent clinical, MR and US examinations. The average time interval from rupture to postoperative imaging was 18 months.

RESULTS

The cross-sectional area of a postoperative tendon was 4.2 times that of the unaffected side. The shape of the operated tendon was more rounded than the unaffected side and it had irregular margins both in MR imaging and in US examination. In 4 of 13 cases an intratendinous area of intermediate to high signal intensity on proton density- and T2-weighted images was seen on MR. The size of this area varied from 4 to 18% of the cross-sectional tendon area. Two patients with the largest intratendinous area had poor clinical outcome. On US the tendon had mixed echogenicity in all cases and the tendon bands were thinner and shorter than normal. Comparison of dimension between MR and US revealed that in a.p. dimension the correlation was good (r = 0.87, p = 0.001), but in transversal width there was no significant correlation (r = 0.58, p = 0.06).

CONCLUSION

The increased size and round irregular area of the operated Achilles tendon rupture was well detected by both MR and US, but intratendinous lesions were seen only by MR.

Adapted techniques for clinical MR imaging of tendons

To determine whether the echo time of magnetic resonance gradient-echo and spin-echo imaging sequences may be important for the occurrence of high signal strength from tendon with pathological alterations, imaging sequences with sufficient spatial resolution and very short echo times were developed for whole-body imagers with standard gradient system. The sequences were applied on the Achilles tendons of five healthy volunteers and seven patients with achillodynia. Some affected regions inside tendon, probably corresponding with tissue with subtle edema in the collagen bundles were only revealed in images recorded with very short echo times TE < 5 ms, whereas stronger affections and protons in liquids between the fiber bundles were also shown in images with longer echo times TE > 10 ms. Gradient-echo methods allow shorter echo times than spin-echo techniques for a given gradient system of the imager and given spatial resolution. So minimum echo time gradient-echo sequences should be used for sensitive imaging of tendon alterations, because no considerable signal dephasing due to susceptibility effects were found in tendon.

Achilles Tendon Ruptures

Despite the well-publicized injuries of US Olympics sprinter Mark Witherspoon and Atlanta Hawks star Dominique Wilkins, an Achilles tendon rupture is rare. But when it does occur-usually among middle-aged recreational athletes-the injury is sometimes misdiagnosed. A thorough history and physical exam will point physicians to the right diagnosis.