Is the May-Thurner Syndrome a Major Risk Factor for Deep Vein Thrombosis in Total Hip Arthroplasty?

Background: May-Thurner syndrome (MTS) is iliac vein compression syndrome associated with postoperative deep vein thrombosis (DVT) resulting from chronic compression of the left iliac vein against lumbar vertebrae by the overlying right or left common iliac artery. MTS is not well known as a risk factor for DVT after total hip arthroplasty (THA). We evaluated the incidence of DVT after THA and analyzed if the MTS is a risk factor for DVT after THA. We hypothesized that MTS would be associated with an increased risk of developing DVT after THA. Methods: All patients > 65 years of age who underwent THA between January 1, 2009, and January 12, 2017, were identified. Among them, the patients who presented for postoperative DVT of the lower extremity were reviewed with medical record data. MTS was diagnosed with computed tomography (CT) angiography of the lower extremity. We analyzed the demographic data, symptoms, diagnoses, and treatment of MTS patients. Results: A total of 492 consecutive patients aged > 65 years who underwent operation for THA were enrolled. Among them, 5 patients (1.0%) presented for postoperative DVT of the lower extremity. After reviewing the CT angiography of the lower extremity, 4 out of 5 DVT patients (80%) were identified as having MTS. All MTS patients were female and presented with pain and swelling of the left leg. All MTS patients were treated with systemic anticoagulation, aspiration thrombectomy, and percutaneous transluminal angioplasty. Complete resolution of thrombus was observed in all patients. Conclusions: If the diagnosis of MTS is delayed, the morbidity and mortality rates are significantly increased. Orthopedic surgeons should be aware of MTS as a risk factor for DVT after THA. Moreover, preoperative evaluation with duplex sonography or CT angiography to confirm MTS should be considered. In this regard, this study is considered to have sufficient clinical value for early diagnosis and appropriate treatment of MTS after THA.

Is there a difference between preoperative and postoperative delirium in elderly hip fracture patients?: A retrospective case control study.

Delirium is associated with greater morbidity, higher mortality, and longer periods of hospital day after hip fracture. There are number of studies on postoperative delirium after a hip fracture. However, few studies have made a distinction between preoperative and postoperative delirium. The purpose of this study is to compare risk factors and clinical outcome between preoperative and postoperative delirium in elderly patients with a hip fracture surgery. A total of 382 consecutive patients aged > 65 years who underwent operation for hip fracture were enrolled. Among them, the patients diagnosed with delirium were divided into 2 groups (a preoperative delirium group and a postoperative delirium group) according to the onset time of delirium. To evaluate risk factors for preoperative and postoperative delirium, we analyzed demographic data, preoperative laboratory data, and perioperative data. To compare clinical outcomes between preoperative and postoperative delirium, we analyzed postoperative complications, KOVAL score, regression, readmission, and 2-year survival rate. Delirium was diagnosed in 150 (39.3%) patients during hospitalization. Preoperative and postoperative delirium occurred in 67 (44.6%) and 83 (55.4%) patients, respectively. Independent risk factors of preoperative delirium included age (odds ratio: 1.47, 95% confidential interval [CI]: 1.13-2.23, P = .004), stroke (odds ratio [OR]: 2.70, 95% CI: 1.11-6.01, P = .015), American Society of Anesthesiologist (OR: 1.68, 95% CI: 1.137-2.24, P = .033), and time from admission to operation (OR: 1.08, 95% CI: 1.01-1.16, P = .031). There was no significant difference in preoperative KOVAL score between the 2 groups. However, postoperative KOVAL score (5.1 ±â€…2.0 vs 4.4 ±â€…2.1, P = .027) and regression rate (68.7% vs 44.6%, P = .029) were significantly higher in the preoperative delirium group than in the postoperative delirium group. Moreover, the 2-year survival rate was significantly lower in the preoperative delirium group than in the postoperative delirium group (62.7% vs 78.3%, P = .046). Characteristics, risk factors, and prognosis are different for patients with preoperative delirium and postoperative delirium. Preoperative delirium patients showed different risk factors with poorer prognosis and higher mortality. Therefore, hip fracture patients with risk factors for preoperative delirium should be monitored more carefully due to their greater risk of mortality.

METAL ION RELEASE ACCORDING TO LEG LENGTH DISCREPANCY IN CERAMIC-ON-METAL HIP ARTHROPLASTY.

Objective: The ceramic-on-metal (CoM) bearing has the theoretical advantages over ceramic-on-ceramic (CoC) and metal-on-metal bearings. This study aimed to analyze factors affecting the metal ion release of CoM bearings and compare clinical performance with CoC bearings. Methods: The 147 patients were divided into 96 patients in group 1 (CoM group) and 51 patients in group 2 (CoC group). Additionally, within group1, 48 patients and 30 patients were sub-categorized into group 1-A with leg length discrepancy (LLD) less than 1cm and group 1-B greater than 1 cm. The level of serum metal ions, functional scores and plain radiographs were obtained for the analysis. Results: The level of cobalt (Co) 2-years after surgery and chromium (Cr) 1-year after surgery showed significantly higher in the group1 than the group2. LLD indicated statistically significant positive correlation between serum metal ion levels among CoM bearing THAs. In comparison of the average metal ions level changes, group 1-B showed higher level of metal ion than group 1-A. Conclusion: In patients underwent THA with CoM bearings, large LLD have a higher risk of complications associated to metal ions. Therefore, it is critical to reduce the LLD to 1 cm or less in using CoM bearing. Level of Evidence III; Case Control Study.

Objetivo: Uma superfície metalocerâmica (CoM) apresenta vantagens teóricas sobre as superfícies cerâmica-cerâmica (CoC) e metal-metal. Este estudo teve como objetivo analisar os fatores que afetam a liberação de íons metálicos das superfícies CoM e comparar o desempenho clínico com as superfícies CoC. Métodos: Os 147 pacientes foram divididos em 96 pacientes no grupo 1 (grupo CoM) e 51 pacientes no grupo 2 (grupo CoC). No grupo 1, 48 pacientes foram subcategorizados em grupo 1-A, com discrepância de comprimento das pernas (LLD) menor que 1 cm; e 30 pacientes no grupo1-B maior que 1 cm. O nível de íons metálicos séricos, escores funcionais e radiografias foram obtidas para a análise. Resultados: Os níveis de cobalto (Co) 2 anos após a cirurgia e de cromo (Cr), após o primeiro ano da cirurgia mostraram-se significativamente mais altos no grupo 1 do que no grupo 2. A LLD indicou correlação positiva estatisticamente significativa entre os níveis de íons do soro metálico entre os portadores de THA de CoM. Em comparação com as alterações médias dos níveis de íons metálicos, o grupo 1-B revelou um nível de íons metálicos mais alto do que o grupo 1-A. Conclusão: Em pacientes submetidos a THA com superfícies CoM e elevada LLD têm um maior risco de complicações associadas a íons metálicos. Sendo fundamental reduzir LLD para 1 cm ou menos no uso de superfícies CoM. Nível de Evidência III; Estudo de Controle de Caso.

Metal ion release according to leg length discrepancy in ceramic-on-metal hip arthroplasty / Liberação de íons metálicos segundo discrepância no comprimento da perna após artroplastia metal-cerâmica total de quadril

ABSTRACT Objective The ceramic-on-metal (CoM) bearing has the theoretical advantages over ceramic-on-ceramic (CoC) and metal-on-metal bearings. This study aimed to analyze factors affecting the metal ion release of CoM bearings and compare clinical performance with CoC bearings. Methods The 147 patients were divided into 96 patients in group 1 (CoM group) and 51 patients in group 2 (CoC group). Additionally, within group1, 48 patients and 30 patients were sub-categorized into group 1-A with leg length discrepancy (LLD) less than 1cm and group 1-B greater than 1 cm. The level of serum metal ions, functional scores and plain radiographs were obtained for the analysis. Results The level of cobalt (Co) 2-years after surgery and chromium (Cr) 1-year after surgery showed significantly higher in the group1 than the group2. LLD indicated statistically significant positive correlation between serum metal ion levels among CoM bearing THAs. In comparison of the average metal ions level changes, group 1-B showed higher level of metal ion than group 1-A. Conclusion In patients underwent THA with CoM bearings, large LLD have a higher risk of complications associated to metal ions. Therefore, it is critical to reduce the LLD to 1 cm or less in using CoM bearing. Level of Evidence III; Case Control Study.

RESUMO Objetivo Uma superfície metalocerâmica (CoM) apresenta vantagens teóricas sobre as superfícies cerâmica-cerâmica (CoC) e metal-metal. Este estudo teve como objetivo analisar os fatores que afetam a liberação de íons metálicos das superfícies CoM e comparar o desempenho clínico com as superfícies CoC. Métodos Os 147 pacientes foram divididos em 96 pacientes no grupo 1 (grupo CoM) e 51 pacientes no grupo 2 (grupo CoC). No grupo 1, 48 pacientes foram subcategorizados em grupo 1-A, com discrepância de comprimento das pernas (LLD) menor que 1 cm; e 30 pacientes no grupo1-B maior que 1 cm. O nível de íons metálicos séricos, escores funcionais e radiografias foram obtidas para a análise. Resultados Os níveis de cobalto (Co) 2 anos após a cirurgia e de cromo (Cr), após o primeiro ano da cirurgia mostraram-se significativamente mais altos no grupo 1 do que no grupo 2. A LLD indicou correlação positiva estatisticamente significativa entre os níveis de íons do soro metálico entre os portadores de THA de CoM. Em comparação com as alterações médias dos níveis de íons metálicos, o grupo 1-B revelou um nível de íons metálicos mais alto do que o grupo 1-A. Conclusão Em pacientes submetidos a THA com superfícies CoM e elevada LLD têm um maior risco de complicações associadas a íons metálicos. Sendo fundamental reduzir LLD para 1 cm ou menos no uso de superfícies CoM. Nível de Evidência III; Estudo de Controle de Caso.

Differences in Acetabular Morphology Related to Sex and Side in South Korean Population.

Background: The normal references for acetabular parameters are important for the diagnosis of hip diseases and planning of total hip arthroplasty. There are wide interindividual differences in acetabular morphology in the normal population, and little is known about differences in acetabular morphology in the average South Korean population. The purpose of this study was to evaluate side and sex differences in acetabular morphology in the South Korean population. Methods: The acetabular parameters, including anteversion angle, abduction angle, center-edge angle, acetabular width and depth, and acetabular-head index, were measured on three-dimensional computed tomography images in 197 healthy Korean adults. Differences in acetabular parameters according to side and sex were evaluated. Results: The mean acetabular anteversion angle of men and women was 17.3° ± 5.2° and 20.1° ± 3.5°, respectively. The mean acetabular width of men and women was 61.5 ± 4.6 cm and 56.5 ± 4.0 cm, respectively. There were significant sex differences in acetabular anteversion angle (p = 0.001) and acetabular width (p = 0.036) when adjusted for age, body height, and weight. The mean acetabular width of the right side and the left side was 60.2 ± 5.2 cm and 57.8 ± 4.5 cm, respectively. There were significant side differences in acetabular width (p = 0.007) when adjusted for age, body height, weight, and sex. Conclusions: Differences and reference ranges of acetabular parameters are important for the diagnosis of acetabular deformity, such as femoroacetabular impingement and acetabular dysplasia. Moreover, these differences and reference ranges are useful for preoperative planning and safe positioning of acetabular components in total hip arthroplasty.

Identification of Stem Cell Related Gene Expression from the Osteosarcoma Cell Core Side.

Osteosarcoma is the most frequent primary malignant bone tumor with higher incidences in children and adolescents. Despite clinical evolutions, patients with osteosacoma have had a poor prognosis. There has been increasing evidence that cancer is a stem cell disease. This study sought to isolate and characterize cancer stem cells from human osteosarcoma with relevant literature reviews. Here we show that the emerging evidence suggests osteosarcoma should be regarded as a differentiation disease such as stem cell disease. Two human osteosarcoma cell lines were cultured in non-adherent culture conditions as sarcospheres. Sarcospheres were observed using histomorphology and alkaline phosphatase (ALP) staining. Expression of the embryonic stem cell marker was analyzed with use of reverse transcriptase-PCR. Sarcospheres could be reproduced consistently throughout multiple passages and produced adherent osteosarcoma cell cultures. Expression of stem cell-associated genes such as those encoding Nanog, octamer-binding transcription factor 3/4, sex determining region Y box 2 , c-Myc and ALP indicated pluripotent stem-like cells. These results support the extension of the cancer stem cell theory to include osteosarcoma. Understanding the cancer stem cell derived from human osteosarcoma could lead to the evolution of diagnosis and treatment for osteosarcoma patients.

Long-Term Clinical and Radiological Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion: 10-Year Follow-up Results.

BACKGROUND: Many studies have reported that minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) provides satisfactory treatment comparable to other fusion methods. However, in the case of MI-TLIF, there are concerns about the long-term outcome compared to conventional bilateral PLIF due to the small amount of disc removal and the lack of autogenous bone graft. Long-term follow-up studies are still lacking as most of the previous reports have follow-up periods of up to 5 years. METHODS: Thirty patients who underwent MI-TLIF were followed up for > 10 years (mean, 11.1 years). Interbody fusion rates were determined using a modified Bridwell grading system. Adjacent segment disease (ASD) was defined as radiological adjacent segment degeneration (R-ASDeg) as seen on plain X-rays; reoperated adjacent segment disease referred to the subsequent need for revision surgery. Clinical outcomes after surgery were assessed based on back and leg pain as well as the Oswestry disability index (ODI). RESULTS: The overall radiological fusion rate, at the 1-, 5-, and 10-year follow-up was 77.1%, 91.4%, and 94.3%, respectively. The incidence of R-ASDeg 1, 5, and 10 years after surgery was 6.7%, 16.7%, and 43.3% at the proximal adjacent segment and 4.8%, 14.3%, and 28.6% at the distal adjacent segment, respectively. R-ASDeg at either the proximal or distal segment was determined in 50.0% of the patients 10 years postoperatively. All clinical parameters improved significantly during follow-up, although the ODI and the visual analog scale (VAS) for leg pain at the 10-year follow-up were significantly worse in the R-ASDeg group than in the other patients (P = 0.009, P = 0.040). CONCLUSION: MI-TLIF improved both clinical and radiological outcomes, and the improvements were maintained for up to 10 years after surgery. However, R-ASDeg developed in up to 50% of the patients within 10 years, and both leg pain on the VAS and the ODI were worse in patients with R-ASDeg.

Comparative Study of Radiological and Clinical Outcomes in Patients Undergoing Minimally Invasive Lateral Lumbar Interbody Fusion Using Demineralized Bone Matrix Alone or with Low-Dose Escherichia coli-Derived rhBMP-2.

OBJECTIVE: To compare the results of interbody fusion in patients undergoing minimally invasive lateral lumbar interbody fusion (LLIF) using demineralized bone matrix (DBM) alone versus DBM+recombinant human bone morphogenetic protein-2 (rhBMP2). METHODS: This retrospective case-controlled study was conducted in patients undergoing minimally invasive LLIF (n = 54) for lumbar interbody fusion; they were divided into 2 groups: DBM-only group and DMB+rhBMP2 group. The improvements of segmental and lumbar lordosis and restoration of disc height were measured, and the interbody fusion rates were determined using a modified Bridwell grading system. Clinical outcomes after surgery, such as visual analog scale scores of back pain and leg pain, and Oswestry disability index were compared. RESULTS: There were no significant differences in disc height, lumbar and segmental lordosis, or interbody fusion rate between the 2 groups. However, the proportion of Bridwell grade 1 as complete interbody bridging was higher in the DBM+rhBMP2 group than in the DBM-only group at both 6 and 12 months (P < 0.001). Clinical parameters showed equally significant improvement during follow-up in both groups, with no significant differences between the groups. CONCLUSION: In minimally invasive LLIF, adding Escherichia coli-derived rhBMP2 to DBM did not affect clinical outcomes or radiation parameters, but increased the speed of fusion and interbody bony bridging rate.

Comparison of Minimally Invasive Lateral Lumbar Interbody Fusion, Minimally Invasive Lateral Lumbar Interbody Fusion, and Open Posterior Lumbar Interbody Fusion in the Treatment of Single-Level Spondylolisthesis of L4-L5.

OBJECTIVE: To compare the outcomes of minimally invasive lateral lumbar interbody fusion (LLIF) with minimally invasive transforaminal lumbar interbody fusion (TLIF) and conventional open posterior lumbar interbody fusion (PLIF) for treating single-level spondylolisthesis at L4-L5. METHODS: The patients underwent minimally invasive LLIF (n = 18), minimally invasive TLIF (n = 17), and conventional open PLIF (n = 20) for spondylolisthesis at L4-L5. Reduction of slippage, improvement in segmental lordosis, and restoration of foraminal height were measured. Perioperative parameters such as blood loss and operation time and clinical outcomes such as visual analog scale score and Oswestry Disability Index were compared. RESULTS: Compared with the open PLIF group, the minimally invasive LLIF group showed greater restoration of mean foraminal height, significantly smaller mean intraoperative estimated blood loss, and less mean hemoglobin reduction on the third day postoperatively. Compared with the minimally invasive TLIF group, the minimally invasive LLIF group showed greater restoration of mean segmental lordosis. The minimally invasive LLIF group showed a significantly shorter mean time to start walking after surgery compared with the conventional open PLIF and minimally invasive TLIF groups. However, compared with the minimally invasive TLIF group, the minimally invasive LLIF group showed a significantly longer mean operating time. Clinical outcomes were not statistically different among the 3 groups. CONCLUSIONS: In the treatment of spondylolisthesis of L4-L5, minimally invasive LLIF provided an effective surgical alternative to minimally invasive TLIF or conventional open PLIF, with the advantages of less blood loss, the faster start of postoperative walking, and comparable improvement in radiologic parameters.

Preoperative Vitamin D Deficiency is Associated with Postoperative Functional Recovery and Complications after Hip Fracture Surgery.

BACKGROUND: Low concentrations of vitamin D are considered one of the risk factors for hip fracture and are associated with worse outcomes. The purpose of this retrospective study was to compare vitamin D deficient group and vitamin D sufficient group and assess the association preoperative vitamin D deficiency and postoperative walking ability after hip fracture surgery. METHODS: Between January 2014 and January 2020, 1,029 elderly patients with hip fracture (243 in men and 785 in women) were measured preoperative serum 25-hydroxy-vitamin D3 levels. Among 1,029 elderly patients, 702 patients were classified as Vitamin D deficient group (<20 ng/mL). Outcome parameters for functional recovery were the length of the hospital stay and KOVAL score, and those for complications were delirium, pneumonia, and thromboembolism. RESULTS: The mean length of the hospital stay in the vitamin D deficient group was significantly longer than in the vitamin D sufficient group (27.7±17.8 vs. 2.9±11.8 days; odds ratio [OR], 1.03; 95% confidence interval [CI], 1.02-1.05; P=0.001). The mean postoperative KOVAL score in the deficient group was significantly higher than in the sufficient group (4.0±2.1 vs. 3.1±1.9 days; OR, 1.21; 95% CI, 1.11-1.32; P=0.001). Vitamin D deficiency was significantly associated with a higher risk of delirium and pneumonia in deficiency group. CONCLUSIONS: Preoperative vitamin D deficiency in hip fractures patients was associated with prolonged duration of hospital stay and decrease of postoperative ambulatory status, and may increase the risk of delirium and pneumonia. Therefore, it is necessary to evaluate the preoperative vitamin D level and recommend vitamin D supplementation in elderly patients with a high probability of hip fracture.

Unique Form of Atypical Subtrochanteric Femoral Fracture at the Medial Cortex: A Report of 3 Cases.

CASE: Three women with unique subtrochanteric femoral fracture occurring at the medial cortex of the femur are presented. One patient had been on drug holiday for the past 2 years after 3 years of risedronate use; the other patients had been taking alendronate for osteoporosis for 4 years and 20 years without drug holiday. CONCLUSION: The fractures met all major criteria for the revised case definition of atypical femoral fracture (AFF) provided by the American Society of Bone and Mineral Research task force except for the location. Hence, we report 3 cases of AFFs developing in the subtrochanteric medial femoral cortex.

Three-dimensional analysis of volumetric changes in herniated discs of the lumbar spine: does spontaneous resorption of herniated discs always occur?

PURPOSE: To investigate volumetric changes in lumbar disc herniation (LDH) using three-dimensional measurements obtained by magnetic resonance imaging (MRI) and to identify possible factors affecting such changes. METHODS: Between January 2004 and December 2011, 43 patients who underwent conservative treatment for LDH were enrolled. In all, 56 disc levels were investigated. MRI was performed on two or more occasions (minimally, at the initial visit and 6 months later). The volume of each herniated disc was determined. For each patient, disc migration, morphology, initial LDH size, and clinical outcome were evaluated. RESULTS: The mean volumes of herniated discs at the initial and follow-up visits were 1,304.57 ± 837.99 and 993.84 ± 610.04 mm(3), respectively. The mean change in volume from the initial to the follow-up visit was 310.73 ± 743.60 mm(3). Volumes decreased at 35 disc levels and increased at 21 levels. The disc containment, the extent of LDH, the initial size of the herniated disc, and the degree of intactness of the posterior longitudinal ligament were significantly correlated with disc resorption and an increase in disc volume (p = 0.01, p = 0.018, p = 0.001, and p < 0.001, respectively). No significant association was evident between disc volumetric change and clinical outcome. CONCLUSIONS: We observed that LDH is a dynamic disease and that a herniated disc is not always spontaneously resorbed, in contrast to what has been reported previously. Alleviation of clinical symptoms can be achieved via conservative treatment even if the volume of the herniated disc changes. Spinal surgeons should not only present an option of initial non-surgical treatment to LDH patients but should also inform them that the LDH may change in size during daily activity or exercise.

Factors associated with clinical and structural outcomes after arthroscopic rotator cuff repair with a suture bridge technique in medium, large, and massive tears.

BACKGROUND: This study was conducted to evaluate clinical outcomes, maintenance of repair integrity, and retear rate after arthroscopic rotator cuff repair by a suture bridge technique among patients with medium, large, and massive rotator cuff tears. METHODS: We evaluated 147 patients who had undergone arthroscopic rotator cuff repair. Clinical and functional evaluations were performed with the Constant and University of California-Los Angeles scores. All patients were confirmed to have magnetic resonance imaging evidence of tendon healing at least 12 months postoperatively. RESULTS: The average postoperative time to follow-up magnetic resonance imaging was 23.4 months (range, 12-48 months). A total of 25 (17.0%) retears were observed. All clinical outcome scores were improved significantly at follow-up. Larger intraoperative tear sizes were correlated with higher retear rates. The incidence of retear was also higher in cases in which the preoperative fatty degeneration grade was higher. The incidence of retear increased with age and in the heavy worker group (e.g., farmers, carriers, car mechanics) but was not statistically significant. CONCLUSIONS: Arthroscopic rotator cuff repair by a suture bridge technique yields improvements in clinical outcome measures and a relatively high degree of patient satisfaction despite the fact that repair integrity is not maintained in many cases.

Frontomaxillary facial angle measurements in euploid Korean fetuses at 11 weeks' to 13 weeks 6 days' gestation.

OBJECTIVE: The purpose of this study was to evaluate the distribution of fetal frontomaxillary facial angles in a euploid Korean population at 11 weeks' to 13 weeks 6 days' gestation. METHODS: Three-dimensional volumes of the fetal head were obtained from women with low-risk singleton pregnancies at 11 weeks' to 13 weeks 6 days' gestation who consented to this prospective study. Only fetuses with either a normal karyotype confirmed by amniocentesis or no abnormalities after delivery were considered eligible for analysis and were characterized as euploid for the purposes of this study. Women with multiple pregnancies and those who were lost to follow-up and fetuses with abnormal karyotypes or anomalies diagnosed in utero or postnatally were excluded. The frontomaxillary facial angle was measured twice offline by a single examiner. Cases were categorized by crown-rump length (CRL) in 10-mm intervals for analysis of the frontomaxillary facial angle. RESULTS: Among 375 enrolled cases, 158 were eligible for frontomaxillary facial angle analysis. The overall mean frontomaxillary facial angle ± SD was 88.6° ± 9.7°. The mean frontomaxillary facial angle for fetuses with a CRL of 40 to 49 mm (n = 35) was 93.7°; 50 to 59 mm (n = 53), 92.6°; 60 to 69 mm (n = 36), 85.3°; and 70 to 79 mm (n = 34), 81.0°, showing an inverse relationship between the mean frontomaxillary facial angle and CRL (r = -0.5334; P < .0001). The proportion of cases with frontomaxillary facial angles of 85° or greater was 60.8%, and that of cases with angles of 90° or greater was 37.3%. CONCLUSIONS: Ethnic differences in frontomaxillary facial angle measurements should be considered when incorporating the frontomaxillary facial angle in fetal aneuploidy screening in the Korean population.