Dyslipidemia in Achilles Tendinopathy Is Characteristic of Insulin Resistance

Risk factors for atraumatic isolated subscapularis tear: glenoid retroversion

BACKGROUND

Subscapularis tendon (SSC) tears have recently become an area of current research focus. However, the risk factors for atraumatic isolated SSC tears, particularly anatomical factors, remain poorly determined. Therefore, the purpose of this study was to identify the associated factors contributing to isolated SSC tears.

METHODS

This study involved single shoulders of 605 subjects drawn from a cohort of rural residents. The inclusion criteria required each subject to sign an informed consent document and to have a complete clinical evaluation. The exclusion criteria comprised the absence of a complete magnetic resonance imaging study, current medication use that might have affected serum lipid levels, a history of shoulder trauma or surgery, and the presence of osteoarthritis, calcific tendinitis, frozen shoulder, or superior or posterosuperior rotator cuff tear. Diagnoses of isolated SSC tear were based on magnetic resonance imaging findings. Logistic regression analysis was conducted using demographic, physical, social, anatomical, comorbidities, and serological parameters. Anatomical variables included the supraspinatus fossa glenoid angle on axial (SGAX), a method to measure glenoid version, coracohumeral distance on axial and sagittal plans, and coracoid index. When multicollinearity among studied variables was detected, separate multivariable analyses were performed to address this issue, with each analysis including only one of those multicollinear variables along with the other significant variables obtained from univariate analyses.

RESULTS

Among anatomical variables, coracohumeral distance on axial and sagittal planes, as well as the coracoid index, did not show significant associations. However, SGAX, an index of glenoid version, was found to be significantly associated with atraumatic isolated SSC tears. Greater glenoid retroversion is significantly associated with atraumatic isolated SSC tears, along with age, waist circumference, dominant side involvement, manual labor, diabetes, metabolic syndrome, and biceps tendon injury (P ≤ .013).

CONCLUSIONS

The SGAX, serving as an index for glenoid version, is an independently associated factor for atraumatic isolated subscapularis tendon tears, with greater glenoid retroversion being an anatomical risk factor for these tears, along with overuse-related factors such as dominant-side involvement and manual labor, as well as metabolic factors such as obesity, diabetes, metabolic syndrome, and biceps tendon injury.

Metabolic Risk Factors Relate to Worse Tendon Health in Individuals With Achilles Tendinopathy

A high proportion of individuals with Achilles tendinopathy continue to demonstrate long-term symptoms and functional impairments after exercise treatment. Thus, there is a need to delineate patient presentations that may require alternative treatment. The objective of this study was to evaluate if the presence of metabolic risk factors relates to tendon symptoms, psychological factors, triceps surae structure, and lower limb function in individuals with Achilles tendinopathy. One hundred and fifty-eight individuals (88 female) with diagnosed midportion Achilles tendinopathy were divided into three groups based on the number of metabolic risk factors linked to cardiovascular disease present at baseline: two or more factors, one factor, no factors. Metabolic risk factors were determined by clinical evaluation and past medical history. Achilles tendinopathy symptoms (Victorian Institute of Sport Assessment-Achilles, Patient Reported Outcome Measurement Information System, movement-evoked pain ratings), psychological factors (Tampa Scale for Kinesiophobia), triceps surae structure (B-mode ultrasound of tendon and muscle morphology, continuous shear wave elastography of tendon mechanical properties), and lower limb function (test battery) were compared among groups. Individuals with two or more metabolic risk factors had worse symptoms with loading (p = 0.011), smaller Achilles tendon size relative to body mass (p = 0.002), and worse lower limb function compared to individuals without metabolic risk factors (p < 0.02). No differences were observed between individuals with one metabolic risk factor and those without metabolic risk factors. Future consideration of multiple metabolic risk factors for individuals with Achilles tendinopathy could facilitate understanding the underlying impairments of tendon pathology and recovery that may be addressed with treatment.

CNPY2 modulates senescence-associated secretory phenotype in tendon stem/progenitor cells

Age-related diseases are often linked to chronic inflammation. Senescent cells secrete inflammatory cytokines, chemokines and matrix metalloproteinases, collectively referred to as the senescence-associated secretory phenotype (SASP). The current study discovered that aging leads to the accumulation of senescent tendon stem/progenitor cells (TSPCs) in tendon tissue, resulting in the development of a SASP. Conditioned medium from aged TSPCs induced cellular inflammation in young TSPCs. In addition, we found that Canopy homolog 2 (CNPY2) expression is reduced during tendon aging. CNPY2 deficiency causes TSPCs senescence and SASP. Our findings showed that the NF-κB signaling pathway is activated in CNPY2 knockdown TSPCs, pharmacological inhibition of NF-κB signaling pathway with BMS-345541 attenuated SASP of senescent TSPCs, which indicated that CNPY2 regulates TSPCs SASP might through NF-κB signaling pathway. Our findings suggested that CNPY2 plays an important role in TSPCs senescence and SASP, CNPY2 could be a promising target for age-related tendon disorders.

Postprandial glycaemic response and pain sensitivity in breast cancer survivors suffering from chronic pain: a double-blind, randomised controlled cross-over pilot experiment

INTRODUCTION

The study's primary goal is to investigate differences in postprandial glycaemic response (PPGR) to beverages with varying glycaemic index (i.e. low and medium) between breast cancer survivors (BCS) with chronic pain and healthy pain-free controls (HC). The secondary goal of the study is to investigate the potential link between PPGR and pain-related outcomes in BCS with chronic pain.

METHODS

In this study, 15 BCS and 15 HC were included. After 12 h of fasting, subjects were randomised between drinking a beverage made with 50 g of sucrose (medium) or isomaltulose (low) within 250 ml water. Blood glucose levels were monitored at fasting as well as at 15, 30, 45, 60, 90 and 120 min following beverage consumption. Furthermore, each participant was evaluated using several experimental pain measurements, including pressure pain thresholds (PPT), electrical detection threshold, electrical pain threshold, temporal summation and electrical offset analgesia (OA).

RESULTS

The BCS group had significantly higher PPGR to sucrose (p = .001) than the HC group. Furthermore, when PPGR to sucrose was compared to PPGR to isomaltulose within the groups, the BCS group showed a considerably larger difference (p = .012). Additionally, correlation analyses indicated both positive and negative associations between PPGR after sucrose intake and specific pain measurements (PPT-tibialis (r = .599), OA (rs = - .549), respectively) in BCS, and a positive association between the difference in PPGR between sucrose and isomaltulose and PPT-tibialis (r = .622).

CONCLUSION

These findings suggest that medium glycaemic index beverage intakes result in significantly higher blood glucose responses (i.e. PPGR) than low-glycaemic index beverage intakes in BCS. Additionally, BCS show an impaired glycaemic response to medium glycaemic index beverage intake and that the impaired glycaemic response might be related to pain sensitivity and endogenous analgesia in BCS. Furthermore, the higher glycaemic response to sucrose and greater difference in the amount of change in PPGR (when isomaltulose was substituted for sucrose) compared to HC highlight the importance of understanding how dietary choices with a lower glycaemic index can alter glycaemic regulation in BCS with chronic pain.

Achilles tendon morphology adaptations in chronic post-stroke hemiparesis: a comparative analysis with neurologically intact controls

Introduction

In individuals with chronic post-stroke hemiparesis, slow walking speed is a significant concern related to inadequate propulsion of the paretic limb. However, an overlooked factor is this population's altered morphology of the Achilles tendon, which may compromise the propulsive forces by the paretic limb. This study aimed to explore changes in Achilles tendon morphology, including gross thickness and intra-tendinous collagen fiber bundle organization, following stroke-induced brain lesions.

Methods

Fifteen individuals with chronic post-stroke hemiparesis (at least 6 months post-stroke) and 19 neurologically intact controls participated. Ultrasound imaging was used to evaluate Achilles tendon thickness and collagen organization in the paretic and non-paretic limbs of post-stroke participants, as well as in the right limb (control limb) of the neurologically intact control group.

Results and discussion

Compared to control individuals, the paretic limb in individuals post-stroke showed increased tendon thickness at the Achilles tendon insertion and 2 cm above it. The collagen fiber bundle at the Achilles tendon insertion of the paretic limb showed reduced organization compared to that in the control limb. Individuals post-stroke also exhibited slower walking speed, and increased plantarflexor muscle tone in the paretic limb compared to controls. In conclusion, individuals with chronic post-stroke hemiparesis demonstrated tendon thickening and collagen disorganization in the paretic limb, particularly at the insertion site of the Achilles tendon, likely due to an abnormal loading environment influenced by increased plantarflexor muscle tone, muscle co-activation, and muscle disuse and atrophy. These changes may increase tendon compliance, impair force transmission and propulsion, and contribute to slower walking speed. Addressing Achilles tendon integrity should be incorporated as a component of strategies to improve neuromuscular control in this population.

Association between copper and Achilles tendon disease: a two-sample Mendelian randomization study

Background

There is a clear association between micronutrients and Achilles tendon disease (AT). An increase in micronutrients may alleviate AT symptoms and have a therapeutic effect. The aim of this study is to clarify the causal relationship between 15 micronutrients (copper, zinc, magnesium, vitamins A, C, E, D, B6, B12, folic acid, carotene, iron, selenium, calcium, and potassium) and AT.

Methods

We employed the Mendelian randomization (MR) method to analyze the causal effects of micronutrients on the risk of AT. The SNPs related to micronutrients were obtained from a large-scale genome-wide association study (GWAS) of circulating micronutrients in European populations. Outcome data were obtained from a meta-analysis of AT in European-ancestry participants from the Finnish FINNGEN BIOBANK. The main analysis was conducted using the inverse variance weighting (IVW) method, with additional sensitivity and pleiotropy analyses performed.

Results

Inverse variance weighting results indicated a causal relationship between copper and AT (P = 0.003, OR = 0.899, 95% CI = 0.839-0.964). Sensitivity analysis validated the robustness and reliability of this finding.

Conclusion

This study revealed a causal relationship between copper and AT, with copper serving as a protective factor. This provides evidence of the causality between copper and AT, offering new insights for clinical research and therapeutic approaches in AT.

Characteristics of patients seeking national health service (NHS) care for Achilles tendinopathy: A service evaluation of 573 patients

BACKGROUND

Achilles tendinopathy is a common condition that is often still symptomatic 10 years after onset. Much of the available research has focussed on active populations, however our experience is patients seeking care in the UK's National Health Service (NHS) may be different.

OBJECTIVES

To determine the characteristics of patients receiving NHS care for Achilles tendinopathy (AT). To describe the utilisation of resources and the effectiveness of AT management in the NHS.

METHODS

A data extraction tool was developed and used to retrospectively extract the characteristics of 573 patients diagnosed with Achilles tendinopathy.

RESULTS

NHS Achilles tendinopathy patients averaged 57 years old, had a Body Mass Index of 31, and 69% had at least one other long-term health condition. These included musculoskeletal complaints (59%), hypertension (30%), Chronic Obstructive Pulmonary Disease or asthma (17%), cardiovascular disease (13%) and diabetes (13%). Subsequently medication usage was higher than the general population and included drugs that have been linked to the pathogenesis of tendinopathy. On average, healthcare providers conducted 3.8 therapy sessions and 26% of patients had radiological investigations. Outcome measures were commonly absent with Visual Analog Scale (VAS) scores documented in 51% of records, and patient-reported outcome measures like VISA-A only appearing in 3% of cases. Reports on psychosocial factors were seldom documented.

CONCLUSION

Individuals diagnosed with Achilles tendinopathy through NHS services exhibit distinct characteristics that diverge considerably from those currently represented in the published research used to develop clinical guidelines. NHS Achilles tendinopathy patients have multiple long-term health conditions and higher medication usage.

Warning Signs: Occult Diabetes and Dysglycemia in the Hand Surgery Patient Population

BACKGROUND

Diabetes mellitus often exists for many years prior to diagnosis, and very little is known about the role of the prediagnosis stage of metabolic impairment in contributing to hand and upper-extremity pathology. The goal of this study is to determine the prevalence of undiagnosed glucose dysregulation in patients presenting with the 2 most commonly treated conditions of the hand and wrist.

METHODS

A retrospective study was performed of hand surgery patients with no established diagnosis of prediabetes or diabetes referred for a 2-hour glucose tolerance test according to American Diabetes Association criteria. Patients were divided into 3 groups: peripheral neuropathies, trigger finger, and controls with various upper-extremity diagnoses. Rates of undiagnosed prediabetes and diabetes were compared between groups, including subgroup analysis of patients based on unilateral or bilateral presentation. Binary logistic regression analysis was also used to calculate odds ratios for multiple variables.

RESULTS

Patients with neuropathy had a significantly higher incidence of undiagnosed dysglycemia compared with the control group. Of those patients, 51.3% were prediabetic and 12.8% were diabetic. The control group had significantly lower rates. Within the bilateral neuropathy patients, 59.6% had prediabetes and 15.4% had diabetes, versus 34.6% with prediabetes and 7.7% with diabetes in the unilateral group.

CONCLUSIONS

Hand surgeons encounter a patient population with high rates of undiagnosed prediabetes and diabetes, with some presentations as much as 6 times higher than the general population. Certain patient presentations should prompt appropriate diagnostic testing and referral, especially those presenting with bilateral compression neuropathy and elevated body mass index.

Influence of body mass index on severity of rotator cuff tears

BACKGROUND

Research on the relationship between obesity and rotator cuff tears (RCTs) has been limited to the impact of obesity on the results of arthroscopic repair of RCTs; thus, a need for rigorous research controlling for other factors affecting RCTs is warranted, especially to better understand the impact of body mass index (BMI) on RCT severity.

METHODS

A retrospective study of admission records contained in electronic medical records pertaining to patients who were admitted for RCT repair on 1 shoulder between January 2018 and July 2022 was conducted. In total, 386 patients were included. In accordance with guidance regarding obesity from Taiwan's Ministry of Health and Welfare, patients were divided into three groups: underweight or normal weight (BMI <24.0 kg/m2), overweight (BMI 24.0-26.9 kg/m2), or obese (BMI ≥27.0 kg/m2). Magnetic resonance imaging was used to assess RCT severity in terms of four parameters: Patte stage (PS), fatty infiltration (FI), anteroposterior tear size (AP), and retraction size. Multinomial logistic regression analysis was performed on PS and FI grade data, and multiple linear regression analysis was performed on AP tear size and retraction size in order to analyze impact.

RESULTS

Our results revealed that the average age of the 386 patients was 63.41 years (SD = 9.29) and the mean BMI was 25.88 (SD = 3.72) kg/m2. We found significant differences in PS (P = .003), FI (P < .001), retraction size (P = .001), and AP tear size (P = .001) among patients who were underweight or normal weight, overweight, and obese. After controlling for other risk factors, including age, gender, RCT-prone occupation, duration of shoulder pain prior to surgery, history of shoulder injury, and tobacco use, we found that obese patients had higher severity levels in PS (B = 1.21, OR = 3.36, P = .029), FI (B = 1.38, OR = 3.96, P < .001), retraction size (β = 0.18, P = .001), and AP tear size (β = 0.18, P = .001) compared to underweight or normal weight patients.

CONCLUSIONS

Our study demonstrates that a correlation exists between BMI-measured obesity and RCT severity. We therefore suggest that adults control their weight given that maintaining a healthy weight is highly associated with better shoulder health.

Associations of normal fasting glucose levels and of insulin resistance with degenerative rotator cuff tear : Normoglycemia and rotator cuff tear

BACKGROUND

The upper normoglycemic range has been proposed as a risk factor for degenerative rotator cuff tendon tear (RCT), and insulin resistance has been suggested as a risk factor for tendinopathy. However, no research has established their association with degenerative RCT in the general population. This study aimed to determine whether fasting glucose levels and insulin resistance are risk factors for degenerative RCT in the normoglycemic population and identify the risk range for fasting glucose.

METHODS

This study included 418 normoglycemic participants from a rural cohort. Participants completed questionnaires, physical exams, blood tests, and MRI evaluations of both shoulders. Insulin resistance was assessed using a triglyceride/high-density-lipoprotein (TG/HDL) ≥ 3.5. Logistic regression analysis was used to determine the association between fasting glucose level, TG/HDL ≥ 3.5, and other factors and degenerative RCT. The study calculated the areas under the receiver operating characteristic curve (AUC) to determine the more appropriate predicting value between the scale and categorical values of fasting glucose levels, and compared the AUCs using the DeLong method.

RESULTS

In the multivariable analyses, both scale and categorical values of fasting glucose levels, and TG/HDL ≥ 3.5 were significantly associated with degenerative RCT. Fasting glucose levels ≥ 90.5 mg/dL (OR: 3.87, 95% CI: 2.10-7.06) in scale value and 90-99 mg/dL (OR: 4.13, 95% CI: 2.87-8.12) in categorical value were significantly associated with degenerative RCT (P < .001). The AUC of the scale value of fasting glucose levels ≥ 90.5 mg/dL was 0.68. The AUC of the categorical value of fasting glucose levels of 90-99 mg/dL was 0.70. Because of the significantly larger AUC of the categorical value of fasting glucose levels of 90-99 mg/dL, those fasting glucose levels were determined to be independently associated with degenerative RCT (P < .001).

CONCLUSIONS

High fasting glucose levels within the normal range may link to increase insulin resistance and risk of degenerative RCT. Normoglycemic levels of 90-99 mg/dL and insulin resistance may be risk factors for degenerative RCT.

LEVEL OF EVIDENCE

Level III, prognostic study.

Patients with Achilles Tendon Rupture Are Prone to Develop Ventricular Arrhythmia

BACKGROUND AND OBJECTIVES

This study aimed to examine the ventricular repolarization (VR) disturbances of patients operated on for acute spontaneous Achilles tendon ruptures (ATRs), by comparing them with a healthy individual control group.

MATERIALS AND METHODS

Between June 2014 and July 2020, a total of 29 patients (28 males, 1 female; mean age: 40 ± 9.78 years; range, 21-66 years) who presented to the emergency department within the first three weeks of injury, and were diagnosed with acute spontaneous ATRs and treated with an open Krackow suture technique, were retrospectively analyzed. Fifty-two healthy individuals (47 males, 5 females; mean age: 39 ± 11.45 years; range, 21-66 years) were recruited as a control group from the cardiology outpatient clinic. Clinical data (demographic features and laboratory parameters (serum glucose, creatinine, hemoglobin, white blood cell count, and lipid profile)) and electrocardiograms (ECGs) were collected from medical records. ECGs were evaluated for heart rate and VR parameters of QRS width, QTc interval, cQTd interval, Tp-e interval, and Tp-e/QT ratio. The clinical data and these ECG parameters were compared between groups.

RESULTS

There was no statistically significant difference between groups, regarding clinical data (all p < 0.05). Among ECG parameters, heart rate, QRS width, QTc interval, and cQTd interval were similar between groups (all p < 0.05). There were two important statistically significant findings of this research: The mean Tp-e interval was longer (ATR group: 72.4 ± 24.7, control group: 58.8 ± 14.5, p: 0.01), and the Tp-e/QT ratio was higher (ATR group: 0.2 ± 0.1, control group: 0.16 ± 0.4, p: 0.027) in the ATR group.

CONCLUSIONS

According to the ventricular repolarization disturbances found in this study, patients with ATR may be at a higher risk of ventricular arrhythmia than healthy people. As a result, ATR patients should be assessed for ventricular arrhythmia risk by an expert cardiologist.

Combined Midportion Achilles and Plantaris Tendinopathy: A 1-Year Follow-Up Study after Ultrasound and Color-Doppler-Guided WALANT Surgery in a Private Setting in Southern Sweden

Background and Objectives: Chronic painful midportion Achilles combined with plantaris tendinopathy can be a troublesome condition to treat. The objective was to prospectively follow patients subjected to ultrasound (US)- and color doppler (CD)-guided wide awake, local anesthetic, no-tourniquet (WALANT) surgery in a private setting. Material and Methods: Twenty-six Swedish patients (17 men and 9 women, mean age 50 years (range 29–62)) and eight international male patients (mean age of 38 years (range 25–71)) with combined midportion Achilles and plantaris tendinopathy in 45 tendons altogether were included. All patients had had >6 months of pain and had tried non-surgical treatment with eccentric training, without effect. US + CD-guided surgical scraping of the ventral Achilles tendon and plantaris removal under local anesthesia was performed on all patients. A 4–6-week rehabilitation protocol with an immediate full-weight-bearing tendon loading regime was used. The VISA-A score and a study-specific questionnaire evaluating physical activity level and subjective satisfaction with the treatment were used for evaluation. Results: At the 1-year follow-up, 32/34 patients (43 tendons) were satisfied with the treatment result and had returned to their pre-injury Achilles tendon loading activity. There were two dropouts (two tendons). For the Swedish patients, the mean VISA-A score increased from 34 (0–64) before surgery to 93 (61–100) after surgery (p < 0.001). There were two complications, one wound rupture and one superficial skin infection. Conclusions: For patients suffering from painful midportion Achilles tendinopathy and plantaris tendinopathy, US + CD-guided surgical Achilles tendon scraping and plantaris tendon removal showed a high satisfaction rate and good functional results 1 year after surgery.

Developmental endothelial locus-1 attenuates palmitate-induced apoptosis in tenocytes through the AMPK/autophagy-mediated suppression of inflammation and endoplasmic reticulum stress

AIMS

Myokine developmental endothelial locus-1 (DEL-1) has been documented to alleviate inflammation and endoplasmic reticulum (ER) stress in various cell types. However, the effects of DEL-1 on inflammation, ER stress, and apoptosis in tenocytes remain unclear.

METHODS

Human primary tenocytes were cultured in palmitate (400 μM) and palmitate plus DEL-1 (0 to 2 μg/ml) conditions for 24 hours. The expression levels of ER stress markers and cleaved caspase 3, as well as phosphorylated 5' adenosine monophosphate-activated protein kinase (AMPK) and autophagy markers, were assessed by Western blotting. Autophagosome formation was measured by staining with monodansylcadaverine, and apoptosis was determined by cell viability assay and caspase 3 activity assay.

RESULTS

We found that treatment with DEL-1 suppressed palmitate-induced inflammation, ER stress, and apoptosis in human primary tenocytes. DEL-1 treatment augmented LC3 conversion and p62 degradation as well as AMPK phosphorylation. Moreover, small interfering RNA for AMPK or 3-methyladenine (3-MA), an autophagy inhibitor, abolished the suppressive effects of DEL-1 on inflammation, ER stress, and apoptosis in tenocytes. Similar to DEL-1, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an activator of AMPK, also attenuated palmitate-induced inflammation, ER stress, and apoptosis in tenocytes, which 3-MA reversed.

CONCLUSION

These results revealed that DEL-1 suppresses inflammation and ER stress, thereby attenuating tenocyte apoptosis through AMPK/autophagy-mediated signalling. Thus, regular exercise or administration of DEL-1 may directly contribute to improving tendinitis exacerbated by obesity and insulin resistance.Cite this article: Bone Joint Res 2022;11(12):854-861.

Dyslipidemia is associated with risk for rotator cuff repair failure: a systematic review and meta-analysis

Background

Lipid deposition secondary to dyslipidemia (DLD) is shown to have a significant impact on tendon pathology, including tendon elasticity, fatty infiltration, and healing properties. Rotator cuff repair is a common procedure, susceptible to influence from many tear-related and patient-related characteristics. The purpose of this study was to determine the relationship between DLD and rotator cuff repair outcomes with analysis of retear risk and function.

Methods

PubMed, Embase, and SPORTDiscus were searched for all English-language, peer-reviewed studies between 2000 and the present, which analyzed relationships between patient-related factors and outcomes of rotator cuff repair. Studies that explicitly examined the effect of DLD on rotator cuff repair outcomes were chosen for inclusion. Included studies were assessed for methodological quality, and data were extracted for meta-analysis.

Results

Of the 3087 titles, 424 were screened by abstract, and 67 were reviewed in full. Inclusion criteria were met by 11 studies. Of these studies, 5 studies assessed retear, 2 studies measured function, 3 studies reported both retear and function, and 1 study evaluated the risk of retear necessitating a revision surgery. The studies report no significant difference in functional outcomes. Meta-analysis revealed that DLD patients had a significantly higher risk of retear after primary rotator cuff repair (odds ratio 1.32, 95% confidence interval 1.06-1.64).

Conclusion

DLD leads to an increased risk of retear after rotator cuff repair, although function appears to be unimpaired. DLD should be considered among other risk factors when counseling patients regarding expected rotator cuff repair outcomes.

Diffuse Peripheral Enthesitis in Metabolic Syndrome: A Retrospective Clinical and Power Doppler Ultrasound Study

OBJECTIVES

To investigate peripheral enthesitis with power Doppler ultrasound (PDUS) in patients presenting low back pain (LBP) and metabolic syndrome (MetS) in comparison with patients with only LBP, to correlate US scores with clinical-anthropometric characteristics, and to define any relationship between enthesitis and concurrent diffuse idiopathic hyperostosis syndrome (DISH).

METHODS

Sixty outpatients with LBP and MetS, evaluated with multi-site entheseal PDUS, scoring inflammatory and structural damage changes, were retrospectively analyzed. A group of 60 subjects with LBP, without MetS and evaluated with the same protocol, was analyzed as the control group.

RESULTS

Patients showed overweight (BMI 29.8) and low-grade inflammatory state (C-reactive protein [CRP] 0.58mg/dL, erythrosedimentation rate [ESR] 20.2mm/h). Enthesitis was demonstrated in 52 (86%) patients (17.6% entheses), and in 8 controls (13.3%) (p<.00001). PD signals (15% of patients) were associated with entheseal pain (p=.0138). US scores correlated with body mass index (BMI), pain, type 2 diabetes. In 28 (46%) patients a concurrent DISH was diagnosed, correlating with older age (p<.0001), CRP (p=.0428), ESR (p=.0069) and PDUS scores (p=.0312 inflammatory, p=.0071 structural). MetS had a strong association (OR 4.375, p=.0007) with concurrent DISH.

CONCLUSIONS

Diffuse peripheral enthesitis is very common in MetS. Almost half of MetS patients can have a concurrent diagnosis of DISH; they are older, with higher inflammation, and higher PDUS enthesitis scores.

A high-fat diet has negative effects on tendon resident cells in an in vivo rat model

BACKGROUND

Tendinopathy is a major complication of diet-induced obesity. However, the effects of a high-fat diet (HFD) on tendon have not been well characterised. We aimed to determine: [1] the impact of a HFD on tendon properties and gene expression; and [2] whether dietary transition to a control diet (CD) could restore normal tendon health.

METHODS

Sprague-Dawley rats were randomised into three groups from weaning and fed either a: CD, HFD or HFD for 12 weeks and then CD thereafter (HF-CD). Biomechanical, histological and structural evaluation of the Achilles tendon was performed at 17 and 27 weeks of age. Tail tenocytes were isolated with growth rate and collagen production determined. Tenocytes and activated THP-1 cells were exposed to conditioned media (CM) of visceral adipose tissue explants, and gene expression was analysed.

RESULTS

There were no differences in the biomechanical, histological or structural tendon properties between groups. However, tenocyte growth and collagen production were increased in the HFD group at 27 weeks. There was lower SOX-9 expression in the HFD and HF-CD groups at 17 weeks and higher expression of collagen-Iα1 and matrix metalloproteinase-13 in the HFD group at 27 weeks. THP-1 cells exposed to adipose tissue CM from animals fed a HFD or HF-CD had lower expression of Il-10 and higher expression of Il-1β.

CONCLUSIONS

In this rodent model, a HFD negatively altered tendon cell characteristics. Dietary intervention restored some gene expression changes; however, adipose tissue secretions from the HF-CD group promoted an increased inflammatory state in macrophages. These changes may predispose tendon to injury and adverse events later in life.

Causal Associations of Obesity With Achilles Tendinopathy: A Two-Sample Mendelian Randomization Study

BACKGROUND

Achilles tendinopathy (AT) is associated with severe pain and is the cause of dysfunction and disability that are associated with significant reduction in social and economic benefits. Several potential risk factors have been proposed to be responsible for AT development; however, the results of observational epidemiological studies remain controversial, presumably because the designs of these studies are subject to residual confounding and reverse causality. Mendelian randomization (MR) can infer the causality between exposure and disease outcomes using genetic variants as instrumental variables, and identification of the causal risk factors for AT is beneficial for early intervention. Thus, we employed the MR strategy to evaluate the causal associations between previously reported risk factors (anthropometric parameters, lifestyle factors, blood biomarkers, and systemic diseases) and the risk of AT.

METHODS

Univariable MR was performed to screen for potential causal associations between the putative risk factors and AT. Bidirectional MR was used to infer reverse causality. Multivariable MR was conducted to investigate the body mass index (BMI)-independent causal effect of other obesity-related traits, such as the waist-hip ratio, on AT.

RESULTS

Univariable MR analyses with the inverse-variance weighted method indicated that the genetically predicted BMI was significantly associated with the risk of AT (P=2.0×10^-3), and the odds ratios (95% confidence intervals) is 1.44 (1.14-1.81) per 1-SD increase in BMI. For the other tested risk factors, no causality with AT was identified using any of the MR methods. Bidirectional MR suggested that AT was not causally associated with BMI, and multivariable MR indicated that other anthropometric parameters included in this study were not likely to causally associate with the risk of AT after adjusting for BMI.

CONCLUSIONS

The causal association between BMI and AT risk suggests that weight control is a promising strategy for preventing AT and alleviating the corresponding disease burden.

Human Achilles tendon mechanical behavior is more strongly related to collagen disorganization than advanced glycation end-products content

Diabetes is associated with impaired tendon homeostasis and subsequent tendon dysfunction, but the mechanisms underlying these associations is unclear. Advanced glycation end-products (AGEs) accumulate with diabetes and have been suggested to alter tendon function. In vivo imaging in humans has suggested collagen disorganization is more frequent in individuals with diabetes, which could also impair tendon mechanical function. The purpose of this study was to examine relationships between tendon tensile mechanics in human Achilles tendon with accumulation of advanced glycation end-products and collagen disorganization. Achilles tendon specimens (n = 16) were collected from individuals undergoing lower extremity amputation or from autopsy. Tendons were tensile tested with simultaneous quantitative polarized light imaging to assess collagen organization, after which AGEs content was assessed using a fluorescence assay. Moderate to strong relationships were observed between measures of collagen organization and tendon tensile mechanics (range of correlation coefficients: 0.570-0.727), whereas no statistically significant relationships were observed between AGEs content and mechanical parameters (range of correlation coefficients: 0.020-0.210). Results suggest that the relationship between AGEs content and tendon tensile mechanics may be masked by multifactorial collagen disorganization at larger length scales (i.e., the fascicle level).

Obesity Impairs Enthesis Healing After Rotator Cuff Repair in a Rat Model

BACKGROUND

Being overweight or obese is associated with poor outcomes and an increased risk of failure after rotator cuff (RC) surgery. However, the effect of obesity on enthesis healing has not been well characterized.

HYPOTHESES

Diet-induced obesity (DIO) would result in inferior enthesis healing in a rat model of RC repair, and a dietary intervention in the perioperative period would improve enthesis healing.

STUDY DESIGN

Controlled laboratory study.

METHODS

Male Sprague-Dawley rats were divided into 3 weight-matched groups (n = 26 per group): control diet (CD), high-fat diet (HFD), or HFD until surgery and then CD thereafter (HF-CD). After 12 weeks, the left supraspinatus tendon was detached, followed by immediate repair. Animals were sacrificed, and RCs were harvested at 2 and 12 weeks after surgery for biomechanical and histological evaluations. Metabolic end points were assessed using dual-energy X-ray absorptiometry and plasma analyses.

RESULTS

DIO was established in the HFD and HF-CD groups before surgery and subsequently reversed in the HF-CD group after surgery. At 12 weeks after surgery, the body fat percentage (P = .0021) and plasma leptin concentration (P = .0025) were higher in the HFD group compared with the CD group. Histologically, the appearance of the repaired entheses was poorer in both the HFD and HF-CD groups compared with the CD group at 12 weeks after surgery, with semiquantitative scores of 6.20 (P = .0078), 4.98 (P = .0003), and 8.68 of 15, respectively. The repaired entheses in the HF-CD group had a significantly lower load to failure (P = .0278) at 12 weeks after surgery compared with the CD group, while the load to failure in the HFD group was low but not significantly different (P = .0960). There were no differences in the biomechanical and histological results between the groups at 2 weeks after surgery. Body mass at the time of surgery, plasma leptin concentration, and body fat percentage were negatively correlated with histology scores and plasma leptin concentration was correlated with load to failure at 12 weeks after surgery.

CONCLUSION

DIO impaired enthesis healing in this rat RC repair model, with inferior biomechanical and histological outcomes. Restoring a normal weight with dietary changes after surgery did not improve healing outcomes.

CLINICAL RELEVANCE

Obesity is a potentially modifiable factor that impairs RC healing and increases the risk of failure after surgery. Exploring interventions that improve the metabolic state of obese patients and counseling patients appropriately about their modest expectations after repair should be considered.

Dyslipidemia Is Associated With Increased Risk of Achilles Tendon Disorders in Underweight Individuals to a Greater Extent Than Obese Individuals: A Nationwide, Population-Based, Longitudinal Cohort Study

BACKGROUND

The association between dyslipidemia and Achilles tendinopathy (AT) or Achilles tendon rupture (ATR) remains controversial, although some studies have examined this topic.

PURPOSE

To evaluate the correlation of dyslipidemia and the risk of AT or ATR, and its association with body mass index (BMI), by assessing data from a nationwide population-based cohort.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We used the National Health Insurance database, which includes the entire population of the Republic of Korea, to evaluate participants in the National Health Screening Program between January 2009 and December 2010. Participants diagnosed with AT or ATR before December 31, 2017, were selected. The variables assessed were age, sex, frequency of high-intensity exercise per week, BMI, waist circumference, systolic blood pressure, and levels of low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and fasting blood glucose. Multivariate Cox proportional hazards regression was used for data analysis.

RESULTS

A total of 16,830,532 participants were included. Of these, 125,814 and 31,424 participants developed AT and ATR, respectively. A higher level of LDL-C was associated with an increased risk of AT (adjusted hazard ratio [HR], 1.16) and ATR (adjusted HR, 1.18). A slightly increased risk of AT was observed in participants with higher TG levels (adjusted HR, 1.03), whereas higher HDL-C level was associated with a slight risk reduction for AT (adjusted HR, 0.95). However, no significant association was observed between higher TG or HDL-C levels and ATR. In the underweight group (BMI <18.5 kg/m2), a higher LDL-C level was associated with an increased risk of AT and ATR by 37% and 116%, respectively, compared with lower LDL-C. Higher LDL-C level was associated with an increased risk of AT and ATR by 10% and 16%, respectively, in the obese group (BMI ≥25 kg/m2).

CONCLUSION

Dyslipidemia was related to the development of AT and ATR. The association of higher LDL-C levels with AT and ATR risk was more pronounced in underweight than in overweight and obese individuals.

Chronic Plantar Heel Pain Is Principally Associated With Waist Girth (Systemic) and Pain (Central) Factors, Not Foot Factors: A Case-Control Study

OBJECTIVE

To determine the independent associations of potential clinical, symptom, physical activity, and psychological factors with chronic plantar heel pain.

DESIGN

Case-control.

METHODS

We investigated associations by comparing 220 participants with chronic (more than 3 months in duration) plantar heel pain to 100 age- and sex-matched controls, who were recruited randomly from the electoral roll. Exposures measured were waist girth, body mass index, body composition, clinical measures of foot and leg function, physical activity via accelerometry, depression and pain catastrophizing, symptoms of prolonged morning stiffness anywhere in the body, and multisite pain. Data were analyzed using multivariable conditional logistic regression.

RESULTS

Waist girth (centimeters) (odds ratio [OR] = 1.06; 95% confidence interval [CI]: 1.03, 1.09), ankle plantar flexor strength (kilograms) (OR = 0.98; 95% CI: 0.97, 0.99), pain at multiple sites (pain at 1 other site: OR = 2.76; 95% CI: 1.29, 5.91; pain at 4 or more other sites: OR = 10.45; 95% CI: 3.66, 29.81), and pain catastrophizing status (none, some, or catastrophizer) (some: OR = 2.91; 95% CI: 1.33, 6.37; catastrophizer: OR = 6.79; 95% CI: 1.91, 24.11) were independently associated with chronic plantar heel pain. There were univariable but not independent associations with morning stiffness, first metatarsophalangeal joint extension range of motion, depression, and body mass index. There were no significant associations with physical activity or body composition (bioelectrical impedance analysis).

CONCLUSION

Waist girth, ankle plantar flexor strength, multisite pain, and pain catastrophizing, but not foot-specific factors, were independently associated with chronic plantar heel pain. Of these 4 factors, 3 (waist girth, multisite pain, and pain catastrophizing) were central or systemic associations. J Orthop Sports Phys Ther 2021;51(9):449-458. Epub 7 May 2021. doi:10.2519/jospt.2021.10018.

The impact of type 2 diabetes on the development of tendinopathy

Tendinopathy is a chronic and often painful condition affecting both professional athletes and sedentary subjects. It is a multi-etiological disorder caused by the interplay among overload, ageing, smoking, obesity (OB) and type 2 diabetes (T2D). Several studies have identified a strong association between tendinopathy and T2D, with increased risk of tendon pain, rupture and worse outcomes after tendon repair in patients with T2D. Moreover, consequent immobilization due to tendon disorder has a strong impact on diabetes management by reducing physical activity and worsening the quality of life. Multiple investigations have been performed to analyse the causal role of the individual metabolic factors occurring in T2D on the development of tendinopathy. Chronic hyperglycaemia, advanced glycation end-products, OB and insulin resistance have been shown to contribute to the development of diabetic tendinopathy. This review aims to explore the relationship between tendinopathy and T2D, in order to define the contribution of metabolic factors involved in the degenerative process and to discuss possible strategies for the clinical management of diabetic tendinopathy.

Mobile diagnostics and consultation for the prevention of the metabolic syndrome and its secondary diseases in Brandenburg-study protocol of a regional prospective cohort study: the Mobile Brandenburg Cohort

BACKGROUND

The metabolic syndrome (MetS) is a risk cluster for a number of secondary diseases. The implementation of prevention programs requires early detection of individuals at risk. However, access to health care providers is limited in structurally weak regions. Brandenburg, a rural federal state in Germany, has an especially high MetS prevalence and disease burden. This study aims to validate and test the feasibility of a setup for mobile diagnostics of MetS and its secondary diseases, to evaluate the MetS prevalence and its association with moderating factors in Brandenburg and to identify new ways of early prevention, while establishing a "Mobile Brandenburg Cohort" to reveal new causes and risk factors for MetS.

METHODS

In a pilot study, setups for mobile diagnostics of MetS and secondary diseases will be developed and validated. A van will be equipped as an examination room using point-of-care blood analyzers and by mobilizing standard methods. In study part A, these mobile diagnostic units will be placed at different locations in Brandenburg to locally recruit 5000 participants aged 40-70 years. They will be examined for MetS and advice on nutrition and physical activity will be provided. Questionnaires will be used to evaluate sociodemographics, stress perception, and physical activity. In study part B, participants with MetS, but without known secondary diseases, will receive a detailed mobile medical examination, including MetS diagnostics, medical history, clinical examinations, and instrumental diagnostics for internal, cardiovascular, musculoskeletal, and cognitive disorders. Participants will receive advice on nutrition and an exercise program will be demonstrated on site. People unable to participate in these mobile examinations will be interviewed by telephone. If necessary, participants will be referred to general practitioners for further diagnosis.

DISCUSSION

The mobile diagnostics approach enables early detection of individuals at risk, and their targeted referral to local health care providers. Evaluation of the MetS prevalence, its relation to risk-increasing factors, and the "Mobile Brandenburg Cohort" create a unique database for further longitudinal studies on the implementation of home-based prevention programs to reduce mortality, especially in rural regions.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00022764 ; registered 07 October 2020-retrospectively registered.

Inhibition of JAK-STAT Signaling Pathway Alleviates Age-Related Phenotypes in Tendon Stem/Progenitor Cells

Diminished regeneration or healing capacity of tendon occurs during aging. It has been well demonstrated that tendon stem/progenitor cells (TSPCs) play a vital role in tendon maintenance and repair. Here, we identified an accumulation of senescent TSPCs in tendon tissue with aging. In aged TSPCs, the activity of JAK-STAT signaling pathway was increased. Besides, genetic knockdown of JAK2 or STAT3 significantly attenuated TSPC senescence in aged TSPCs. Pharmacological inhibition of JAK-STAT signaling pathway with AG490 similarly attenuated cellular senescence and senescence-associated secretory phenotype (SASP) of aged TSPCs. In addition, inhibition of JAK-STAT signaling pathway also restored the age-related dysfunctions of TSPCs, including self-renewal, migration, actin dynamics, and stemness. Together, our findings reveal the critical role of JAK-STAT signaling pathway in the regulation of TSPC aging and suggest an ideal therapeutic target for the age-related tendon disorders.

Diffuse Peripheral Enthesitis in Metabolic Syndrome: A Retrospective Clinical and Power Doppler Ultrasound Study

OBJECTIVES

To investigate peripheral enthesitis with power Doppler ultrasound (PDUS) in patients presenting low back pain (LBP) and metabolic syndrome (MetS) in comparison with patients with only LBP, to correlate US scores with clinical-anthropometric characteristics, and to define any relationship between enthesitis and concurrent diffuse idiopathic hyperostosis syndrome (DISH).

METHODS

Sixty outpatients with LBP and MetS, evaluated with multi-site entheseal PDUS, scoring inflammatory and structural damage changes, were retrospectively analyzed. A group of 60 subjects with LBP, without MetS and evaluated with the same protocol, was analyzed as the control group.

RESULTS

Patients showed overweight (BMI 29.8) and low-grade inflammatory state (C-reactive protein [CRP] 0.58mg/dL, erythrosedimentation rate [ESR] 20.2mm/h). Enthesitis was demonstrated in 52 (86%) patients (17.6% entheses), and in 8 controls (13.3%) (p<.00001). PD signals (15% of patients) were associated with entheseal pain (p=.0138). US scores correlated with body mass index (BMI), pain, type 2 diabetes. In 28 (46%) patients a concurrent DISH was diagnosed, correlating with older age (p<.0001), CRP (p=.0428), ESR (p=.0069) and PDUS scores (p=.0312 inflammatory, p=.0071 structural). MetS had a strong association (OR 4.375, p=.0007) with concurrent DISH.

CONCLUSIONS

Diffuse peripheral enthesitis is very common in MetS. Almost half of MetS patients can have a concurrent diagnosis of DISH; they are older, with higher inflammation, and higher PDUS enthesitis scores.

A Narrative Review of the Classification and Use of Diagnostic Ultrasound for Conditions of the Achilles Tendon

Enthesitis is a cardinal feature of spondyloarthropathies. The Achilles insertion on the calcaneus is a commonly evaluated enthesis located at the hindfoot, generally resulting in hindfoot pain and possible tendon enlargement. For decades, diagnosis of enthesitis was based upon patient history of hindfoot or posterior ankle pain and clinical examination revealing tenderness and/or enlargement at the site of the tendon insertion. However, not all hindfoot or posterior ankle symptoms are related to enthesitis. Advanced imaging, including magnetic resonance imaging (MRI) and ultrasound (US), has allowed for more precise evaluation of hindfoot and posterior ankle conditions. Use of US in diagnosis has helped confirm some of these cases but also identified other conditions that may have otherwise been misclassified without use of advanced imaging diagnostics. Conditions that may result in hindfoot and posterior ankle symptoms related to the Achilles tendon include enthesitis (which can include retrocalcaneal bursitis and insertional tendonopathy), midportion tendonopathy, paratenonopathy, superficial calcaneal bursitis, calcaneal ossification (Haglund deformity), and calcific tendonopathy. With regard to classification of these conditions, much of the existing literature uses confusing nomenclature to describe conditions in this region of the body. Some terminology may imply inflammation when in fact there may be none. A more uniform approach to classifying these conditions based off anatomic location, symptoms, clinical findings, and histopathology is needed. There has been much debate regarding appropriate use of tendonitis when there is no true inflammation, calling instead for use of the terms tendinosis or tendonopathy. To date, there has not been clear examination of a similar overuse of the term enthesitis in conditions where there is no underlying inflammation, thus raising the need for more comprehensive taxonomy.

Does moxonidine reduce Achilles tendon or musculoskeletal pain in women with polycystic ovarian syndrome? A secondary analysis of a randomised controlled trial

BACKGROUND

Sympathetic activity and insulin resistance have recently been linked with chronic tendon and musculoskeletal pain. Polycystic ovarian syndrome is linked with insulin resistance and increased sympathetic drive and was therefore an appropriate condition to study the effects of modulating sympathetic activity on Achilles tendon and musculoskeletal symptoms.

METHODS

A secondary analysis of a double-blinded, randomised controlled trial on women with polycystic ovarian syndrome was conducted. Participants received 12 weeks of moxonidine (n = 14) or placebo (n = 18). Musculoskeletal symptom and Victorian Institute of Sport Assessment - Achilles (VISA-A) questionnaires were distributed, and ultrasound tissue characterisation quantified tendon structure at 0 and 12 weeks. 2-way ANOVA was used for multiple comparisons.

RESULTS

There was no difference in mean change in musculoskeletal symptoms (- 0.6 ± 1.7 vs - 0.4 ± 1.8, p = 0.69) or VISA-A (moxonidine - 0.2 ± 8.8 vs placebo + 4.2 ± 14.6, p = 0.24) attributable to the intervention. There was no difference in any measures of Achilles structure. Moxonidine did not reduce sympathetic drive when compared to placebo.

CONCLUSIONS

This was the first study to investigate the effects of blocking sympathetic drive on musculoskeletal and Achilles tendon symptoms in a metabolically diverse population. While the study was limited by small sample size and lack of sympathetic modulation, moxonidine did not change tendon pain/structure or musculoskeletal symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01504321 . Registered 5 January 2012.

Obesity Increases the Risk of Tendinopathy, Tendon Tear and Rupture, and Postoperative Complications: A Systematic Review of Clinical Studies

BACKGROUND

Inflammation and mechanical demands play a role in the development of tendon conditions and the dysregulation of tendon healing. In patients with obesity, high levels of pro-inflammatory cytokines and a high mechanical demand promote chronic low-grade inflammation. Although controversial results have been reported, we aimed to summarize current evidence while highlighting the role of obesity in tendinopathy.

QUESTIONS/PURPOSES

(1) Do patients with obesity have a greater risk of tendinopathy, stratified by upper and lower extremity sites, than patients who do not have obesity? (2) Is obesity associated with a higher risk of upper and lower extremity tendon tear and ruptures? (3) Is obesity associated with an increased risk of complications after upper and lower extremity tendon surgery?

METHODS

We performed a systematic review by searching the PubMed, Embase, and Cochrane Library databases, combining the term "tendon" with common terms for tendinopathy and rupture such as "tendon injury OR tendinopathy OR tendon rupture" and "obese" OR "obesity." We included studies with any level of evidence published from January 2000 to July 10, 2019 in peer-reviewed journals reporting clinical results. After we removed the duplicates, there were 365 records. Two independent authors screened these records and excluded 320 based on abstract and title screening. Of the remaining 45 studies, 23 were excluded because the topic did not address the research questions (n = 19), the article was outdated (n = 3), or because there was a serious risk of bias (n = 1). Finally, we included 22 studies with 49,914 participants (5984 with obesity), 31,100 (1884 with obesity) of whom had upper-extremity tendinopathy, while 18,814 (4010 with obesity) had lower-extremity tendinopathy. Obesity was defined as a BMI ≥ 30 kg/m according to the WHO's criteria. Data were extracted and analyzed critically. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied, and the risk of bias (ROBINS tool) of the studies was assessed, as was the methodological quality (Coleman score). The assessment was performed independently by two authors. Inter-rater agreement for the assessments of the risk of bias and methodological quality were 89% and 94%, respectively. All studies were observational, and most were retrospective case-control studies. Any discrepancy was discussed and solved by consensus. The articles had a moderate risk of bias (eight articles) or a low risk of bias (fourteen articles). We excluded one article because of a serious risk of bias. The mean (range) Coleman score was 53.5 (42-74).

RESULTS

Obesity was associated with a greater risk of upper extremity tendinopathy (rotator cuff: odds ratio 1.25 [95% confidence interval 1.12 to 1.40]; p < 0.001; medial epicondylitis: OR 1.9 [95% CI 1.0 to 3.7]; p < 0.05) and lower-extremity tendinopathy (Achilles tendon: OR 3.81 [95% CI 2.57 to 5.63]; OR 3.77 [95% CI 2.24 to 6.34]; OR 6.56 [95% CI 3.18 to 13.55], for obesity Classes I, II and III, respectively; patellar tendon: OR 1.10 [95% CI 1.05 to 1.90]; p = 0.001; plantar fascia: OR 2.97 [95% CI 1.64 to 5.37]; p = 0.004). Obesity was associated with a greater risk of upper extremity tendon tear (rotator cuff: OR 2.35 [95% CI 1.62 to 3.40]; p < 0.001) and rupture leading to tendon surgery (rotator cuff in men: OR 3.13 [95% CI 1.29 to 7.61]; p < 0.001 and women: OR 3.51 [95% CI 1.80 to 6.85]; p < 0.001). However, no association was found between BMI and lower extremity rupture (Achilles mean BMI: 27.77 kg/m [95% CI 26.94 to 28.49] versus control: 26.66 kg/m [95% CI 26.06 to 27.27]; p = 0.047). Upper extremity complications (n = 359) after tendon repair surgery had a weighted incidence of 13.27% and 8.13% for rotator cuff surgery in patients with and without obesity, respectively. In the lower extremity (n = 21,152), the weighted incidence for Achilles tendon surgery was 11.28% and 8.6% in patients with and without obesity, respectively.

CONCLUSIONS

Obesity is associated with a higher risk of tendinopathy, tendon tear and rupture, and complications after tendon surgery than non-obesity. However, the high heterogeneity and observational nature of the studies highlight the need to be cautious about the results of our study. We encourage researchers to perform clinical and preclinical studies to explore pathways related to the metabolic state of this population.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Achilles tendinopathy

BACKGROUND

Achilles Tendinopathy (AT) is essentially a failed healing response with haphazard proliferation of tenocytes, abnormalities in tenocytes with disruption of collagen fibers, and subsequent increase in non-collagenous matrix.

METHODS

The diagnosis of Achilles tendinopathy is clinical, and MRI and utrasound imaging can be useful in differential diagnosis. Conservative manegement, open surgery or minimally invasive techniques are available. Injections and physical therapy are also vauable options.

RESULTS

Eccentric exercises are useful tools to manage the pathology. If the condition does not ameliorate, shock wave therapy, or nitric oxide patches might be considered. Peritendinous injections or injections at the interface between the Achilles tendon and Kager's triangle could be considered if physical therapy should fail. Surgery is indicated after 6 months of non-operative management.

CONCLUSIONS

The clinical diagnosis and management of AT are not straightforward. Hence, patients should understand that symptoms may recur with either conservative or surgical approaches.

Does glucocorticoid exposure explain the association between metabolic dysfunction and tendinopathy?

BACKGROUND

While metabolic health is acknowledged to affect connective tissue structure and function, the mechanisms are unclear. Glucocorticoids are present in almost every cell type throughout the body and control key physiological processes such as energy homeostasis, stress response, inflammatory and immune processes, and cardiovascular function. Glucocorticoid excess manifests as visceral adiposity, dyslipidaemia, insulin resistance, and type 2 diabetes. As these metabolic states are also associated with tendinopathy and tendon rupture, it may be that glucocorticoids excess is the link between metabolic health and tendinopathy.

OBJECTIVE

To synthesise current knowledge linking glucocorticoids exposure to tendon structure and function.

METHODS

Narrative literature review.

RESULTS

We provide an overview of endogenous glucocorticoid production, regulation, and signalling. Next we review the impact that oral glucocorticoid has on risk of tendon rupture and the effect that injected glucocorticoid has on resolution of symptoms. Then we highlight the clinical and mechanistic overlap between tendinopathy and glucocorticoid excess in the areas of visceral adiposity, dyslipidaemia, insulin resistance and type 2 diabetes. In these areas, we highlight the role of glucocorticoids and how these hormones might underpin the connection between metabolic health and tendon dysfunction.

CONCLUSIONS

There are several plausible pathways through which glucocorticoids might mediate the connection between metabolic health and tendinopathy.

Cheiroarthropathy and tendinopathy in diabetes

Joint problems commonly occur in people with diabetes. Cheiroarthropathy affects the hands and results in painless limited finger joint extension, appearing to be associated with longer diabetes duration and the presence of microvascular complications. The prevalence of cheiroarthropathy seems to be falling, perhaps as a result of improvements in glycaemic management. Non-enzymatic glycation of collagen results in abnormally crosslinked protein resistant to degradation with subsequent increased build-up of collagen in joints. The management of cheiroarthropathy is predominantly conservative, with occupational and hand therapy at the forefront. Tendinopathy is more common in people with diabetes than those without, and is associated with obesity and insulin resistance. As with cheiroarthropathy, the exact causative mechanism of tendinopathy in diabetes is not known, but may be linked to inflammation, apoptosis and increased vascularity of affected tendons, driven by hyperinsulinaemia. Local fat pads have also been suggested to play a role in the pathogenesis of tendinopathy.

Clinical risk factors for Achilles tendinopathy: a systematic review

Background

Achilles tendinopathy is a common problem, but its exact aetiology remains unclear.

Objective

To evaluate the association between potential clinical risk factors and Achilles tendinopathy.

Design

Systematic review.

Data sources

The databases Embase, MEDLINE Ovid, Web of Science, Cochrane Library and Google Scholar were searched up to February 2018.

Eligibility criteria

To answer our research question, cohort studies investigating risk factors for Achilles tendinopathy in humans were included. We restricted our search to potential clinical risk factors (imaging studies were excluded).

Results

We included 10 cohort studies, all with a high risk of bias, from 5111 publications identified. There is limited evidence for nine risk factors: (1) prior lower limb tendinopathy or fracture, (2) use of ofloxacin (quinolone) antibiotics, (3) an increased time between heart transplantation and initiation of quinolone treatment for infectious disease, (4) moderate alcohol use, (5) training during cold weather, (6) decreased isokinetic plantar flexor strength, (7) abnormal gait pattern with decreased forward progression of propulsion, (8) more lateral foot roll-over at the forefoot flat phase and (9) creatinine clearance of <60 mL/min in heart transplant patients. Twenty-six other putative risk factors were not associated with Achilles tendinopathy, including being overweight, static foot posture and physical activity level.

Conclusion

From an ocean of studies with high levels of bias, we extracted nine clinical risk factors that may increase a person’s risk of Achilles tendinopathy. Clinicians may consider ofloxacin use, alcohol consumption and a reduced plantar flexor strength as modifiable risk factors when treating patients with Achilles tendinopathy.

Trial registration number

CRD42017053258.

Oral Supplementation of Specific Collagen Peptides Combined with Calf-Strengthening Exercises Enhances Function and Reduces Pain in Achilles Tendinopathy Patients

The current pilot study investigates whether oral supplementation of specific collagen peptides improves symptoms and tendon vascularisation in patients with chronic mid-portion Achilles tendinopathy in combination with structured exercise. Participants were given a placebo or specific collagen peptides (TENDOFORTE^®) in combination with a bi-daily calf-strengthening program for 6 months. Group AB received specific collagen peptides for the first 3 months before crossing over to placebo. Group BA received placebo first before crossing over to specific collagen peptides. At baseline (T1), 3 (T2) and 6 (T3) months, Victorian Institute of Sports Assessment–Achilles (VISA-A) questionnaires and microvascularity measurements through contrast-enhanced ultrasound were obtained in 20 patients. Linear mixed modeling statistics showed that after 3 months, VISA-A increased significantly for group AB with 12.6 (9.7; 15.5), while in group BA VISA-A increased only by 5.3 (2.3; 8.3) points. After crossing over group AB and BA showed subsequently a significant increase in VISA-A of, respectively, 5.9 (2.8; 9.0) and 17.7 (14.6; 20.7). No adverse advents were reported. Microvascularity decreased in both groups to a similar extent and was moderately associated with VISA-A (R_c²:0.68). We conclude that oral supplementation of specific collagen peptides may accelerate the clinical benefits of a well-structured calf-strengthening and return-to-running program in Achilles tendinopathy patients.

Clinical presentation and surgical management of chronic Achilles tendon disorders - A retrospective observation on a set of consecutive patients being operated by the same orthopedic surgeon

BACKGROUND

Non-invasive treatment is not always successful in patients with Achilles tendon disorders, and surgical treatment is instituted as the next step. There is sparse knowledge about the diagnoses, pain levels before surgery, surgically confirmed pathologies and postoperative complications in large patient groups.

AIMS

To study the diagnoses, pain scores before surgery, macroscopic surgical findings and postoperative complications in a series of patients treated for Achilles disorders.

MATERIAL AND METHODS

One surgeon operated on 771 Achilles tendons of 481 men and 290 women during a 10-year period. The clinically and ultrasound confirmed diagnoses, pre-operative pain and functional scores (Visual Analogue Scale, VAS, range 0-100; Victorian Institute Sports Tendon Assessment - Achilles questionnaire, VISA-A), macroscopic findings during surgery and postoperative complications, were retrospectively collected from a database.

RESULTS

Clinically, by ultrasound and during surgery midportion Achilles tendinopathy was confirmed in 519 (67%) patients, 41% of them had a thickened plantaris tendon located close the Achilles tendon. Partial midportion rupture was found in 31 (4%) patients, chronic midportion rupture in 12 (2%) patients and insertional Achilles tendinopathy, including superficial and retro-calcaneal bursitis, Haglund deformity, distal Achilles tendinopathy, plantaris tendon pathology, and bone spurs, in 209 (27%) patients. The mean pre-operative pain scores for midportion Achilles tendinopathy were 73 (VAS) and 45 (VISA-A), and for insertional Achilles tendinopathy 77 (VAS) and 39 (VISA-A). For midportion Achilles tendinopathy there were 14 (3%), and for insertional Achilles tendinopathy 10 (5%), postoperative complications.

CONCLUSIONS

Patients presenting high pain scores from midportion Achilles tendinopathy were the most common. Plantaris tendon involvement is a frequent observation. For insertional Achilles tendinopathy the combination of pathology in the subcutaneous and retrocalcaneal bursa, a Haglund deformity and distal Achilles tendinopathy/tendinosis was most frequent.

SERIES STUDY, LEVEL OF EVIDENCE

4.

An Updated Subsequent Injury Categorisation Model (SIC-2.0): Data-Driven Categorisation of Subsequent Injuries in Sport

BACKGROUND

Accounting for subsequent injuries is critical for sports injury epidemiology. The subsequent injury categorisation (SIC-1.0) model was developed to create a framework for accurate categorisation of subsequent injuries but its operationalisation has been challenging.

OBJECTIVES

The objective of this study was to update the subsequent injury categorisation (SIC-1.0 to SIC-2.0) model to improve its utility and application to sports injury datasets, and to test its applicability to a sports injury dataset.

METHODS

The SIC-1.0 model was expanded to include two levels of categorisation describing how previous injuries relate to subsequent events. A data-driven classification level was established containing eight discrete injury categories identifiable without clinical input. A sequential classification level that sub-categorised the data-driven categories according to their level of clinical relatedness has 16 distinct subsequent injury types. Manual and automated SIC-2.0 model categorisation were applied to a prospective injury dataset collected for elite rugby sevens players over a 2-year period. Absolute agreement between the two coding methods was assessed.

RESULTS

An automated script for automatic data-driven categorisation and a flowchart for manual coding were developed for the SIC-2.0 model. The SIC-2.0 model was applied to 246 injuries sustained by 55 players (median four injuries, range 1-12), 46 (83.6%) of whom experienced more than one injury. The majority of subsequent injuries (78.7%) were sustained to a different site and were of a different nature. Absolute agreement between the manual coding and automated statistical script category allocation was 100%.

CONCLUSIONS

The updated SIC-2.0 model provides a simple flowchart and automated electronic script to allow both an accurate and efficient method of categorising subsequent injury data in sport.

Factors Associated with Atraumatic Posterosuperior Rotator Cuff Tears

BACKGROUND

Certain metabolic factors have been proposed as risk factors for a posterosuperior rotator cuff tear. Although metabolic syndrome is of increasing concern in industrialized societies, little information exists regarding its association with posterosuperior rotator cuff tears. The purpose of this study was to determine the risk factors for an atraumatic posterosuperior rotator cuff tear, including metabolic factors and metabolic syndrome.

METHODS

This study involved 634 subjects (634 shoulders) drawn from a cohort of rural residents. Posterosuperior rotator cuff tear diagnoses were based on magnetic resonance imaging (MRI) findings. Logistic regression analysis was used to determine the odds ratios (ORs) and 95% confidence intervals (CIs) for various demographic, physical, and social factors, including age, sex, dominant-side involvement, body mass index (BMI), and participation in manual labor; the comorbidities of diabetes, hypertension, dyslipidemia, thyroid dysfunction, ipsilateral carpal tunnel syndrome, and metabolic syndrome; and the serum metabolic parameters of serum lipid profile, glycosylated hemoglobin A1c, and level of thyroid hormone. Two multivariable analyses were performed: the first excluded metabolic syndrome while including diabetes, hypertension, BMI, and hypo-high-density lipoproteinemia (hypo-HDLemia), and the second included metabolic syndrome while excluding the formerly included variables.

RESULTS

Age, BMI, waist circumference, dominant-side involvement, manual labor, diabetes, hypertension, metabolic syndrome, ipsilateral carpel tunnel syndrome, HDL (high-density lipoprotein), and hypo-HDLemia were significantly associated with posterosuperior rotator cuff tears in univariate analyses (p ≤ 0.035). In the first multivariable analysis, age (OR. 1.86 [95% CI, 1.47 to 2.35]), BMI (OR, 1.09 [95% CI, 1.02 to 1.18]), dominant-side involvement (OR, 2.04 [95% CI, 1.38 to 3.01]), manual labor (OR, 9.48 [95% CI, 5.13 to 17.51]), diabetes (OR, 3.38 [95% CI, 1.98 to 5.77]), and hypo-HDLemia (OR, 2.07 [95% CI, 1.30 to 3.29]) were significantly associated with posterosuperior rotator cuff tears (p ≤ 0.019). In the second multivariable analysis, age (OR, 1.85 [95% CI, 1.48 to 2.31]), dominant-side involvement (OR, 1.83 [95% CI, 1.26 to 2.67]), manual labor (OR, 7.71 [95% CI, 4.33 to 13.73]), and metabolic syndrome (OR, 1.98 [95% CI, 1.35 to 2.91]) were significantly associated with posterosuperior rotator cuff tears (p ≤ 0.002).

CONCLUSIONS

The metabolic factors of diabetes, BMI, hypo-HDLemia, and metabolic syndrome were significant independent factors associated with the development of posterosuperior rotator cuff tears.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Tendon pathology in hypercholesterolaemia patients: Epidemiology, pathogenesis and management

Tendon pathology is a general term used to describe a group of musculoskeletal conditions related to tendons and surrounding structures. There is only limited evidence available regarding the exact aetiology and natural history of tendon pathology. In hypercholesterolaemia environments, lipids could accumulate within the extracellular matrix of the tendon and thus affect the mechanical properties of the tendon. Current evidence suggested that hypercholesterolaemia was an important risk factor in the development and progression of tendon pathology. The severity of hypercholesterolaemia was correlated with the severity of tendon pathology.

The translational potential of this article: Hypercholesterolaemia lead to the structural, inflammatory and mechanical changes in tendons, which predispose hypercholesterolaemia patients to a greater risk of tendon pathology. Measurements of serum cholesterol are suggested to be performed in patients presenting with tendon pathology. The strict control of hypercholesterolaemia would mitigate the development and progression of tendon pathology.

Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2018

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to midportion Achilles tendinopathy. J Orthop Sports Phys Ther 2018;48(5):A1-A38. doi:10.2519/jospt.2018.0302.

Correlation of some predisposing intrinsic conditions with the morphological integrity of the Achilles tendon

BACKGROUND

Most studies have focused on ill-tendons with a little insight on how intrinsic factors correlate with the Achilles tendon (AT) morphology.

AIM

This study aims at establishing how blood pressure (BP), blood glucose (BG), and body mass index (BMI) correlate with the morphology of the AT with emphasis on width changes.

MATERIALS AND METHODS

Participants were volunteers who were recruited during and after an organized health fair by the Medical Students' body of All Saints University, School of Medicine, Commonwealth of Dominica. A total of 336 people, consisting of 135 males and 201 females volunteered for the study. The most dominant age group was between 60 and 65 years. A self-administered questionnaire was used to acquire necessary information, and a preliminary clinical procedure was used to check for BP, BG, and BMI. Ultrasound examination was done in B-mode using a linear array high-frequency probe with a mediolateral approach at the AT.

RESULTS

Among the participants, 42.68%, 69.75%, and 30.38% had normal BP, BG, and BMI readings, respectively. BP, BG, and BMI statistically supported the hypothesis. Individuals with extreme BP, BG, and BMI had their AT width wider when compared with individuals with normal systemic readings. Sonographic examination revealed most participants with normal tendon morphology while some identifiable changes were observed among others.

CONCLUSION

This study suggests that BP, BG, and BMI could affect the morphological integrity of the AT. It indicates that asymptomatic high blood sugar and BP could weaken the AT, leading to pain which may appear unrelated to the physician and patient.

Apolipoprotein A1 distribution pattern in the human Achilles tendon

Metabolic factors such as cholesterol appear to play an important role in the development of Achilles tendinopathy. There is, however, no morphologic proof explaining the link between high cholesterol and tendinopathy. As apolipoprotein A1 (Apo-A1) is essential for reverse cholesterol transport, it may be related to cholesterol overload in tendon. Nothing is known about Apo-A1 expression in tendon tissue. We examined the distribution of Apo-A1 protein in biopsies from normal and tendinopathy-affected human Achilles tendons, and APOA1 mRNA production from cultured human hamstring tenocytes. Specific immunoreactions for Apo-A1 were detected. The tenocytes showed specific Apo-A1 immunoreactions. These reactions were usually distinct in the tendinopathy specimens. While the tendinopathy specimens often showed granular/small deposit reactions, the slender tenocytes of control specimens did not show this pattern. The magnitude of Apo-A1 immunoreactivity was especially marked in the tendinopathy specimens, as there is a high number of tenocytes. Reactions were also seen in the walls of blood vessels located within the tendon tissue proper of both the normal and tendinopathy tendons and within the peritendinous/fatty tissue of the tendinopathy tendons. The reactions were predominantly in the form of deposit reactions within the smooth muscle layer of the vessel walls. Cultured hamstring tenocytes produced APOA1 mRNA. We demonstrated the presence of Apo-A1 in human tendon tissue. This suggests there may be a link between Achilles tendinopathy and cholesterol metabolism. We hypothesize that Apo-A1 may be important for tenocyte and blood vessel function within tendons.

Hyperglycemia Augments the Adipogenic Transdifferentiation Potential of Tenocytes and Is Alleviated by Cyclic Mechanical Stretch

Diabetes mellitus is associated with damage to tendons, which may result from cellular dysfunction in response to a hyperglycemic environment. Tenocytes express diminished levels of tendon-associated genes under hyperglycemic conditions. In contrast, mechanical stretch enhances tenogenic differentiation. However, whether hyperglycemia increases the non-tenogenic differentiation potential of tenocytes and whether this can be mitigated by mechanical stretch remains elusive. We explored the in vitro effects of high glucose and mechanical stretch on rat primary tenocytes. Specifically, non-tenogenic gene expression, adipogenic potential, cell migration rate, filamentous actin expression, and the activation of signaling pathways were analyzed in tenocytes treated with high glucose, followed by the presence or absence of mechanical stretch. We analyzed tenocyte phenotype in vivo by immunohistochemistry using an STZ (streptozotocin)-induced long-term diabetic mouse model. High glucose-treated tenocytes expressed higher levels of the adipogenic transcription factors PPARγ and C/EBPs. PPARγ was also highly expressed in diabetic tendons. In addition, increased adipogenic differentiation and decreased cell migration induced by high glucose implicated a fibroblast-to-adipocyte phenotypic change. By applying mechanical stretch to tenocytes in high-glucose conditions, adipogenic differentiation was repressed, while cell motility was enhanced, and fibroblastic morphology and gene expression profiles were strengthened. In part, these effects resulted from a stretch-induced activation of ERK (extracellular signal-regulated kinases) and a concomitant inactivation of Akt. Our results show that mechanical stretch alleviates the augmented adipogenic transdifferentiation potential of high glucose-treated tenocytes and helps maintain their fibroblastic characteristics. The alterations induced by high glucose highlight possible pathological mechanisms for diabetic tendinopathy. Furthermore, the beneficial effects of mechanical stretch on tenocytes suggest that an appropriate physical load possesses therapeutic potential for diabetic tendinopathy.

Effect of Metabolic Syndrome on the Functional Outcome of Corticosteroid Injection for Lateral Epicondylitis: Retrospective Matched Case-Control Study

Both obesity and diabetes mellitus are well-known risk factors for tendinopathies. We retrospectively compared the efficacy of single corticosteroid injections in treating lateral epicondylitis in patients with and without metabolic syndrome (MetS). Fifty-one patients with lateral epicondylitis and MetS were age- and sex-matched with 51 controls without MetS. Pain severity, Disability of the Arm, Shoulder, and Hand score, and grip strength were assessed at base line and at 6, 12 and 24 weeks post-injection. The pain scores in the MetS group were greater than those in the control group at 6 and 12 weeks. The disability scores and grip strength in the MetS group were significantly worse than those of the control group at 6 weeks. However, there were no significant differences at 24 weeks between the groups in terms of pain, disability scores and grip strengths. After 24 weeks, three patients (6%) in the control group and five patients (10%) in the MetS group had surgical decompression (p = 0.46). Patients with MetS are at risk for poor functional outcome after corticosteroid injection for lateral epicondylitis in the short term, but in the long term there was no difference in outcomes of steroid injection in patients with and without MetS.

Association between Epicondylitis and Cardiovascular Risk Factors in Pooled Occupational Cohorts

Background

The pathophysiology of lateral epicondylitis (LE) is unclear. Recent evidence suggests some common musculoskeletal disorders may have a basis in cardiovascular disease (CVD) risk factors. Thus, we examined CVD risks as potential LE risks.

Methods

Workers (n = 1824) were enrolled in two large prospective studies and underwent structured interviews and physical examinations at baseline. Analysis of pooled baseline data assessed the relationships separately between a modified Framingham Heart Study CVD risk score and three prevalence outcomes of: 1) lateral elbow pain, 2) positive resisted wrist or middle finger extension, and 3) a combination of both symptoms and at least one resisted maneuver. Quantified job exposures, personal and psychosocial confounders were statistically controlled. Odds ratios (ORs) and 95% Confidence Intervals (CIs) were calculated.

Results

There was a strong relationship between CVD risk score and lateral elbow symptoms, resisted wrist or middle finger extension and LE after adjustment for confounders. The adjusted ORs for symptoms were as high as 3.81 (95% CI 2.11, 6.85), for positive examination with adjusted odds ratios as high as 2.85 (95% CI 1.59, 5.12) and for combined symptoms and physical examination 6.20 (95% CI 2.04, 18.82). Relationships trended higher with higher CVD risk scores.

Conclusions

These data suggest a potentially modifiable disease mechanism for LE.

Biomedical Risk Factors of Achilles Tendinopathy in Physically Active People: a Systematic Review

Background

Achilles tendinopathy is the most prevalent tendon disorder in people engaged in running and jumping sports. Aetiology of Achilles tendinopathy is complex and requires comprehensive research of contributing risk factors. There is relatively little research focussing on potential biomedical risk factors for Achilles tendinopathy. The purpose of this systematic review is to identify studies and summarise current knowledge of biomedical risk factors of Achilles tendinopathy in physically active people.

Methods

Research databases were searched for relevant articles followed by assessment in accordance with PRISMA statement and standards of Cochrane collaboration. Levels of evidence and quality assessment designation were implemented in accordance with OCEBM levels of evidence and Newcastle-Ottawa Quality Assessment Scale, respectively.

Results

A systematic review of the literature identified 22 suitable articles. All included studies had moderate level of evidence (2b) with the Newcastle-Ottawa score varying between 6 and 9. The majority (17) investigated genetic polymorphisms involved in tendon structure and homeostasis and apoptosis and inflammation pathways.

Overweight as a risk factor of Achilles tendinopathy was described in five included studies that investigated non-genetic factors. COL5A1 genetic variants were the most extensively studied, particularly in association with genetic variants in the genes involved in regulation of cell-matrix interaction in tendon and matrix homeostasis. It is important to investigate connections and pathways whose interactions might be disrupted and therefore alter collagen structure and lead to the development of pathology. Polymorphisms in genes involved in apoptosis and inflammation, and Achilles tendinopathy did not show strong association and, however, should be considered for further investigation.

Conclusions

This systematic review suggests that biomedical risk factors are an important consideration in the future study of propensity to the development of Achilles tendinopathy. The presence of certain medical comorbidities and genetic markers should be considered when contemplating the aetiology of Achilles tendinopathy. Further elucidation of biomedical risk factors will aid in the understanding of tendon pathology and patient risk, thereby informing prevention and management strategies for Achilles tendinopathy.

Trial Registration

PROSPERO CRD42016036558

Nonsurgical Management of Midsubstance Achilles Tendinopathy

Midsubstance Achilles tendinopathy is one of the most common lower leg conditions. Most patients can recover with nonsurgical treatment that focuses on tendon loading exercises and, when necessary, symptom modulating treatments such as topical, oral, or injected medication, ice, shoe inserts, manual therapy, stretching, taping, or low-level laser. If unresponsive to initial management, a small percentage of patients may consider shockwave or sclerosing treatment and possibly surgery.

Tendinopathy in diabetes mellitus patients-Epidemiology, pathogenesis, and management

Chronic tendinopathy is a frequent and disabling musculo-skeletal problem affecting the athletic and general populations. The affected tendon is presented with local tenderness, swelling, and pain which restrict the activity of the individual. Tendon degeneration reduces the mechanical strength and predisposes it to rupture. The pathogenic mechanisms of chronic tendinopathy are not fully understood and several major non-mutually exclusive hypotheses including activation of the hypoxia-apoptosis-pro-inflammatory cytokines cascade, neurovascular ingrowth, increased production of neuromediators, and erroneous stem cell differentiation have been proposed. Many intrinsic and extrinsic risk/causative factors can predispose to the development of tendinopathy. Among them, diabetes mellitus is an important risk/causative factor. This review aims to appraise the current literature on the epidemiology and pathology of tendinopathy in diabetic patients. Systematic reviews were done to summarize the literature on (a) the association between diabetes mellitus and tendinopathy/tendon tears, (b) the pathological changes in tendon under diabetic or hyperglycemic conditions, and (c) the effects of diabetes mellitus or hyperglycemia on the outcomes of tendon healing. The potential mechanisms of diabetes mellitus in causing and exacerbating tendinopathy with reference to the major non-mutually exclusive hypotheses of the pathogenic mechanisms of chronic tendinopathy as reported in the literature are also discussed. Potential strategies for the management of tendinopathy in diabetic patients are presented.