Sex Hormones and Tendon

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.

Gender differences in spine surgery for degenerative lumbar disease: prospective cohort study

OBJECTIVE

Despite efforts toward achieving gender-based equality in clinical trial enrollment, females are frequently underrepresented and gender-specific data analysis is lacking. Identifying and addressing gender bias in medical decision-making and outcome reporting may facilitate more equitable healthcare delivery. This study aimed to determine if gender differences exist in the clinical evaluation and surgical management of patients with degenerative lumbar conditions.

METHODS

Consecutive adult patients undergoing spinal surgery for degenerative lumbar conditions (disc herniation [DH], spinal canal stenosis [SCS], and degenerative spondylolisthesis [DS]) were prospectively enrolled across 16 tertiary academic centers. Outcome domains included pain, disability, health-related quality of life (HRQOL), expectations of surgery, and satisfaction with surgical outcome. Covariates pertaining to the preoperative use of healthcare resources, diagnostic testing, and visits to healthcare providers were compared between genders before and after propensity score matching for 13 baseline demographic and procedural variables.

RESULTS

Data were analyzed for 5038 patients (2396 female, 2642 male) with degenerative spinal pathologies including SCS (40.2%), DS (33.2%), and DH (26.6%). Surgical treatment effect was similar for both genders. For all conditions, female patients had worse pre- and postoperative pain, disability, and HRQOL. Significant gender differences were identified for marital status, education, employment status, exercise activities, and disability claims. Female patients were more likely to use select medications, diagnostic imaging tests, and nonsurgical therapeutic interventions, and access various healthcare providers. Findings were similar following post hoc propensity score matching.

CONCLUSIONS

In this multicenter, prospective, observational cohort study, male and female patients benefitted similarly from surgery for degenerative lumbar spine disease. However, female patients had worse preoperative clinical assessment scores and were more likely to use select healthcare resources.

Chiropractic Care for a Posterior Tibialis Tendon Tear in a Transgender Male Athlete with Gender-Affirming Hormone Therapy

Objective

The purpose of this case study was to report the management of a patient with posterior tibialis tendon injury concurrent with gender-affirming hormone therapy (GAHT).

Clinical Features

A 31-year-old transgender male presented to a chiropractic clinic with spontaneous, right medial foot pain following running that day. Medical history revealed bilateral congenital pes planus and intramuscular administration of testosterone for 8 years. Physical examination revealed swelling and tenderness around the medial and lateral malleoli and anterior ankle and along the medial longitudinal arch. Plantarflexion and dorsiflexion strength measured 4 out of 5. An 8 out of 10 pain level affected weight-bearing activities and sleep. Lower extremity functional scale measured 81% disability. Multimodal imaging was used in the patient's workup. Diagnostic ultrasound revealed a grade 2 tear of the posterior tibialis tendon adjacent to the medial malleolus along with additional sites of tendinosis. Referral to orthopedist and subsequent magnetic resonance imaging of the right foot and ankle confirmed the diagnosis of grade 2 tear in the posterior tibialis tendon.

Intervention and Outcome

The patient elected chiropractic care following the surgical recommendation. Nonpharmacologic management included neuromuscular re-education using whole body vibration therapy, therapeutic exercise, and ankle mortise joint mobilizations. The patient's clinical status improved, and the lower extremity functional scale measured 27% disability.

Conclusion

Although the patient was 31 years old, GAHT is recognized as a risk factor for tendinosis in older adults. An improved understanding of the correlation between tendinosis and GAHT could optimize patient outcomes and clarify the role of musculoskeletal rehabilitation for treatment.

Prescription Testosterone is Associated with an Increased Risk of Anterior Cruciate Ligament Injury

PURPOSE

To characterize the relationship between testosterone replacement therapy (TRT) and anterior cruciate ligament (ACL) injuries.

METHODS

A retrospective cohort study using a large insurance database was conducted. Patients who were prescribed TRT for at least 3 months were matched with controls who were not prescribed TRT. Rates of ACL tears were compared between the cohorts. Multiple subgroups were created based on age (<25 years, 25-35, 36-45, 46-55, 56-65, and 65+). Multivariable logistic regressions were performed to determine the association of TRT with ACL tears while accounting for demographic variables and comorbidities.

RESULTS

After matching, there were 160,839 patients in both the TRT cohort and control cohort. The incidence of ACL injuries was 17.8 per 10,000 person-years (95% CI: 16.4-19.2) for patients who were prescribed TRT and 4.9 per 10,000 person-years (95% CI: 4.1-5.7) for controls (p<0.001). Within 2 years of filling a testosterone prescription for at least 3 months, 572 (0.35%) patients experienced an ACL injury compared to only 157 (0.10%) controls during the same follow-up period (OR: 2.77; 95% CI: 2.26-3.42, p<0.001). When stratified by age, all groups except the <25 years of age group demonstrated significantly higher rate of ACL tears (OR 3.91-12.3, p<0.001-0.009). When separated by sex, males on TRT were 3.13 (95% CI: 2.50-3.93, p<0.001) times more likely while females on TRT were 1.94 (95% CI: 1.13-3.41, p=0.018) times more likely to experience an ACL injury compared to controls.

CONCLUSION

This study found that patients prescribed at least three months of TRT had a significantly higher incidence of ACL injuries compared to controls within a two-year follow-up period.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Fatiguing exercise reduces cellular passive Young's modulus in human vastus lateralis muscle

Previous studies demonstrated that acute fatiguing exercise transiently reduces whole-muscle stiffness, which might contribute to increased risk of injury and impaired contractile performance. We sought to elucidate potential intracellular mechanisms underlying these reductions. To that end, the cellular passive Young's modulus was measured in muscle fibres from healthy, young males and females. Eight volunteers (four male and four female) completed unilateral, repeated maximal voluntary knee extensions until task failure, immediately followed by bilateral percutaneous needle muscle biopsy of the post-fatigued followed by the non-fatigued control vastus lateralis. Muscle samples were processed for mechanical assessment and separately for imaging and phosphoproteomics. Fibres were passively (pCa 8.0) stretched incrementally to 156% of initial sarcomere length to assess Young's modulus, calculated as the slope of the resulting stress-strain curve at short (sarcomere length = 2.4-3.0 µm) and long (sarcomere length = 3.2-3.8 µm) lengths. Titin phosphorylation was assessed by liquid chromatography followed by high-resolution mass spectrometry. The passive modulus was significantly reduced in post-fatigued versus control fibres from male, but not female, participants. Post-fatigued samples showed altered phosphorylation of five serine residues (four located within the elastic region of titin) but did not exhibit altered active tension or sarcomere ultrastructure. Collectively, these results suggest that acute fatigue is sufficient to alter phosphorylation of skeletal titin in multiple locations. We also found reductions in the passive modulus, consistent with prior reports in the literature investigating striated muscle stiffness. These results provide mechanistic insight contributing to the understanding of dynamic regulation of whole-muscle tissue mechanics in vivo. HIGHLIGHTS: What is the central question of this study? Previous studies have shown that skeletal muscle stiffness is reduced following a single bout of fatiguing exercise in whole muscle, but it is not known whether these changes manifest at the cellular level, and their potential mechanisms remain unexplored. What is the main finding and its importance? Fatiguing exercise reduces cellular stiffness in skeletal muscle from males but not females, suggesting that fatigue alters tissue compliance in a sex-dependent manner. The phosphorylation status of titin, a potential mediator of skeletal muscle cellular stiffness, is modified by fatiguing exercise. Previous studies have shown that passive skeletal muscle stiffness is reduced following a single bout of fatiguing exercise. Lower muscle passive stiffness following fatiguing exercise might increase risk for soft-tissue injury; however, the underlying mechanisms of this change are unclear. Our findings show that fatiguing exercise reduces the passive Young's modulus in skeletal muscle cells from males but not females, suggesting that intracellular proteins contribute to reduced muscle stiffness following repeated loading to task failure in a sex-dependent manner. The phosphorylation status of the intracellular protein titin is modified by fatiguing exercise in a way that might contribute to altered muscle stiffness after fatiguing exercise. These results provide important mechanistic insight that might help to explain why biological sex impacts the risk for soft-tissue injury with repeated or high-intensity mechanical loading in athletes and the risk of falls in older adults.

Preparing the soil: Adjusting the metabolic health of patients with chronic wounds and musculoskeletal diseases

In recent years, systemic inflammation has emerged as a pivotal player in the development and progression of various degenerative diseases. This complex, chronic inflammatory state, often undetected, can have far-reaching consequences for the body's physiology. At the molecular level, markers such as C-reactive protein, cytokines and other inflammatory mediators serve as indicators of systemic inflammation and often act as predictors of numerous musculoskeletal diseases and even certain forms of cancer. The concept of 'meta-inflammation', specifically referring to metabolically triggered inflammation, allows healthcare professionals to understand inflammatory responses in patients with metabolic syndrome. Driven by nutrient excess and the expansion of adipose tissue, meta-inflammation is closely associated with insulin resistance, further propagating the metabolic dysfunction observed in many Western societies. Wound persistence, on the other hand, exacerbates the detrimental effects of prolonged inflammation at the local level. Acute inflammation is a beneficial and essential process for wound healing and infection control. However, when inflammation fails to resolve, it can impede the healing process, leading to chronic wounds, excessive scarring and even the activation of fibrotic pathways. This approach significantly reduces the efficacy of regenerative biological therapies. Our review focuses on the vital role of proteins, vitamins and minerals in collagen synthesis and cell proliferation for tissue healing. We also examine hormonal influences on regeneration, noting the negative effects of imbalances, and emphasize glucose regulation's importance in creating a stable environment for chronic wound healing.

Patient, imaging, and surgical factors associated with supraspinatus re-tear pattern after rotator cuff repair

Background

This study aimed to characterize patient, imaging, and surgical factors associated with re-tear patterns after rotator cuff repair, as well as to identify predictors of type 2 failure in a large patient cohort.

Methods

A retrospective case-control study was performed at a single urban academic institution. All patients who underwent an arthroscopic rotator cuff repair by 2 fellowship-trained shoulder and elbow surgeons between 2005 and 2022 and were subsequently found to have a symptomatic re-tear on magnetic resonance imaging were included. Patients were characterized as either a type 1 (failure at bone-tendon interface) or type 2 (failure medial to the bone-tendon junction) re-tear based on the Cho classification. Chart review was performed to collect demographic, imaging, and intraoperative surgical factors. Multivariable analysis was performed to determine patient and imaging factors associated with type 2 failure.

Results

Fifty-seven patients were included in the study. Overall, 33 (57.9%) patients were classified as a Cho 1 re-tear and 24 (42.1%) were classified as Cho 2 re-tear. No differences in preoperative tear characteristics (tear width, tear retraction, and tendon length) or fatty infiltration were found between Cho 1 and Cho 2 re-tears. Bivariate analysis comparing Cho 1 vs. Cho 2 found male sex was associated with a higher incidence of a Cho 2 re-tear (79.2% vs. 20.8%; P = .033). No significant differences in repair construct (single row vs. double row) (P = .816), biceps treatment (P = .552), concomitant subscapularis repair (P = .306), number of medial anchors (P = .533), or number of lateral anchors (P = .776) were noted between re-tear types. After controlling for potential confounding factors, multivariable regression analysis demonstrated that male sex was predictive of developing a Cho 2 re-tear (odds ratio 3.8; 95% confidence interval 1.1-13.3; P = .039). Repair construct was not found to be predictive of re-tear pattern (P = .580).

Conclusion

Repair construct used during rotator cuff repair does not appear to influence re-tear pattern. Male sex was associated with a higher rate of type 2 failure.

Functional Changes to Achilles Tendon and Enthesis in a Mouse Model of an Adolescent Masculine Gender-Affirming Hormone Treatment

Many transgender youth seek gender affirming care, such as puberty suppression, to prolong decision-making and to align their physical sex characteristics with their gender identity. During peripubertal growth, connective tissues such as tendon rapidly adapt to applied mechanical loads (e.g., exercise) yet if and how tendon adaptation is influenced by sex and gender affirming hormone therapy during growth remains unknown. The goal of this study was to understand the how pubertal suppression influences the structural and functional properties of the Achilles tendon using an established mouse model of transmasculine gender affirming hormone therapy. C57BL/6N female-born mice were assigned to experimental groups to mimic gender-affirming hormone therapy in human adolescents, and treatment was initiated prior to the onset of puberty (at postnatal day 26, P26). Experimental groups included controls and mice serially treated with gonadotropin release hormone analogue (GnRHa), delayed Testosterone (T), or GnRHa followed by T. We found that puberty suppression using GnRHa, with and without T, improved the overall tendon load capacity in female-born mice. Treatment with T resulted in an increase in the maximum load that tendon can withstand before failure. Additionally, we found that GnRHa, but not T, treatment resulted in a significant increase in cell density at the Achilles enthesis.

Regional variations and sex-related differences of stiffness in human tracheal ligaments

PURPOSE

There have been numerous studies focused on the stiffness of tracheal cartilage. However, no research has been conducted specifically on the annular ligament, nor have any regional differences in the annular ligament been identified. The purpose of this study was to investigate the stiffness of the ligaments present between the thyroid, cricoid and tracheal cartilages.

METHODS

The ligaments were identified in the cervical region of living subjects with ultrasonography. The stiffness of the ligaments was measured from the body surface using a digital palpation device (MyotonPRO). Since it is impossible to measure the entire trachea in a living subject, an additional measurement was performed on human cadavers.

RESULTS

Both in vivo and cadaveric investigations found that the stiffness of annular ligaments decreased gradually from the superior to inferior parts. There was no difference in the stiffness between males and females in the superior part of the trachea. However, the stiffness of the middle and inferior parts was predominantly higher in females than in males. Furthermore, males showed significant differences in stiffness between the superior and middle parts, while females showed no significant differences.

CONCLUSION

These results reveal that there are regional and sex-related differences in the stiffness of human tracheal ligaments.

Differences in the surgical management of degenerative lumbar spondylolisthesis based on self-reported sex: analysis of the CSORN prospective DLS study

OBJECTIVE

Surgical treatment of degenerative lumbar spondylolisthesis (DLS) reliably improves patient-reported quality of life; however, patient population heterogeneity, in addition to other factors, ensures ongoing equipoise in choosing the ideal surgical treatment. Surgeon preference for fusion or decompression alone influences surgical treatment decision-making. Meanwhile, at presentation, patient-reported outcome measures (PROMs) differ considerably between females and males. The aims of this study were to determine whether there exists a difference in the rates of decompression and fusion versus decompression alone based on patient-reported sex, and to determine if widely accepted indications for fusion justify any observed differences or if surgeon preference plays a role.

METHODS

This study is a retrospective cohort analysis of patients enrolled in the Canadian Spine Outcomes Research Network (CSORN) DLS study, a multicentered Canadian prospective study, investigating the surgical management and outcome of DLS. Decompression and fusion rates, patient characteristics, preoperative PROMs, and radiographic measures were compared between males and females before and after propensity score matching.

RESULTS

In the unmatched cohort, female patients were more likely to undergo decompression and fusion than male patients. Females were more likely to have the recognized indications for fusion, including kyphotic disc angle, higher spondylolisthesis grade and slip percentage, and patient-reported back pain. Other radiographic findings associated with the decision to fuse, including facet effusion, facet distraction, or facet angle, were not more prevalent in females. After propensity score matching for demographic and radiographic characteristics, similar proportions of male and female patients underwent decompression and fusion and decompression alone.

CONCLUSIONS

Although it remains unclear who should or should not undergo fusion, in addition to surgical decompression of DLS, female patients undergo fusion at a higher rate than their male counterparts. After matching baseline radiographic factors indicating fusion, this analysis showed that the decision to fuse was not biased by sex differences. Rather, the higher proportion of females undergoing fusion is largely explained by the radiographic and clinical indications for fusion, suggesting that specific clinical and anatomical features of this condition are indeed different between sexes.

Epidemiologic investigation of pediatric distal humerus fractures: An American insurance claims database study

BACKGROUND

Distal humerus elbow fractures are one of the most common traumatic fractures seen in pediatric patients and present as three main types: Supracondylar (SC), lateral condyle (LC), and medial epicondyle (ME) fractures.

AIM

To evaluate the epidemiology of pediatric distal humerus fractures (SC, LC, and ME) from an American insurance claims database.

METHODS

A retrospective review was performed on patients 17 years and younger with the ICD 9 and 10 codes for SC, LC and ME fractures based on the IBM Truven MarketScan® Commercial and IBM Truven MarketScan Medicare Supplemental databases. Patients from 2015 to 2020 were queried for treatments, patient age, sex, length of hospitalization, and comorbidities.

RESULTS

A total of 1133 SC, 154 LC, and 124 ME fractures were identified. SC fractures had the highest percentage of operation at 83%, followed by LC (78%) and ME fractures (41%). Male patients were, on average, older than female patients for both SC and ME fractures.

CONCLUSION

In the insurance claims databases used, SC fractures were the most reported, followed by LC fractures, and finally ME fractures. Age was identified to be a factor for how a pediatric distal humerus fractures, with patients with SC and LC fractures being younger than those with ME fractures. The peak age per injury per sex was similar to reported historic central tendencies, despite reported trends for younger physiologic development.

Testosterone replacement therapy is associated with increased odds of Achilles tendon injury and subsequent surgery: a matched retrospective analysis

BACKGROUND

Prescription of testosterone replacement therapy (TRT) has increased in the United States in recent years, and though anabolic steroids have been associated with tendon rupture, there is a paucity of literature evaluating the risk of Achilles tendon injury with TRT. This study aims to evaluate the associative relationship between consistent TRT, Achilles tendon injury, and subsequent surgery.

METHODS

This is a one-to-one matched retrospective cohort study utilizing the PearlDiver database. Records were queried for patients aged 35-75 who were prescribed at least 3 consecutive months of TRT between January 1, 2010 and December 31, 2019. Achilles tendon injuries and subsequent surgeries were identified using ICD-9, ICD-10, and CPT billing codes. Multivariable logistic regression was used to compare odds of Achilles tendon injury, Achilles tendon surgery, and revision surgery, with a p-value < 0.05 representing statistical significance.

RESULTS

A sample of 423,278 patients who filled a TRT prescription for a minimum of 3 consecutive months was analyzed. The 2-year incidence of Achilles tendon injury was 377.8 (95% CI, 364.8-391.0) per 100,000 person-years in the TRT cohort, compared to 245.8 (95% CI, 235.4-256.6) in the control (p < 0.001). The adjusted analysis demonstrated TRT to be associated with a significantly increased likelihood of being diagnosed with Achilles tendon injury (aOR = 1.24, 95% CI, 1.15-1.33, p < 0.001). Of those diagnosed with Achilles tendon injury, 287/3,198 (9.0%) of the TRT cohort subsequently underwent surgery for their injury, compared to 134/2,081 (6.4%) in the control cohort (aOR = 1.54, 95% CI, 1.19-1.99, p < 0.001).

CONCLUSIONS

There is a significant association between Achilles tendon injury and prescription TRT, with a concomitantly increased rate of undergoing surgical management. These results provide insight into the risk profile of TRT and further research into the science of tendon pathology in the setting of TRT is an area of continued interest.

Effects of pregnancy and lactation on muscle-tendon morphology

Pregnancy and lactation hormones have been shown to mediate anatomical changes to the musculoskeletal system that generates animal movement. In this study, we characterize changes in the medial gastrocnemius muscle, its tendon and aponeuroses that are likely to have an effect on whole animal movement and energy expenditure, using the rat model system, Rattus norvegicus. We quantified muscle architecture (mass, cross-sectional area, and pennation angle), muscle fiber type and diameter, and Young's modulus of stiffness for the medial gastrocnemius aponeuroses as well as its contribution to Achilles tendon in three groups of three-month-old female rats: virgin, primiparous pregnant, and primiparous lactating animals. We found that muscle mass drops by 23% during lactation but does not change during pregnancy. We also found that during pregnancy muscle fibers switch from Type I to IIa and during lactation from Type IIb to Type I. The stiffness of connective tissues that has a demonstrated role in locomotion, the aponeurosis and tendon, also changed. Pregnant animals had a significantly less stiff aponeurosis. However, tendon stiffness was most affected during lactation, with a significant drop in stiffness and interindividual variation. We propose that the energetic demands of locomotion may have driven the evolution of these anatomical changes in muscle-tendon units during pregnancy and lactation to ensure more energy can be allocated to fetal development and lactation.

The Women's Soccer Health Study: From Head to Toe

OBJECTIVES

Women are under-represented in the sports literature despite increasing rates of sports participation. Our objective was to investigate the risks and benefits of an elite women's soccer career in five health domains: general, musculoskeletal, reproductive endocrinology, post-concussion, and mental.

METHODS

An online survey was distributed to retired US college, semi-professional, professional, and national team soccer players using personal networks, email, and social media. Short validated questionnaires were used to evaluate the health domains, including the Patient-Reported Outcomes Measurement Information System (PROMIS), Single Assessment Numerical Evaluation (SANE), Post-Concussion Symptom Scale (PCSS), and Patient Health Questionnaire (PHQ).

RESULTS

A total of 560 eligible players responded to the survey over a 1-year period. The highest competitive levels were 73% college, 16% semi-professional, 8% professional, and 4% national team. The mean number of years since retirement was 12 (SD = 9), and 17.0% retired for involuntary reasons. The mean SANE scores (0-100 scale as percentage of normal) were knee = 75% (SD = 23), hip = 83% (SD = 23), and shoulder = 87% (SD = 21). The majority (63%) reported that their current activity level included participation in impact sports. A substantial proportion of players reported menstrual irregularities during their careers: 40% had fewer periods with increasing exercise and 22% had no periods for ≥ 3 months. The players (n = 44) who felt that post-concussion symptoms were due to soccer reported more time-loss concussions (F[2] = 6.80, p = 0.002) and symptom severity (F[2] = 30.26, p < 0.0001). Players who recently retired (0-5 years) reported the highest anxiety/depression scores and lowest satisfaction rates compared with those who retired 19+ years ago.

CONCLUSION

Health concerns include musculoskeletal injuries, post-concussion symptoms, and lower mental health in the early years following retirement. This comprehensive survey provides initial results that will lay the foundation for further analyses and prioritize research studies that can help all female athletes.

Dynamics of atlantoaxial rotation related to age and sex: a cross-sectional study of 308 subjects

BACKGROUND CONTEXT

Physiological ranges and dynamic changes of atlantoaxial rotation (ROTC1/2), total cervical spine rotation (ROTCs) and the percentage of ROTC1/2 from ROTCs (ROTCperc) for different age groups have not yet been investigated in a sufficiently sized cohort. Furthermore, it is not clear whether demographic variables such a sex, smoking status or diabetes affect ROTC1/2, ROTCs and ROTCperc.

PURPOSE

Obtain physiological ranges of ROTC1/2, ROTCs and ROTCperc for different age groups and determine their age-based dynamics. Investigate whether ROTC1/2, ROTCs and ROTCperc are affected by sex, smoking status or diabetes.

DESIGN

Observational cross-sectional study.

PATIENT SAMPLE

Patients undergoing elective CT examinations of the head and neck region between August 2020 and January 2022.

OUTCOME MEASURES

Ranges of motion of ROTC1/2, ROTCs and ROTCperc in degrees.

METHODS

A total of 308 subjects underwent dynamic rotational CT examinations of the upper cervical spine. Patients were divided into three age categories A1 (27-49 years), A2 (50-69 years) and A3 (≥70 years). Category A3 was further divided into B1 (70-79 years) and B2 (≥80 years). Values of ROTC1/2, ROTCs and ROTCperc were compared between all age groups, males and females, smokers and nonsmokers, diabetics a nondiabetics. Dynamics of ROTC1/2, ROTCs related to age and sex were visualized using scatterplot and trendline models.

RESULTS

ROTC1/2 significantly decreased from group A1 (64.4°) to B2 (46.7°) as did ROTCs from A1 (131.2°) to B2 (97.6°). No significant differences of ROTperc were found between groups A1-B2 with values oscillating between 49% and 51%. Smoking and diabetes did not significantly affect ROTC1/2, ROTCs and ROTCperc, females had significantly higher ROTCs than males. Males and females demonstrated a different dynamic of ROTC1/2 and ROTCs demonstrated by out scatterplot and trendline models.

CONCLUSIONS

Both ROTC1/2 and ROTCs significantly decrease with age, whereas ROTCperc remains stable. Females demonstrated higher ROTCs and their decrease of ROTC1/2 and ROTCs occurred in higher age groups compared to males. The functional repercussions atlantoaxial fusion are variable based on patient age and sex and should be taken into account prior to surgery.

Ultra-high field magnetic resonance imaging of the quadriceps tendon enthesis in healthy subjects

PURPOSE

Although enthesitis is a hallmark of several rheumatologic conditions, current imaging methods are still unable to characterize entheses changes because of the corresponding short transverse relaxation times (T2). A growing number of MR studies have used Ultra-High Field (UHF) MRI in order to assess low-T2 tissues e.g., tendon but never in humans. The purpose of the present study was to assess in vivo the enthesis of the quadriceps tendon in healthy subjects using UHF MRI.

METHODS

Eleven healthy subjects volunteered in an osteoarthritis imaging study. The inclusion criteria were: no knee trauma, Lequesne index = 0, less than 3 h of sport activities per week, and Kellgren and Lawrence grade = 0. 3D MR images were acquired at 7 T using GRE sequences and a T2* mapping. Regions of interest i.e., trabecular bone, subchondral bone, enthesis, and tendon body were identified, and T2* values were quantified and compared.

RESULTS

Quadriceps tendon enthesis was visible as a hyper-intense signal. The largest and the lowest T2* values were quantified in the subchondral bone region and the tendon body respectively. T2* value within subchondral bone was significantly higher than T2* value within the enthesis. T2* in subchondral bone region was significantly higher than the whole tendon body T2*.

CONCLUSION

A T2* gradient was observed along the axis from the enthesis toward the tendon body. It illustrates different water biophysical properties. These results provide normative values which could be used in the field of inflammatory rheumatologic diseases and mechanical disorders affecting the tendon.

In vivo potentiation of muscle torque is enhanced in female mice through estradiol-estrogen receptor signaling

Estradiol affects several properties of skeletal muscle in females including strength. Here, we developed an approach to measure in vivo posttetanic twitch potentiation (PTP) of the anterior crural muscles of anesthetized mice and tested the hypothesis that 17β-estradiol (E2) enhances PTP through estrogen receptor (ER) signaling. Peak torques of potentiated twitches were ∼40%-60% greater than those of unpotentiated twitches and such PTP was greater in ovary-intact mice, or ovariectomized (Ovx) mice treated with E2, compared with Ovx mice (P ≤ 0.047). PTP did not differ between mice with and without ERα ablated in skeletal muscle fibers (P = 0.347). Treatment of ovary-intact and Ovx mice with ERβ antagonist and agonist (PHTPP and DPN, respectively) did not affect PTP (P ≥ 0.258). Treatment with G1, an agonist of the G protein-coupled estrogen receptor (GPER), significantly increased PTP in Ovx mice from 41 ± 10% to 66 ± 21% (means ± SD; P = 0.034). Collectively, these data indicate that E2 signals through GPER, and not ERα or ERβ, in skeletal muscles of female mice to augment an in vivo parameter of strength, namely, PTP.NEW & NOTEWORTHY A novel in vivo approach was developed to measure potentiation of skeletal muscle torque in female mice and highlight another parameter of strength that is impacted by estradiol. The enhancement of PTP by estradiol is mediated distinctively through the G-protein estrogen receptor, GPER.

Optimizing repair of tendon ruptures and chronic tendinopathies: Integrating the use of biomarkers with biological interventions to improve patient outcomes and clinical trial design

Tendons are dense connective tissues of the musculoskeletal system that link bones with muscles to foster mobility. They have complex structures and exist in varying biomechanical, metabolic and biological environments. In addition, tendon composition and mechanical properties can change over the lifespan as an individual ages. Many tendons function in high stress conditions with a low vascular and neuronal supply, conditions often leading to development of chronic tendinopathies, and in some cases, overt rupture of the tissues. Given their essential nature for human mobility and navigation through the environment, the effective repair and regeneration of different tendons after injury or damage is critical for quality of life, and for elite athletes, the return to sport participation at a high level. However, for mainly unknown reasons, the outcomes following injury are not always successful and lead to functional compromise and risk for re-injury. Thus, there is a need to identify those patients who are at risk for developing tendon problems, as well those at risk for poor outcomes after injury and to design interventions to improve outcomes after injury or rupture to specific tendons. This review will discuss recent advances in the identification of biomarkers prognostic for successful and less successful outcomes after tendon injury, and the mechanistic implications of such biomarkers, as well as the potential for specific biologic interventions to enhance outcomes to improve both quality of life and a return to participation in sports. In addition, the implication of these biomarkers for clinical trial design is discussed, as is the issue of whether such biomarkers for successful healing of one tendon can be extended to all tendons or are valid only for tendons in specific biomechanical and biological environments. As maintaining an active lifestyle is critical for health, the successful implementation of these advances will benefit the large number of individuals at risk.

Can maternal hormones play a significant role in delivery mode?

The aim of this study was primarily to evaluate the levels of progesterone, oestradiol and relaxin during different delivery modes and secondarily to assess specific traits and changes in maternal pelvic dimensions during pregnancy and childbirth, in correlation with foetal size and maternal hormonal profile. Nulliparous women (n = 448) were evaluated at three different stages, during first trimester, at the time of admission for childbirth and finally just before childbirth. Each examination included clinical internal pelvimetry, blood sample collection for defining the hormones levels in peripheral maternal circulation and ultrasonographic measurements of specific variables of the pubic symphysis and the foetus. We included 304 nulliparous women divided in three groups. According to our results, there was statistically significant difference at the mean progesterone, oestradiol and relaxin range during different modes of childbirth (p-value < .01). We also found significant correlation between the newborn's weight and the changes in pubic symphysis dimensions. However, no significant association was noted between maternal hormones studied and the changes in pelvic dimensions.IMPACT STATEMENTWhat is already known on this subject? Mode of childbirth can be affected by various aspects, like maternal pelvic anatomy, foetal size and hormonal status at the time of labour. Hormonal fluctuations along with mechanical forces caused by the foetus are believed to lead to morphological alterations to promote natural vaginal childbirth.What do the results of this study add? Our results clearly showed that successful vaginal delivery is characterised by the prevalence of a hyperoestrogenic environment with higher values of intrapartum oestradiol range and significant increase in maternal serum relaxin levels. We also proved that progesterone levels do not decrease during vaginal childbirth, and we concluded that foetal size seems to be the most crucial factor causing alterations in maternal pelvis during parturition.What are the implications of these findings for clinical practice and further research? Our findings could form part of a set of key factors included in future algorithms or computerised biomechanical models for predicting potential childbirth mode. Larger multicenter studies should confirm our results and evaluate their clinical significance in the decision making to ensure safe childbirth and optimal maternal and perinatal outcomes.

Disrupted development from head to tail: Pervasive effects of postnatal restricted resources on neurobiological, behavioral, and morphometric outcomes

When a maternal rat nurtures her pups, she relies on adequate resources to provide optimal care for her offspring. Accordingly, limited environmental resources may result in atypical maternal care, disrupting various developmental outcomes. In the current study, maternal Long-Evans rats were randomly assigned to either a standard resource (SR) group, provided with four cups of bedding and two paper towels for nesting material or a limited resource (LR) group, provided with a quarter of the bedding and nesting material provided for the SR group. Offspring were monitored at various developmental phases throughout the study. After weaning, pups were housed in same-sex dyads in environments with SRs for continued observations. Subsequent behavioral tests revealed a sex × resource interaction in play behavior on PND 28; specifically, LR reduced play attacks in males while LR increased play attacks in females. A sex × resource interaction was also observed in anxiety-related responses in the open field task with an increase in thigmotaxis in LR females and, in the social interaction task, females exhibited more external rears oriented away from the social target. Focusing on morphological variables, tail length measurements of LR males and females were shorter on PND 9, 16, and 21; however, differences in tail length were no longer present at PND 35. Following the behavioral assessments, animals were perfused at 56 days of age and subsequent immunohistochemical assays indicated increased glucocorticoid receptors in the lateral habenula of LR offspring and higher c-Fos immunoreactivity in the basolateral amygdala of SR offspring. Further, when tail vertebrae and tail tendons were assessed via micro-CT and hydroxyproline assays, results indicated increased trabecular separation, decreased bone volume fraction, and decreased connectivity density in bones, along with reduced collagen concentration in tendons in the LR animals. In sum, although the restricted resources only persisted for a brief duration, the effects appear to be far-reaching and pervasive in this early life stress animal model.

Is There a "Window of Opportunity" for Flexibility Development in Youth? A Systematic Review with Meta-analysis

BACKGROUND

Flexibility is an important component of physical fitness for competitive and recreational athletes. It is generally suggested that flexibility training should start from childhood (6-11 years of age) to optimize joint range of motion (ROM) increases; however, evidence is limited and inconsistent.

OBJECTIVE

To examine whether there is a difference in the effect of stretching training on flexibility during childhood (6-11 years of age) and adolescence (12-18 years of age).

DESIGN

Systematic review and meta-analysis.

METHODS

We searched PubMed Central, Web of Science, Scopus, Embase, and SPORTDiscus, to conduct this systematic review. Randomized controlled trials and non-randomized controlled trials were eligible. No language and date of publication restrictions were applied. Risk of bias was assessed using Cochrane RoB2 and ROBINS-I tools. Meta-analyses were conducted via an inverse variance random-effects model. GRADE analysis was used to assess the methodological quality of the studies.

RESULTS

From the 2713 records retrieved 28 studies were included in the meta-analysis (n = 1936 participants). Risk of bias was low in 56.9% of all criteria. Confidence in cumulative evidence was moderate. We found that stretching was effective in increasing ROM in both children (SMD = 1.09; 95% CI = 0.77-1.41; Z = 6.65; p < 0.001; I² = 79%) and adolescents (SMD = 0.90; 95% CI = 0.70-1.10; Z = 8.88; p < 0.001; I² = 81%), with no differences between children and adolescents in ROM improvements (p = 0.32; I² = 0%). However, when stretching volume load was considered, children exhibited greater increases in ROM with higher than lower stretching volumes (SMD = 1.21; 95% CI = 0.82-1.60; Z = 6.09; p < 0.001; I² = 82% and SMD = 0.62; 95% CI = 0.29-0.95; Z = 3.65; p < 0.001; I² = 0%, respectively; subgroup difference: p = 0.02; I² = 80.5%), while adolescents responded equally to higher and lower stretching volume loads (SMD = 0.90; 95% CI = 0.47-1.33; Z = 4.08; p < 0.001; I² = 83%, and SMD = 0.90; 95% CI = 0.69-1.12; Z = 8.18; p < 0.001; I² = 79%, respectively; subgroup difference: p = 0.98; I² = 0%).

CONCLUSIONS

Systematic stretching training increases ROM during both childhood and adolescence. However, larger ROM gains may be induced in childhood than in adolescence when higher stretching volume loads are applied, while adolescents respond equally to high and low stretching volume loads.

REGISTRATION

INPLASY, registration number: INPLASY202190032; https://inplasy.com/inplasy-2021-9-0032/.

Ginsenoside Rg1 enhances the healing of injured tendon in achilles tendinitis through the activation of IGF1R signaling mediated by oestrogen receptor

Background

During the pathogenesis of tendinopathy, the chronic inflammation caused by the injury and apoptosis leads to the generation of scars. Ginsenoside Rg1 (Rg1) is extracted from ginseng and has anti-inflammatory effects. Rg1 is a unique phytoestrogen that can activate the estrogen response element. This research aimed to explore whether Rg1 can function in the process of tendon repair through the estrogen receptor.

Methods

In this research, the effects of Rg1 were evaluated in tenocytes and in a rat model of Achilles tendinitis (AT). Protein levels were shown by western blotting. qRT-PCR was employed for evaluating mRNA levels. Cell proliferation was evaluated through EdU assay and cell migration was evaluated by transwell assay and scratch test assay.

Results

Rg1 up-regulated the expression of matrix-related factors and function of tendon in AT rat model. Rg1 reduced early inflammatory response and apoptosis in the tendon tissue of AT rat model. Rg1 promoted tenocyte migration and proliferation. The effects of Rg1 on tenocytes were inhibited by ICI182780. Rg1 activates the insulin-like growth factor-I receptor (IGF1R) and MAPK signaling pathway.

Conclusion

Rg1 promotes injured tendon healing in AT rat model through IGF1R and MAPK signaling pathway activation.

Risk factors for degenerative, symptomatic rotator cuff tears: a case-control study

BACKGROUND

Despite the considerable public health burden of rotator cuff tears, there is no consensus on risk factors associated with symptomatic rotator cuff tears. In this study, a large data source was used to identify factors associated with symptomatic rotator cuff tears. We defined cases of rotator cuff tears as those verified by imaging or operative reports and controls as symptomatic shoulders without rotator cuff tears as verified by imaging or operative reports.

METHODS

We performed a case-control study of patients with and without symptomatic rotator cuff tears by use of the Vanderbilt University Medical Center de-identified electronic medical record system, the Synthetic Derivative, with records on >2.5 million patients from 1998 to 2017. Cases and controls were confirmed by individual chart review and review of imaging and/or operative notes. A final set of 11 variables were analyzed as potential risk factors for cuff tears: age, sex, body mass index (BMI), race, smoking history, hypertension, depression/anxiety, dyslipidemia, carpal tunnel syndrome, overhead activity, and affected side. Multivariable logistic regression was used to estimate the association between predictor variables and the risk of having a rotator cuff tear.

RESULTS

A total of 2738 patients were selected from the Synthetic Derivative, which included 1731 patients with rotator cuff tears and 1007 patients without rotator cuff tears. Compared with individuals without tears, those with rotator cuff tears were more likely to be older (odds ratio [OR], 2.44; 95% confidence interval [CI], 2.12-2.89), to have a higher BMI (OR, 1.45; 95% CI, 1.24-1.69), to be of male sex (OR, 1.56; 95% CI, 1.32-1.85), and to have carpal tunnel syndrome (OR, 1.41; 95% CI, 1.03-1.93). Patients with rotator cuff tears were less likely to have left shoulder symptoms (OR, 0.68; 95% CI, 0.57-0.82) and to have depression/anxiety (OR, 0.77; 95% CI, 0.62-0.95) compared with the control group, which had symptomatic shoulder pain without rotator cuff tears.

CONCLUSIONS

In a large imaging and operative report-verified case-control study, we identified advancing age, male sex, higher BMI, and diagnosis of carpal tunnel syndrome as risk factors significantly associated with an increased risk of rotator cuff tears. Left shoulder symptoms and depression/anxiety were less likely to be associated with rotator cuff tears compared with symptomatic shoulders without rotator cuff tears. Contrary to some prior reports in the literature, smoking was not associated with rotator cuff tears.

The Usefulness of Serological Inflammatory Markers in Patients with Rotator Cuff Disease-A Systematic Review

Background and Objectives: Rotator cuff disease (RCD) is a prominent musculoskeletal pain condition that spans a variety of pathologies. The etiology and precise diagnostic criteria of this condition remain unclear. The current practice of investigating the biochemical status of RCD is by conducting biopsy studies but their invasiveness is a major limitation. Recent biochemical studies on RCD demonstrate the potential application of serological tests for evaluating the disease which may benefit future clinical applications and research. This systematic review is to summarize the results of available studies on serological biochemical investigations in patients with RCD. Methods: An electronic search on databases PubMed and Virtual Health Library was conducted from inception to 1 September 2021. The inclusion criteria were case-control, cross-sectional, and cohort studies with serological biochemical investigations on humans with RCD. Methodological quality was assessed using the Study Quality Assessment Tool for Observational Cohort and Cross-sectional studies from the National Heart, Lung, and Blood Institute. Results: A total of 6008 records were found in the databases; of these, 163 full-text studies were checked for inclusion and exclusion criteria. Nine eligible studies involving 984 subjects with RCD emerged from this systematic review. The quality of the studies found ranged from poor to moderate. In summarizing all the studies, several fatty acids, nonprotein nitrogen, interleukin-1 β, interleukin-8, and vascular endothelial growth factor were found to be significantly higher in blood samples of patients with RCD than with control group patients, while Omega-3 Intex, vitamin B12, vitamin D, phosphorus, interleukin-10, and angiogenin were observed to be significantly lower. Conclusions: This is the first systematic review to summarize current serological studies in patients with RCD. Results of the studies reflect several systemic physiological changes in patients with RCD, which may prove helpful to better understand the complex pathology of RCD. In addition, the results also indicate the possibility of using serological tests in order to evaluate RCD; however, further longitudinal studies are required.

Combining Yoga Exercise with Rehabilitation Improves Balance and Depression in Patients with Chronic Stroke: A Controlled Trial

Background: We combined yoga with standard stroke rehabilitation and compared it to the rehabilitation alone for depression and balance in patients. Methods: Forty patients aged from 30 to 80 who had suffered a stroke 90 or more days previously were divided evenly with age stratification and patients’ will (hence not randomized). In the intervention group 16 completed 8-week stroke rehabilitation combined with 1 h of yoga twice weekly. Another 19 patients completed the standard rehabilitation as the control group. Results: The yoga group showed significant improvement in depression (Taiwanese Depression Questionnaire, p = 0.002) and balance (Berg Balance Scale, p < 0.001). However, the control group showed improvement only in balance (p = 0.001) but not in depression (p = 0.181). Further analysis showed both sexes benefitted in depression, but men had a greater improvement in balance than women. Depression in left-brain lesion patients improved more significantly than in those with right-brain lesion, whereas balance improved equally despite lesion site. For patients under or above the age of 60, depression and balance both significantly improved after rehabilitation. Older age is significantly related to poor balance but not depression. Conclusions: Combining yoga with rehabilitation has the potential to improve depression and balance. Factors related to sex, brain lesion site and age may influence the differences.

Gender-specific difference in the recurrence of flexion contracture after total knee arthroplasty

Background

Range of motion after total knee arthroplasty (TKA) can impact patients’ daily lives. Nevertheless, flexion contracture (FC) often recurs after TKA, even upon achieving full extension intraoperatively. This study aimed to evaluate the relationship among preoperative, intraoperative, and postoperative knee extension angles, and clarify the risk factor for postoperative FC.

Methods

One hundred forty-seven knees undergoing TKA using a navigation system were evaluated. We measured the pre- and postoperative (6 months after TKA) extension angles using a goniometer, and intraoperative (before and after TKA) extension angle using a navigation system; the correlation between these angles at each time point was evaluated.

Results

The mean preoperative, intraoperative (before and after TKA) and postoperative extension angles were -9.9°, -6.8°, -0.1°, and -2.0°. Regarding intraoperative extension angle after TKA, 58 knees showed ≤ 5° hyperextension and six knees showed > 5° hyperextension. At 6 months, no cases showed hyperextension and 105 knees showed full extension. The mean intraoperative extension angle after TKA in the postoperative full extension group was 0.4°. A significant correlation was found among extension angles at each point (p<0.01, respectively). However, the intraoperative extension angle after TKA correlated with the postoperative extension angle only in females. Contrarily, the recurrence rate of FC was significantly higher in males than in females (p<0.01).

Conclusion

Intraoperative extension angles significantly correlated with pre- and postoperative extension angles in TKA. Moreover, intraoperative mild (≤ 5°) hyperextension is acceptable for postoperative full extension. There was a gender-specific difference in correlation between intra- and postoperative knee extension angles.

Level of evidence

III.

The patellar ligament: A comprehensive review

The patellar ligament (PL) is an epiphyseal ligament and is part of the extensor complex of the knee. The ligament has gained attention due to its clinical relevance to autograft and tendinopathy. A variety of anatomical variations of the PL such as aplasia, numerical variations, and vascularity are being reported recently by clinicians and anatomists. The aim of this literature was to review the available literature to provide a consensus regarding anatomic variations of the PL, neurovasculature surrounding the PL, histology of the PL, and various aspects of PL measurements with relevance to the surgical considerations and sex and age-related differences. A narrative review of the patellar ligament was performed by conducting a detailed literature search and review of relevant articles. A total of 90 articles on the patellar ligament were included and were categorized into studies based on anatomical variations, neurovasculature, morphometrics, microanatomy, sex and age-related difference, and ACL reconstruction. The anatomical variations and morphometrics of the PL were found to correlate with the frequency of strain injuries, tendinopathy, and efficacy of the PL autograft in anterior cruciate ligament reconstruction. The sex differences in PL measurements and the effect of estrogen on collagen synthesis explained a higher incidence of patellar tendinopathy in women. An awareness of its variations enables careful selection of surgical incisions, thereby avoiding complications related to nerve injury. Accurate knowledge of the PL microanatomy assists in understanding the mechanism of ligament degeneration, rupture, autograft harvesting, and ligamentization results.

Young's Modulus of Bilateral Infraspinatus Tendon Measured in Different Postures by Shear Wave Elastography Before and After Exercise

Objective

To investigate the Young's modulus value of infraspinatus tendons using shear wave elastography (SWE) technique in normal adults, and to analyze the influence of gender, postures, exercise, and dominant side on Young's modulus of infraspinatus tendons.

Methods

This is a prospective cross‐sectional study. From January 2019 to July 2020, 14 healthy subjects were identified, including seven males and seven females aged between 24 to 34, with a mean age of 27.67 ± 3.08 years. The Young's modulus of their infraspinatus tendons was measured by two operators using SWE in neutral and maximum external rotation positions of both sides before exercise and the dominant side after exercise. The Young's modulus values in different sexes, different postures, before vs after exercise, and dominant vs non‐dominant side were statistically analyzed.

Results

All 14 subjects completed the data collection process. The mean Young's modulus values of infraspinatus tendon for dominant sides in neutral position were 33.04 ± 3.01 kPa for males and 28.76 ± 3.09 kPa for females. And for non‐dominant sides in the neutral position, the values were 33.02 ± 2.38 kPa for males and 28.86 ± 2.47 kPa for females. In the maximum external rotation position, the values for dominant sides were 50.19 ± 4.86 kPa for males and 42.79 ± 4.44 kPa for females, and for non‐dominant sides were 50.95 ± 3.24 kPa for males and 42.42 ± 3.66 kPa for females. After exercise, the mean Young's modulus values of infraspinatus tendon for dominant sides in neutral position were 54.56 ± 3.76 kPa for males and 46.66 ± 5.99 kPa for females. And for the maximum external rotation position, the values were 59.13 ± 3.78 kPa for males and 54.49 ± 5.67 kPa for females. The Young's modulus of infraspinatus tendon in the neutral and maximum external rotation positions showed statistically significant differences in males and females, as well as before and after exercise (P < 0.05). However, the difference in Young's modulus between the dominant and non‐dominant sides was not statistically significant (P > 0.05). Intergroup reliability between both operators was excellent (ICC > 0.85).

Conclusion

There are gender‐related differences and post‐exercise increase in Young's modulus, yet such a difference cannot be witnessed between the dominant and non‐dominant sides.

A prolonged hiatus in postmenopausal HRT, does not nullify the therapy's positive impact on ageing related sarcopenia

Background

Previous work suggest a positive skeletal muscle effect of hormone replacement therapy (HRT) on skeletal muscle characteristics This study aimed to quantify any continued positive effect of HRT even after a sustained hiatus in treatment, controlling for two key muscle modulation hormones: Estradiol (E2) and Tri-iodo-thyronine (T3).

Method and findings

In 61 untrained women (18-78yrs) stratified as pre-menopausal, post-menopausal without (No_HRT) and post-menopausal with (Used_HRT) HRT history, body composition, physical activity, serum E2 and T3 were assessed by dual energy x-ray absorptiometry, Baecke questionnaire and ELISA. Gastrocnemius medialis (GM) and tibialis anterior (TA) electromyographic profiles (mean power frequency (mPowerF)), isometric plantar-flexion (PF) and dorsi-flexion (DF) maximum voluntary contraction (MVC), rate of torque development (RTD), isokinetic MVC and muscle volume, were assessed using surface electromyography, dynamometry and ultrasonography. Muscle quality was quantified as MVC per unit muscle size. E2 and E2:T3 ratio were significantly lower in postmenopausal participants, and were positively correlated with RTD even after controlling for adiposity and/or age. Pre-menopausal females had greater MVC in 8/8 PF and 2/5 DF (23.7–98.1%; P<0.001–0.049) strength measures compared to No_HRT, but only 6/8 PF (17.4–42.3%; P<0.001–0.046) strength measures compared to Used_HRT. Notably, Used_HRT had significant higher MVC in 7 PF MVC (30.0%-37.7%; P = 0.006–0.031) measures than No_HRT, while premenopausal and Used_HRT had similar uncorrected muscle size or quality. In addition, this cross-sectional data suggest an annual reduction in GM muscle volume corrected for intra-muscular fat by 1.3% in No_HRT and only 0.5% in Used_HRT.

Conclusion

Even years after cessation of the therapy, a history of HRT is positively associated with negating the expected post-menopausal drop in muscle quantity and quality. Whilst mPowerF did not differ between groups, our work highlights positive associations between RTD against E2 and E2:T3. Notwithstanding our study limitation of single time point for blood sampling, our work is the first to illustrate an HRT attenuation of ageing-related decline in RTD. We infer from these data that high E2, even in the absence of high T3, may help maintain muscle contractile speed and quality. Thus our work is the first to points to markedly larger physiological reserves in women with a past history of HRT.

Is There a Relationship between the Morphology of Connective Tissue and Reactivity during a Drop Jump? Influence of Sex and Athletic Performance Level

The influence of the morphologic characteristics of connective tissue, which plays an essential role during sports activities, on sporting tasks needs further research given the controversial findings reported in the literature. This study aimed at examining the relationship between lower limb connective tissue morphology and drop jump reactivity and determining the influence of sex and athletic performance level. A total of 30 men and 14 women, runners, executed 6 drop jumps (3 × 20 cm and 30 cm height respectively) and their thickness and cross-sectional area were recorded for Achilles and patellar tendons and plantar fascia. No significant results were found in the relationship between the morphology of the connective tissue and reactivity strength index for both sexes. Significant sex differences were found, while women showed greater values (p < 0.005) for Achilles tendon and plantar fascia; men showed greater values for reactivity strength index and drop jump performance (p < 0.001). The present study shows a limited relationship between connective tissue morphology and drop jump reactivity. Additionally, women showed greater normalized values for Achilles tendon and plantar fascia, and men showed greater reactivity strength index and jumping performance values. No relationships between athletic performance level and connective tissue were found.

Characteristics of Non-Spine Musculoskeletal Ambulatory Care Visits in the United States, 2009-2016

BACKGROUND

Despite the enormous economic and societal impact of musculoskeletal disorders, detailed data on the patient demographics and visit characteristics of nonspine musculoskeletal ambulatory care are sparse. Such data are essential to inform policymakers on population health needs and to justify health care resource allocation.

OBJECTIVE

To determine the demographic, patient, and visit characteristics of adult musculoskeletal ambulatory clinic visits, with the exception of spine visits, in the United States.

DESIGN

Survey/registry.

SETTING

National Ambulatory Medical Care Survey (NAMCS), Centers for Disease Control and Prevention (CDC) 2009 to 2016.

PATIENTS

The NAMCS was designed to capture information regarding the provision and use of ambulatory medical care services in the United States. Nonfederally employed office-based physicians reported data for this survey from 2009 to 2016.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE(S)

Average annual estimated number (in 100 000s), Average annual estimated rate of ambulatory care musculoskeletal visits per 100 U.S. adults.

RESULTS

During 2009 to 2016, the leading cause of musculoskeletal visits was knee symptoms (15.3 million annually from 2009 to 2010, 14.0 million annually from 2011 to 2012, 12.5 million annually from 2013 to 2014, and 12.4 million annually from 2015 to 2016). Musculoskeletal visits were most frequent in patients that were 45 to 64 years of age (40.4% to 43.6% of visits were for patients 45 to 64 years of age depending on body region). Orthopedic surgeons conducted more musculoskeletal visits than any other physician specialty for all body regions. Among body regions, magnetic resonance imaging (MRI) studies were ordered most commonly for patients with shoulder (total visits in 100 000 ± standard error [SE] 47.00 ± 0.21; 12.5% of total visits for shoulders) and knee symptoms (61.85 ± 0.15; 11.4% of total visits for knees). Opioid and opioid analgesic combinations (9.2% to 14.8% of visits) were most commonly prescribed in visits related to hip complaints.

CONCLUSIONS

Visits were most frequent for knee symptoms and in patients of working age groups, which likely affects work productivity. Orthopedic surgeons were the most common provider specialty. Opioid medications were prescribed most commonly for patients with hip symptoms, which may highlight an area for potential intervention given the ongoing opioid crisis.

The absence of oestrogen receptor beta disturbs collagen I type deposition during Achilles tendon healing by regulating the IRF5-CCL3 axis

Achilles tendon healing (ATH) remains an unanswered question in the field of sports medicine because it does not produce tissue with homology to the previously uninjured tissue. Oestrogen receptor β (ERβ) is involved in the injury and repair processes of tendons. Our previous study confirmed that ERβ plays a role in the early stage of ATH by affecting adipogenesis, but its role in extracellular matrix (ECM) remodelling is unknown. We established a 4‐week Achilles tendon repair model to investigate the mechanism through which ERβ affects ATH at the very beginning of ECM remodelling phase. In vitro studies were performed using tendon‐derived stem cells (TDSCs) due to their promising role in tendon healing. Behavioural and biomechanical tests revealed that ERβ‐deficient mice exhibit weaker mobility and inferior biomechanical properties, and immunofluorescence staining and qRT‐PCR showed that these mice exhibited an erroneous ECM composition, as mainly characterized by decreased collagen type I (Col I) deposition. The changes in gene expression profiles between ERβ‐knockout and WT mice at 1 week were analysed by RNA sequencing to identify factors affecting Col I deposition. The results highlighted the IRF5‐CCL3 axis, and this finding was verified with CCL3‐treated TDSCs. These findings revealed that ERβ regulates Col I deposition during ATH via the IRF5‐CCL3 axis.

Sex-Specific Analysis at Two Time Points in Three High-Impact Orthopaedic Sports Medicine Journals

Purpose

To determine how well the orthopaedic sports medicine literature reported sex-specific analysis (SSA) in 2011 and 2016.

Methods

The 3 highest-impact orthopaedic sports medicine subspecialty journals (American Journal of Sports Medicine; Arthroscopy; and Knee Surgery, Sports Traumatology, Arthroscopy) were selected for review. Two independent investigators reviewed all journal issues published during 2 different calendar years (2011 and 2016). All randomized controlled, prospective and retrospective group, and case-control studies were included. Studies were stratified into those that involved SSA, where sex was a variable in a multifactorial statistical model, and those that only reported sex as a demographic characteristic or used sex-matched groups without further analysis.

Results

A total of 960 studies evaluating 3,400,569 patients met criteria and were included in this review. Although 44.4% of the overall study population was female, only 293 (30.5%) studies included patient sex as variable in a multifactorial statistical model. The proportion of studies that performed SSA did not differ between 2011 (29.6%) and 2016 (31.1%; P = .607), although publications from American Journal of Sports Medicine were likely to report SSA (P < .05). Of the 293 studies that reported SSA, 91 (31%) demonstrated a significant difference in outcomes. The most commonly reported differences were in outcomes following anterior cruciate ligament, medial patellofemoral ligament, and posterior cruciate ligament reconstruction; autograft preparation; postoperative use of opiates following arthroscopy; and recovery after sports-related concussions.

Conclusions

Although most sports medicine studies include approximately 50% female and 50% male patients, statistical analysis differentiating the 2 subsets is not routinely performed. Only 30.5% of all studies performed SSA, 31% of which reported a statistically significant difference in the data when comparing outcomes between male and female patients with the same treatment modalities.

Clinical Relevance

The current study demonstrates that the orthopaedic sports medicine subspecialty literature is lacking in reporting SSA, and that there has been minimal improvement over a 5-year time period. In addition, this study highlights the high percentage of significant findings within the studies that performed SSA and underscores the differences in sex-specific injury patterns and treatment outcomes.

Factors associated with positive outcomes of platelet-rich plasma therapy in Achilles tendinopathy

BACKGROUND

The efficacy of platelet-rich plasma in the treatment for Achilles tendinopathy is debated. Therefore, it is important to know which factors, related to the subjects and/or the disease, are associated with positive or negative outcomes. Aim of this study was to evaluate in a large cohort of patients with Achilles mid-portion tendinopathy which variables were independently associated with a positive outcome after platelet-rich plasma treatment.

MATERIAL AND METHODS

Eighty-four subjects with Achilles tendinopathy were evaluated by means of VISA-A score and ultrasound and treated with a single platelet-rich plasma injection once a week for 3 weeks. Afterward, a rehabilitation program, based on eccentric training, was implemented. At 3 and 6 months, the relationship between the mean VISA-A score and the following putative predictors was evaluated: sex, age, physical activity, sport, smoking, metabolic risk factors, BMI, symptoms duration, tendon damage, neovessels, adherence to eccentric training. Finally, the percentage of clinically evident positive outcomes (defined as an increase in VISA-A score ≥ 20 points) related to each variable was computed.

RESULTS

At final follow-up, using the General Linear Model for Repeated Measures procedure, male sex (0.02), age ≤ 40 (0.05) and adequate eccentric training (0.02) were found to be independently associated with a significant increase in the mean VISA-A score. Moreover, the clinically evident positive outcomes, as previously defined, were significantly associated with male sex (0.01), age ≤ 40 (0.000), BMI ≤ 25 (0.001), symptoms duration ≤ 12 months (0.02) and good adherence to eccentric training (0.004).

CONCLUSION

Younger age, male sex and good adherence to eccentric training can be considered predictors of better results after platelet-rich plasma therapy in Achilles tendinopathy.

Tendon response to matrix unloading is determined by the patho-physiological niche

Although the molecular mechanisms behind tendon disease remain obscure, aberrant stromal matrix turnover and tissue hypervascularity are known hallmarks of advanced tendinopathy. We harness a tendon explant model to unwind complex cross-talk between the stromal and vascular tissue compartments. We identify the hypervascular tendon niche as a state-switch that gates degenerative matrix remodeling within the tissue stroma. Here pathological conditions resembling hypervascular tendon disease provoke rapid cell-mediated tissue breakdown upon mechanical unloading, in contrast to unloaded tendons that remain functionally stable in physiological low-oxygen/-temperature niches. Analyses of the stromal tissue transcriptome and secretome reveal that a stromal niche with elevated tissue oxygenation and temperature drives a ROS mediated cellular stress response that leads to adoption of an immune-modulatory phenotype within the degrading stromal tissue. Degradomic analysis further reveals a surprisingly rich set of active matrix proteases behind the progressive loss of tissue mechanics. We conclude that the tendon stromal compartment responds to aberrant mechanical unloading in a manner that is highly dependent on the vascular niche, with ROS gating a complex proteolytic breakdown of the functional collagen backbone.

Imaging of transgender patients: expected findings and complications of gender reassignment therapy

OBJECTIVES

Gender dysphoria is defined as a conflict between the biological gender and the gender with which the person identifies. Gender reassignment therapy can alter external sexual features to resemble those of the desired gender and are broadly classified into two types, female to male (FTM) and male to female (MTF). In this paper we describe expected findings and complications of gender reassignment therapy.

METHODS

Collaborative multi-institutional project supported by Ovarian and Uterine Cancer Disease Focused panel of Society of Abdominal Radiology.

RESULTS

Gender dysphoria is defined as a conflict between the biological gender and the gender with which the person identifies. Gender reassignment therapy can alter external sexual features to resemble those of the desired gender and are broadly classified into two types, female to male (FTM) and male to female (MTF). These therapies include hormonal treatment as well as surgical procedures. FTM genital reconstructive therapy includes creation of a neophallus, which can be achieved by metoidioplasty or phalloplasty with mastectomy, along with testosterone administration. MTF gender reassignment surgery includes complete removal of external genitalia with penectomy and orchiectomy, with vaginoplasty, clitoroplasty, labiaplasty, and breast augmentation along with estrogen supplements.

CONCLUSION

Surgical techniques alter the standard anatomy and make imaging interpretation challenging if radiologists are unfamiliar with expected post-operative appearances. It is important to recognize the complications related to surgical and non-surgical treatment of gender dysphoria to avoid interpretation errors. Furthermore, increasing the prevalence of transgender patients requires increased sensitivity when interpreting imaging studies to reduce the potential for misdiagnoses in reporting due to frequently incomplete available clinical history.

Relaxin inhibits patellar tendon healing in rats: a histological and biochemical evaluation

BACKGROUND

Female patients are more likely to have tendon injuries than males, especially those who has a higher concentration of relaxin. Previous studies have demonstrated that relaxin attenuates extracellular matrix (ECM) formation. However, the mechanism of relaxin on tendon repair remains unclear. We hypothesize that relaxin inhibits tendon healing by disrupting collagen synthesis.

METHODS

A patellar tendon window defect model was established using Sprague-Dawley rats. The center of the patellar tendon was removed from the patella distal apex and inserted to the tibia tuberosity in width of 1 mm. Then, the rats were injected with saline (0.2 μg/kg/day) or relaxin (0.2 μg/kg/day) for two and four weeks, which was followed by biomechanical analysis and histological and histochemical examination.

RESULTS

Mechanical results indicated that relaxin induces a significant decrease in tear resistance, stiffness, and Young's modulus compared to those rats without relaxin treatment. In addition, it was shown that relaxin activates relaxin family peptide receptor 1(RXFP1), disturbs the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteases (TIMPs), and reduces the deposition of collagen in injury areas.

CONCLUSIONS

Relaxin impairs tendon healing in rats. Also, relaxin might lead to tendon injury more commonly for females than males.

Influence of Oral Contraceptive Use on Adaptations to Resistance Training

Introduction: The majority of young women use oral contraceptives (OCs). Use of OCs has been associated with lower myofibrillar protein and tendon collagen synthesis rates, but it is unknown whether OCs will limit the adaptive response of myotendinous tissue to resistance training.

Design and Methods: Fourteen healthy untrained young regular OC users (24 ± 1 years, fat% 32 ± 1, 35 ± 2 ml⋅min^-1⋅kg^-1) and 14 NOC users (non-OC, controls) (24 ± 1 years, fat% 32 ± 2, 34 ± 2 ml⋅min^-1⋅kg^-1) performed a 10-week supervised lower extremity progressive resistance training program. Before and after the intervention biopsies from the vastus lateralis muscle and the patellar tendon were obtained. Muscle (quadriceps) and tendon cross-sectional area (CSA) was determined by magnetic resonance imaging (MRI) scans, and muscle fiber CSA was determined by histochemistry. Maximal isometric knee extension strength was assessed by dynamometry while 1 repetition maximum (RM) was determined during knee extension.

Results: Training enhanced CSA in both muscle (p < 0.001) and tendon (p < 0.01). A trend toward a greater increase in muscle CSA was observed for OC (11%) compared to NOC (8%) (interaction p = 0.06). Analysis of mean muscle fiber type CSA showed a trend toward an increase in type II muscle fiber area in both groups (p = 0.11, interaction p = 0.98), whereas type I muscle fiber CSA increased in the OC group (n = 9, 3821 ± 197 to 4490 ± 313 mm², p < 0.05), but not in NOC (n = 7, 4020 ± 348 to 3777 ± 354 mm², p = 0.40) (interaction p < 0.05). Post hoc analyses indicated that the effect of OCs on muscle mass increase was induced by the OC-users (n = 7), who used OCs containing 30 μg ethinyl estradiol (EE), whereas the response in users taking OCs with 20 μg EE (n = 7) did not differ from NOC. Both the OC and NOC group experienced an increase in maximal knee strength (p < 0.001) and 1RM leg extension (p < 0.001) after the training period with no difference between groups.

Conclusion: Use of OCs during a 10-week supervised progressive resistance training program was associated with a trend toward a greater increase in muscle mass and a significantly greater increase in type I muscle fiber area compared to controls. Yet, use of OCs did not influence the overall increase in muscle strength related to training.

Previous History of Breast Cancer Increases Rates of Pulmonary Embolism and Costs after Total Knee Arthroplasty: An Evaluation of 185,114 Matched Patients

Risk factors for adverse events after total knee arthroplasty (TKA) relating to malignancy have not been well studied. Thus, the purpose of this study was to conduct a retrospective case-control outcome and cost analysis after TKA in this population. Patients with a history of breast cancer (BrCa) were identified based on the International Classification of Disease 9th revision codes. An age- and sex-matched cohort was also identified of patients without a history of BrCa. Complications, length of stay, comorbidity burden, and reimbursements were tracked at 90 days. Each cohort comprised 92,557 patients. Length of stay was similar between cohorts (p = 0.627). Comorbidity status and incidence of pulmonary embolism (PE), lower extremity ultrasound, and chest computed tomography (CT) use were higher in patients with a history of BrCa (p < 0.05 for all). Control patients had a lower incidence of acute myocardial infarction (0.14 vs. 0.21%; p < 0.001). Surgical complications were similar. The 90-day reimbursements were greater in patients with a history of BrCa (US$13,990 vs. US$13,033 for controls; p = 0.021). Surgeons should be aware of the increased risk of PE after TKA in patients with a history of BrCa as well as increased 90-day costs, which warrant great attention.

Effect of Estrogen on Musculoskeletal Performance and Injury Risk

Estrogen has a dramatic effect on musculoskeletal function. Beyond the known relationship between estrogen and bone, it directly affects the structure and function of other musculoskeletal tissues such as muscle, tendon, and ligament. In these other musculoskeletal tissues, estrogen improves muscle mass and strength, and increases the collagen content of connective tissues. However, unlike bone and muscle where estrogen improves function, in tendons and ligaments estrogen decreases stiffness, and this directly affects performance and injury rates. High estrogen levels can decrease power and performance and make women more prone for catastrophic ligament injury. The goal of the current work is to review the research that forms the basis of our understanding how estrogen affects muscle, tendon, and ligament and how hormonal manipulation can be used to optimize performance and promote female participation in an active lifestyle at any age.

Is there sufficient evidence to explain the cause of sexually dimorphic behaviour in force steadiness?

Neuromuscular noise is a determining factor in the control of isometric force steadiness (FS), quantified as coefficient of variation (CV) of force around a preestablished target output. In this paper we examine sex-related differences of neural, muscular, and tendon influences on neuromuscular noise to understand FS in females and males. We use evidence from the literature to identify that CV of force is higher in females compared with males in the upper and lower body, with sex-related differences becoming less apparent with increasing age. Evaluation of sex-related physiology in tandem with results from FS studies indicate that differences in fibre type, contractile properties, and number of motor units (MUs) are unlikely contributors to differences in FS between females and males. MU type, behaviour of the population (inclusive of number of active MUs from the population), agonist–antagonist activity, maximal strength, and tendon mechanics are probable contributors to sexually dimorphic behaviour in FS. To clearly determine underlying causes of sex-related differences in FS, further study and reporting between females and males is required. Females and males are included in many studies; however, rich data on sexually dimorphic behaviour is lost when data are collapsed across sex or identified as nonsignificant without supporting values. This poses a challenge to identifying the underlying cause of females having higher CV of force than males. This review provides evidence of sexually dimorphic behaviour in FS and suggests that physiological differences between females and males effect neuromuscular noise, and in-turn contribute to sex-related differences in FS.

Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes: A Longitudinal Study

Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 ± 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean ± SD) and statistical testing for group differences was performed (α = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 ± 0.7 mm/5.6 ± 0.7 mm) nor in controls (4.8 ± 0.4 mm/4.9 ± 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (M1: 3.5 ± 0.5 mm, M2: 3.8 ± 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p ≤ 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports.

Female hormones: do they influence muscle and tendon protein metabolism?

Due to increased longevity, women can expect to live more than one-third of their lives in a post-menopausal state, which is characterised by low circulating levels of oestrogen and progesterone. The aim of this review is to provide insights into current knowledge of the effect of female hormones (or lack of female hormones) on skeletal muscle protein turnover at rest and in response to exercise. This review is primarily based on data from human trials. Many elderly post-menopausal women experience physical disabilities and loss of independence related to sarcopenia, which reduces life quality and is associated with substantial financial costs. Resistance training and dietary optimisation can counteract or at least decelerate the degenerative ageing process, but lack of oestrogen in post-menopausal women may reduce their sensitivity to these anabolic stimuli and accelerate muscle loss. Tendons and ligaments are also affected by sex hormones, but the effect seems to differ between endogenous and exogenous female hormones. Furthermore, the effect seems to depend on the age, and as a result influence the biomechanical properties of the ligaments and tendons differentially. Based on the present knowledge oestrogen seems to play a significant role with regard to skeletal muscle protein turnover. Therefore, oestrogen/hormonal replacement therapy may counteract the degenerative changes in skeletal muscle. Nevertheless, there is a need for greater insight into the direct and indirect mechanistic effects of female hormones before any evidence-based recommendations regarding type, dose, duration and timing of hormone replacement therapy can be provided.

Postinjury biomechanics of Achilles tendon vary by sex and hormone status

Achilles tendon ruptures are common injuries. Sex differences are present in mechanical properties of uninjured Achilles tendon, but it remains unknown if these differences extend to tendon healing. We hypothesized that ovariectomized females (OVX) and males would exhibit inferior postinjury tendon properties compared with females. Male, female, and OVX Sprague-Dawley rats (n = 32/group) underwent acclimation and treadmill training before blunt transection of the Achilles tendon midsubstance. Injured hindlimbs were immobilized for 1 wk, followed by gradual return to activity and assessment of active and passive hindlimb function. Animals were euthanized at 3 or 6 wk postinjury to assess tendon structure, mechanics, and composition. Passive ankle stiffness and range of motion were superior in females at 3 wk; however, by 6 wk, passive and active function were similar in males and females but remained inferior in OVX. At 6 wk, female tendons had greater normalized secant modulus, viscoelastic behavior, and laxity compared with males. Normalized secant modulus, cross-sectional area and tendon glycosaminoglycan composition were inferior in OVX compared with females at 6 wk. Total fatigue cycles until tendon failure were similar among groups. Postinjury muscle fiber size was better preserved in females compared with males, and females had greater collagen III at the tendon injury site compared with males at 6 wk. Despite male and female Achilles tendons withstanding similar durations of fatigue loading, early passive hindlimb function and tendon mechanical properties, including secant modulus, suggest superior healing in females. Ovarian hormone loss was associated with inferior Achilles tendon healing.