Evidence of genetic variations associated with rotator cuff disease

Predicting Injuries in Elite Female Football Players With Global-Positioning-System and Multiomics Data

PURPOSE

Injury prevention is a crucial aspect of sports, particularly in high-performance settings such as elite female football. This study aimed to develop an injury prediction model that incorporates clinical, Global-Positioning-System (GPS), and multiomics (genomics and metabolomics) data to better understand the factors associated with injury in elite female football players.

METHODS

We designed a prospective cohort study over 2 seasons (2019-20 and 2021-22) of noncontact injuries in 24 elite female players in the Spanish Premiership competition. We used GPS data to determine external workload, genomic data to capture genetic susceptibility, and metabolomic data to measure internal workload.

RESULTS

Forty noncontact injuries were recorded, the most frequent of which were muscle (63%) and ligament (20%) injuries. The baseline risk model included fat mass and the random effect of the player. Six genetic polymorphisms located at the DCN, ADAMTS5, ESRRB, VEGFA, and MMP1 genes were associated with injuries after adjusting for player load (P < .05). The genetic score created with these 6 variants determined groups of players with different profile risks (P = 3.1 × 10-4). Three metabolites (alanine, serotonin, and 5-hydroxy-tryptophan) correlated with injuries. The model comprising baseline variables, genetic score, and player load showed the best prediction capacity (C-index: .74).

CONCLUSIONS

Our model could allow efficient, personalized interventions based on an athlete's vulnerability. However, we emphasize the necessity for further research in female athletes with an emphasis on validation studies involving other teams and individuals. By expanding the scope of our research and incorporating diverse populations, we can bolster the generalizability and robustness of our proposed model.

Shoulder pathologies in CrossFit: a magnetic resonance imaging study of 51 cases

BACKGROUND

Recent scientific work shows that the most common injuries in CrossFit© occur in the shoulder joint. This paper aims to provide a review of shoulder pathologies in a young CrossFit© cohort via MRI and clinical examination.

METHODS

A survey was conducted in 13 CrossFit "boxes" in Germany, in which athletes with recurrent shoulder pain could report for a clinical examination and MRI diagnostic. Fifty-one CrossFit athletes with chronic shoulder pain agreed to participate in the study and were then examined physically and by MRI.

RESULTS

Fifty-one active CrossFit athletes aged 21-45 years (mean 33.7 years, 35 male and 16 female) were recruited. The most frequently detected pathologies were partial lesions of the supraspinatus tendon (N.=25; 49%) and labral lesions (N.=11; 21.6%). The findings also identified partial lesions of the subscapularis tendon (N.=9; 17.6%), pulley lesions (N.=9; 17.6%), and partial lesions of the infraspinatus muscle (N.=2; 3.9%).

CONCLUSIONS

These data demonstrate the need for a specific focus on particular shoulder injuries in CrossFit. Knowledge about the type of shoulder pathologies caused by CrossFit training allows for training-specific adaptations with regard to prevention, as well as a more targeted, sport-specific therapy. This study is the first in the literature to present on structural changes in the shoulders of active CrossFit athletes.

Factors associated with genetic markers for rotator cuff disease in patients with atraumatic rotator cuff tears

For atraumatic rotator cuff tears, genetics contributes to symptomatic tear risk and may influence rotator cuff healing after surgical repair. But little is known about how genetic factors influence rotator cuff tear patient characteristics at presentation. We collected saliva samples for genotyping from atraumatic rotator cuff tear patients. We examined nine single nucleotide polymorphisms (SNPs) associated with cuff tears in prior literature. We estimated associations of SNP dosage with (1) age at tear diagnosis, (2) bilateral atraumatic tear prevalence, and (3) tear size. Linear regression was used to estimate associations with diagnosis age adjusted for sex and principal components. Logistic regression and ordinal logistic regression were used to estimate associations with bilateral tear prevalence and tear size category, respectively, adjusting for age, sex, and principal components. Of 344 eligible patients, 336 provided sufficient samples for genotyping. Median age at tear diagnosis was 61, 22% (N = 74) had bilateral atraumatic tears, and 9% (N = 29) had massive tears. SNP rs13107325 in the SLC39A8 gene and rs11850957 in the STXBP6 gene were associated with younger diagnosis age even after accounting for multiple comparisons (rs13107325: -4 years, 95% CI = -6.5, -1.4; rs11850957: -2.7 years, 95% CI = -4.3, -1.1). No other significant associations were observed with diagnosis age, tear size, or bilateral tear prevalence. SLC39A8 encodes a Mn transporter. STXBP6 may play a role in inflammatory responses by altering phagocytosis and antigen presentation of monocytes and macrophages. Further research is needed to determine if genetic markers can be used alongside patient characteristics to aid in identifying optimal surgical repair candidates.

The Relationship Among Probable SARCopenia, Osteoporosis and SuprasPinatus Tendon Tears in Postmenopausal Women: The SARCOSP Study

We aimed to investigate the relationship among probable sarcopenia, osteoporosis (OP) and supraspinatus tendon (SSP) tears in postmenopausal women. Postmenopausal women screened/followed for OP were recruited. Demographic data, comorbidities, exercise/smoking status, and handgrip strength values were recorded. Probable sarcopenia was diagnosed as handgrip strength values < 20 kg. Achilles and SSP thicknesses were measured using ultrasound. Among 1443 postmenopausal women, 268 (18.6%) subjects had SSP tears. Unilateral tears were on the dominant side in 146 (10.1%) and on the non-dominant side in 55 women (3.8%). In contrast to those without, women with SSP tears had older age, lower level of education, thinner SSP and lower grip strength (all p < 0.05). In addition, they had higher frequencies of hypertension, hyperlipidemia, DM, OP and probable sarcopenia, but lower exercise frequency (all p < 0.05). Binary logistic regression modeling revealed that age [odds ratio (OR): 1.046 (1.024-1.067 95% CI)], hypertension [OR: 1.560 (1.145-2.124 95% CI)], OP [OR: 1.371 (1.022-1.839 95% CI)] and probable sarcopenia [OR: 1.386 (1.031-1.861 95% CI)] were significant predictors for SSP tears (all p < 0.05). This study showed that age, presence of hypertension, probable sarcopenia and OP were related with SSP tears in postmenopausal women. To this end, although OP appeared to be related to SSP tears, SSP tear/thickness evaluation can be recommended for OP patients, especially those who have other risk factors such as older age, higher BMI, hypertension, and probable sarcopenia.

Clinical Approach to Inconclusive Subscapularis Tear Diagnosis: a Meta-analysis

To identify factors associated with subscapularis (SSC) tears and provide a theoretical basis for clinical diagnosis, we included studies related to subscapularis tears published before February 1, 2023. We screened for six predictors across previous studies for the meta-analysis. The predictors included age, sex, coracoid overlap (CO), coracohumeral distance (CHD), impairment of the long head of the biceps tendon (LHB), and dominant arm. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the studies. The risk ratios (RRs) and the weighted mean differences (WMDs) were used to evaluate the effect size of categorical variables and continuous variables, respectively. The Egger test was used to assess the publication bias of the studies. Ten studies were included from seven countries. A total of 2 126 patients were enrolled, of whom 1 041 had subscapularis tears and 1 085 did not. The study showed that age (WMD, 4.23 [95% CI, 2.32-6.15]; P<.00001), coracoid overlap (WMD, 1.98 [95% CI, 1.55-2.41]; P<.00001), coracohumeral distance(WMD, -1.03 [95% CI, -1.17- -0.88]; P<.00001), and an injury of the long head of the biceps tendon (RR, 4.98 [95% CI, 3.75-6.61]; P<.00001) were risk factors for subscapularis tears. These risk factors can help clinicians identify subscapularis tears early and select appropriate interventions. The level of evidence is 3.

Genome-wide association study identifying variants related to performance and injury in high-performance athletes

A growing body of evidence exists supporting the role that genetic variation plays in athletic performance and injury. This study sought to identify genetic variants associated with performance and lower limb musculoskeletal injury in a high-level athletic cohort. A total of 126 Estonian National Team members (Olympic athletes and participants of International Championships) (104 males, 82.5%) underwent a genome-wide association analysis between 2017 and 2018, to identify single-nucleotide polymorphisms (SNPs) associated with performance and/or injury. The athletic cohort was stratified within each sport based on performance and whether they were a medalist (n = 29) or not (n = 97), whether they sustained an injury (n = 47) or not (n = 79), and the type of injury (patella tendinopathy n = 22, Achilles tendinopathy n = 17, hamstring injury n = 3, anterior cruciate ligament rupture n = 6). Three SNPs demonstrated strong genome-wide association with athletic performance (podium/medalist versus not), including DSG1 (rs10502567, OR 14.3) and DSG4 (rs73410248, OR 17.4), while 76 SNPs demonstrated suggestive significance. Overall, 37 SNPs gave genome-wide suggestive association with any type of injury, including PAPPA2 (rs11580456, OR 13.8) and MAS1 (rs220735, rs170219, OR 3.1) which demonstrated positive signal with multiple SNPs. Several genes demonstrated positive association for the specific injury types, including COL22A1 (rs3924862) and PLXNA2 (rs11799530), as well as PAPPA2 (rs11580456), DOK5 (rs73142922), GNG12 (rs28435277), and DAP (rs267959, rs2930047, rs1080440, rs267939). The current study identified genetic variants associated with high-level athletic performance and musculoskeletal injury. Further work is required to permit integration of this and future knowledge into individualized training practices, as well as injury mitigation and rehabilitation programs.

Association Between COL5a1, COL11a1, and COL11a2 Gene Variations and Rotator Cuff Tendinopathy in Young Athletes

OBJECTIVE

Tendinopathy is a prevalent condition in young athletes and in older nonathletic people. Recent tendinopathy research has shown a growing interest in the role played by genetic factors, basically genes involved in collagen synthesis and regulation, in view of collagen disorganization typically present in tendon pathologies.

DESIGN

A case-control, genotype-phenotype association study.

SETTING

La Ribera Hospital, Valencia, Spain.

PARTICIPANTS

A group of 137 young athletes (49 with rotator cuff tendon pathology and 88 healthy counterparts) who played upper-limb-loading sports were clinically and ultrasound (US) assessed for rotator cuff tendinopathy were included.

INTERVENTION

Genetic analysis was performed to determine whether there was a relationship between rotator cuff pathology and the genotype.

MAIN OUTCOME MEASURES

We hypothesized that the following single nucleotide polymorphisms: COL5a1 rs12722, COL11a1 rs3753841, COL11a1 rs1676486, and COL11a2 rs1799907 would be associated with rotator cuff tendinopathy.

RESULTS

A direct relationship between CC genotype and bilateral US pathological images was statistically significant (χ 2 = 0.0051) and confirmed by the Fisher test, with a correlation coefficient of 0.345 and a Cramer's v of 0.26.

CONCLUSION

A significant association was found between COL5a1 rs12722 genotype and rotator cuff pathology, with the CC genotype conferring increased risk of tendon abnormalities and being associated with rotator cuff pathology.

Progression of symptomatic bilateral rotator cuff disease

Background

Prior studies have demonstrated that conservatively treated rotator cuff tears and rotator cuff tendinopathy may continue to progress. It is unclear whether that rate of progression differs between sides in patients with bilateral disease. This study evaluated the likelihood of progression of rotator cuff disease as confirmed via magnetic resonance imaging (MRI) in individuals with symptomatic bilateral pathology, treated conservatively for a minimum of 1 year.

Methods

We identified patients with bilateral rotator cuff disease confirmed via MRI within the Veteran's Health Administration electronic database. A retrospective chart review via the Veteran's Affairs electronic medical record was performed. Progression was determined using 2 separate MRIs with a minimum of 1 year apart. We defined progression as (1) a progression from tendinopathy to tearing, (2) an increase from partial-thickness to full-thickness tearing, or (3) an increase in tear retraction or tear width of at least 5 mm.

Results

Four hundred eighty MRI studies from 120 Veteran's Affair patients with bilateral, conservatively treated rotator cuff disease were evaluated. Overall, 42% (100/240) of rotator cuff disease had progressed. No significant difference was found between progression of right vs. left rotator cuff pathology, with right shoulder pathology progressing at a rate of 39% (47/120), while left shoulder disease progressed at a rate of 44% (53/120). The likelihood of disease progression was associated with less initial tendon retraction (P value = .016) and older age (P value = .025).

Conclusions

Rotator cuff tears are no more likely to progress on the right, as compared to the left side. Older age and less initial tendon retraction were found to be predictors of disease progression. These suggest that higher activity level may not associate with greater progression of rotator cuff disease. Future prospective studies evaluating progression rates between dominant vs. nondominant shoulders are warranted.

Abnormal Laboratory Values for Metabolic and Hormonal Syndromes Are Prevalent Among Patients Undergoing Rotator Cuff Repair

Purpose

To determine the prevalence of systemic laboratory abnormalities among patients undergoing rotator cuff repair (RCR).

Methods

Patients who underwent RCR at the authors' institution for 1 year between October 2021 to September 2022 were retrospectively identified. Preoperative laboratory values, including serum sex hormones, vitamin D, hemoglobin A1C, and a lipid panel, were obtained as part of our routine practice during the study period. Demographics and tear characteristics were compared in patients with laboratory data and those without. For included patients with laboratory data, mean laboratory values and percentage of patients with abnormal laboratory values were recorded.

Results

During a 1-year period of time, 135 RCRs were performed, of which preoperative labs were obtained on 105. Of these, 67% were sex hormone deficient, 36% were vitamin D deficient, 45% had an abnormal hemoglobin A1C, and 64% had an abnormal lipid panel. In total 4% had "normal" labs.

Conclusions

In this retrospective study, sex hormone deficiency is highly prevalent among patients undergoing RCR. Nearly all patients undergoing RCR have systemic laboratory abnormalities involving either sex hormone deficiency, vitamin D deficiency, dyslipidemia, and/or prediabetes.

Level of Evidence

Level IV, prognostic case series.

Characterization of Histone Modifications in Late-Stage Rotator Cuff Tendinopathy

The development and progression of rotator cuff tendinopathy (RCT) is multifactorial and likely to manifest through a combination of extrinsic, intrinsic, and environmental factors, including genetics and epigenetics. However, the role of epigenetics in RCT, including the role of histone modification, is not well established. Using chromatin immunoprecipitation sequencing, differences in the trimethylation status of H3K4 and H3K27 histones in late-stage RCT compared to control were investigated in this study. For H3K4, 24 genomic loci were found to be significantly more trimethylated in RCT compared to control (p < 0.05), implicating genes such as DKK2, JAG2, and SMOC2 in RCT. For H3K27, 31 loci were shown to be more trimethylated (p < 0.05) in RCT compared to control, inferring a role for EPHA3, ROCK1, and DEFβ115. Furthermore, 14 loci were significantly less trimethylated (p < 0.05) in control compared to RCT, implicating EFNA5, GDF6, and GDF7. Finally, the TGFβ signaling, axon guidance, and regulation of focal adhesion assembly pathways were found to be enriched in RCT. These findings suggest that the development and progression of RCT is, at least in part, under epigenetic control, highlighting the influence of histone modifications in this disorder and paving the way to further understand the role of epigenome in RCT.

Ethnicity, sex, and socioeconomic disparities in the treatment of traumatic rotator cuff injuries in Aotearoa/New Zealand

HYPOTHESIS AND BACKGROUND

Traumatic rotator cuff injuries can be a leading cause of prolonged shoulder pain and disability and contribute to significant morbidity and health care costs. Previous studies have shown evidence of sociodemographic disparities with these injuries. The purpose of this nationwide study was to better understand these disparities based on ethnicity, sex, and socioeconomic status, in order to inform future health care strategies.

METHODS

Accident Compensation Corporation (ACC) is a no-fault comprehensive compensation scheme encompassing all of Aotearoa/New Zealand (population in 2018, 4.7 million). Using the ACC database, traumatic rotator cuff injuries were identified between January 2010 and December 2018. Injuries were categorized by sex, ethnicity, age, and socioeconomic deprivation index of the claimant.

RESULTS

During the 9-year study period, there were 351,554 claims accepted for traumatic rotator cuff injury, which totaled more than NZ$960 million. The greatest proportion of costs was spent on vocational support (49.8%), then surgery (26.3%), rehabilitation (13.1%), radiology (8.1%), general practitioner (1.6%), and "Other" (1.1%). Asian, Māori (indigenous New Zealanders), and Pacific peoples were under-represented in the age-standardized proportion of total claims and had lower rates of surgery than Europeans. Māori had higher proportion of costs spent on vocational support and lower proportions spent on radiology, rehabilitation, and surgery than Europeans. Males had higher number and costs of claims and were more likely to have surgery than females. There were considerably fewer claims from areas of high socioeconomic deprivation.

DISCUSSION AND CONCLUSION

This large nationwide study demonstrates the important and growing economic burden of rotator cuff injuries. Indirect costs, such as vocational supports, are a major contributor to the cost, suggesting improving treatment and rehabilitation protocols would have the greatest economic impact. This study has also identified sociodemographic disparities that need to be addressed in order to achieve equity in health outcomes.

Sports-Related Shoulder Injuries Among Female Athletes

PURPOSE OF REVIEW

The objectives of this review are to explore the recent literature evaluating sports-related shoulder injuries among female athletes.

RECENT FINDINGS

Recent literature has highlighted sex-related differences in injury trends and patterns among athletes. Increased participation of women in both recreational and professional sports has resulted in increased exposure to injury. While men experience greater rates of shoulder injury overall, women tend to experience more overuse-related injuries. Evidence also suggests women are more susceptible to shoulder laxity and rotator cuff tears. In comparison to their male counterparts, women note poorer function, increased pain, and decreased activity level following shoulder injuries. Women may also be more likely to experience worse outcomes following surgical intervention. Sex-related differences in injury patterns and outcomes results from a combination of molecular and environmental influences, including hormone pathways, shoulder morphology, and differing rates of participation in, and athletic regulations among, certain sports. Sex-related differences occur in how athletes sustain, experience, and recover from sports-related injuries. A comprehensive understanding of sex-related injuries enhances clinical decision making, treatment, and recovery. Further research is needed to clarify sex as an independent variable when evaluating sports-related shoulder injuries.

Genetic Characterization in Familial Rotator Cuff Tear: An Exome Sequencing Study

Background: multiple gene variants seem to contribute to rotator cuff (RC) tear susceptibility. The aim of the study is to perform an exome sequencing analysis within a family to identify rare gene variants predisposing to the development of RC tear. Material and methods: the exome sequencing was conducted in a family consisting of four individuals, two healthy and the remaining ones with bilateral RC tears. Variants in common among the two affected subjects were selected, and those in common with the healthy subject and those with a frequency >1% were removed. The potential pathogenicity of the variants was investigated using the predictions of several in silico tools from VarSome. Results: the exome sequencing yielded approximately 600,000 variants per patient, subsequently filtered according to frequency <1% and absence of association with other diseases. Removing variants common with the healthy subject, 348 rare variants among 248 genes were identified. Based on the risk of damaging, three candidate genes for RC tear were found: COL23A1, EMILIN3, and HDAC10. Conclusion: this is the first whole-exome sequencing analysis within a family to explore genetic predisposition in RC tear. The results reveal the presence of common damaging variants among affected individuals in the COL23A1, EMILIN3, and HDAC10 genes.

Genome-Wide Association Study Identifies Genetic Variants Associated with Rotator Cuff Tear-A Pilot Study

A rotator cuff is a muscle and tendon surrounding the shoulder joint, and a rotator cuff tear can be caused by overuse or injury, which leads to great pain in affected individuals. However, rotator cuff tear is a multifactorial process whose underlying mechanism is still unclear. Many previous studies have suggested an important role of genetic predisposition, such as single-nucleotide polymorphisms (SNPs), in explaining the genesis of tendinopathy. This study aimed to identify specific genes or genetic variants associated with rotator cuff tears by performing a genome-wide association study (GWAS) using an independent case of rotator cuff tears. GWAS was performed using data from CHA Bundang Medical Center with 20 cases of rotator cuff tears, and 20 cases of healthy controls genotyped on the Illumina HiSeq 2500. Tests of association were performed using the Burrows−Wheeler Aligner (BWA) software at 284,246 SNPs. Data were filtered based on sequence ontology, minor allele frequency, and Hardy−Weinberg equilibrium values, and SNPs were considered significant if the p-value was <0.05. The tests of association revealed more than 20 significantly associated SNPs. SNPs showing the highest significance occurred in candidate genes, including LAIR2 (rs2287828, OR 9.116, p-value 5.49 × 10−4) on chromosome 19 and CRIPAK (rs9328733, OR 6, p-value 1.11 × 10−3) and REST (rs2228991, OR 8.222, p-value 1.20 × 10−3) on chromosome 4. This study attempted to identify genetic variants influencing rotator cuff tears through a genome-wide association study using a dense set of SNPs. More than 20 SNPs were significantly associated with rotator cuff tears. The major limitation of this study is that it was conducted on a small study group and requires further validation. Nevertheless, the identification of potential genetic variants related to rotator cuff injury would aid in the early detection of individuals at risk for the development of tendinopathy and will provide insight into future gene therapies.

The 100 most impactful articles on the rotator cuff: an altmetric analysis of online media

Purpose

The purpose of our study was to use the Altmetric Attention Score (AAS) to evaluate the 100 most impactful articles in online media pertaining to the rotator cuff and compare their characteristics to the most-cited rotator cuff articles in the scientific literature.

Methods

We performed an article extraction using Altmetric Explorer to identify all published articles pertaining to the rotator cuff. The top 100 articles with the highest AAS were included for analysis. Several data elements were extracted for each included article: title, article type, article topic, year of publication, journal name, authors, institutional affiliations, and online mentions (i.e. the number of times the article was mentioned in news, blog, Twitter, Facebook, and Wikipedia sources). The geographic origin of each article was also determined by the institutional affiliation of the first author, which was categorized as American (originating in the United States), European (originating in Europe), or other.

Results

The 100 articles with the highest AAS were published between 2009 and 2020, with AAS ranging from 47 to 676 (median: 74.5, 25^th percentile: 59.5, 75^th percentile: 114.5). Of all online media sources, Twitter correlated most strongly with AAS (r = 0.9007, r² = 0.8112). The selected articles were most frequently published in the American Journal of Sports Medicine (13), the Journal of Shoulder and Elbow Surgery (11), and the Journal of Bone and Joint Surgery (7). The most common article type was Systematic Review/Meta-Analysis (29%), followed by Randomized Controlled Trial (15%). The top 3 AAS articles were all published by authors based in Europe.

Conclusion

The most impactful rotator cuff articles in online media generated substantial online attention. These studies were often performed in Europe and tended to be high level of evidence, focusing on treatment of rotator cuff pathology. The rotator cuff articles that produced the most online attention differed from a previous report of the most-cited rotator cuff articles, suggesting that alternative metrics may be used in concert with conventional bibliometrics to obtain a more complete representation of scientific impact.

Challenges and perspectives of tendon-derived cell therapy for tendinopathy: from bench to bedside

Tendon is composed of dense fibrous connective tissues, connecting muscle at the myotendinous junction (MTJ) to bone at the enthesis and allowing mechanical force to transmit from muscle to bone. Tendon diseases occur at different zones of the tendon, including enthesis, MTJ and midsubstance of the tendon, due to a variety of environmental and genetic factors which consequently result in different frequencies and recovery rates. Self-healing properties of tendons are limited, and cell therapeutic approaches in which injured tendon tissues are renewed by cell replenishment are highly sought after. Homologous use of individual’s tendon-derived cells, predominantly differentiated tenocytes and tendon-derived stem cells, is emerging as a treatment for tendinopathy through achieving minimal cell manipulation for clinical use. This is the first review summarizing the progress of tendon-derived cell therapy in clinical use and its challenges due to the structural complexity of tendons, heterogeneous composition of extracellular cell matrix and cells and unsuitable cell sources. Further to that, novel future perspectives to improve therapeutic effect in tendon-derived cell therapy based on current basic knowledge are discussed.

The Effect of Sex Hormone Deficiency on the Incidence of Rotator Cuff Repair: Analysis of a Large Insurance Database

BACKGROUND

The purpose of the present study was to analyze the association between sex hormone deficiency and rotator cuff repair (RCR) with use of data from a large United States insurance database.

METHODS

A retrospective analysis of insured subjects from the Truven Health MarketScan database was conducted, collecting data for RCR cases as well as controls matched for age, sex, and years in the database. Multivariable logistic regression models adjusted for matching variables were utilized to compare RCR status with estrogen deficiency status and testosterone deficiency status. These associations were confirmed with use of data from the Veterans Genealogy Project database, with which the relative risk of RCR was estimated for patients with and without sex hormone deficiency.

RESULTS

The odds of RCR for female patients with estrogen deficiency were 48% higher (odds ratio, 1.48; 95% confidence interval, 1.44 to 1.51; p < 0.001) than for those without estrogen deficiency. The odds of RCR for males with testosterone deficiency were 89% higher (odds ratio, 1.89; 95% confidence interval, 1.82 to 1.96; p < 0.001) than for those without testosterone deficiency. Within the Veterans Genealogy Project database, the relative risk of estrogen deficiency among RCR patients was 2.58 (95% confidence interval, 2.15 to 3.06; p < 0.001) and the relative risk of testosterone deficiency was 3.05 (95% confidence interval, 2.67 to 3.47; p < 0.001).

CONCLUSIONS

Sex hormone deficiency was significantly associated with RCR. Future prospective studies will be necessary to understand the pathophysiology of rotator cuff disease as it relates to sex hormones.

LEVEL OF EVIDENCE

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

Tendon and Ligament Genetics: How Do They Contribute to Disease and Injury? A Narrative Review

A significant proportion of patients requiring musculoskeletal management present with tendon and ligament pathology. Our understanding of the intrinsic and extrinsic mechanisms that lead to such disabilities is increasing. However, the complexity underpinning these interactive multifactorial elements is still not fully characterised. Evidence highlighting the genetic components, either reducing or increasing susceptibility to injury, is increasing. This review examines the present understanding of the role genetic variations contribute to tendon and ligament injury risk. It examines the different elements of tendon and ligament structure and considers our knowledge of genetic influence on form, function, ability to withstand load, and undertake repair or regeneration. The role of epigenetic factors in modifying gene expression in these structures is also explored. It considers the challenges to interpreting present knowledge, the requirements, and likely pathways for future research, and whether such information has reached the point of clinical utility.

What Factors Are Associated with Symptomatic Rotator Cuff Tears: A Meta-analysis

BACKGROUND

Rotator cuff tears are common. A previous systematic review reported on factors associated with rotator cuff tears; however, it included relatively few studies and few variables, and in addition, it had considerable heterogeneity. To identify the factors associated with symptomatic rotator cuff tears and to help guide clinicians to potentially modifiable factors, we felt a broader and more inclusive meta-analysis would be useful.

QUESTIONS/PURPOSES

In this systematic review and meta-analysis, we asked what (1) demographic, (2) disease, and (3) imaging factors are associated with symptomatic rotator cuff tears?

METHODS

PubMed, Embase, and Web of Science were searched, and the search period were from the inception of each database through February 2021. The keywords included "risk factor," "rotator cuff injury," "rotator cuff tears," and "rotator cuff tendinitis." All comparative studies on symptomatic rotator cuff tears were included. We considered that the diagnosis of rotator cuff tear could be made by any imaging tool (MRI or ultrasound). We considered either partial- or full-thickness tears to be a rotator cuff tear. No language restrictions were applied. Twenty-six articles from 14 countries involving 9809 individuals, consisting of 3164 patients and 6645 controls, were included. The Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality (AHRQ) scale were used to evaluate the risk of bias of the included studies, and the highest scores were 9 and 11, respectively. The Newcastle-Ottawa Scale was used for retrospective comparative studies, and the AHRQ was used to evaluate prospective comparative studies. The eight retrospective comparative studies we included were scored from 4 to 9. The quality score of the 18 prospective comparative studies ranged from 6 to 9. Publication bias was explored using the Egger test. Heterogeneity was estimated using the I2 value. If there was no heterogeneity (I2 ≤ 50%), a fixed-effects model was used to determine the overall effect size; if there was heterogeneity (I2 > 50%), a random-effects model was used to merge the effect values. A meta-analysis was performed with RevMan 5.3, and the risk ratio (RR) and weighted mean difference of related factors were calculated.

RESULTS

Our meta-analysis identified the following demographic factors associated with an increased risk of rotator cuff tears: older age (mean difference 3.1 [95% CI 1.4 to 4.8]; p < 0.001), greater BMI (mean difference 0.77 [95% CI 0.37 to 1.17]; p < 0.001), smoking (RR 1.32 [95% CI 1.17 to 1.49]; p < 0.001), dominant arm (RR 1.15 [95% CI 1.06 to 1.24]; p < 0.001), greater height (mean difference 0.9 [95% CI 0.4 to 1.4]; p < 0.001), and heavier weight (mean difference 2.24 [95% CI 0.82 to 3.66]; p = 0.002). Regarding disease factors, we found that traumatic events (RR 1.91 [95% CI 1.40 to 2.54]; p < 0.001) and hypertension (RR 1.50 [95% CI 1.32 to 1.70]; p < 0.001) were associated with symptomatic rotator cuff tears. Regarding imaging factors, we found that the following three factors were associated with symptomatic rotator cuff tears: greater acromion index (mean difference 0.11 [95% CI 0.06 to 0.16]; p < 0.001), greater critical shoulder angle (mean difference 1.9 [95% CI 1.5 to 2.3]; p < 0.001), and smaller glenoid version angle (mean difference -1.3 [95% CI -1.9 to -0.8]; p < 0.001). We found no association between the patient's sex or the presence or absence of thyroid disease and the likelihood of a rotator cuff tear being present.

CONCLUSION

This study identified several factors associated with symptomatic rotator cuff tears, including blood glucose, blood pressure, weight, and smoking. Clinicians may seek to modify these factors, possibly in patients with symptomatic rotator cuff tears, but also in symptomatic patients who have not yet been diagnosed with rotator cuff tears because there would be no harm or risk associated with modifying any of the factors we identified. Future research should further study whether addressing these factors can delay the progression and size of rotator cuff tears.Level of Evidence Level III, prognostic study.

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.

Risk Factors for Supraspinatus Tears: A Meta-analysis of Observational Studies

Background:

The pathogenesis of rotator cuff tears remains unclear, and there is a lack of high-quality evidence-based research on the risk factors for supraspinatus tears.

Purpose:

To explore 10 potential risk factors for supraspinatus muscle tears.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

This review was conducted according to the MOOSE (Meta-analysis Of Observational Studies in Epidemiology) guidelines. PubMed, Embase, and Web of Science were searched for cohort, case-control and cross-sectional studies published before January 2021 on supraspinatus tears. The following potential risk factors were analyzed: age, body mass index, male sex, female sex, arm dominance, diabetes mellitus, smoking, hypertension, thyroid disease, and the critical shoulder angle (CSA). Risk ratios (RRs) or weighted mean differences (WMDs) of related risk were calculated. The Egger test was used to evaluate publication bias.

Results:

A total of 9 articles from 8 countries were included; among the 3240 patients, 687 were included in the supraspinatus tear group, and 2553 were included in the nonsupraspinatus tear group. The meta-analysis showed that older age (WMD, 3.36 [95% confidence interval (CI), 0.53-6.20]; P = .02), male sex (RR, 0.87 [95% CI, 0.78-0.97]; P = .01), smoking (RR, 2.21 [95% CI, 1.56-3.14]; P < .00001), diabetes (RR, 1.67 [95% CI, 1.03-2.70]; P = .04), hypertension (RR, 1.51 [95% CI, 1.16-1.97]; P = .002), and the CSA (WMD, 2.25 [95% CI, 1.39-3.12]; P < .00001) were risk factors for supraspinatus tears.

Conclusion:

Older age, male sex, smoking, diabetes, hypertension, and a higher CSA were found to be risk factors for supraspinatus tears in this meta-analysis review. Identifying risk factors for supraspinatus tears early can help clinicians identify these high-risk patients and choose appropriate treatments.

Tendon and multiomics: advantages, advances, and opportunities

Tendons heal by fibrosis, which hinders function and increases re-injury risk. Yet the biology that leads to degeneration and regeneration of tendons is not completely understood. Improved understanding of the metabolic nuances that cause diverse outcomes in tendinopathies is required to solve these problems. 'Omics methods are increasingly used to characterize phenotypes in tissues. Multiomics integrates 'omic datasets to identify coherent relationships and provide insight into differences in molecular and metabolic pathways between anatomic locations, and disease stages. This work reviews the current literature pertaining to multiomics in tendon and the potential of these platforms to improve tendon regeneration. We assessed the literature and identified areas where 'omics platforms contribute to the field: (1) Tendon biology where their hierarchical complexity and demographic factors are studied. (2) Tendon degeneration and healing, where comparisons across tendon pathologies are analyzed. (3) The in vitro engineered tendon phenotype, where we compare the engineered phenotype to relevant native tissues. (4) Finally, we review regenerative and therapeutic approaches. We identified gaps in current knowledge and opportunities for future study: (1) The need to increase the diversity of human subjects and cell sources. (2) Opportunities to improve understanding of tendon heterogeneity. (3) The need to use these improvements to inform new engineered and regenerative therapeutic approaches. (4) The need to increase understanding of the development of tendon pathology. Together, the expanding use of various 'omics platforms and data analysis resulting from these platforms could substantially contribute to major advances in the tendon tissue engineering and regenerative medicine field.

A genome-wide association study for shoulder impingement and rotator cuff disease

BACKGROUND

The purpose of the study was to identify genetic variants associated with rotator cuff disease by performing a genome-wide association study (GWAS) for shoulder impingement using the UK Biobank (UKB) cohort and then combining the GWAS data with a prior GWAS for rotator cuff tears. The loci identified by the GWAS and meta-analysis were examined for changes in expression following rotator cuff tearing using RNA sequencing.

METHODS

A GWAS was performed using data from UKB with 3864 cases of shoulder impingement. The summary statistics from shoulder impingement and a prior study on rotator cuff tears were combined in a meta-analysis. Also, the previous association of 2 single-nucleotide polymorphisms (SNPs) with shoulder impingement from a published GWAS using the UKB was tested. Rotator cuff tendon biopsies were obtained from 24 patients with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair (cases) and 9 patients who underwent open reduction internal fixation for a proximal humeral fracture (controls). Total RNA was extracted and differential gene expression was measured by RNA sequencing for genes with variants associated with rotator cuff tearing.

RESULTS

The shoulder impingement GWAS identified 4 new loci: LOC100506457, LSP1P3, LOC100506207, and MIS18BP1/LINC00871. Combining data with a prior GWAS for rotator cuff tears in a meta-analysis resulted in the identification of an additional 7 loci: SLC39A8/UBE2D3, C5orf63, ASTN2, STK24, FRMPD4, ACOT9/SAT1, and LINC00890/ALG13. Many of the identified loci have known biologic functions or prior associations with diseases, suggesting possible biologic pathways leading to rotator cuff disease. RNA sequencing experiments show that expression of STK24 increases whereas expression of SAT1 and UBE2D3 decreases following rotator cuff tearing. Two SNPs previously reported to show an association with shoulder impingement from a prior UKB GWAS were not validated in our study.

CONCLUSION

This is the first GWAS for shoulder impingement in which new data from UKB enabled the identification of 4 loci showing a genetic association. A meta-analysis with a prior GWAS for rotator cuff tearing identified an additional 7 loci. The known biologic roles of many of the 11 loci suggest plausible biologic mechanisms underlying the etiology of rotator cuff disease. The risk alleles from each of the genetic loci can be used to assess the risk for rotator cuff disease in individual patients, enabling preventative or restorative actions via personalized medicine.

Identification of a Novel Genetic Marker for Risk of Degenerative Rotator Cuff Disease Surgery in the UK Biobank

BACKGROUND

While evidence indicates that familial predisposition influences the risk of developing degenerative rotator cuff disease (RCD), knowledge of specific genetic markers is limited. We conducted a genome-wide association study of RCD surgery using the UK Biobank, a prospective cohort of 500,000 people (40 to 69 years of age at enrollment) with genotype data.

METHODS

Cases with surgery for degenerative RCD were identified using linked hospital records. The cases were defined as an International Classification of Diseases, Tenth Revision (ICD-10) code of M75.1 determined by a trauma/orthopaedic specialist and surgery consistent with RCD treatment. Cases were excluded if a diagnosis of traumatic injury had been made during the same hospital visit. For each case, up to 5 controls matched by age, sex, and follow-up time were chosen from the UK Biobank. Analyses were limited to European-ancestry individuals who were not third-degree or closer relations. We used logistic regression to test for genetic association of 674,405 typed and >10 million imputed markers, after adjusting for age, sex, population principal components, and follow-up.

RESULTS

We identified 2,917 RCD surgery cases and 14,158 matched controls. We observed 1 genome-wide significant signal (p < 5 × 10-8) for a novel locus tagged by rs2237352 in the CREB5 gene on chromosome 7 (odds ratio [OR] = 1.17, 95% confidence interval [CI] = 1.11 to 1.24). The single-nucleotide polymorphism (SNP) rs2237352 was imputed with a high degree of confidence (info score = 0.9847) and is common, with a minor allele frequency of 47%. After expanding the control sample to include additional unmatched non-cases, rs2237352 and another SNP in the CREB5 gene, rs12700903, were genome-wide significant. We did not detect genome-wide significant signals at loci associated with RCD in previous studies.

CONCLUSIONS

We identified a novel association between a variant in the CREB5 gene and RCD surgery. Validation of this finding in studies with imaging data to confirm diagnoses will be an important next step.

CLINICAL RELEVANCE

Identification of genetic RCD susceptibility markers can guide understanding of biological processes in rotator cuff degeneration and help inform disease risk in the clinical setting.

LEVEL OF EVIDENCE

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

Shoulder and elbow pathology in the female athlete: sex-specific considerations

Unique biologic and biomechanical aspects of the female body make women more prone to certain orthopedic injuries. Sex differences are well understood with regard to certain orthopedic pathologies such as anterior cruciate ligament injury, hallux valgus, carpal tunnel, and carpometacarpal joint arthritis; however, sex differences are less commonly discussed with regard to shoulder and elbow pathology. The purpose of this review is to elucidate sex differences specific to sports-related shoulder and elbow injuries in the female athlete population.

Genetic variants associated with rotator cuff tearing utilizing multiple population-based genetic resources

BACKGROUND

The etiology of rotator cuff tearing is likely multifactorial, including a potential genetic predisposition. The purpose of the study was to identify genetic variants associated with rotator cuff tearing utilizing the UK Biobank (UKB) cohort, confirm variants using a separate genetic database, and evaluate tissue expression of genes with associated variants following rotator cuff tearing using RNA sequencing.

METHODS

Genome-wide association study (GWAS): A GWAS was performed using data from UKB with 5701 cases of rotator cuff injury. RNA sequencing analyses: rotator cuff biopsies were obtained from 24 patients with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair (cases) and 9 patients who underwent open reduction internal fixation for a proximal humerus fracture (controls). Total RNA was extracted and differential gene expression was measured by RNAseq for genes with variants associated with rotator cuff tearing.

RESULTS

The results of the UKB GWAS identified 3 loci that reached genome-wide statistical significance: 2 loci on chromosome 7 in GLCCI1 (rs4725069; P = 5.0E-09) and THSD7A (rs575224171; P = 5.3E-09), and 1 locus on chromosome 2 in ZNF804A (rs775583810; P = 3.9E-09). The association with rotator cuff injury of the GLCCI1 single-nucleotide polymorphism (SNP; rs4725069) was confirmed in the Kaiser Permanente Research Bank cohort (P = .008). Twenty previously reported SNPs in 12 genes were evaluated using summary statistics from the UKB GWAS, which confirmed 3 SNPs in TNC with rotator cuff injury (rs1138545, rs72758637, and rs7021589; all P < .0024). Of 17 genes with variants associated with rotator cuff injury (14 previously from literature plus 3 new genes from current UKB GWAS), TIMP2, Col5A1, TGFBR1, and TNC were upregulated (P < .001 for all) and THSD7A was downregulated (P = .005) in tears vs. controls in the RNA sequencing data set.

CONCLUSION

The UKB GWAS has identified 3 novel loci associated with rotator cuff tearing (ZNF804A, GLCCI1, THSD7A). Expression of the THSD7A gene was significantly downregulated in rotator cuff tears vs. controls supporting a potential functional role. Three previously reported SNPs in the TNC gene were validated in the UKB GWAS, supporting a role for this gene in rotator cuff tearing. Finally, TIMP2, Col5A1, TGFBR1, and TNC genes were found to have significantly upregulated tissue expression in cases vs. controls supporting a biologic role in tearing for these genes.

Polymorphisms and alterations in gene expression associated with rotator cuff tear and healing following surgical repair: a systematic review

BACKGROUND

Rotator cuff tears (RCTs) are a common cause of shoulder disability, yet both conservative and surgical treatment strategies can lead to poor results in some patient populations. Enhanced understanding of the genetic processes associated with RCTs can assist in the development of more effective management options and help predict individual responses to surgical treatment. This systematic review analyzes the current literature on the genetic footprint associated with RCTs and interprets these findings to enhance the current understanding of RCT pathogenesis, potential treatment regimens, and prognostic biomarkers of outcomes after surgical repair.

METHODS

A systematic search of the Embase, PubMed, and Web of Science electronic databases was performed. Medical Subject Headings (MeSH) and Emtree index terms were formulated from the concept terms "rotator cuff tear," "genetics," and "human," and synonyms of these concepts were applied to the Web of Science search. Articles were screened against predefined inclusion and exclusion criteria. Eligible studies compared gene expression patterns and genetic polymorphisms between cases (with RCTs) and controls (without RCTs). Quality assessment was performed with studies being rated as high, moderate, or poor quality. A modified best-evidence synthesis was applied, and studies were determined to be of strong, moderate, or limited evidence.

RESULTS

The search identified 259 articles. Of these studies, 26 were eligible for review. Two studies were considered poor quality; 15 studies, moderate quality; and 9 studies, high quality. Analysis of these articles found that RCTs were associated with alterations in genes that code for the extracellular matrix, cell apoptosis, immune and inflammatory responses, and growth factor pathways. In particular, there was strong evidence of a significant association between RCTs and the genes MMP3, TNC, and ESRRB. Strong evidence of an association between BMP5 upregulation and successful healing after surgical repair was also found.

CONCLUSION

This review provides strong evidence of an genetic association with RCTs. The genotype and gene expression patterns detailed within this review can assist in deciphering the biological mechanisms resulting in RCTs, as well as predicting an individual's response to surgical repair. Future research could investigate whether manipulating these genes-or their associated signaling pathways-could assist in RCT healing and whether genetic biomarkers could be used clinically to predict patient outcomes after surgical repair of RCTs.

Genetic Aspects in Shoulder Disorders

The influence of genetic inheritance has been increasingly investigated in shoulder disorders, such as rotator cuff injury, instability and frozen shoulder. Although the initial findings are enlightening, it is necessary to progressively build a database of genetic markers to catalog genomic profiles that, later, may contribute for predicting the risk of the disease, as well as to the development of better diagnostic and treatment tools. The present article seeks to update what is evidence of genetic studies in the literature for these diseases, from polymorphism analyses, expression of candidate genes in tissues and broad genomic association studies (GWAS). However, it is necessary to point out that there is great difficulty in replicating and using the findings, mainly due to the lack of statistical power, the high rate of false-positive results and the large number of variables involved.

SAP30BP gene is associated with the susceptibility of rotator cuff tear: a case-control study based on Han Chinese population

Background

Multiple studies have indicated that genetic components contribute significantly to the risk of rotator cuff tears. Previous studies have suggested that the SAP30BP gene may play an essential role in the development of rotator cuff tears. The aim of this study was to evaluate the potential association of the SAP30BP gene with the susceptibility to rotator cuff tears in a Han Chinese population.

Methods

A total of 394 patients with rotator cuff tears and 998 healthy controls were included in the study. Twelve tag single nucleotide polymorphisms (SNPs) located in the region of the SAP30BP gene were selected for genotyping. Genetic association analyses were performed using χ² tests for each SNP. Significant associations were searched in the GTEx database for their functional consequences.

Results

SNP rs820218 was significantly associated with rotator cuff tears (χ² = 9.49, P = 0.0021, OR [95% CI] = 0.67 [0.52–0.87]). In addition, SNP rs820218 was found to be significantly associated with the gene expression level of SAP30BP in whole blood (NES = 0.12, P = 1.00 × 10⁻⁶).

Conclusion

Our study has shown that the genetic polymorphism of SAP30BP contributes to the risk of rotator cuff tears in Chinese Han people. Individuals with the A allele for SNP rs820218 were less susceptible to developing rotator cuff tears.

Predisposição familiar para rotura do manguito rotador e outras tendinopatias – Um estudo de caso-controle

Objective  To evaluate the prevalence of family history of rotator cuff tear and the presence of tendinopathy in other joints in patients with rotator cuff tears and to compare them with paired controls. To estimate the odds ratio for rotator cuff tear for these two risk factors.

Methods  We performed a case-control study comparing patients submitted to treatment for rotator cuff tear with asymptomatic controls. All cases and controls were evaluated by imaging exams and matched by age (±2 years) and gender. We conducted an interview using a standardized questionnaire, and collected data on various risk factors.

Results  We evaluated 144 patients, 72 per group. Patients with rotator cuff tears reported a higher number of consanguineous relatives who underwent treatment for the same disease and tendon injuries in other joints compared to the controls ( p  = 0.005 and p  = 0.045 respectively). Individuals with a family history of treatment for rotator cuff tear or with tendinopathies in other joints were more likely to present a rotator cuff tear, with odds ratios of 3.3 (95% confidence interval [95%CI] = 1.4–7.7) and 2.7 (95%CI = 1.1–6.9) respectively.

Conclusions  Patients with rotator cuff tear have a higher prevalence of family members with the same disease and tendinopathies or tendon injuries in other joints. The presence of consanguineous relatives with treatment for rotator cuff and tendinopathies in other joints are risk factors for the presence of rotator cuff tears.

Genetic factors in rotator cuff pathology: potential influence of col 5A1 polymorphism in outcomes of rotator cuff repair

Background

Investigations in genetics have provided valuable information about the correlation between gene variants and tendinopathy. Single Nucleotide Polymorphisms of COL5A1 gene are reported to be involved in Achilles tendinopathy, chronic degenerative tendon changes at the elbow, and other tendinopathies. The influence of Single Nucleotide Polymorphisms of COL5A1 was previously analyzed in rotator cuff disease with confounding results. Moreover, the rs12722 polymorphism in COL5A1 gene has been implicated in the aetiology of musculoskeletal soft tissue injuries in several association studies. This study aims to analyse the possible influence of rs12722 polymorphism in COL5A1 in the outcomes of rotator cuff repair.

Methods

Seventy-nine patients were included in the study. DNA was extracted from 1.2 ml of venous blood and genotyped for COL5A1 SNPs rs12722. Rotator cuff muscle strength and range of motion (ROM) in anterior elevation, external and internal rotation of the shoulder were evaluated.

Results

Patients presenting COL5A1 SNP rs12722 CC showed a ROM of passive external rotation statistically significantly higher compared to patients with CT genotype and TT genotype.

Conclusions

COL5A1 SNP rs12722 may influence the functional outcomes of RCRs, even though further studies are required to confirm these preliminary results.

Development and Validation of an Electronic Medical Record Algorithm to Identify Phenotypes of Rotator Cuff Tear

BACKGROUND

A lack of studies with large sample sizes of patients with rotator cuff tears is a barrier to performing clinical and genomic research.

OBJECTIVE

To develop and validate an electronic medical record (EMR)-based algorithm to identify individuals with and without rotator cuff tear.

DESIGN

We used a deidentified version of the EMR of more than 2 million subjects. A screening algorithm was applied to classify subjects into likely rotator cuff tear and likely normal rotator cuff groups. From these subjects, 500 likely rotator cuff tear and 500 likely normal rotator cuff were randomly chosen for algorithm development. Chart review of all 1000 subjects confirmed the true phenotype of rotator cuff tear or normal rotator cuff based on magnetic resonance imaging and operative report. An algorithm was then developed based on logistic regression and validation of the algorithm was performed.

RESULTS

The variables significantly predicting rotator cuff tear included the number of times a Current Procedural Terminology code related to rotator cuff procedures was used (odds ratio [OR] = 3.3; 95% confidence interval [CI]: 1.6-6.8 for ≥3 vs 0), the number of times a term related to rotator cuff lesions occurred in radiology reports (OR = 2.2; 95% CI: 1.2-4.1 for ≥1 vs 0), and the number of times a term related to rotator cuff lesions occurred in physician notes (OR = 4.5; 95% CI: 2.2-9.1 for 1 or 2 times vs 0). This phenotyping algorithm had a specificity of 0.89 (95% CI: 0.79-0.95) for rotator cuff tear, area under the curve (AUC) of 0.842, and diagnostic likelihood ratios (DLRs), DLR+ and DLR- of 5.94 (95% CI: 3.07-11.48) and 0.363 (95% CI: 0.291-0.453).

CONCLUSION

Our informatics algorithm enables identification of cohorts of individuals with and without rotator cuff tear from an EMR-based data set with moderate accuracy.

Rotator Cuff Tear Susceptibility Is Associated With Variants in Genes Involved in Tendon Extracellular Matrix Homeostasis

Rotator cuff tears (RCT) is a multifactorial disease with genetic factors contributing for the disease etiology. We hypothesized that genetic variants in genes involved in extracellular matrix (ECM) homeostasis may alter susceptibility to RCT. We evaluated 20 polymorphisms of genes involved in ECM homeostasis in 211 cases of full-thickness tears of the supraspinatus (N_females  = 130; N_males  = 81) and 567 age-matched controls (N_females  = 317; N_males  = 250). Multivariate logistic regressions were carried out with age, gender, genetic ancestry (based on the analysis of 61 biallelic short insertion/deletion polymorphisms), and common co-morbidities (diabetes, dyslipidemia, and smoking habits) as covariates. We observed that carriers of the rare allele of both studied variants of TGFB1, as well as their G/A (rs1800470/rs1800469) haplotype, were less susceptible to RCT (p < 0.05). In contrast, carriers of the G allele of MMP9 rs17576 (p = 0.014) or G/G haplotype (rs17576/rs17577; p < 0.001) had an increased risk for tendon tears. The presence of the T allele of MMP2 rs2285053 (p = 0.033), the T allele of MMP3 rs679620 (p = 0.024), and the TT-genotype of TIMP2 rs2277698 (p = 0.01) was associated with susceptibility to tears, especially in females. In males, the A allele of COL5A1 rs3196378 (p = 0.032) and the G allele of TGFBR1 rs1590 (p = 0.039) were independent risk factors for RCT. The C/T COL5A1 (rs3196378/rs11103544) haplotype was associated with a reduced risk of tears in males (p = 0.03). In conclusion, we identified the genetic variants associated with RCT susceptibility, thereby reinforcing the role of genes involved in the structure and homeostasis of the ECM of tendons in disease development. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:192-201, 2020.

Translation, cross-cultural adaptation and validation of the polish version of the Oxford Shoulder Score in patients undergoing arthroscopic rotator cuff repair

Background

The Oxford Shoulder Score (OSS) is a simple and reliable, joint-specific, self-reported outcome measure. It can be applied in patients with shoulder disease other than instability. The purpose of this study was to perform a translation, cultural adaptation of the Polish version of the OSS and to evaluate its selected psychometric properties in patients after arthroscopic rotator cuff repair.

Methods

Sixty-nine subjects participated in the study, with a mean age 55.5 (ranging from 40 to 65 years). The OSS has been translated using the widely accepted guidelines. All patients completed the Polish version of OSS (OSS-PL), the short version of the Disabilities of Arm, Shoulder and Hand Questionnaire (QuickDASH), the Short Form-36 v. 2.0 (SF-36) and the 7-point Global Rating of Change Scale (GRC).

Results

High internal consistency of 0.96 was found using Cronbach’s alpha coefficient. Reliability of the OSS resulted in Intraclass Correlation Coefficient (ICC) = 0.99, Standard Error of Measurement (SEM) = 1.14 and Minimal Detectable Change (MDC) = 3.15. The validity analysis showed a moderate (General health r = 0.34) to high (Physical role functioning r = 0.82) correlation between the OSS-PL and SF-36 and a high correlation between the OSS-PL and the QuickDASH (r = − 0.92).

Conclusions

The Polish version of OSS is a reliable and valid, self-reported questionnaire, which can be applied in patients with a rotator cuff tear undergoing reconstruction surgery. The very good psychometric properties of the Polish version of the OSS indicate that it can be used in clinical practice and scientific research.

Genetic basis of rotator cuff injury: a systematic review

Background

Rotator cuff disease is a widespread musculoskeletal pathology and a major cause of shoulder pain. Studies on familial predisposition suggest that genetic plays a role in the pathogenesis of rotator cuff disease. Several genes are responsible for rotator cuff disease. The aim of this study was to perform a systematic review on genetic association between rotator cuff disease and genes variations.

Methods

A systematic review of the literature was performed, in accordance with the PRISMA guidelines. PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases were searched comprehensively using the keywords: “Rotator cuff”, “Gene”, “Genetic”, “Predisposition”, “Single-nucleotide polymorphism” and “Genome-wide association”.

Results

8 studies investigating genes variations associated with rotator cuff tears were included in this review. 6 studies were case-control studies on candidate genes and 2 studies were GWASs. A significant association between SNPs and rotator cuff disease was found for DEFB1, FGFR1, FGFR3, ESRRB, FGF10, MMP-1, TNC, FCRL3, SASH1, SAP30BP, rs71404070 located next to cadherin8. Contradictory results were reported for MMP-3.

Conclusion

Further investigations are warranted to identify complete genetic profiles of rotator cuff disease and to clarify the complex interaction between genes, encoded proteins and environment. This may lead to individualized strategies for prevention and treatment of rotator cuff disease.

Level of evidence

Level IV, Systematic Review.

Is there a relation between rotator cuff injury and core stability?

BACKGROUND

Strong core stabilization not only minimizes the load on the vertebral column, but also improves strength and endurance of peripheral joints, and enables the energy transfer to distal segments. Despite the current interest surrounding core stability, none of the studies investigated the effect of core stability on the formation of rotator cuff tear or healing after repair.

OBJECTIVE

To determine the relationship between core stability and upper extremity functional performance in patients who underwent rotator cuff repair surgery and to compare those with healthy subjects of similar age.

METHODS

Patients who underwent rotator cuff repair (RC repair group, n= 58 patient) and healthy subjects of the similar age group (control group, n= 114) were included in the study. The mean age was 55.03 ± 9.84 years in the RC repair group and 52.71 ± 6.31 years in the control group. The RC repair group took standardized rehabilitation. The rehabilitation program did not include core strength and stability exercise. Core endurance was assessed with Flexor Endurance, Prone Bridge and Supine bridge test. Disabilities of the Arm, Shoulder and Hand (DASH), Short Form-36 (SF-36) and the Close Kinetic Chain Upper Extremity Stability (CKCUES) test were used to evaluate the upper extremity functional performance.

RESULTS

The core endurance (prone and supine bridge test) of the control group was statistically significantly better than the RC repair group (p⩽ 0.005). The DASH-T, SF-36 and CKCUES scores of the control group were also statistically significantly better.

CONCLUSION

The neuromuscular system should be considered as a whole, and addition of the core stabilization exercises to an effective rehabilitation program after RC repair surgery may be beneficial.

Rotator Cuff Degeneration: The Role of Genetics

BACKGROUND

The literature is certain regarding the multifactorial etiology of rotator cuff degeneration. However, it remains unclear if rotator cuff degeneration exclusively depends on intrinsic and extrinsic factors or if it is also genetically determined. We compared the health status of cuff tendons, evaluated with a magnetic resonance imaging (MRI) study, between elderly monozygotic and dizygotic twins with the aim of separating the contributions of genetics from shared and unique environments.

METHODS

The rotator cuff tendon status was assessed using the Sugaya classification by MRI. Heritability, defined as the proportion of total variance of a specific characteristic in a particular population due to a genetic cause, was calculated as twice the difference between the intraclass correlation coefficients for monozygotic and dizygotic pairs. The influence of shared environment, which contributes to twin and sibling similarity, was calculated as the difference between the monozygotic correlation coefficient and the heritability index.

RESULTS

We identified 33 pairs of elderly twins: 17 monozygotic pairs and 16 dizygotic pairs, with a mean age (and standard deviation) of 64.62 ± 3.32 years. The polychoric correlation was 0.62 in monozygotic twins and 0.53 in dizygotic twins. The calculated heritability index was 0.18 (18%), and the contribution was 0.44 (44%) for the shared environment and 0.38 (38%) for the unique environment.

CONCLUSIONS

The role of genetics in rotator cuff degeneration is quantified by our study on elderly monozygotic and dizygotic twins; however, it is only partial with respect to the contribution of shared and unique environments.

Structural integrity of rotator cuff at 16 years following repair: good long-term outcomes despite recurrent tears

BACKGROUND

There are few studies reporting long-term rotator cuff integrity following repair. The present study reports a case series of surgically repaired supraspinatus tendons followed up with clinical outcomes and ultrasound imaging after an average of 16 years.

METHODS

The prospectively studied clinical outcomes at short-, medium- and long-term follow-up in 27 shoulders in 25 patients treated with arthroscopic subacromial decompression and mini-open rotator cuff repair have been reported previously. The functional outcomes scores recorded were the University of California Los Angeles (UCLA), American Shoulder and Elbow Surgeons (ASES) and Simple Shoulder Test (SST) measures. These patients then underwent an ultrasound scan with respect to the long-term assessment of the shoulder and the integrity of the repair.

RESULTS

A recurrent tear was noted in 37% of patients at 16.25 years after surgery, of which 50% were small. Two patients required repeat surgery. Patients had a mean UCLA score of 30, an ASES score of 91.3 and a SST score of 9.5 with a 85% level of satisfaction with surgery. Patients with a recurrent tear had outcome scores equivalent to those with an intact cuff with no significant pain. No independent risk factors were identified as predictors for recurrent tear.

CONCLUSIONS

Patients showed sustained benefit and satisfaction at long-term follow-up despite a 37% recurrence of full-thickness supraspinatus tear.

Genetics of rotator cuff tears: no association of col5a1 gene in a case-control study

Background

The incidence of RC tears increases with aging, affecting approximately 30 to 50% of individuals older than 50 years, and more than 50% of individuals older than 80 years. Intrinsic factors (age or gender), extrinsic factors (sports activity or occupation), and biological factors were identified in the onset and progression of RC tears. The attention in the study of aetiology of RC tendinopathy has shifted to the identification of gene variants. Genes encoding for proteins regulating the concentration of pyrophosphate in the extracellular matrix and genes encoding for fibroblastic growth factors, defensin beta 1 and estrogen-related receptor-beta were analyzed. However, only in one study the role of variants of collagen type V alpha 1 (col5a1) gene in RC tears was assessed. The objective of this study was to determine whether a col5a1 DNA sequence variant, rs12722 (C/T) was associated with rotator cuff (RC) tears in a case-control study.

Methods

The study included 93 Caucasian patients undergoing surgery for RC tears and 206 patients with no history and sign of RC disease as evaluated by MRI. Patients were divided into two groups. Group 1 included patients with RC tear diagnosed on clinical and imaging grounds and confirmed at the time of surgery. Group 2 (control group) included patients without history or clinical symptoms of RC disorders and with a MRI negative for RC disease. DNA was obtained from approximately 1.2 ml of venous blood using the MagCore extractor system H16 with a MagCore Genomic DNA Large Volume Whole Blood Kit (RBC Bioscience Corp., Taiwan). All study participants were genotyped for SNPs rs12722.

Results

We first estimated that our study had 92% power at p < 0.05 to detect a genetic effect size of 2.05 in the RT tears (93 individuals) and healthy population (206 individuals) cohorts, assuming a minor allele frequency for col5a1 variant rs12722 of 0.5707 in the Italian population (gnomAD frequency). No significant difference in allele and genotype frequencies was observed between RT tears patients and healthy controls. Similarly, no significant association was seen between the RT tears and healthy controls participants in the combined genotype distributions.

Conclusion

In conclusion, no correlations between the SNP rs12722 of col5a1 gene and RC tears susceptibility was found.

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.

A Comparative Study to Evaluate the Risk Factors for Medium-Sized Rotator Cuff Tear in Patients Younger Than 50 Years of Age

PURPOSE

The purpose of this study was to evaluate preoperative and intraoperative factors associated with rotator cuff tears (RCTs) among patients younger than 50 years and to compare arthroscopic rotator cuff repair (RCR) results in patients younger than 50 years (group A) and patients older than 70 years (group B). We also analyzed the results after arthroscopic RCR in these 2 age groups.

METHODS

Data were collected from 56 patients allocated to group A and 55 patients allocated to group B who had medium-sized RCTs and had undergone arthroscopic RCR between January 2006 and August 2015. Preoperative variables included demographic data, radiologic data, and surgical procedure. We evaluated fatty degeneration on preoperative magnetic resonance imaging (MRI) and intraoperative variables, including concomitant subscapularis repair, as well as repair technique. Pain visual analog scale, functional visual analog scale, American Shoulder and Elbow Surgeons, and Constant scores were documented to compare functional results in each age group. Postoperative MRI scans were conducted to evaluate the retear rate after RCR after a mean postoperative duration of 5.4 months (range, 2-48 months).

RESULTS

Multivariate regression analysis showed acute-on-chronic injury and a history of hypertension were independent factors for differentiation of the groups. Stepwise regression analysis found sex, hypertension, and fatty infiltration of the supraspinatus and infraspinatus to be comparable factors for each group. All patients showed improved results after arthroscopic RCR, but there was no difference between the 2 groups in functional outcomes. However, cuff retears on postoperative MRI scans were found in only 3.9% of the patients in group A versus 16% of the patients in group B.

CONCLUSIONS

The results of this study showed that sex, acute-on-chronic injury, and preoperative fatty infiltration of the rotator cuff were significant factors affecting medium-sized RCTs in patients younger than 50 years. In addition, there were no significant differences in functional outcomes after arthroscopic RCR in both groups at 2 years, but postoperative MRI showed a lower retear rate in group A.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Anabolic steroids and tendons: A review of their mechanical, structural, and biologic effects

One of the suspected deleterious effects of androgenic-anabolic steroids (AAS) is the increased risk for tendon rupture. However, investigations to date have produced inconsistent results and it is still unclear how AAS influence tendons. A systematic review of the literature was conducted to identify studies that have investigated the mechanical, structural, or biologic effects that AAS have on tendons. In total, 18 highly heterogeneous studies were identified. Small animal studies made up the vast majority of published research, and contradictory results were reported frequently. All of the included studies focused on the potential deleterious effects that AAS have on tendon, which is striking given the recent use of AAS in patients following tendon injury. Rather than providing strong evidence for or against the use of AAS, this review highlights the need for additional research. Future studies investigating the use of AAS as a possible treatment for tendon injury/pathology are supported by reports suggesting that AAS may counteract the irreparable structural/functional changes that occur in the musculotendinous unit following rotator cuff tears, as well as studies suggesting that the purported deleterious effects on tendon may be transient. Other possible areas for future research are discussed in the context of key findings that may have implications for the therapeutic application of AAS. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2830-2841, 2018.

The greater tuberosity angle: a new predictor for rotator cuff tear

BACKGROUND

The implication of scapular morphology in rotator cuff tears has been extensively studied. However, the role of the greater tuberosity (GT) should be of equal importance. The aim of this study was to propose a new radiographic marker, the GT angle (GTA), which measures the position of the GT in relation to the center of rotation of the humeral head. The hypothesis was that a higher angle value would be associated with a higher likelihood in detecting a rotator cuff tear.

METHODS

During 1 year, patients were prospectively recruited from a single institution specialized shoulder clinic in 2 different groups. The patient group consisted of individuals with a degenerative rotator cuff tear involving at least the supraspinatus. The control group consisted of individuals with no rotator cuff pathology. Individuals in both groups with congenital, post-traumatic, or degenerative alterations of the proximal humerus were excluded. The GTA was measured on an anteroposterior shoulder x-ray image with the arm in neutral rotation by 3 observers at 2 different times.

RESULTS

The study recruited 71 patients (33 patients, 38 controls). Mean GTA value was 72.5° (range, 67.6°-79.2°) in patients and 65.2° (range, 55.8°-70.5°) for controls (P <.001). A value above 70° resulted in 93-fold higher odds of detecting a rotator cuff tear (P <.001). Interobserver and intraobserver reliability were high.

CONCLUSIONS

GT morphology is implicated in rotator cuff tears. The GTA is a reliable radiographic marker, with more than 70° being highly predictive in detecting such lesions.

Fc receptor-like 3 (-169T>C) polymorphism increases the risk of tendinopathy in volleyball athletes: a case control study

Background

Tendinopathy pathogenesis is associated with inflammation. Regulatory T (Treg) cells contribute to early tissue repair through an anti-inflammatory action, with the forkhead box P3 (FOXP3) transcription factor being essential for Treg function, and the FC-receptor-like 3 (FCRL3) possibly negatively regulating Treg function. FCRL3 –169T>C and FOXP3 –2383C>T polymorphisms are located near elements that regulate respective genes expression, thus it was deemed relevant to evaluate these polymorphisms as risk factors for tendinopathy development in athletes.

Methods

This case-control study included 271 volleyball athletes (146 tendinopathy cases and 125 controls) recruited from the Brazilian Volleyball Federation. Genotyping analyses were performed using TaqMan assays, and the association of the polymorphisms with tendinopathy evaluated by multivariate logistic regression.

Results

Tendinopathy frequency was 63% patellar, 22% rotator cuff and 15% Achilles tendons respectively. Tendinopathy was more common in men (OR = 2.87; 95% CI = 1.67–4.93). Higher age (OR = 8.75; 95% CI = 4.33–17.69) and more years of volleyball practice (OR = 8.38; 95% CI = 3.56–19.73) were risk factors for tendinopathy. The FCRL3 –169T>C frequency was significantly different between cases and controls. After adjustment for potential confounding factors, the FCRL3 –169C polymorphism was associated with increased tendinopathy risk (OR = 1.44; 95% CI = 1.02–2.04), either considering athletes playing with tendon pain (OR = 1.98; 95% CI = 1.30–3.01) or unable to train due to pain (OR = 1.89; 95% CI = 1.01–3.53). The combined variant genotypes, FCRL3 –169TC or –169CC and FOXP3 –2383CT or –2383TT, were associated with an increased risk of tendinopathy among athletes with tendon pain (OR = 2.24; 95% CI: 1.14–4.40 and OR = 2.60; 95% CI: 1.11–6.10). The combined analysis of FCRL3 –169T>C and FOXP3 –2383C>T suggests a gene-gene interaction in the susceptibility to tendinopathy.

Conclusions

FCRL3 –169C allele may increase the risk of developing tendinopathy, and together with knowledge of potential risk factors (age, gender and years playing) could be used to personalize elite athletes’ training or treatment in combination with other approaches, with the aim of minimizing pathology development risk.

The potential role of angiogenesis in the development of shoulder pain, shoulder dysfunction, and lymphedema after breast cancer treatment

Shoulder morbidity is a well-documented sequela of breast cancer treatment, which includes various manifestations such as pain, reduced range of motion, and lymphedema, among others. The multifactorial nature of such morbidities has long been appreciated, and research on reliable risk predictors of development thereof still continues. Previous studies have demonstrated the potential of different types of physical therapy to treat such shoulder problems, and the integration of such interventions into routine care for breast cancer survivors is a requirement in most high-income countries. Although patients at risk for developing shoulder problems would most likely benefit from posttreatment physical therapy, currently, there is no gold standard for identifying this patient group. This is particularly important in low- and middle-income countries where scarce monetary resources need to be directed specifically to those most in need. Modulators of the angiogenesis pathway have been implicated in noncancer shoulder conditions such as rotator cuff disease, adhesive capsulitis, and tendon injuries. The present review summarizes the role of angiogenesis in the development of shoulder morbidity among breast cancer survivors and sets forth the rationale for our belief that angiogenesis signaling may help explain a proportion of the reported clinical variability noted in the development of shoulder pain and dysfunction and upper-limb lymphedema after breast cancer treatment.

Genome-wide association study identifies a locus associated with rotator cuff injury

Rotator cuff tears are common, especially in the fifth and sixth decades of life, but can also occur in the competitive athlete. Genetic differences may contribute to overall injury risk. Identifying genetic loci associated with rotator cuff injury could shed light on the etiology of this injury. We performed a genome-wide association screen using publically available data from the Research Program in Genes, Environment and Health including 8,357 cases of rotator cuff injury and 94,622 controls. We found rs71404070 to show a genome-wide significant association with rotator cuff injury with p = 2.31x10-8 and an odds ratio of 1.25 per allele. This SNP is located next to cadherin8, which encodes a protein involved in cell adhesion. We also attempted to validate previous gene association studies that had reported a total of 18 SNPs showing a significant association with rotator cuff injury. However, none of the 18 SNPs were validated in our dataset. rs71404070 may be informative in explaining why some individuals are more susceptible to rotator cuff injury than others.

Association Between Polymorphisms in the Genes of Estrogen Receptors and the Presence of Temporomandibular Disorders and Chronic Arthralgia

PURPOSE

The high prevalence of painful temporomandibular disorders (TMDs) in women suggests that estrogen and its receptors play a fundamental etiologic role in the development of this joint pathology through complex action mechanisms. The aim of this study was to evaluate the possible association between polymorphisms in the ESR1 (estrogen receptor-1) and ESRRB (estrogen-related receptor-β) genes and the risk of simultaneous development of TMDs and pain in other joints in the body.

MATERIALS AND METHODS

All participants were clinically evaluated for the presence of TMD (Research Diagnostic Criteria for TMD) and asked about the presence of chronic joint pain. The control group consisted of 72 patients without TMD and without pain. Participants with arthralgia were divided into 3 groups: with muscular TMD (n = 42), with articular TMD (n = 16), and without TMD and with systemic arthralgia (n = 82). Eight single-nucleotide polymorphisms in the ESR1 (rs12154178, rs1884051, rs2273206, rs7774230) and ESRRB (rs1676303, rs4903399, rs10132091, rs7151924) genes were investigated. The χ² test and Student t and Mann-Whitney tests were used to assess the relevance of nominal and continuous variables, respectively. A P value less than .05 was considered significant.

RESULTS

The TT (timin/timin) genotype for the ESR1 (rs2273206) gene was strongly associated with the risk of developing muscle TMDs and temporomandibular joint pain (P = .04). For the ESRRB (rs1676303) gene, an association was observed between the CC (cytosine/cytosine) genotype and the presence of articular TMDs associated with other chronic arthralgia (P = .02). These results were confirmed by the increased risk of developing articular TMDs associated with the C allele (P = .04).

CONCLUSIONS

This study supports the hypothesis that changes in the ESR1 and ESRRB genes influence the presence of TMDs associated with chronic joint pain.