1.Successful Realignment Arthrodesis using a Superconstruct Technique and Adjuvant Denosumab in Severe Midfoot Charcot Neuroarthropathy:A Case Report
Inuk KIM ; Yeo Kwon YOON ; Seung Hwan HAN ; Jin Woo LEE ; Dong Woo SHIM ; Kwang Hwan PARK
Journal of Korean Foot and Ankle Society 2026;30(1):38-42
Severe midfoot Charcot neuroarthropathy (CN) presents a significant surgical challenge because of extensive bone loss and poor bone quality. This report presents the outcome of a case treated with realignment arthrodesis using a superconstruct technique, supplemented by the postoperative use of denosumab. A patient with Eichenholtz Stage III CN (Brodsky Type 1 and 2) underwent a single-stage surgical reconstruction. Postoperatively, denosumab was administered to enhance bone stability. The 1-year and 1-month follow-up showed that the severe deformity had been successfully corrected to a stable, plantigrade foot, confirmed by radiographic and clinical evaluation.This case suggests that a combined surgical approach using a superconstruct with adjuvant denosumab can be an effective treatment for severe midfoot CN.
2.Minimally Invasive Surgery for Hallux Valgus: Current Concept Review
Yeo Kwon YOON ; Dong Woo SHIM ; Seung Hwan HAN ; Jin Woo LEE ; Gi Won CHOI ; Kwang Hwan PARK
Journal of Korean Foot and Ankle Society 2026;30(1):6-13
Minimally invasive surgery (MIS) for hallux valgus correction has become increasingly popular over the past decade as an alternative to traditional open osteotomy techniques. Following the limitations of first- and second-generation percutaneous techniques, third-generation MIS, characterized by percutaneous osteotomy with a Shannon burr and stable screw fixation, has shown improved reproducibility and clinical outcomes. This review summarizes the current concepts of third-generation and later MIS techniques for hallux valgus correction, focusing on the surgical principles, technical considerations, fixation strategies, and postoperative management. In addition, the clinical and radiographic outcomes of MIS are compared with conventional open osteotomies. The available evidence consistently shows that MIS provides comparable deformity correction, functional improvement, complication rates, and recurrence rates to those of open procedures, while offering advantages such as reduced early postoperative pain, smaller incisions, and faster recovery. Recent studies support expanding MIS indications to include severe hallux valgus deformities that can provide satisfactory correction and acceptable complication profiles when appropriate techniques and fixation methods are used. Despite the ongoing debates regarding the optimal osteotomy type, fixation strategy, and proximal correction in severe deformities, MIS has emerged as a safe and effective surgical option across a broad spectrum of hallux valgus severity. Continued refinement of the surgical techniques, broader application across a wide range of hallux valgus etiologies, and long-term outcome data will further define the role of MIS in hallux valgus surgery.
3.Tibiotalocalcaneal Arthrodesis Using a Retrograde Intramedullary Nail without Subtalar Joint Preparation after Failed Total Ankle Arthroplasty
Yeo Kwon YOON ; Kwang Hwan PARK ; Dong Woo SHIM ; Seung Hwan HAN ; Jin Woo LEE
Clinics in Orthopedic Surgery 2026;18(1):151-158
Background:
Tibiotalocalcaneal (TTC) arthrodesis is a viable salvage option for failed total ankle arthroplasty (TAA), but it is typically a complex procedure associated with a high complication rate. This study analyzed outcomes of salvage TTC arthrodesis using a retrograde intramedullary (IM) nail without subtalar joint preparation after failed TAA.
Methods:
This study included 18 patients (18 ankles) who underwent TTC arthrodesis without subtalar joint preparation for failed TAA from July 2008 to March 2023 and were followed up for at least 2 years. Visual analog scale pain scores and Ankle Osteoarthritis Scale pain and disability scores were used to assess functional outcomes. Radiographic union, time to union, complications, and clinical success—defined as pain improvement without the need for revision surgery or amputation—were also evaluated.
Results:
The mean follow-up duration after TTC arthrodesis was 79.8 months (range, 26–199 months). Tibiotalar joint union was achieved in 13 ankles (72.2%) at a mean of 7.5 months after TTC arthrodesis. Subtalar joint union was achieved in 7 ankles (38.9%). All functional scores improved significantly from preoperatively to the last follow-up. The overall clinical success rate was 83.3% (15 ankles).
Conclusions
TTC arthrodesis using a retrograde IM nail without subtalar joint preparation produced favorable outcomes in patients with failed TAA. No complications associated with the subtalar joint were observed in any patient during follow-up. Therefore, TTC arthrodesis using a retrograde IM nail without subtalar joint preparation may be a considerable salvage option for failed TAA.
4.Total Ankle Arthroplasty in Rheumatoid Arthritis:Clinical Outcomes and Prosthesis Survivorship with Mean 8-Year Follow-up
Yeo Kwon YOON ; Dong Woo SHIM ; Seung Hwan HAN ; Kwang Hwan PARK ; Jin Woo LEE
Yonsei Medical Journal 2026;67(1):48-55
Purpose:
Total ankle arthroplasty (TAA) is a surgical option for end-stage ankle arthritis, including that caused by rheumatoid arthritis (RA). However, concerns persist regarding postoperative complications associated with inflammatory responses and immunosuppression in patients with RA. This study evaluated clinical outcomes and prosthesis survivorship in RA patients who underwent TAA for painful ankle arthritis.
Materials and Methods:
Thirty-four consecutive TAAs performed in RA patients with a minimum follow-up of 2 years were included and reviewed retrospectively. The visual analog scale for pain, ankle osteoarthritis scale pain and disability subscores, and ankle range of motion were used to assess clinical outcomes. Prosthesis survivorship, reoperations, complications, and risk factors were also analyzed.
Results:
The mean follow-up duration was 95.5 months (range, 26–221 months). All clinical scores significantly improved from preoperative values to the final follow-up. Revision surgery was performed on 6 ankles (17.6%), and 1 ankle (2.9%) failed due to deep infection. No minor wound complications were observed. Kaplan–Meier survival analysis demonstrated prosthesis survivorship rates of 97.4% at both 5 and 10 years postoperatively, and revision-free survivorship rates of 81.5% at 5 years and 74.7% at 10 years.No individual factor was significantly associated with revision.
Conclusion
Mobile-bearing TAA resulted in favorable clinical outcomes and high prosthesis survivorship in RA patients. No disease-specific factor was associated with revision surgery. These findings support TAA as a viable surgical option for RA patients with painful end-stage ankle arthritis.
5.Minimally Invasive Correctional Osteotomy for Severe Hallux Valgus with Metatarsus Adductus: A Case Report
Inuk KIM ; Dong Woo SHIM ; Seung Hwan HAN ; Jin Woo LEE ; Yeo Kwon YOON ; Kwang Hwan PARK
Journal of Korean Foot and Ankle Society 2025;29(4):181-184
Hallux valgus (HV) accompanied by metatarsus adductus (MA) is a surgical challenge because of its anatomical characteristics, often presenting with a high hallux valgus angle (HVA) despite a low intermetatarsal angle (IMA). This case report describes a 66-year-old female who presented with a 15-year history of left foot pain and deformity. The radiographs revealed an HVA of 45.0° and a low IMA of 7.2°, consistent with concomitant MA. Instead of a traditional proximal osteotomy for severe HV, the patient underwent a minimally invasive transverse distal metatarsal osteotomy along with distal metatarsal minimally invasive osteotomies (DMMOs) of the lesser metatarsals. At the 2-year follow-up, the radiographs showed excellent correction (HVA 12.5°, IMA 1.0°). The patient was asymptomatic and reported high functional and cosmetic satisfaction. This case shows that a minimally invasive transverse distal metatarsal osteotomy, combined with adequate ancillary procedures, can achieve a successful correction even in complex, severe HV with MA.
6.A Novel Approach to Total Ankle Arthroplasty with Simultaneous Structural Tibial Cut Autograft for Anterior Tibial Bone Defects
Yeo Kwon YOON ; Kwang Hwan PARK ; Dong Woo SHIM ; Wonwoo LEE ; Seung Hwan HAN ; Jin Woo LEE
Clinics in Orthopedic Surgery 2024;16(4):674-678
Severe bone defects pose a clinical challenge in total ankle arthroplasty (TAA) and are frequently considered contraindicated. We introduce an innovative approach that utilizes a structural tibial cut autograft to address anterior distal tibia bone defects during TAA. This technique is a viable alternative to employing revision TAA systems or resorting to excessively high tibial cuts. Furthermore, it facilitates achieving favorable sagittal alignment and ensures adequate fixation strength of the tibial component.
8.Early Prediction of Mortality for Septic Patients Visiting Emergency Room Based on Explainable Machine Learning: A Real-World Multicenter Study
Sang Won PARK ; Na Young YEO ; Seonguk KANG ; Taejun HA ; Tae-Hoon KIM ; DooHee LEE ; Dowon KIM ; Seheon CHOI ; Minkyu KIM ; DongHoon LEE ; DoHyeon KIM ; Woo Jin KIM ; Seung-Joon LEE ; Yeon-Jeong HEO ; Da Hye MOON ; Seon-Sook HAN ; Yoon KIM ; Hyun-Soo CHOI ; Dong Kyu OH ; Su Yeon LEE ; MiHyeon PARK ; Chae-Man LIM ; Jeongwon HEO ; On behalf of the Korean Sepsis Alliance (KSA) Investigators
Journal of Korean Medical Science 2024;39(5):e53-
Background:
Worldwide, sepsis is the leading cause of death in hospitals. If mortality rates in patients with sepsis can be predicted early, medical resources can be allocated efficiently. We constructed machine learning (ML) models to predict the mortality of patients with sepsis in a hospital emergency department.
Methods:
This study prospectively collected nationwide data from an ongoing multicenter cohort of patients with sepsis identified in the emergency department. Patients were enrolled from 19 hospitals between September 2019 and December 2020. For acquired data from 3,657 survivors and 1,455 deaths, six ML models (logistic regression, support vector machine, random forest, extreme gradient boosting [XGBoost], light gradient boosting machine, and categorical boosting [CatBoost]) were constructed using fivefold cross-validation to predict mortality. Through these models, 44 clinical variables measured on the day of admission were compared with six sequential organ failure assessment (SOFA) components (PaO 2 /FIO 2 [PF], platelets (PLT), bilirubin, cardiovascular, Glasgow Coma Scale score, and creatinine).The confidence interval (CI) was obtained by performing 10,000 repeated measurements via random sampling of the test dataset. All results were explained and interpreted using Shapley’s additive explanations (SHAP).
Results:
Of the 5,112 participants, CatBoost exhibited the highest area under the curve (AUC) of 0.800 (95% CI, 0.756–0.840) using clinical variables. Using the SOFA components for the same patient, XGBoost exhibited the highest AUC of 0.678 (95% CI, 0.626–0.730). As interpreted by SHAP, albumin, lactate, blood urea nitrogen, and international normalization ratio were determined to significantly affect the results. Additionally, PF and PLTs in the SOFA component significantly influenced the prediction results.
Conclusion
Newly established ML-based models achieved good prediction of mortality in patients with sepsis. Using several clinical variables acquired at the baseline can provide more accurate results for early predictions than using SOFA components. Additionally, the impact of each variable was identified.
9.Evaluation of the Current Urgency-Based Lung Allocation System in Korea with Simulation of the Eurotransplant Lung Allocation Score
Woo Sik YU ; Sun Mi CHOI ; Hye Ju YEO ; Dong Kyu OH ; Sung Yoon LIM ; Young Tae KIM ; Kyeongman JEON ; Jin Gu LEE
Yonsei Medical Journal 2024;65(8):463-471
Purpose:
Due to the shortage of lung donors relative to the number of patients waiting for lung transplantation (LTx), more than one-third of patients on the waitlist have died without receiving LTx in Korea. Therefore, the importance of fair and effective allocation policies has been emphasized. This study investigated the characteristics of the current urgency-based allocation system in Korea by simulating the Eurotransplant lung allocation score (ET-LAS) using a nationwide multi-institutional registry for LTx in Korea.
Materials and Methods:
This study used data from the Korean Organ Transplantation Registry (KOTRY), along with additional retrospective data for ET-LAS calculation. A total of 194 patients were included in this study between January 2015 and December 2019. The Korean urgency definition classifies an LTx candidate as having statuses 0–3 according to urgency. The ET-LAS was analyzed according to the Korean urgency status.
Results:
In total, 92 patients received lung transplants at status 0, 85 at status 1, and 17 at status 2/3. The ET-LAS showed a bimodal distribution with distinct peaks corresponding to status 0 and non-status 0. There was no significant difference in the ET-LAS among non-status 0 patients. In logistic and decision tree analyses, oxygen supplementation methods, particularly oxygen masks and high-flow nasal cannulas, were significantly associated with a high ET-LAS (≥50) among non-status 0 patients.
Conclusion
Simulation of the ET-LAS with KOTRY data showed that the Korean urgency definition may not allocate lungs by urgency, especially for patients in non-status 0; therefore, it needs to be revised.
10.Real-World Study of Osimertinib in Korean Patients with Epidermal Growth Factor Receptor T790M Mutation–Positive Non–Small Cell Lung Cancer
Jang Ho LEE ; Eun Young KIM ; Cheol-Kyu PARK ; Shin Yup LEE ; Min ki LEE ; Seong-Hoon YOON ; Jeong Eun LEE ; Sang Hoon LEE ; Seung Joon KIM ; Sung Yong LEE ; Jun Hyeok LIM ; Tae-Won JANG ; Seung Hun JANG ; Kye Young LEE ; Seung Hyeun LEE ; Sei Hoon YANG ; Dong Won PARK ; Chan Kwon PARK ; Hye Seon KANG ; Chang Dong YEO ; Chang-Min CHOI ; Jae Cheol LEE
Cancer Research and Treatment 2023;55(1):112-122
Purpose:
Although osimertinib is the standard-of-care treatment of epidermal growth factor receptor (EGFR) T790M mutation–positive non–small cell lung cancer, real-world evidence on the efficacy of osimertinib is not enough to reflect the complexity of the entire course of treatment. Herein, we report on the use of osimertinib in patients with EGFR T790M mutation–positive non–small cell lung cancer who had previously received EGFR tyrosine kinase inhibitor (TKI) treatment in Korea.
Materials and Methods:
Patients with confirmed EGFR T790M after disease progression of prior EGFR-TKI were enrolled and administered osimertinib 80 mg daily. The primary effectiveness outcome was progression-free survival, with time-to-treatment discontinuation, treatment and adverse effects leading to treatment discontinuation, and overall survival being the secondary endpoints.
Results:
A total of 558 individuals were enrolled, and 55.2% had investigator-assessed responses. The median progression-free survival was 14.2 months (95% confidence interval [CI], 13.0 to 16.4), and the median time-to-treatment discontinuation was 15.0 months (95% CI, 14.1 to 15.9). The median overall survival was 36.7 months (95% CI, 30.9 to not reached). The benefit with osimertinib was consistent regardless of the age, sex, smoking history, and primary EGFR mutation subtype. However, hepatic metastases at the time of diagnosis, the presence of plasma EGFR T790M, and the shorter duration of prior EGFR-TKI treatment were poor predictors of osimertinib treatment. Ten patients (1.8%), including three with pneumonitis, had to discontinue osimertinib due to severe adverse effects.
Conclusion
Osimertinib demonstrated its clinical effectiveness and survival benefit for EGFR T790M mutation–positive in Korean patients with no new safety signals.

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