The Estrogen Receptor-β Expression in De Quervain's Disease

A Case Report of Surgical Approach in Managing De Quervain's Tenosynovitis

De Quervain's tenosynovitis is characterized by swelling of muscles (abductor pollicis longus (APL) and extensor pollicis (EPB) brevis), and they are located at the base of the thumb. This is a very irritating and painful condition. In many cases, late detection causes an increase in inflammation, and due to prolonged ignorance and neglect, the patient suffers from pain and discomfort that affects and restricts their daily routine work. The disorder tenosynovitis is triggered by preexisting tendon degeneration induced by excessive twisting actions. Inflammatory arthritis is primarily associated with the disorder. The tendon sheath thickens and becomes constricted if the inflammation and swelling persist. Patients who undergo high-torque wrist turning or other repetitive everyday movements, such as handshaking, have a higher risk of developing tenosynovitis. This disease can also occur without any sort of visible prior trauma or injury. Clinical evaluation is usually required for diagnosis; however, imaging studies might be used to confirm the diagnosis or check out alternate diseases. Nonsteroidal anti-inflammatory medication (NSAIDs), physical therapy, immobilization with splints, and rest are among the treatment options. Applying ice to the affected area and applying a splint are a few ways to ease the pain. Corticosteroid injections or surgery may be considered in situations that do not respond to preventive treatment; thus, patients are advised to go for minor surgery to get relief from prolonged pain.

Equol production capability and family history as risk factors for hand osteoarthritis in menopausal and postmenopausal women. Cross-sectional study

BACKGROUND

Hand disorders are common in menopausal women. Equol is a soy metabolite produced in humans and its production level differs among individuals. The purpose of this research is to investigate the correlative relationship between variables indicating equol production levels and the occurrence of hand disorders in menopausal and postmenopausal women.

METHODS

Female subjects were divided into two groups: women 45-70 years of age with hand osteoarthritis (patient group) and women in the same age range without hand osteoarthritis (control group). The equol production level of each subject was estimated by measuring her urine equol concentration. We also surveyed the subjects' family histories of osteoarthritis.

RESULTS

Equol levels in the patient group were significantly lower than those in the control group (p < 0.05). This difference was most apparent for women in their 50s. Individuals with family histories of Heberden's and Bouchard's nodes were found to be 48.1 times more likely to develop these conditions than individuals in the control group.

CONCLUSIONS

Women with early menopausal hand symptoms (i.e., stiff and arthritic hands) often develop hand osteoarthritis during their late menopausal and postmenopausal periods, which may cause their QoL to significantly deteriorate. Although a link between the probability of women developing hand osteoarthritis and their clinical backgrounds (i.e., family history) had been suspected, it had not been thoroughly investigated. Our survey of women with and without Heberden's nodes and Bouchard's nodes found a significant correlation between the likelihood of women developing osteoarthritis and a family history of this disease. We also found a significant correlation between the likelihood of women developing hand osteoarthritis and their equol production levels. These results indicate that women with family histories of finger osteoarthritis and low equol production have higher risks of developing finger osteoarthritis.

Approach to chronic wrist pain in adults: Review of common pathologies for primary care practitioners

OBJECTIVE

To develop an approach for identifying, investigating, and initially managing common causes of chronic wrist pain seen by primary care practitioners.

SOURCES OF INFORMATION

Relevant clinical evidence and literature were identified using the PubMed database.

MAIN MESSAGE

Chronic wrist pain is a common presentation in the primary care setting. The complex anatomy of the wrist leads to a broad differential diagnosis. Elements of history, findings of physical examinations and investigations, and management relevant to the following pathologies are discussed, including scaphoid fracture nonunion, thumb carpometacarpal joint osteoarthritis, scapholunate ligament instability, triangular fibrocartilage complex injuries, de Quervain tenosynovitis, extensor carpi ulnaris tendinopathy, carpal tunnel syndrome, and ganglion cysts. When evaluating chronic wrist pain, diagnostic imaging with x-ray scans can serve as an important ancillary investigation tool but should not override clinical suspicion. Advanced imaging (computed tomography or magnetic resonance imaging) is generally best ordered by a hand surgeon when it will help clarify a diagnosis and guide treatment.

CONCLUSION

Chronic wrist pain is a functionally limiting problem best managed with timely diagnosis and treatment. A thorough history and physical examination are the cornerstones of an effective evaluation. When diagnosis is delayed, some wrist pathologies can lead to relatively poor outcomes, such as a scaphoid fracture nonunion resulting in diffuse wrist osteoarthritis.

Approche de la douleur chronique au poignet chez les adultes: Revue des pathologies courantes à l'intention des praticiens des soins primaires

OBJECTIF

Élaborer une approche pour déterminer, investiguer et initialement prendre en charge les causes courantes de la douleur chronique au poignet que voient les professionnels des soins primaires.

SOURCES DE L'INFORMATION

Les données probantes et la littérature scientifique pertinentes ont été recensées à l'aide de la base de données PubMed.

MESSAGE PRINCIPAL

Les consultations pour une douleur chronique au poignet sont fréquentes en soins primaires. L'anatomie complexe du poignet est propice à la multiplicité des diagnostics différentiels. Les éléments de l'anamnèse, les constatations aux examens physiques et aux investigations, et la prise en charge qui sont applicables aux pathologies suivantes sont présentés : pseudarthrose du scaphoïde, arthrose de l'articulation carpométacarpienne du pouce, instabilité du ligament scapholunaire, lésions au complexe triangulaire fibrocartilagineux, ténosynovite de De Quervain, tendinopathie de l'extenseur ulnaire du carpe, syndrome du tunnel carpien et kystes ganglionnaires. Lors de l'évaluation de la douleur chronique au poignet, l'imagerie diagnostique par radiographies peut servir d'outil auxiliaire important, mais ne devrait pas l'emporter sur la suspicion clinique. L'imagerie avancée (tomodensitométrie ou imagerie par résonance magnétique) devrait généralement être plus judicieusement prescrite par un chirurgien de la main, lorsqu'il s'agit de préciser le diagnostic et d'orienter le traitement.

CONCLUSION

La douleur chronique au poignet est un problème invalidant sur le plan fonctionnel, dont la prise en charge optimale est un diagnostic et un traitement sans délai. Une anamnèse et un examen physique rigoureux sont les pierres angulaires d'une évaluation efficace. Lorsque le diagnostic est tardif, certaines pathologies du poignet peuvent entraîner des issues relativement défavorables, comme la pseudarthrose du scaphoïde causant une arthrose diffuse du poignet.

Analysis of a National Database Investigating Development of Trigger Finger after Treatment of Dupuytren Disease

Dupuytren disease is associated with inflammation and myofibroblast overgrowth, as is stenosing tenosynovitis (trigger finger). Both are linked with fibroblast proliferation, but a potential associative link between the diseases is unknown. The purpose of this study was to evaluate the progression of trigger finger following treatment for Dupuytren contracture in a large database.

Methods

A commercial database encompassing 53 million patients was utilized from January 1, 2010 to March 31, 2020. The study cohort included patients diagnosed with either Dupuytren disease or trigger finger utilizing International Classification Codes 9 and 10. Terminology codes were used to identify common Dupuytren procedures, as well as trigger finger release. Logistic regression analysis was used to define independent risk factors for developing trigger finger.

Results

A total of 593,606 patients were diagnosed with trigger finger. Of these patients, 15,416 (2.6%) were diagnosed with trigger finger after diagnosis of Dupuytren disease, whereas 2603 (0.4%) patients were diagnosed with trigger finger after treatment of Dupuytren contracture. Independent risk factors for trigger finger included age 65 years or older (OR 1.00, P < 0.05), diabetes (OR 1.12, P < 0.05) and obesity (OR 1.20, P < 0.005). Patients who received collagenase clostridium histolyticum treatment (OR 0.34, P < 0.005) for Dupuytren contracture were significantly less likely to develop trigger finger.

Conclusions

Dupuytren contracture is associated with inflammation and subsequent trigger finger development at a higher rate than the background population frequency. Collagenase clostridium histolyticum injection may lead to a decreased risk of trigger finger requiring surgical intervention in patients with risk factors.

Are the Pathologic Features of Enthesopathy, Tendinopathy, and Labral and Articular Disc Disease Related to Mucoid Degeneration? A Systematic Review

BACKGROUND

Tendinopathy, enthesopathy, labral degeneration, and pathologic conditions of the articular disc (knee meniscus and ulnocarpal) are sometimes described in terms of inflammation or damage, while the histopathologic findings are often consistent with mucoid degeneration. A systematic review of the histopathology of these structures at diverse locations might reconceptualize these diseases as expected aspects of human aging. The potential benefits of this evolution might include healthier patient and clinician mindsets as well as a reduced likelihood of overdiagnosis and overtreatment resulting from greater awareness of base rates of pathology.

QUESTION/PURPOSE

In this systematic review of studies of surgical specimens, we asked: Are there are any differences in the histopathologic findings of structural soft tissue conditions (mucoid degeneration, inflammation, and vascularity) by anatomic site (foot, elbow, or knee) or structure (tendon body, muscle or tendon origin or insertion [enthesis], labrum, or articular disc)?

METHODS

Studies between 1980 and 2021 investigating the histopathologic findings of specimens from surgery for trigger digit, de Quervain tendinopathy, plantar fasciitis, lateral and medial elbow enthesopathy, rotator cuff tendinopathy, posterior tibial tendinopathy, patellar tendinopathy, Achilles tendinopathy, or disease of the hip labrum, ulnocarpal articular disc, or knee meniscus were searched for in the PubMed, EMBASE, and CINAHL databases. Inclusion criteria were the prespecified anatomic location or structure being analyzed histologically and any findings described with respect to inflammation, vascularity, or mucoid degeneration. Studies were excluded if they were nonhuman studies or review articles. Search terms included "anatomy," "pathology," and "histopathology." These terms were coupled with anatomic structures or disorders and included "trigger finger," "de Quervain," "fasciitis, plantar," "tennis elbow," "rotator cuff tendinopathy," "elbow tendinopathy," "patellar tendonitis," "posterior tibial tendon," and "triangular fibrocartilage." This resulted in 3196 studies. After applying the inclusion criteria, 559 articles were then assessed for eligibility according to our exclusion criteria, with 52 eventually included. We recorded whether the study identified the following histopathologic findings: inflammatory cells or molecular markers, greater than expected vascularity (categorized as quantitative count, with or without controls; molecular markers; or qualitative judgments), and features of mucoid degeneration (disorganized collagen, increased extracellular matrix, or chondroid metaplasia). In the absence of methods for systematically evaluating the pathophysiology of structural (collagenous) soft tissue structures and rating histopathologic study quality, all studies that interpreted histopathology results were included. The original authors' judgment regarding the presence or absence of inflammation, greater than expected vascularity, and elements of mucoid degeneration was recorded along with the type of data used to reach that conclusion.

RESULTS

Regarding differences in the histopathology of surgical specimens of structural soft tissue conditions by anatomic site, there were no differences in inflammation or mucoid degeneration, and the knee meniscus was less often described as having greater than normal vascularity. There were no differences by anatomic structure. Overall, 20% (10 of 51) of the studies that investigated for inflammation reported it (nine inflammatory cells and one inflammatory marker). Eighty-three percent (43 of 52) interpreted increased vascularity: 40% (17 of 43) using quantitative methods (14 with controls and three without) and 60% (26 of 43) using imprecise criteria. Additionally, 100% (all 52 studies) identified at least one element of mucoid degeneration: 69% (36 of 52) reported an increased extracellular matrix, 71% (37 of 52) reported disorganized collagen, and 33% (17 of 52) reported chondroid metaplasia.

CONCLUSION

Our systematic review of the histopathology of diseases of soft tissue structures (enthesopathy, tendinopathy, and labral and articular disc) identified consistent mucoid degeneration, minimal inflammation, and imprecise assessment of relative vascularity; these findings were consistent across anatomic sites and structures, supporting a reconceptualization of these diseases as related to aging (senescence or degeneration) rather than injury or activity.

CLINICAL RELEVANCE

This reconceptualization supports accommodative mindsets known to be associated with greater comfort and capability. In addition, awareness of the notable base rates of structural soft tissue changes as people age might reduce overdiagnosis and overtreatment of incidental, benign, or inconsequential signal changes and pathophysiology.

De Quervain's Disease: A Discourse on Etiology, Diagnosis, and Treatment

Since Fritz De Quervain first postulated stenosing tenosynovitis within the radial dorsum of the wrist, much research has been conducted to provide further insights. De Quervain's Disease (DQD) is a condition that affects the tendons that control the movement of the thumb, specifically the abductor pollicis longus and extensor pollicis brevis. Numerous studies have shown that structural divergence from normal anatomy is partly related to contingency for developing DQD. Even though this condition was discovered many years ago, its exact etiology remains a subject of debate. Two schools of thought exist, one that contends an inflammatory-mediated pathway and the other degenerative changes. Substantial evidence exists for both theories, thus necessitating further studies into the etiology of DQD. Classically, Finkelstein's and Eichhoff's tests have been used as the physical examinations of choice for clinically diagnosing this condition. However, these tests have been shown to have low specificity, hence, the emergence of the wrist hyperflexion and abduction of the thumb test. Evidence also suggests that ultrasonography may become a critical diagnostic tool, especially to identify anatomical variations before invasive treatment, reducing the risk of further complications. The management of DQD is typically conservative, with escalation to steroid injections before surgery is indicated. Future research into this disease should focus on establishing a clearer picture of how anatomical variations and other pathological and occupational factors may interplay to bring about this condition. While current research has suggested possible novel approaches for diagnosing and treating DQD, more studies are required to gain greater insights into the effectiveness of these interventions.

Incidence and Risk Factors for Pregnancy-Related de Quervain's Tenosynovitis in South Korea: A Population-Based Epidemiologic Study

Background

Although pregnant or lactating women have been recognized to be predisposed to de Quervain's tenosynovitis (DQT), there is a lack of epidemiologic evidence. The purpose of this study was to estimate the nationwide incidence of pregnancy-related DQT (PRDQT) and to analyze risk factors using the Korean National Health Insurance (NHI) database.

Methods

A retrospective epidemiologic study of pregnant women in South Korea from 2013 to 2017 was conducted using the NHI claims database. Using corresponding diagnostic codes, we identified women diagnosed with DQT during pregnancy or the postpartum period. We calculated the cumulative incidence and analyzed risk factors such as demographics, pregnancy type, delivery method, gestational complications, and comorbidities using multivariate logistic regression analysis.

Results

Between 2013 and 2017, 34,342 patients with PRDQT were identified among 1,601,501 pregnant women, representing a cumulative incidence of approximately 2.1%. Age ≥ 30 years, multiple gestation, cesarean delivery, hypertensive disorders in pregnancy, and underlying rheumatoid arthritis were all identified as significant risk factors for the occurrence of PRDQT, whereas diabetic disorders in pregnancy and underlying diabetes mellitus were not.

Conclusions

In South Korea, PRDQT was found to affect approximately 2.1 out of 100 pregnant women between 2013 and 2017. The incidence and risk factors identified in this study can be used for clinical consultations and prediction, as well as for development of national health policies.

Time to Reconsider Occupation Induced De Quervain's Tenosynovitis: An Updated Review of Risk Factors

De Quervain's tenosynovitis (DQT) is described to be an attritional and degenerative process, triggered by stenosing inflammation of the tendon sheath in the first dorsal compartment of the wrist. Understanding and targeting the risk factors associated with DQT will help clinicians and patients to reduce its prevalence. This review aims to evaluate the current literature surrounding the risk factors which were divided into the anatomical, patient, and occupational factors associated with the condition. The two main anatomical variations associated with DQT are subcomparmentalization and multiple tendon slips of the abductor pollicus longus (APL) and extensor pollicus brevis (EPB) tendons. DQT is more common in females and is often noted in pregnancy and the postpartum period. When considering occupational factors, work-related activity has not been shown to be a direct cause of DQT, despite leading organisations supporting the converse.

Association between de Quervain syndrome and herpes zoster: a population-based cohort study

OBJECTIVE

Both physical diseases such as infection and chronic pain and psychological disorders such as depression have been associated with herpes zoster (HZ) reactivation. However, the relationship between de Quervain syndrome (DQS), a painful tenosynovitis and HZ remains unclear. We investigated whether DQS increases the risk of HZ reactivation.

DESIGN

A retrospective population-based cohort study.

SETTING

Taiwan.

PARTICIPANTS

We used a subset of Taiwan's National Health Insurance Research Database, the Longitudinal Health Insurance Database which contains the registration files and original claims data of 1 million randomly selected individuals from the National Health Insurance programme. The case group in this study comprised patients newly diagnosed with DQS between 2000 and 2012. Individuals without DQS comprised the control group. Cases and controls were 1:1 matched by age, sex and index year (defined as the year of DQS diagnosis).

RESULTS

Approximately 55% of the participants were ≤49 years. Most participants were women (77%). The incidence rate of HZ in the DQS group was 8.39 per 1000 person years. After adjustments for age, sex and comorbidities, patients with DQS had a 1.30 times higher risk of HZ reactivation than the control group. Stratification analysis revealed taht DQS increases the HZ risk in individuals ≤64 years, women, and patients without comorbidities.

CONCLUSION

DQS is associated with an increased risk of HZ. Clinicians should be aware of this risk when dealing with patients with DQS, particularly in young adults.

The role of estrogen and progesterone receptors in the rotator cuff disease: a retrospective cohort study

Background

Rotator cuff (RC) tears represent a common cause of shoulder pain and dysfunction in adults. The disease affects primarily women and occurs mainly in the postmenopausal period.

This study aimed to investigate immunohistochemically the presence of estrogen receptor-alpha (ER-⍺), estrogen receptor-beta (ER-β) and progesterone receptor (PR) in the supraspinatus tendon of patients with RC tendinopathy, searching for gender differences of expression. A secondary aim was to evaluate potential links between their expression and the typical histopathological findings of the ailment.

Methods

Biopsies of the supraspinatus tendon were collected intraoperatively from 15 postmenopausal women and 9 men undergoing RC surgery. Specimens were stained with Haematoxylin/Eosin, Masson-Goldner Trichrome, Alcian Blu and immunohistochemical stainings for ER-⍺, ER-β and PR were performed. Tendon alterations were evaluated with the Bonar histopathological scale. Statistical tests used in this study were the Spearman correlation coefficient and the Mann-Whitney U test.

Results

In the supraspinatus tendon, cells expressed ER-⍺ (p = 0.043), ER-β (p = 0.048) and PR (p = 0.004) with statistically significant differences related to age and sex of patients. Immunoreactivity was seen in the nuclei of tenocytes and vascular cells. Postmenopausal women’s samples showed a markedly higher expression of these receptors compared to their male counterpart. There was a positive correlation between the expression of ER-⍺ and ER-β (r = 0.59; p = 0.02) and between ER-β and PR (r = 0.72; p = 0.002) in women’s samples. Furthermore, in postmenopausal women the PR expression decreased with age (r = − 0.56; p = 0.027). Only in women, the ER-β expression positively correlated with the total Bonar histopathological score (p = 0.019) and the ER-β vascular expression positively correlated with ground substance alterations (p = 0.029).

Conclusions

These results reveal that ERs and PR are present in the supraspinatus tendon of patients with RC tears, suggesting a role of sex hormones in the pathogenesis of the disease.

Pregnancy and Lactation Impair Subchondral Bone Leading to Reduced Rat Supraspinatus Tendon-to-Bone Insertion Site Failure Properties

Pregnant women experience weight gain, gait changes, and biochemical fluctuations that impair joint function and alter the maternal skeleton. Hormonal changes increase pelvic ligament laxity in preparation for childbirth and affect peripheral joint laxity. Calcium demands also rise during pregnancy and lactation, resulting in reduced bone mineral density (BMD) and maternal bone loss. Altered tendon properties and bone loss during pregnancy and lactation may impact tendon insertion sites, such as rotator cuff tendons where insertion site ruptures are common. However, the effects of pregnancy and lactation at the tendon-to-bone interface have not been investigated. Therefore, the objective of this study was to evaluate supraspinatus tendon mechanical properties and insertion site microstructure during pregnancy, lactation, and postweaning recovery in female rats. We hypothesized that pregnancy and lactation would compromise supraspinatus tendon mechanical properties and subchondral bone microstructure. Female rats were divided into virgin, pregnancy, lactation, and recovery groups, and supraspinatus tendons were mechanically evaluated. Surprisingly, tendon mechanics was unaffected by pregnancy and lactation. However, tendon modulus decreased two-weeks postweaning. Additionally, tendons failed by bony avulsion at the insertion site, and the lactation group exhibited reduced failure properties corresponding to decreased subchondral bone mineralization. Lactation also resulted in dramatic bone loss at the epiphysis, but trabecular bone microarchitecture recovered postweaning. In conclusion, lactation following pregnancy impaired trabecular bone microstructure and subchondral bone mineralization, leading to reduced supraspinatus tendon-to-bone insertion site failure properties. These findings will contribute toward understanding the pathogenesis of tendon-to-bone disorders.

Association of estrogen receptor β polymorphisms with posterior tibial tendon dysfunction

Posterior tibial tendon (PTT) dysfunction is three times more common in females, and some patients may have a predisposition without a clinically evident cause, suggesting that individual characteristics play an important role in tendinopathy. The present study investigated the association of rs4986938 (+ 1730G > A; AluI RFLP) and rs1256049 (- 1082G > A; RsaI RFLP) single nucleotide polymorphisms (SNPs) of estrogen receptor-beta (ER-β) gene with PTT dysfunction. A total of 400 participants were recruited. The PTT dysfunction group: these patients underwent surgery, with PTT tendinopathy confirmed by histopathology and magnetic resonance image (MRI). The control group was composed of participants with no clinical or MRI evidence of PTT dysfunction. Each group was composed of 100 postmenopausal women, 50 premenopausal women, and 50 men. Genomic DNA was extracted from saliva samples, and genotypes were obtained by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Concerning the ER-β SNP rs4986938, there were significant differences in the frequencies of alleles between test and control groups of all the cases, only postmenopausal women and only men (p < 0.0001, p = 0.0016 and p = 0.0001). Considering the PTT dysfunction group and comparing postmenopausal women versus premenopausal women adding men, the analysis showed significant differences in the allelic distribution (p = 0.0450): the allele A in postmenopausal women is a risk factor. The ER-β SNP rs1256049 did not show differences in the frequencies of alleles and genotypes between groups. The ER-β SNP rs4986938, but not ER -β SNPs rs1256049, may contribute to PTT insufficiency in the Brazilian population, with additional risk in postmenopausal women. Addition, in men the genetic factor could be more determinant.

Hand tendinopathy risk factors in Taiwan: A population-based cohort study

De Quervain's disease, carpal tunnel syndrome (CTS), and trigger finger (digit) are three common pathological conditions of the hand. They are considered overuse syndromes and occur predominantly in females. The prevalence rate and cause-specific risks of these three tendinopathies have not yet been clarified. Data from 41,871 cases listed in the Taiwan National Health Insurance Research Database (NHIRD) from 2010 to 2014 were analyzed. The prevalence rate of these 3 conditions by age, sex, and the risk factors of female-dominant diseases (e.g., osteoporosis, rheumatoid arthritis [RA], and tendinopathy), diabetes mellitus, and hormone antagonist treatment was evaluated. We found that 1.59% of the population developed CTS, 0.49% developed de Quervain's, and 1.07% developed trigger finger. Cases were more likely to develop the three hand tendinopathies if they were female, between 50 and 59 years old, and, according to a multivariate analysis, comorbid with RA, diabetes, using hormone antagonists. Our findings should provide an understanding of the risk factors associated with hand tendinopathy.

ERα PvuII and XbaI polymorphisms in postmenopausal women with posterior tibial tendon dysfunction: a case control study

Background

Posterior tibial tendon (PTT) insufficiency is considered as the main cause of adult acquired flat foot and is three times more frequent in females. High estrogen levels exert a positive effect on the overall collagen synthesis in tendons. We have previously demonstrated the association between some genetic single-nucleotide polymorphism (SNP) and tendinopathy. In the present study, we investigated the association of PvuII c454-397T>C (NCBI ID: rs2234693) and XbaI c454-351A>G (NCBI ID: rs9340799) SNPs in estrogen receptor alfa (ER-α) gene with PPT dysfunction.

Methods

A total of 92 female subjects with PTT dysfunction, with histopathological examination of the tendon and magnetic resonance image (MRI) evidence of tendinopathy, were compared to 92 asymptomatic females who presented an intact PPT at MRI for PvuII and XbaI SNPs in the ER-α gene. Genomic DNA was extracted from saliva and genotypes were obtained by polymerase chain reaction restriction fragment length polymorphism.

Results

The analysis of PvuII SNPs showed no significant differences in the frequency of alleles and genotypes between control and PTT dysfunction groups. The XbaI SNPs in the ER-α gene showed significant differences in the frequency of genotypes between control and test groups (p = 0.01; OR 95% 1.14 (0.55–2.33).

Conclusions

The XbaI SNP in the ERα gene may contribute to tendinopathy, and the A/A genotype could be a risk factor for PTT tendinopathy in this population. The PvuII SNP studied was not associated with PTT tendinopathy.

Estrogen and mechanical loading-related regulation of estrogen receptor-β and apoptosis in tendinopathy

Female-dominant tendinopathies are musculoskeletal disorders caused by repetitive hand posture and motion; they are considered overuse syndromes. Both external mechanical stress and changes in hormone levels might affect disease progression. We have previously reported that estrogen receptor-β (ER)-β expression was associated with the pathogenesis of de Quervain's disease. To study the underlying mechanisms, a cyclic stretching culture system was applied to tendon tissue from ovariectomized (OVX) rats. Furthermore, a collagenase I-induced rat tendinopathy model was established to examine the association of ER-β with disease progression. Our results showed that ER-β expression and the number of apoptotic cells were higher and associated with disease severity in rats with tendinopathy. Mechanical stress altered the morphology of primary tenocytes and collagen fiber alignment in tendons, and up-regulated the expression of matrix metalloproteinase-9, ER-β, and interleukin-1β, as well as induced apoptosis in tenocytes and tendon tissue from OVX rats. This is the first report on the effects of ER-β and mechanical stress in tendinopathy. We hope these findings contribute to new pharmacological therapies targeting ER-β signaling pathways to treat tendon-related diseases.

The effect of estrogen on tendon and ligament metabolism and function

Tendons and ligaments are crucial structures inside the musculoskeletal system. Still many issues in the treatment of tendon diseases and injuries have yet not been resolved sufficiently. In particular, the role of estrogen-like compound (ELC) in tendon biology has received until now little attention in modern research, despite ELC being a well-studied and important factor in the physiology of other parts of the musculoskeletal system. In this review we attempt to summarize the available information on this topic and to determine many open questions in this field.