Achilles tendon and paratendon microcirculation in midportion and insertional tendinopathy in athletes

BACKGROUND: Neovascularisation can be detected qualitatively by Power Doppler in Achilles tendinopathy. Quantitative data regarding tendon microcirculation have not been established and may be substantial. PURPOSE: To assess the microcirculation of the Achilles tendon and the paratendon in healthy volunteers as well as in athletes with either midportion or insertional tendinopathy. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: In 66 physically active volunteers, parameters of Achilles tendon and paratendon microcirculation, such as tissue oxygen saturation, relative postcapillary venous filling pressures, and microcirculatory blood flow, were determined at rest at 2-mm and 8-mm tissue depths. Forty-one patients never had Achilles pain (25 men, 27 +/- 8 years), 14 patients had insertional pain (7 men, 29 +/- 8 years), and 11 patients had midportion tendinopathy (7 men, 38 +/- 13 years, not significant). RESULTS: Achilles tendon diameter 2 cm and 6 cm proximal to the insertion was increased in symptomatic tendons. Compared with the uninvolved opposite tendon, deep microcirculatory blood flow was significantly elevated at insertional (160 +/- 79 vs 132 +/- 42, P < .05) as well as in midportion tendinopathy (150 +/- 74 vs 119 +/- 34, P < .05). The microcirculation in the uninvolved opposite tendon and the normal athlete controls were not significantly different from each other (132 +/- 42 insertional asymptomatic vs 119 +/- 34 mid-portion vs 120 +/- 48 healthy tendon). Insertional paratendon deep microcirculatory flow was elevated in all groups, whereas tissue oxygen saturation and relative postcapillary venous filling pressures were not significantly different. CONCLUSION: Microcirculatory blood flow is significantly elevated at the point of pain in insertional and midportion tendinopathy. Postcapillary venous filling pressures are increased at both the midportion Achilles tendon and the midportion paratendon, whereas tissue oxygen saturation is not different among the studied groups. We found no evidence of an abnormal microcirculation of the asymptomatic limb in Achilles tendinopathy.     

Do physical tests have a prognostic value in chronic midportion Achilles tendinopathy?

ObjectivesTo determine whether baseline physical tests have a prognostic value on patient-reported outcomes in Achilles tendinopathy.DesignProspective cohort study, secondary analysis of data from a randomized trial.MethodsPatients with chronic midportion Achilles tendinopathy performed a progressive calf muscle exercise program. At baseline and after 2, 6, 12 and 24 weeks, patients completed the Victorian Institute of Sports Assessment—Achilles questionnaire and performed the following physical tests: ankle dorsiflexion range of motion with a bent knee or an extended knee, calf muscle strength, jumping height and pain on palpation (Visual Analogue Scale; 0–100) and after 10 hops (Visual Analogue Scale-10-hops). Associations between baseline test results and improvement (Victorian Institute of Sports Assessment—Achilles scores) were determined using a Mixed Linear Model.Results80 patients were included. The mean Victorian Institute of Sports Assessment—Achilles score improved 20 points (95 % confidence interval, 16–25, P < .001) after 24 weeks. There were significant associations between the baseline ankle dorsiflexion range of motion with a bent knee (β 0.2, 95 % confidence interval 0.001 to 0.3, P = .049), the baseline pain provocation tests (Visual Analogue Scale palpation: β − 0.2; 95 % confidence interval: − 0.4 to − 0.1; P < .001, Visual Analogue Scale-10-hops: β − 0.3; 95 % confidence interval: − 0.4 to − 0.2; P < .001) and the change in the Victorian Institute of Sports Assessment—Achilles score.ConclusionsIn patients with chronic midportion Achilles tendinopathy, easy-to-perform pain provocation tests have a clinically relevant prognostic value on patient-reported improvement. Patients with less pain during pain provocation tests at baseline have a better improvement in pain, function and activities after 24 weeks than patients with high baseline pain scores.     

Sclerosing injections to treat midportion Achilles tendinosis: a randomised controlled study evaluating two different concentrations of Polidocanol

Two to three ultrasound (US) and colour Doppler (CD)-guided injections of the sclerosing substance Polidocanol (5 mg/ml) have been demonstrated to give good clinical results in patients with chronic midportion Achilles tendinopathy. This study aimed to investigate if a higher concentration of Polidocanol (10 mg/ml) would lead to a less number of treatments, and lower volumes, needed for good clinical results. Fifty-two consecutive Achilles tendons (48 patients, mean age 49.6 years) with chronic painful midportion Achilles tendinopathy, were randomised to treatment with Polidocanol 5 mg/ml (group A) or 10 mg/ml (group B). The patients and treating physician were blinded to the concentration of Polidocanol injected. All patients had structural tendon changes and neovascularisation in the Achilles midportion. Treatment was US + CD-guided injections targeting the region with neovascularisation (outside ventral tendon). A maximum of three treatments (6-8 weeks in between) were given before evaluation. Patients not satisfied after three treatments were given additional treatment with Polidocanol 10 mg/ml, up to five treatments. For evaluation, the patients recorded the severity of Achilles tendon pain during activity on a visual analogue scale (VAS), before and after treatment. Patient satisfaction with treatment was also assessed. At follow-up (mean 14 months) after three treatments, 18/26 patients in group A and 19/26 patients in group B were satisfied with the treatment and had a significantly reduced level of tendon pain (P < 0.05). After completion of the study, additional treatments with Polidocanol 10 mg/ml in the not satisfied patients resulted in 26/26 satisfied patients in both groups A and B. In summary, we found no significant differences in the number of satisfied patients, number of injections or volumes given, between patients treated with 5 or 10 mg/ml Polidocanol.     

Psychological factors during rehabilitation of patients with Achilles or patellar tendinopathy: a cross-sectional study

Objectiveto examine psychological factors during rehabilitation of patients with Achilles or patellar tendinopathy as well as the association between psychological factors and tendinopathy severity, sport participation, and satisfaction with activity level and tendon function.Designcross-sectional study. Setting: online survey platform.Participants119 patients (mean age: 44 years (SD 14)) diagnosed with Achilles or patellar tendinopathy.Main outcome measuresA range of patient-reported psychological and outcome measures were recorded. Multivariate regression analyses were performed to establish the association between each psychological factor and outcome measures, adjusted for relevant confounders.ResultsPsychological readiness and confidence to return to sports (I-PRRS) and pain catastrophizing (PCS) were significantly associated with tendinopathy severity (modified VISA), sport participation(OSTRC-O), and satisfaction. Kinesiophobia (TSK) and the importance to patients of returning to pre-injury activity level were significantly associated with sports participation and satisfaction.ConclusionThe current study provides evidence of impairments in psychological factors during rehabilitation of patients with Achilles and patellar tendinopathy. Most investigated psychological factors were associated with tendinopathy severity, function, participation, and satisfaction. Physical therapists should recognize patients with lack of psychological readiness to return to sports and also patients with kinesiophobia or catastrophizing thoughts when experiencing pain.     

Leg stiffness changes in athletes with Achilles tendinopathy

Overuse injuries of the Achilles tendon cause impairment in lower leg muscle-tendon function. The purpose of this study was to evaluate leg stiffness in patients suffering unilateral Achilles tendinopathy. 51 athletes with unilateral Achilles tendinopathy underwent leg stiffness testing by modeling the vertical ground reaction force in a contact mat, measuring flight and contact time during hopping. Clinical status was estimated with a pain VAS and a validated questionnaire (VISA-A). The 'leg stiffness ratio' (LSR=stiffness of injured leg/stiffness of healthy leg) was calculated to determine the relative patient affectation and for intra-group comparison. 84 percent of subjects showed lower leg stiffness in the affected side during hopping. Leg stiffness was significantly lower in the limb affected by Achilles tendinopathy than in the healthy side (14.07±3.74 kN/m vs. 15.61±4.01 kN/m, p=0.047); overall LSR was 0.90±0.09. Intra-group comparison did not show significant differences related to patients' age, gender, sport level, and site of tendon injury (midportion or insertional). Leg stiffness was significantly reduced in patients with unilateral Achilles tendinopathy probably related to increasing ankle compliance. Regular leg stiffness assessment would be beneficial for athletes suffering Achilles tendon problems in terms of quantifying performance capabilities and providing objective data for a safer return to sport activity.     

Characterisation of Achilles tendon pain in recreational runners using multidimensional pain scales

ObjectivesThe main assessment tool for Achilles tendinopathy (AT) is the VISA-A. However, the VISA-A only assesses the physical impairments that result from tendon pain. This study sought to describe and assess tendon pain using other multidimensional pain scales; the short forms of the McGill pain questionnaire (sf-MPQ) and the Brief Pain Inventory (sf-BPI).DesignCross sectional observational study.Methods124 recreational runners with clinically confirmed mid-portion Achilles tendinopathy for at least 3 months were recruited from Cape Town, South Africa. They described and rated their tendinopathy symptoms by completing the VISA-A, sf-BPI and sf-MPQ questionnaires.ResultsTendon pain was largely described as a sensory type of pain with minimal affective elements. Sixty percent described their pain as aching. Significant proportions described it as tender (52.9%), throbbing (33.9%), hot burning (24.8%) and 33.8% ranked it as discomfiting or worse on the pain intensity score of the sf-MPQ. Tendon pain interfered with mood in 50.8% of the participants as well as with walking ability (72.5%), sleep (34.8%) and enjoyment of life (54.2%).ConclusionsTendon pain was described using a variety of adjectives which may suggest that AT has clinical subtypes. Tendon pain interferes with more than just physical function. Therefore, the recommendation is to conduct further studies using various pain questionnaires to elicit more details and better understand the nature of Achilles tendon pain.     

Do people with unilateral mid-portion Achilles tendinopathy who participate in running-related physical activity exhibit a meaningful conditioned pain modulation (CPM) effect: a pilot study

ObjectivesOur primary objective was to report the presence of a conditioned pain modulation (CPM) effect in people with localised mid-portion Achilles tendinopathy and whether changes occur over a 12-week period. Our secondary objectives were to quantify the proportion of participants who present for tendinopathy research with previous interventions or co-morbidities, which may impact the CPM-effect and investigate modulating factors.DesignProspective, observational cohort pilot study.Method215 participants presented for this Achilles tendinopathy research and were screened for inclusion with nine being included. Included participants had the CPM-effect (cold-pressor test) assessed using pressure pain thresholds at the Achilles tendon and quantified as absolute, relative and meaningful change at baseline and 12-week follow-up.ResultsThe most common reasons for exclusion were failure to meet a load-related diagnosis for Achilles tendinopathy (15.5%), presence of confounding other injury (14.1%) and previous injection therapy (13.6%). All participants had a meaningful CPM-effect at baseline and 12-week follow-up. The mean (SD, n) baseline relative CPM effect (reduction in PPTs) was ?40.5 (32.7, 9) percent. Moderators of the CPM-effect as well as follow-up changes were not statistically analysed due to a small sample size.ConclusionBased on these data, we would suggest that a homogenous population of patients with chronic, unilateral mid-portion Achilles tendinopathy and no other co-morbidities are likely to exhibit a meaningful CPM-effect. Impairments to endogenous analgesic mechanisms seen in people presenting with mid-portion Achilles tendinopathy may be due to other confounding variables.     

Terminology for Achilles tendon related disorders

The terminology of Achilles tendon pathology has become inconsistent and confusing throughout the years. For proper research, assessment and treatment, a uniform and clear terminology is necessary. A new terminology is proposed; the definitions hereof encompass the anatomic location, symptoms, clinical findings and histopathology. It comprises the following definitions: Mid-portion Achilles tendinopathy: a clinical syndrome characterized by a combination of pain, swelling and impaired performance. It includes, but is not limited to, the histopathological diagnosis of tendinosis. Achilles paratendinopathy: an acute or chronic inflammation and/or degeneration of the thin membrane around the Achilles tendon. There are clear distinctions between acute paratendinopathy and chronic paratendinopathy, both in symptoms as in histopathology. Insertional Achilles tendinopathy: located at the insertion of the Achilles tendon onto the calcaneus, bone spurs and calcifications in the tendon proper at the insertion site may exist. Retrocalcaneal bursitis: an inflammation of the bursa in the recess between the anterior inferior side of the Achilles tendon and the posterosuperior aspect of the calcaneus (retrocalcaneal recess). Superficial calcaneal bursitis: inflammation of the bursa located between a calcaneal prominence or the Achilles tendon and the skin. Finally, it is suggested that previous terms as Haglund’s disease; Haglund’s syndrome; Haglund’s deformity; pump bump (calcaneus altus; high prow heels; knobbly heels; cucumber heel), are no longer used.     

Self-reported pain with single leg heel raise or single leg hop offer distinct information as measures of severity in men with midportion and insertional Achilles tendinopathy: An observational cross-sectional study

ObjectivesTo investigate if self-reported pain with single leg heel raise (SLHR) or single leg hop (SLH) are concurrently valid to assess midportion (MPAT) or insertional Achilles tendinopathy (IAT) symptom severity, compared to the VISA-A. Additionally, if SLHR or SLH pain accounts for VISA-A variability, and if they are associated with psychological factors.Participants60 men with MPAT, 26 men with IAT.Main outcomesParticipants rated SLHR and SLH pain on a numerical rating scale (0 = none, 10 = worst). We investigated relationships between loading task pain, VISA-A, VISA-A constructs, and psychological outcomes (Pearson’s correlation coefficients). Linear regression determined best model accounting for VISA-A variability.ResultsIn MPAT, load tests shared fair-negative relationship with VISA-A, and VISA-A function. In IAT, SLHR had moderately strong-negative relationship with VISA-A, and pain and function constructs, and SLH shared fair-negative relationship with VISA-A, and pain and function constructs. Relationships were negligible between load tests and VISA-A activity in both conditions, and VISA-A pain in MPAT. In IAT, there was fair-positive relationship between pain catastrophising and load tests. Remaining psychological outcome relationships were negligible. Best model accounting for VISA-A included SLH in MPAT, and SLHR in IAT.ConclusionsDespite VISA-A and selected VISA-A construct associations, self-reported SLHR and SLH pain appears to provide distinct information.     

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

ObjectivesSeveral substances are routinely injected in and around tendons. The present study evaluated the long term effects of high volume image guided injection (HVIGI) of normal saline, local anaesthetic and aprotinin in athletic patients with resistant tendinopathy of the main body of the Achilles tendon.DesignCase series.MethodsThe study included a series of 94 athletes (69 men and 25 women; average age 37.5 years, range 22–63) with ultrasound confirmed tendinopathy of the main body of the Achilles tendon. All the patients had not improved after at least three months of conservative management. Patients were injected with 10 mL of 0.5% Bupivacaine Hydrochloride, 25 mg aprotinin, and up to 40 mL of injectable normal saline. We prospectively administered the Victorian Institute of Sport Assessment–Achilles tendon (VISA-A) to assess the short- and long-term pain and functional improvement.ResultsAt baseline (n = 94), the VISA-A score was 41.7 ± 23.2 (range 11–60), and had improved to 74.6 ± 21.4 (range 71–100) by 12 months (n = 87) (p = 0.003), with no significant difference between sexes.ConclusionHVIGI with aprotinin significantly reduces pain and improves function in patients with chronic Achilles tendinopathy in the short- and long-term follow up.     

Magnetic resonance signal, rather than tendon volume, correlates to pain and functional impairment in chronic Achilles tendinopathy

PURPOSE: To depict abnormal tendon matrix composition using magnetic resonance imaging (MRI) in chronic Achilles tendinopathy, and correlate intratendinous signal alterations to pain and functional impairment. MATERIAL AND METHODS: MRI of the Achilles tendon was performed on 25 patients with chronic Achilles tendinopathy (median age 50, range 37-71 years). All patients suffered from pain in the mid-portion of the Achilles tendon. Intratendinous signal was calculated from five different sagittal sequences, using a computerized 3D seed-growing technique. Pain and functional impairment were evaluated using a questionnaire completed by patients. RESULTS: Severity of pain and functional impairment correlated to increased mean intratendinous signal in the painful tendon in all MR sequences (P < 0.05, median r = 0.38, range 0.28-0.43 for pain; P < 0.05, median r = 0.48, range 0.29-0.49 for functional impairment). However, tendon volume did not correlate to pain or functional impairment (P > 0.05). Difference in mean intratendinous signal between symptomatic and contralateral asymptomatic tendons was highly significant in all sequences (P < 0.05) except on T2-weighted images (P = 0.6). CONCLUSION: Severity of pain and disability correlated to increased MR signal rather than to tendon volume in patients with unilateral mid-portion chronic Achilles tendinopathy.     

Pain duration is associated with increased muscle sympathetic nerve activity in patients with Achilles tendinopathy

Tendinopathy is a common condition, which has been linked to surrogate measures of sympathetic nervous system (SNS) activity and insulin resistance. This study aimed to compare in vivo measures of the SNS and insulin resistance between individuals with and without Achilles tendinopathy. This case–control study compared Achilles tendinopathy sufferers to healthy controls. SNS activity was quantified using muscle sympathetic nerve activity (MSNA), while metabolic status was assessed via a modified glucose tolerance test and fasting lipid panel. Ultrasound tissue characterization assessed tendon structure. Resting MSNA did not differ between the 15 cases and 20 controls. Tendon pain duration in tendinopathy patients was correlated with burst frequency (R²=.32, P=.02) and burst incidence (R²=.41, P=.01) of MSNA. After adjusting for multiple comparisons, there was a trend suggesting fasting glucose was greater in cases (median 4.80, IQR .70 in cases vs 4.51, .38 in controls) and correlated with pain severity (R²=.14, P=.03), but no other metabolic measures were associated with tendon pain/structure. This study indicates that SNS activity is associated with tendon pain duration, building on previous data indicating the SNS is involved in recalcitrant tendinopathy. Metabolic parameters had little relationship with Achilles tendinopathy in this metabolically homogenous sample. Prospective studies are required to uncover the precise relationship between SNS activity, insulin resistance, and tendinopathy.     

Noninsertional Achilles tendinopathy: Pathology and management

Many patients present to their physician's office with the chief complaint of pain at the Achilles tendon. This review discusses the pathology, diagnosis, and treatment of Achilles tendinopathy. Achilles tendinopathy is generally caused by chronic stress to the tendon, leading to a defective arrangement of collagen fibers in the Achilles tendon. This then results in pain and limited function. Ultrasound imaging can help identify the abnormal portion of the tendon. Various treatments are available for Achilles tendinopathy, the most current of which are discussed in this article. Appropriate treatment can potentially lead to a full recovery.     

Endoscopic Achilles tenodesis: a surgical alternative for chronic insertional tendinopathy

This report describes an endoscopic approach for visualization and repair of heel structures potentially involved in patients presenting chronic calcaneal tendon insertion pain. Tendon–bone junction separation allows enthesis debridement. Tenodesis with a knotless absorbable anchor completes this minimally invasive surgical procedure for chronic insertional Achilles tendinopathy.     

Chronic Achilles tendon pain treated with eccentric calf-muscle training

Injuries involving the Achilles tendon and manifested as chronic tendon pain are common, especially among recreational athletes. In a pilot study on a small group of patients with chronic painful mid-portion Achilles tendinosis, eccentric calf-muscle training was shown to give good clinical results. The aim of this prospective study was to investigate if the previously achieved good clinical results could be reproduced in a larger group of patients, and also to investigate the effects of eccentric calf-muscle training in patients with chronic insertional Achilles tendon pain. Seventy-eight consecutive patients, having chronic painful Achilles tendinosis at the mid-portion (2–6 cm level) in a total of 101 tendons (55 unilateral and 23 bilateral), and thirty consecutive patients with chronic insertional Achilles tendon pain in 31 tendons (29 unilateral and one bilateral) were treated with eccentric calf-muscle training for 12 weeks. Most patients were recreational athletes. Evaluation of the amount of tendon pain during activity was recorded on a visual analogue scale (VAS), before and after treatment. In 90 of the 101 Achilles tendons (89%) with chronic painful mid-portion Achilles tendinosis, treatment was satisfactory and the patients were back on their pre-injury activity level after the 12-week training regimen. In these patients, the amount of pain during activity, registered on the VAS-scale (mean±SD), decreased significantly from 66.8±19.4 to 10.2±13.7. On the contrary, in only ten of the tendons (32%) with chronic insertional Achilles tendon pain was treatment satisfactory, with a significant decrease on the VAS-scale (mean±SD), from 68.3±7.0 to 13.3±13.2. Our conclusion is that treatment with eccentric calf-muscle training produced good clinical results in patients with chronic painful mid-portion Achilles tendinosis, but not in patients with chronic insertional Achilles tendon pain.     

Treatment of midportion Achilles tendinosis: similar clinical results with US and CD-guided surgery outside the tendon and sclerosing polidocanol injections

Sclerosing polidocanol injections targeting the area with vasculo/neural ingrowth on the ventral side of the tendon have previously been demonstrated to give good clinical results in patients with chronic painful midportion Achilles tendinosis. In this study, 20 consecutive patients (9 men and 11 women, mean age 46 years) with chronic painful midportion Achilles tendinosis were treated with either sclerosing polidocanol injections (Group A) or open surgical revision of the area with vasculo/neural ingrowth on the ventral side of the Achilles tendon (Group B). Before treatment, all patients had structural tendon changes and increased blood flow-neovascularisation demonstrated with US and colour Doppler. Under US and colour Doppler-guidance, both the injections and the surgical revision targeted the area with neovessels just outside the ventral part of the tendon. A maximum of two sclerosing injection treatments, with 6–8 weeks in-between, were given. For evaluation, the patients recorded the severity of Achilles tendon pain during tendon loading activity (their recreational or sport activity), before and after treatment, on a VAS. Patient global satisfaction with treatment was also assessed. At the 3 months follow-up 6/9 (one patient was excluded) patients in Group A, and 8/10 patients in Group B, were satisfied with the treatment and had a significantly reduced level of tendon pain (Group A VAS from 76 to 24, P < 0.05, Group B VAS from 75 to 21, P < 0.05). There was one deep infection in Group B. At the 6 months follow-up, 6/9 patients in Group A, and 10/10 patients in Group B were satisfied. In summary, both treatment with sclerosing polidocanol injections and open surgical revision outside the ventral Achilles midportion show promising short-term clinical results.     

Blood flow of the Achilles tendon during military training

The purpose of this study was to evaluate the vascular response of the Achilles tendon as indicated by power Doppler activity during a military training program of 6 weeks. 49 male military recruits (98 tendons) volunteered for this study. Before and during the military training program, the Achilles tendons were screened with gray-scale ultrasonography and power Doppler US. Reactive tendinopathies of the Achilles tendons were registered by means of a clinical examination, VAS-scores and VISA-A scores. The US examination, the clinical examination, VAS-scores and VISA-A scores showed that 13/98 tendons developed a reactive tendinopathy. 3 of these 13 symptomatic tendons showed intratendinous Doppler activity. In these tendons, pain was always present before the vascular response of the Achilles tendon. Both pain and hypervascularisation remained visible till the end of the basic military training. In 5 asymptomatic tendons with no structural changes of the tendon, a vascular response was seen during one single measurement. It can be hypothesized that there is no relationship between the vascular response of the Achilles tendon and the pain in a reactive tendinopathy. In a reactive tendinopathy, other pain mechanisms must be investigated in future research.     

Biomechanische Eigenschaften bei Achillessehnen-Tendinopathien und deren Korrelation mit der elastosonografisch bestimmten Sehnenqualität

BackgroundThe aim of this study was to assess the correlation of the (reduced) quality of tendons in Achilles tendinopathy and the efficiency of the muscle-tendon system. Thereby the biomechanical variables of the isokinetic strength as well as the gait analysis in patients with Achilles tendinopathy were correlated to the strain scores of the TDI elastosonography.Materials and MethodsThe tendon quality in Achilles tendinopathies was determined using the TDI elastosonography in 25 athletes (Æ 48±10.2 years). Additionally, a plantar pressure analysis (FDM-T, zebris Medical GmbH) as well as an isokinetic strength test (Humac®NormTM, CSMI) was conducted with the subjects.ResultsThere were moderate correlations between the strength of the plantar flexors and the amount of the strain scores (tendon quality) with r=0.473 (absolut) und r=0.554 (normalized KG). Additionally, there was a significant correlation between the strength deficit of the plantar flexors on the injured side and the amount of the strain scores with r=0.794.ConclusionsNext to the anamnesis and clinical finding the elastosonography as well as the biomechanical examination can be used in a comprehensive assessment of Achilles pathology to provide additional information for a differentiated and cause related choice of therapy.Level of Evidence: III     

Variability within the human iNOS gene and Achilles tendon injuries: Evidence for a heterozygous advantage effect

ObjectivesThe aim of this case control genetic association study was to explore whether two variants within the inducible nitric oxide synthase (iNOS) gene, rs2779249 (C/A) and rs2248814 (A/G), influenced the risk of Achilles tendinopathy in a British population.DesignCandidate gene, case control association study.MethodWe recruited 145 individuals diagnosed with Achilles tendon pathology and 132 asymptomatic controls. All participants were genotyped for the iNOS variants using qPCR and significant associations were discovered using a combination of Chi squared and ANOVA type analysis.ResultsThe CA genotype of the iNOS rs2779249 variant was protective and conformed to a heterozygous advantage model of inheritance as it was overrepresented in the control participants (p = 0.009). In sex specific analysis the protective association persisted in male participants (p = 0.016) but not in females. Unlike the rs2779249 variant, the rs2248814 variant was not associated with Achilles tendinopathy or Achilles tendon rupture.ConclusionThe rs2779249 CA genotype within the human iNOS gene appears to protect individuals from Achilles tendinopathy. This study further supports a genetic contribution to modifying the risk of Achilles tendon problems. The study also infers an important role for nitric oxide in tendon healing and/or degradation.     

Prevalence of Achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes

Achilles (AT) and patellar tendons (PT) are commonly affected by tendinopathy in adult athletes but prevalence of symptoms and morphological changes in adolescents is unclear. The study aimed to determine prevalence of tendinopathy and intratendinous changes in ATs and PTs of adolescent athletes. A total of 760 adolescent athletes (13.0 ± 1.9 years; 160 ± 13 cm; 50 ± 14 kg) were examined. History, local clinical examination, and longitudinal Doppler ultrasound analysis for both ATs and PTs were performed including identification of intratendinous echoic changes and vascularization. Diagnosis of tendinopathy was complied clinically in case of positive history of tendon pain and tendon pain on palpation. Achilles tendinopathy was diagnosed in 1.8% and patellar tendinopathy in 5.8%. Vascularizations were visible in 3.0% of ATs and 11.4% of PTs, hypoechogenicities in 0.7% and 3.2% as well as hyperechogenicities in 0% and 0.3%, respectively. Vascularizations and hypoechogenicities were statistically significantly more often in males than in females (P ≤ 0.02). Subjects with patellar tendinopathy had higher prevalence of structural intratendinous changes than those without PT symptoms (P ≤ 0.001). In adolescent athletes, patellar tendinopathy is three times more frequent compared with Achilles tendinopathy. Longitudinal studies are necessary to investigate physiological or pathological origin of vascularizations and its predictive value in development of tendinopathy.