James E. Gaida

Is Adiposity an Under-Recognized Risk Factor for Tendinopathy? A Systematic Review

OBJECTIVE Tendon injuries have been reported to occur more frequently in individuals with increased adiposity. Treatment also appears to have poorer outcomes among these individuals. Our objective was to examine the extent and consistency of associations between adiposity and tendinopathy. METHODS A systematic review of observational studies was conducted. Eight electronic databases were searched (Allied and Complementary Medicine, Biological Abstracts, CINAHL, Current Contents, EMBase, Medline, SPORTDiscus, and Web of Science) and citation tracking was performed on included reports. Studies were included if they compared adiposity between subjects with and without tendon injury or examined adiposity as a predictor of conservative treatment success. RESULTS Four longitudinal cohorts, 14 cross-sectional studies, 8 case-control studies, and 2 interventional studies (28 in total) met the inclusion criteria, providing a total of 19,949 individuals. Forty-two subpopulations were identified, 18 of which showed elevated adiposity to be associated with tendon injury (43%). Sensitivity analyses indicated a clustering of positive findings among studies that included clinical patients (81% positive) and among case-control studies (77% positive). CONCLUSION Elevated adiposity is frequently associated with tendon injury. Published reports suggest that elevated adiposity is a risk factor for tendon injury, although this association appears to vary depending on aspects of study design and measurement. Adiposity is of particular interest in tendon research because, unlike a number of other reported risk factors for tendon injury, it is somewhat preventable and modifiable. Further research is required to determine if reducing adiposity will reduce the risk of tendon injury or improve the results of treatment.

Are unilateral and bilateral patellar tendinopathy distinguished by differences in anthropometry, body composition, or muscle strength in elite female basketball players?

Background: Overuse injury to the patellar tendon (patellar tendinopathy) is a major reason for interrupted training and competition for elite athletes. In both sexes, the prevalence of unilateral and bilateral tendinopathy has been shown to differ. It has been proposed that bilateral pathology may have a different aetiology from unilateral pathology. Investigation of risk factors that may be unique to unilateral and bilateral patellar tendinopathy in female athletes may reveal insights into the aetiology of this condition. Objectives: To examine whether anthropometry, body composition, or muscle strength distinguished elite female basketball players with unilateral or bilateral patellar tendinopathy. Methods: Body composition, anthropometry, and muscle strength were compared in elite female basketball players with unilateral (n  =  8), bilateral (n  =  7), or no (n  =  24) patellar tendinopathy. Body composition was analysed using a dual energy x ray absorptiometer. Anthropometric measures were assessed using standard techniques. Knee extensor strength was measured at 180°/s using an isokinetic dynamometer. z scores were calculated for the unilateral and bilateral groups (using the no tendinopathy group as controls). z scores were tested against zero. Results: The tibia length to stature ratio was approximately 1.3 (1.3) SDs above zero in both the affected and non-affected legs in the unilateral group (p<0.05). The waist to hip ratio was 0.66 (0.78) SD above zero in the unilateral group (p<0.05). In the unilateral group, leg lean to total lean ratio was 0.42 (0.55) SD above zero (p<0.07), the trunk lean to total lean ratio was 0.63 (0.68) SD below zero (p<0.05), and leg fat relative to total fat was 0.47 (0.65) SD below zero (p<0.09). In the unilateral group, the leg with pathology was 0.78 (1.03) SD weaker during eccentric contractions (p<0.07). Conclusions: Unilateral patellar tendinopathy has identifiable risk factors whereas bilateral patellar tendinopathy may not. This suggests that the aetiology of these conditions may be different. However, interpretation must respect the limitation of small subject numbers.

Dyslipidemia in Achilles tendinopathy is characteristic of insulin resistance.

UNLABELLED Overuse is considered to be a main causative factor for tendinopathies; however, recent reports indicate that tendinopathy is also common among both overweight and inactive individuals. These factors are associated with abdominal obesity, dyslipidemia, hypertension, and insulin resistance. We hypothesized that these features would be associated with tendinopathy. PURPOSE To compare lipid profile between participants with Achilles tendinopathy and matched controls. METHODS Fasting serum lipids were measured among 60 participants with chronic painful midportion Achilles tendinopathy (54% male) and 60 control subjects matched for gender, age (+/-10 yr), and body mass index (+/-2 kg x m(-2)). RESULTS The participants with Achilles tendinopathy showed evidence of underlying dyslipidemia. They had higher triglyceride (TG) levels (P = 0.039), lower %HDL-C (P = 0.016), higher TG/HDL-C ratio (P = 0.036), and elevated apolipoprotein B concentration (P = 0.017) in comparison to the well-matched control group. CONCLUSIONS This pattern of dyslipidemia is characteristic of the dyslipidemia displayed by individuals with insulin resistance and is common in the metabolic syndrome. Two additional aspects of tendinopathy research support a connection with the metabolic syndrome. First, tendinopathy has been associated with greater waist circumference, as has the metabolic syndrome. Second, insulin resistance has been associated with fat deposition in muscle (primarily intracellular), whereas fat deposition in tendon has been found among those with tendon pain.If tendinopathy is confirmed to be associated with dyslipidemia and the metabolic syndrome in larger studies, it may be appropriate to redefine our concept of tendinopathy to that of a cardiovascular disease (CVD). In this case, we may be able to draw considerably on CVD research to improve our understanding of tendinopathy, and perhaps treating CVD risk factors will improve the treatment of tendinopathy.

Tenocyte hypercellularity and vascular proliferation in a rabbit model of tendinopathy: contralateral effects suggest the involvement of central neuronal mechanisms

Objective To determine whether there are objective findings of tendinosis in a rabbit tendinopathy model on exercised and contralateral (non-exercised) Achilles tendons. Design Four groups of six New Zealand white rabbits per group were used. The animals of one (control) group were not subjected to exercise/stimulation. Interventions Animals were subjected to a protocol of electrical stimulation and passive flexion–extension of the right triceps surae muscle every second day for 1, 3 or 6 weeks. Main Outcome Measures Tenocyte number and vascular density were calculated. Morphological evaluations were also performed as well as in-situ hybridisation for vascular endothelial growth factor (VEGF) messenger RNA. Results There was a significant increase in the tenocyte number after 3 and 6 weeks of exercise, but not after 1 week, in comparison with the control group. This was seen in the Achilles tendons of both legs in experimental animals, including the unexercised limb. The pattern of vascularity showed an increase in the number of tendon blood vessels in rabbits that had exercised for 3 weeks or more, compared with those who had exercised for 1 week or not at all. VEGF-mRNA was detected in the investigated tissue, with the reactions being more clearly detected in the tendon tissue with tendinosis-like changes (6-week rabbits) than in the normal tendon tissue (control rabbits). Conclusions There were bilateral tendinosis-like changes in the Achilles tendons of rabbits in the current model after 3 weeks of training, suggesting that central neuronal mechanisms may be involved and that the contralateral side is not appropriate as a control.

Asymptomatic Achilles tendon pathology is associated with a central fat distribution in men and a peripheral fat distribution in women: a cross sectional study of 298 individuals

BackgroundAdiposity is a modifiable factor that has been implicated in tendinopathy. As tendon pain reduces physical activity levels and can lead to weight gain, associations between tendon pathology and adiposity must be studied in individuals without tendon pain. Therefore, the purpose of this study was to determine whether fat distribution was associated with asymptomatic Achilles tendon pathology.MethodsThe Achilles tendons of 298 individuals were categorised as normal or pathological using diagnostic ultrasound. Fat distribution was determined using anthropometry (waist circumference, waist hip ratio [WHR]) and dual-energy x-ray absorptiometry.ResultsAsymptomatic Achilles tendon pathology was more evident in men (13%) than women (5%) (p = 0.007). Men with tendon pathology were older (50.9 ± 10.4, 36.3 ± 11.3, p < 0.001), had greater WHR (0.926 ± 0.091, 0.875 ± 0.065, p = 0.039), higher android/gynoid fat mass ratio (0.616 ± 0.186, 0.519 ± 0.142, p = 0.014) and higher upper-body/lower body fat mass ratio (2.346 ± 0.630, 2.022 ± 0.467, p = 0.013). Men older than 40 years with a waist circumference >83 cm had the greatest prevalence of tendon pathology (33%). Women with tendon pathology were older (47.4 ± 10.0, 36.0 ± 10.3, p = 0.008), had less total fat (17196 ± 3173 g, 21626 ± 7882 g, p = 0.009), trunk fat (7367 ± 1662 g, 10087 ± 4152 g, p = 0.003) and android fat (1117 ± 324 g, 1616 ± 811 g, p = 0.005). They had lower central/peripheral fat mass ratios (0.711 ± 0.321 g, 0.922 ± 0.194 g, p = 0.004) than women with normal tendons. Women with tendon pathology were more often menopausal (63%, 13%, p = 0.002).ConclusionsMen with Achilles tendon pathology were older and had a central fat distribution. Women with tendon pathology were older and had a peripheral fat distribution. An interaction between age and waist circumference was observed among men.

Adiposity and tendinopathy

Purpose. Tendon injuries (tendinopathy) are prevalent across the population, affecting active and inactive individuals and manual workers. The aetiology of tendinopathy is not known. However, extrinsic factors such as load are known to affect the prevalence. More recently, intrinsic factors have been shown to also affect tendons; genes, biomechanics, and strength have been shown to influence tendon disease. One intrinsic factor that appears to have an association with tendinopathy is body composition; more specifically central adiposity. Several studies have reported this association, and several studies have found the association when reporting other aspects of tendinopathy. Method. This paper will detail what is known about the association between tendinopathy and body composition, examine the strength of the association by evaluating studies in the area and speculate on potential mechanisms for the association. Results. The association between tendon health and adiposity, especially central adiposity, warrants further investigation. Conclusion. There may be an interaction between adiposity and tendon pathology. Adiposity may be a key intrinsic risk factor that is translated into tendon disease in the presence of additional intrinsic (e.g., diabetes) and extrinsic factors (e.g., load).

Treatment options for patellar tendinopathy: critical review.

Patellar tendinopathy is a painful knee injury due to overuse common among jumping athletes. Because rest from sport is neither a feasible nor an effective treatment for patellar tendinopathy in elite athletes, active treatment options are needed. Treatment may be conservative, injection-based, or surgical. This review synthesizes findings from 32 studies of varying quality published between 2001 and 2011. Painful eccentric squats using a 25°-decline board is supported as a first-line treatment. Extracorporeal shock wave therapy is no more effective than placebo. Sclerosing injections seem to be effective, but the evidence is not definitive. Shaving of abnormal tissue via arthroscopic surgery with real-time ultrasound guidance is superior to sclerosing injections. Steroid injections are inferior to exercise interventions and are not recommended. Injections of autologous blood, platelet-rich plasma, and hyperosmolar dextrose are unproven and experimental. Clinicians need to have a comprehensive knowledge of the evidence in the literature, as well as training and experience, when treating patellar tendinopathy.

The Acceptability Among Health Researchers and Clinicians of Social Media to Translate Research Evidence to Clinical Practice: Mixed-Methods Survey and Interview Study

Background Establishing and promoting connections between health researchers and health professional clinicians may help translate research evidence to clinical practice. Social media may have the capacity to enhance these connections. Objective The aim of this study was to explore health researchers’ and clinicians’ current use of social media and their beliefs and attitudes towards the use of social media for communicating research evidence. Methods This study used a mixed-methods approach to obtain qualitative and quantitative data. Participation was open to health researchers and clinicians. Data regarding demographic details, current use of social media, and beliefs and attitudes towards the use of social media for professional purposes were obtained through an anonymous Web-based survey. The survey was distributed via email to research centers, educational and clinical institutions, and health professional associations in Australia, India, and Malaysia. Consenting participants were stratified by country and role and selected at random for semistructured telephone interviews to explore themes arising from the survey. Results A total of 856 participants completed the questionnaire with 125 participants declining to participate, resulting in a response rate of 87.3%. 69 interviews were conducted with participants from Australia, India, and Malaysia. Social media was used for recreation by 89.2% (749/840) of participants and for professional purposes by 80.0% (682/852) of participants. Significant associations were found between frequency of professional social media use and age, gender, country of residence, and graduate status. Over a quarter (26.9%, 229/852) of participants used social media for obtaining research evidence, and 15.0% (128/852) of participants used social media for disseminating research evidence. Most participants (95.9%, 810/845) felt there was a role for social media in disseminating or obtaining research evidence. Over half of the participants (449/842, 53.3%) felt they had a need for training in the use of social media for professional development. A key barrier to the professional use of social media was concerns regarding trustworthiness of information. Conclusions A large majority of health researchers and clinicians use social media in recreational and professional contexts. Social media is less frequently used for communication of research evidence. Training in the use of social media for professional development and methods to improve the trustworthiness of information obtained via social media may enhance the utility of social media for communicating research evidence. Future studies should investigate the efficacy of social media in translating research evidence to clinical practice.

Evidence of the TNF-α System in the Human Achilles Tendon: Expression of TNF-α and TNF Receptor at both Protein and mRNA Levels in the Tenocytes

Understanding adaption to load is essential for prevention and treatment of tendinopathy/tendinosis. Cytokine release in response to load is one mechanism involved in mechanotransduction. The cytokine tumor necrosis factor alpha (TNF-α) is implicated in tendinosis and can induce apoptotic effects via tumor necrosis factor receptor 1 (TNFR1). The complete absence of information concerning the TNF-α system in Achilles tendon is a limitation as mid-portion Achilles tendinosis is very frequent. Purpose: To examine expression patterns of TNF-α and its two receptors (TNFR1 and TNFR2) in human Achilles tendinosis and control tissue and to biochemically confirm the presence of TNF-α in tendinosis tissue. Methods: TNF-α and TNFR1 mRNA were detected via in situ hybridization. TNF-α, TNFR1, and TNFR2 were demonstrated immunohistochemically. Apoptosis markers were utilized. ELISA was used to detect TNF-α. Results: TNF-α and TNFR1 mRNA was detected in tenocytes of both tendinosis and control tendons. Tenocytes from both groups displayed specific immunoreactions for TNF-α, TNFR1, and TNFR2. The widened/rounded tenocytes of tendinosis samples exhibited the most intense immunoreactions. Apoptosis was detected in only a subpopulation of the tenocytes in tendinosis tissue. TNF-α was measurable in tendinosis tissue. Inflammatory cells were not seen. Conclusion: This is the first evidence of the existence of the TNF-α system in the human Achilles tendon. Findings are confirmed at mRNA and protein levels as well as biochemically. The TNF-α system was in principle confined to the tenocytes. The connection between tenocyte morphology and the expression pattern of TNF-α, TNFR1, and TNFR2 suggests that the TNF-α system may be involved in tenocyte activation in Achilles tendinosis.

Do isometric and isotonic exercise programs reduce pain in athletes with patellar tendinopathy in-season? A randomised clinical trial

OBJECTIVES Many athletes with patellar tendinopathy participate in sports with symptoms during or after activities. Current treatments do not decrease pain in-season; eccentric exercises in-season result in an increase in pain. This study examined if isometric and isotonic exercises relieved pain in competing athletes with patellar tendinopathy. DESIGN Randomised clinical trial. METHODS Jumping athletes with patellar tendinopathy playing at least three times per week participated in this study. Athletes were randomised into an isometric or isotonic exercise group. The exercise programs consisted of four isometric or isotonic exercise sessions per week for four weeks. Pain during a single leg decline squat (SLDS) on a Numeric Rating Scale (NRS; 0-10) was used as the main outcome measure; measurements were completed at baseline and at 4-week follow-up. RESULTS Twenty-nine athletes were included in this study. Median pain scores improved significantly over the 4-week intervention period in both the isometric group (Z=-2.527, p=0.012, r=-0.63) and isotonic group (Z=-2.952, p=0.003, r=-0.63). There was no significant difference in NRS pain score change (U=29.0, p=0.208, r=0.29) between the isometric group (median (IQR), 2.5 (1-4.5)) and isotonic group (median (IQR), 3.0 (2-6)). CONCLUSIONS This is the first study to show a decrease in patellar tendon pain without a modification of training and competition load and the first study to investigate isometric exercises in a clinical setting. Both isometric and isotonic exercise programs are easy-to-use exercises that can reduce pain from patellar tendinopathy for athletes in-season.