Diagnosis and Management of Thyroid Disease during Pregnancy and Postpartum: 2023 Revised Korean Thyroid Association Guidelines

Thyroid hormone plays a critical role in fetal growth and development, and thyroid dysfunction during pregnancy is associated with several adverse outcomes, such as miscarriage and preterm birth. In this review, we introduce and explain three major changes in the revised Korean Thyroid Association (KTA) guidelines for the diagnosis and management of thyroid disease during pregnancy: first, the normal range of thyroid-stimulating hormone (TSH) during pregnancy; second, the treatment of subclinical hypothyroidism; and third, the management of euthyroid pregnant women with positive thyroid autoantibodies. The revised KTA guidelines adopt 4.0 mIU/L as the upper limit of TSH in the first trimester. A TSH level between 4.0 and 10.0 mIU/L, combined with free thyroxine (T4) within the normal range, is defined as subclinical hypothyroidism, and a TSH level over 10 mIU/L is defined as overt hypothyroidism regardless of the free T4 level. Levothyroxine treatment is recommended when the TSH level is higher than 4 mIU/L in subclinical hypothyroidism, regardless of thyroid peroxidase antibody positivity. However, thyroid hormone therapy to prevent miscarriage is not recommended in thyroid autoantibody-positive women with normal thyroid function.

Prevalence, Treatment Status, and Comorbidities of Hyperthyroidism in Korea from 2003 to 2018: A Nationwide Population Study

Background@#This study aimed to investigate the changes of incidence and treatment of choice for hyperthyroidism from 2003 to 2018 and explore the treatment-related complications and concomitant comorbidities in South Korea using data from the National Health Insurance Service. @*Methods@#This is a retrospective observational study. Hyperthyroidism was defined as a case having two or more diagnostic codes of thyrotoxicosis, with antithyroid drug intake for more than 6 months. @*Results@#The average age-standardized incidence of hyperthyroidism from 2003 to 2018 was 42.23 and 105.13 per 100,000 men and women, respectively. In 2003 to 2004, hyperthyroidism was most often diagnosed in patients in their 50s, but in 2017 to 2018, people were most often diagnosed in their 60s. During the entire period, about 93.7% of hyperthyroidism patients were prescribed with antithyroid drugs, and meanwhile, the annual rates of ablation therapy decrease from 7.68% in 2008 to 4.56% in 2018. Antithyroid drug-related adverse events, mainly agranulocytosis and acute hepatitis, as well as complications of hyperthyroidism such as atrial fibrillation or flutter, osteoporosis, and fractures, occurred more often in younger patients. @*Conclusion@#In Korea, hyperthyroidism occurred about 2.5 times more in women than in men, and antithyroid drugs were most preferred as the first-line treatment. Compared to the general population, hyperthyroid patients may have a higher risk of atrial fibrillation or flutter, osteoporosis, and fractures at a younger age.

Validity and Reliability of the Korean-Translated Version of the International Cooperative Ataxia Rating Scale in Cerebellar Ataxia

Objective@#The International Cooperative Ataxia Rating Scale (ICARS) is a semiquantitative clinical scale for ataxia that is widely used in numerous countries. The purpose of this study was to investigate the validity and reliability of the Korean-translated version of the ICARS. @*Methods@#Eighty-eight patients who presented with cerebellar ataxia were enrolled. We investigated the construct validity using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). We also investigated the internal consistency using Cronbach’s α and intrarater and interrater reliability using intraclass correlation coefficients. @*Results@#The Korean-translated ICARS showed satisfactory construct validity using EFA and CFA. It also revealed good interrater and intrarater reliability and showed acceptable internal consistency. However, subscale 4 for assessing oculomotor disorder showed moderate internal consistency. @*Conclusion@#This is the first report to investigate the validity and reliability of the Korean-translated ICARS. Our results showed excellent construct and convergent validity. The reliability is also acceptable.

Big Data Research in the Field of Endocrine Diseases Using the Korean National Health Information Database

The Korean National Health Information Database (NHID) contains big data combining information obtained from the National Health Insurance Service and health examinations. Data are provided in the form of a cohort, and the NHID can be used to conduct longitudinal studies and research on rare diseases. Moreover, data on the cause and date of death are provided by Statistics Korea. Research and publications based on the NHID have increased explosively in the field of endocrine disorders. However, because the data were not collected for research purposes, studies using the NHID have limitations, particularly the need for the operational definition of diseases. In this review, we describe the characteristics of the Korean NHID, operational definitions of endocrine diseases used for research, and an overview of recent studies in endocrinology using the Korean NHID.

Immunogenicity and Safety of Vaccines against Coronavirus Disease in Actively Treated Patients with Solid Tumors: A Prospective Cohort Study / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#We aimed to assess the humoral response to and reactogenicity of coronavirus disease 2019 (COVID-19) vaccination according to the vaccine type and to analyze factors associated with immunogenicity in actively treated solid cancer patients (CPs). @*Materials and Methods@#Prospective cohorts of CPs, undergoing anticancer treatment, and healthcare workers (HCWs) were established. The participants had no history of previous COVID-19 and received either mRNA-based or adenovirus vector–based (AdV) vaccines as the primary series. Blood samples were collected before the first vaccination and after 2 weeks for each dose vaccination. Spike-specific binding antibodies (bAbs) in all participants and neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type, Delta, and Omicron variants in CPs were analyzed and presented as the geometric mean titer. @*Results@#Age-matched 20 HCWs and 118 CPs were included in the analysis. The bAb seroconversion rate and antibody concentrations after the first vaccination were significantly lower in CPs than in HCWs. After the third vaccination, antibody levels in CPs with a primary series of AdV were comparable to those in HCWs, but nAb titers against the Omicron variant did not quantitatively increase in CPs with AdV vaccine as the primary series. The incidence and severity of adverse reactions post-vaccination were similar between CPs and HCWs. @*Conclusion@#CPs displayed delayed humoral immune response after SARS-CoV-2 vaccination. The booster dose elicited comparable bAb concentrations between CPs and HCWs, regardless of the primary vaccine type. Neutralization against the Omicron variant was not robustly elicited following the booster dose in some CPs, implying the need for additional interventions to protect them from COVID-19.

Axillary temperature measurements based on smart wearable thermometers in South Korean children: comparison with tympanic temperature measurements

Purpose@#This study explored the validity of a new type of thermometer and parent satisfaction with the new device. This 24-hour continuous monitoring smart wearable wireless thermometer (TempTraq®) uses a very small semiconductor sensor with a thin patch-like shape. @*Methods@#We obtained 397 sets of TempTraq® axillary temperatures and tympanic temperatures from 44 pediatric patients. Agreement between the axillary and tympanic measurements, as well as the validity of the TempTraq® axillary temperatures, were evaluated. Satisfaction surveys were completed by 41 caregivers after the measurements. @*Results@#The TempTraq® axillary temperatures demonstrated a strong positive correlation with the tympanic temperatures. The Bland-Altman plot and analysis of TempTraq® axillary temperatures and tympanic temperatures showed that the mean difference was +0.45 ℃, the 95% limits of agreement were -0.57 to +1.46 ℃. Based on a tympanic temperature of 38 ℃, the results of validity of fever detection were sensitivity 0.85 and specificity 0.86. Satisfaction scores for TempTraq® temperature measurement were all > 4 points (satisfactory). @*Conclusion@#TempTraq® smart axillary temperature measurement is an appropriate method for measuring children's temperatures since it was highly correlated to tympanic temperatures, had a reliable level of sensitivity and specificity, and could be used safely and conveniently.

The Role of Collagen VI α6 Chain Gene in Atopic Dermatitis

Background@#In a previous study, we carried out whole-exome sequencing to identify genetic variants associated with early onset atopic dermatitis (AD) in Koreans and found that collagen VI α6 chain (COL6A6) gene polymorphisms are associated. COL6A6 is one of the chains that makes up the triple helix of collagen VI, and little is known about its role in AD. @*Objective@#To identify how COL6A6 changes in AD and clarify its role. @*Methods@#Immunohistochemical staining for COL6A6 was performed on tissues of AD, other skin diseases, and healthy controls. Human keratinocytes and fibroblasts were exposed to inflammatory cytokines and cultured to evaluate changes in COL6A6 expression. COL6A6 small interfering RNA (siRNA) was transfected into cells to identify the role of COL6A6. @*Results@#Total COL6A6 mRNA was higher in AD than in controls. In AD tissues, COL6A6 mRNA decreased significantly in the epidermis compared to controls, whereas COL6A6 protein was increased in the dermis. In the cultured cells, COL6A6 mRNA was suppressed in the epidermis by interleukin (IL)-4 and IL-13, whereas COL6A6 protein was induced in the dermis. In the COL6A6 siRNA-transfected keratinocyte, mRNA of FLG, LOR, and CASP14 decreased compared to controls; in contrast, mRNA of MMP1 increased. @*Conclusion@#The reduction of epidermal COL6A6 due to the genetic mutation can cause skin barrier damage and it can contributes to the early onset of AD. COL6A6 is induced by IL-4 and IL-13, and it may play a role in fibrotic remodeling and inflammatory processes, which are major features of AD.

Can a Biomechanical Foot Orthosis Affect Gait in Patients With Hallux Valgus? A Pilot Study

Objective@#To investigate the effects of customized biomechanical foot orthosis (BFO) on kinematic data during gait in patients with hallux valgus (HV) deformities and compare the results with those of a normal control group. @*Methods@#Ten patients with HV deformities and 10 healthy volunteers were enrolled in this study. HV deformity was diagnosed using biomechanical and radiological assessments by a rehabilitation physician. Patients received the customized BFO manufactured at a commercial orthosis laboratory (Biomechanics, Goyang, South Korea) according to the strictly defined procedure by a single experienced technician. The spatiotemporal and kinematic data acquired by the Vicon 3D motion capture system (Oxford Metrics, Oxford, UK) were compared between the intervention groups (control vs. HV without orthosis) and between the HV groups (with vs. without orthosis). @*Results@#The temporal-spatial and kinematic parameters of the HV group were significantly different from those of the control group. After applying BFO to the HV group, significantly increased ranges of plantar flexion motion and hindfoot inversion were observed. Furthermore, the HV group with BFO showed improved gait cadence, walking speed, and stride length, although the results were not statistically significant. @*Conclusion@#Our results suggest that it is imperative to understand the pathophysiology of HV, and the application of customized BFO can be useful for improving kinematics in HV deformities.

Comparison of Clinical Outcomes for Glycopeptides and Beta-Lactams in Methicillin-Susceptible Staphylococcus Aureus Bloodstream Infections

Purpose@#This study aimed to provide compelling evidence of anti-staphylococcal beta-lactam use for methicillin-susceptible Staphylococcus aureus bloodstream infection (MSSA BSI). @*Materials and Methods@#We retrospectively collected data on patients with MSSA BSI who were admitted to two academic tertiary-care hospitals from 2010 to 2018. Only patients who received nafcillin, cefazolin, vancomycin, or teicoplanin as definitive therapy were included. The primary outcome was 28-day mortality. To perform unbiased comparisons between both treatments, we used inverse probability of treatment weighting (IPTW) analysis. @*Results@#A total of 359 patients were divided into two groups based on the definitive therapy used: beta-lactams (n=203), including nafcillin or cefazolin; and glycopeptides (n=156), including vancomycin or teicoplanin. In the IPTW analysis, glycopeptides were associated with significantly increased odds of 28-day mortality (adjusted odds ratio, 3.37; 95% confidence interval, 1.71– 6.61; p<0.001). The rate of primary outcome in prespecified subgroups was largely consistent with the main analysis. @*Conclusion@#Definitive therapy with beta-lactams in patients with MSSA BSI was associated with lower 28-day mortality compared to definitive therapy with glycopeptides.

Survey and Proposal of Critical Value Reporting and Management in Clinical Chemistry

Objective@#It is one of the major functions of the clinical laboratory to clearly, accurately, and quickly communicate critical values directly to the patient care providers. Laboratory professionals are often confronted with many obstacles in critical value reporting, including establishing critical values, notifying the critical values to provider, and ensuring that the provider understands the severity of a critical result. @*Methods@#A total of 30 laboratory directors voluntarily answered the questionnaire by e-mail. The questionnaire covered demographic characteristics, establishing and updating critical values lists in clinical chemistry, thresholds of critical values, appropriate timeframes for critical results, notification process, and so on. @*Results@#Of the 30 participating institutions, 12 were general hospitals, three were commercial laboratories, and 15 were tertiary hospitals. The tests included in critical value lists are as follows in order of frequency: potassium, glucose, sodium, total calcium, chloride, ionized calcium, creatinine, magnesium, total bilirubin, phosphorus, pH, and so on. Ten of the 30 institutions notified critical value reports to the patient care providers within 1 hour. @*Conclusion@#This study presents the status of critical value reporting policy in Korean hospitals and a literature review on critical value reporting. In addition, this article provides core components and current regulatory requirements for critical value reporting. Critical value reporting systems should be approved, reviewed, and revised periodically.

Pediatric Hip Disease (II): Developmental Dysplasia of the Hip – Treatment of Residual Dysplasia / 대한정형외과학회잡지

Residual dysplasia is common in spite of early treatment of developmental dysplasia of the hip and often requires a harness or femoral/ acetabular surgery. Operative treatment is roughly divided into two categories: reconstructive and salvage; but the reconstruction such as re-directional osteotomy of the acetabulum should always be considered first. Operative treatment consists of osteotomy on femur or acetabulum, or both. Before the surgery, thorough evaluation of the patient is necessary to select appropriate operation. Avascular necrosis is one of the most catastrophic complications, which is often seen in delayed diagnosis or surgically treated patients.

Suicidality and Its Risk Factor in Migraine Patients

Background@#Migraine patients have a higher frequency of suicidality than people without migraine. The aim of this study was to identify suicidality and its risk factors in migraine patients. @*Methods@#We enrolled 358 migraine patients from 11 hospitals. We collected data regarding their clinical characteristics and the patients completes the questionnaires. We also interviewed patients with the Mini International Neuropsychiatric Interview (MINI)plus version 5.0.0 to identify their suicidality. The International Classification of Headache Disorders, third edition, beta version was used in headache diagnosis. @*Results@#The frequency of suicidality in migraine patients was 118 (33.0%). Migraine patients with suicidality were more likely to have a major depressive disorder or generalized anxiety disorder than those without suicidality. Among variables, risk factors for suicidality in migraine patients were female (odds ratio [OR], 4.110; 95% confidence interval [CI], 1.55310.878; p=0.004), attack duration (OR, 2.559; 95% CI, 1.2105.413; p=0.011), Patient Health Questionnaire9 (OR, 1.111; 95% CI, 1.0381.189; p=0.002), and Generalized Anxiety Disorder7 (OR, 1.194; 95% CI, 1.1011.294; p<0.001). @*Conclusions@#Suicidality in migraine patients is common. Therefore, clinicians who take care of migraine patients should be concerned about suicidality and its risk factors such as female gender, attack duration, depression or anxiety.

Surveillance of Close Contacts and Implications of Pediatric Patients with COVID-19–Experiences from a Single Residential Treatment Center

Residential treatment centers (RTCs) are successful in isolating and closely monitoring adults confirmed with coronavirus disease 2019 (COVID-19), but there are concerns for children who need care. This study was conducted as a retrospective analysis of the surveillance of guardians who entered an RTC with infected pediatric patients to identify the secondary attack rate of COVID-19 to close contacts in a single RTC and to provide directions for developing guidelines for caregivers who co-isolate with infected children. When caregivers were admitted to this RTC, aside from negative confirmation before discharge, tests were additionally performed one or two times. There were 57 index children and adolescent patients who entered the RTC with their parents as caregivers. The secondary attack rate by pediatric patients to close contacts outside their households was 25% (95% confidence interval, 10.0 to 40.0) (8 out of 32 contacts). The transmissibility of SARS-CoV-2 in children was close to zero at 6 days after the confirmation tests. It is reasonable to test the close contacts of pediatric patients after 7 days of isolation to identify infections among caregivers.

A Study on the Correlation of Skin Types with Genetic Factors and Environmental Factors in Koreans / 대한피부과학회지

Background@#The Baumann skin type (BST) classification provides a new approach for clinical care of dermatologic patients. @*Objective@#To investigate the correlation of skin types with genetic factors and environmental factors that have an important influence on Korean skin by comparing and analyzing the correlation between phenotype and genotype. @*Methods@#From July to October 2016, 774 adults who visited the one online shopping mall were subjected to skin BST questionnaire and gene single-nucleotide polymorphism (SNP) tests. Oral epithelial cells of the subjects were collected using a Genoplan DNA analysis kit, and 14 genes were analyzed by a genetic analysis agency (Genoplan Inc., Fukuoka, Japan). @*Results@#The most abundant skin type was OSNT (oily, sensitive, non-pigmented, tight) observed in 205 participants (26.5%). Of the filaggrin (FLG) SNPs, 143 participants (18.5%) had the GG (good) SNP; 391 (50.5%), GA (normal) SNP; and 240 (31.0%), AA (poor) SNP. Among those whose FLG SNP was GG (good), 121 (84.6%) were sensitive and 22 (15.4%) were resistant. Of those whose filaggrin (FLG) SNP was GA (normal), 337 (86.2%) were sensitive and 54 (13.8%) were resistant. Of those whose FLG SNP was AA (poor), 213 (88.8%) were sensitive and 27 (11.3%) were resistant. There was also a statistically significant difference in the fruit-vegetable consumption and use of a sunbathing bed between sensitive and resistant type in the groups that classified the FLG SNP as GA. @*Conclusion@#This is the first study to investigate the association of BST with genetic factors and environmental factors.

A Case of African Tick-Bite Fever in a Returning Traveler from Southern Africa / 감염과화학요법

African tick-bite fever (ATBF), caused by Rickettsia africae, is the second most frequent cause of fever after malaria in travelers returning from Southern Africa. As the Korean outbound travelers are increasing every year, tick-borne rickettsial diseases as a cause of febrile illness are likely to increase. We describe a febrile Korean returning traveler who showed two eschars after visiting the rural field in Manzini, Swaziland. We performed nested polymerase chain reaction using the eschar and diagnosed the patient with ATBF. He was treated with oral doxycycline for 7 days, and recovered without any complications. We believe that the present case is the first ATBF case diagnosed in a Korean traveler.

Evaluation and Management of Bone Health in Patients with Thyroid Diseases: a Position Statement from the Korean Thyroid Association

Thyroid hormones have an important physiological role in maintaining adult bone structure and strength. Therefore, thyroid dysfunction is inevitably associated with various degrees of skeletal consequences. Endogenous overt hyperthyroidism is an established cause of high bone turnover with accelerated bone loss, resulting in osteoporosis and an increased risk of fractures. Hyperthyroidism induced by thyroid stimulating hormone suppression therapy in patients with differentiated thyroid cancer also has emerged as a contributing factor to osteoporosis and fragility fractures. While, there is lack of evidence that hypothyroidism negatively affects bone health. Although there is growing clinical evidence of the importance of bone health in hyperthyroidism, clinical guidelines on how to evaluate and manage bone health in these diseases have not yet been published worldwide. The Task Force from the Korean Thyroid Association Committee of Clinical Practice Guideline has developed this position statement for the evaluation and management of bone health in patients with thyroid diseases, particularly focused on endogenous hyperthyroidism and thyroid stimulating hormone suppression therapyassociated hyperthyroidism in patients with differentiated thyroid cancer.

Expression of Estrogen and Progesterone Receptors in Papillary Thyroid Carcinoma in Korea / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#The aim of this study was to examine the rate of expression of estrogen receptor α (ERα) and β1 (ERβ1), progesterone receptor (PR), and rate of overexpression of epidermal growth factor receptor (EGFR) in a relatively large cohort of patients with papillary thyroid carcinoma (PTC). We also aimed to examine whether each receptor influenced clinicopathological characteristics and prognosis of PTC. @*Materials and Methods@#We made a microarray of paraffin-embedded PTC surgical tissues from 436 patients. We compared the results of the immunohistochemical staining for each hormone receptor with clinicopathological characteristics. @*Results@#The positive expression rate of hormonal receptors was 40.4% for ERα, 83.7% for ERβ1, and 71.3% for PR in patients with PTC. Overexpression of EGFR was shown in 19.3% of patients with PTC. The age was lower (44.6±12.1 years vs. 47.1±12.5 years, p=0.040) and tumor smaller (0.96±0.69 cm vs. 1.13±0.82 cm, p=0.020) in the ERα positive group, which also showed higher PR positivity (80.7% vs. 65.0%, p < 0.001) and overexpression of EGFR (27.3% vs. 13.8%, p < 0.001). However, neither the positivity of hormone receptors nor overexpression of EGFR affected the recurrence of PTC. @*Conclusion@#In conclusion, most (94.6%) patients with PTC were found to exhibit positive expression for ERs or PR. We also found that neither the positive expression of hormone receptors nor overexpression of EGFR were associated with the recurrence of PTC.

Developing and Evaluating a Mobile-based Parental Education Program for Preventing Unintentional Injuries in Early Childhood: A Randomized Controlled Trial

Purpose@#This randomized controlled experimental study verified the educational effect of a mobile-based parental education program for preventing unintentional early childhood injuries. @*Methods@#(Design and Methods) From August 2019 to September 2019, 167 participants were recruited from parenting portal sites and randomly assigned to an e-learning group (n = 59), an electronic document distribution (EDD) group (n = 53), and a control group with no intervention (n = 55). Participants self-reported data regarding their safety knowledge and behavior before and after the experiment. Each intervention group received an e-learning program and electronic educational documents for two weeks and a satisfaction survey. Using an ADDIE (Analysis, Design, Development, Implementation, and Evaluation) model, the relevant e-learning contents were developed with the Storyline 360 program. The collected data were analyzed using 1-way ANOVA, 2-way ANOVA, and independent t-test. @*Results@#were as follows: (1) Postintervetion, no significant differences regarding safety knowledge were observed between the e-learning group, EDD group, and control group. (2) Postintervention, statistically significant differences regarding safety behaviors were observed between the three groups: 3.52 ± 0.28 (e-learning group), 3.51 ± 0.28 (EDD group), and 3.32 ± 0.25 (control group) (F = 10.091, p < .001). (3) No significant differences regarding education-related satisfaction were observed. @*Conclusions@#The mobile-based educational program for preventing unintentional injuries positively affected safety behavior in this study. Mobile-based parental education programs could contribute toward effectively preventing unintentional injuries in early childhood because many parents can use these without time and space constraints.

Decreased Maximal Tongue Protrusion Length May Predict the Presence of Dysphagia in Stroke Patients

Objective@#To investigate the relationship between maximal tongue protrusion length (MTPL) and dysphagia in post-stroke patients. @*Methods@#Free tongue length (FTL) was measured using the quick tongue-tie assessment tool and MTPL was measured using a transparent plastic ruler in 47 post-stroke patients. The MTPL-to-FTL (RMF) ratio was calculated. Swallowing function in all patients was evaluated via videofluoroscopic swallowing study (VFSS), PenetrationAspiration Scale (PAS), Functional Oral Intake Scale (FOIS), and Videofluoroscopic Dysphagia Scale (VDS). @*Results@#The MTPL and RMF values were significantly higher in the non-aspirator group than in the aspirator group (MTPL, p=0.0049; RMF, p<0.001). MTPL and RMF showed significant correlations with PAS, FOIS and VDS scores. The cut-off value in RMF for the prediction of aspiration was 1.56, with a sensitivity of 84% and a specificity of 86%. @*Conclusion@#There is a relationship between MTPL and dysphagia in post-stroke patients. MTPL and RMF can be useful for detecting aspiration in post-stroke patients.

Effect of Foot Orthoses in Children With Symptomatic Flexible Flatfoot Based on Ultrasonography of the Ankle Invertor and Evertor Muscles

Objective@#To examine the changes in the cross-sectional area (CSA) ratio of the ankle invertors and evertors following rigid foot orthosis (RFO) application in children with symptomatic flexible flatfoot and to determine the correlation between the degree of change in CSA ratio and pain-severity after RFO application. @*Methods@#We included 24 children with symptomatic flexible flatfoot without comorbidities and measured the CSAs of tibialis anterior (TA), tibialis posterior (TP), and peroneus longus (PL) using ultrasonography, resting calcaneal stance position (RCSP) angle, calcaneal pitch (CP), Meary’s angle, talonavicular coverage angle, and talocalcaneal angle using radiography, and foot function index (FFI) at baseline and 12 months after RFO application. We analyzed 48 data by measuring both feet of 24 children. The CSA ratios, the ratio of CSA of each muscle to the sum of CSA of TA, TP, and PL, were also compared. Correlations between the degree of change in FFI, each muscle’s CSA ratio, RCSP angle, and radiographic measurements were investigated. @*Results@#Following RFO application, significant increase in the PL ratio and CP and significant decrease in the RCSP angle, FFI total, pain, and disability scores were observed. The degree of change in the total score, pain, and disability score of FFI were significantly correlated with the degree of change in the PL ratio and RCSP angle. @*Conclusion@#RFOs applied to children with symptomatic flexible flatfoot might reduce the compensatory activities of the ankle invertors, thereby increasing the PL ratio, and pain decreases as the PL ratio increases.