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.Stress Accelerates Depressive-Like Behaviors through Increase of Notch2 Expression in N141I Mutation Presenilin-2 Transgenic Mice
Seung Sik YOO ; Sun Mi GU ; Kyung Tak NAM ; Jeong Soon CHOI ; Yong Sun LEE ; In Jun YEO ; Ji Eun YU ; Sanghyeon KIM ; Dong Won LEE ; Hyeon Joo HAM ; Ju Young CHANG ; Jaesuk YUN ; Dong Ju SON ; Sang-Bae HAN ; Jin Tae HONG
Biomolecules & Therapeutics 2026;34(3):544-555
Alzheimer’s disease (AD) is characterized by progressive cognitive deterioration and significant depression. However, the mechanisms linking depression to AD pathology remain unclear. Here, we investigated whether Notch2 signaling mediates depressionlike behaviors in presenilin-2 (PS2) N141I mutant mice, an early-onset AD model. PS2 wild-type (WT) and mutant (MT) mice aged 12-15 months were subjected to unpredictable chronic mild stress (UCMS) for 4 weeks, followed by sucrose preference, tail-hanging, and forced swimming tests. Behavioral assessments showed that UCMS exacerbated anhedonia and immobility only in PS2 MT mice. Molecular analysis revealed concomitant increases in plasma corticosterone, hippocampal γ-secretase activity, and Notch2 expression, and elevated total and phosphorylated glucocorticoid receptor levels in PS2 MT-UCMS mice. Gene expression profiling of human hippocampal datasets confirmed upregulation of NOTCH2 in Alzheimer’s disease and depression.Pharmacological inhibition of γ-secretase and Notch signaling with DAPT normalizes depressive behavior, reduces corticosterone release, attenuates GR phosphorylation, and inhibits Notch2 signaling in PS2 MT mice. These findings identify Notch2 as a pivotal mediator linking chronic stress to molecular changes associated with depression and AD, and suggest that targeting Notch2 signaling may provide therapeutic benefits for comorbid mood and neurodegenerative disorders.
4.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.
5.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.
6.Relationship between the Geriatric Nutrition Risk Index and the Prognosis of Severe Coronavirus Disease 2019 in Korea
Hye Ju YEO ; Daesup LEE ; Mose CHUN ; Jin Ho JANG ; Sunghoon PARK ; Su Hwan LEE ; Onyu PARK ; Tae Hwa KIM ; Woo Hyun CHO
Tuberculosis and Respiratory Diseases 2025;88(2):369-379
Background:
Malnutrition exacerbates the prognosis of numerous diseases; however, its specific impact on severe coronavirus disease 2019 (COVID-19) outcomes remains insufficiently explored.
Methods:
This multicenter study in Korea evaluated the nutritional status of 1,088 adults with severe COVID-19 using the Geriatric Nutritional Risk Index (GNRI) based on serum albumin levels and body weight. The patients were categorized into two groups: GNRI >98 (no-risk) and GNRI ≤98 (risk). Propensity score matching, adjusted for demographic and clinical variables, was conducted.
Results:
Of the 1,088 patients, 642 (59%) were classified as at risk of malnutrition. Propensity score matching revealed significant disparities in hospital (34.3% vs. 19.4%, p<0.001) and intensive care unit (ICU) mortality (31.5% vs. 18.9%, p<0.001) between the groups. The risk group was associated with a higher hospital mortality rate in the multivariate Cox regression analyses following propensity score adjustment (hazard ratio [HR], 1.64; p=0.001). Among the 670 elderly patients, 450 were at risk of malnutrition. Furthermore, the risk group demonstrated significantly higher hospital (52.1% vs. 29.5%, p<0.001) and ICU mortality rates (47.2% vs. 29.1%, p<0.001). The risk group was significantly associated with increased hospital mortality rates in the multivariate analyses following propensity score adjustment (HR, 1.66; p=0.001).
Conclusion
Malnutrition, as indicated by a low GNRI, was associated with increased mortality in patients with severe COVID-19. This effect was also observed in the elderly population. These findings underscore the critical importance of nutritional assessment and effective interventions for patients with severe COVID-19.
7.Prevalence of New Frailty at Hospital Discharge in Severe COVID-19 Survivors and Its Associated Factors
Jong Hwan JEONG ; Manbong HEO ; Sunghoon PARK ; Su Hwan LEE ; Onyu PARK ; Taehwa KIM ; Hye Ju YEO ; Jin Ho JANG ; Woo Hyun CHO ; Jung-Wan YOO ;
Tuberculosis and Respiratory Diseases 2025;88(2):361-368
Background:
The development of frailty at hospital discharge affects the clinical outcomes in severe coronavirus disease 2019 (COVID-19) survivors who had no frailty before hospitalization. We aimed to describe the prevalence of new frailty using the clinical frailty scale (CFS) and evaluate its associated factors in patients with severe COVID-19 without pre-existing frailty before hospitalization.
Methods:
We performed a secondary analysis of clinical data from a nationwide retrospective cohort collected from 22 hospitals between January 1, 2020 and August 31, 2021. The patients were at least 19 years old and survived until discharge after admission to the intensive care unit (ICU) because of severe COVID-19. Development of new frailty was defined as a CFS score ≥5 at hospital discharge.
Results:
Among 669 severe COVID-19 survivors without pre-existing frailty admitted to the ICU, the mean age was 65.2±12.8 years, 62.5% were male, and 50.2% received mechanical ventilation (MV). The mean CFS score at admission was 2.4±0.9, and new frailty developed in 27.8% (186/483). In multivariate analysis, older age, cardiovascular disease, CFS score of 3–4 before hospitalization, increased C-reactive protein level, longer duration of corticosteroid treatment, and use of MV and extracorporeal membrane oxygenation were identified as factors associated with new-onset frailty.
Conclusion
Our study suggests that new frailty is not uncommon and is associated with diverse factors in survivors of severe COVID-19 without pre-existing frailty.
8.Tanshinone, a Natural NADPH Oxidase Inhibitor, Mitigates Testosterone-Induced Hair Loss
Yeo Kyu HUR ; Jin Yeong CHAE ; Min Hye CHOI ; Kkotnara PARK ; Da-Woon BAE ; Soo-Bong PARK ; Sun-Shin CHA ; Hye Eun LEE ; In Hye LEE ; Yun Soo BAE
Biomolecules & Therapeutics 2025;33(1):210-220
Previous studies have shown that testosterone activates the GPRC6A-Duox1 axis, resulting in the production of H 2O 2 which leads to the apoptosis of keratinocytes and ultimately hair loss. Here, we elucidated a molecular mechanism by which the non-genomic action of testosterone regulates cellular redox status in androgenetic alopecia (AGA). Building upon this molecular understanding, we conducted a high-throughput screening assay of Nox inhibitors from a natural compounds library. This screening identified diterpenoid compounds, specifically Tanshinone I, Tanshinone IIA, Tanshinone IIB, and Cryptotanshinone, derived from Salviae Miltiorrhizae Radix. The IC50 values for Nox isozymes were found to be 2.6-12.9 μM for Tanshinone I, 1.9-7.2 μM for Tanshinone IIA, 5.2-11.9 μM for Tanshinone IIB, and 2.1-7.9 μM for Cryptotanshinone. Furthermore, 3D computational docking analysis confirmed the structural basis by which Tanshinone compounds inhibit Nox activity. These compounds were observed to substitute for NADPH at the π-π bond site between NADPH and FAD, leading to the suppression of Nox activity. Notably, Tanshinone I and Tanshinone IIA effectively inhibited Nox activity heightened by testosterone, consequently reducing the production of intracellular H2O2 and preventing cell apoptosis. In an animal study involving the application of testosterone to the back skin of 8-week-old C57BL/6J mice to inhibit hair growth, subsequent treatment with Tanshinone I or Tanshinone IIA alongside testosterone resulted in a substantial increase in hair follicle length compared to testosterone treatment alone. These findings underscore the potential efficacy of Tanshinone I and Tanshinone IIA as therapeutic agents for AGA by inhibiting Nox activity.
9.Stress Accelerates Depressive-Like Behavior through Increase of SPNS2 Expression in Tg2576 Mice
Seung Sik YOO ; Yuri KIM ; Dong Won LEE ; Hyeon Joo HAM ; Jung Ho PARK ; In Jun YEO ; Ju Young CHANG ; Jaesuk YUN ; Dong Ju SON ; Sang-Bae HAN ; Jin Tae HONG
Biomolecules & Therapeutics 2025;33(3):417-428
To investigate the relationship between depression and AD, water avoidance stress (WAS) was induced for 10 days in both Tg2576 mice and wild-type (WT) mice. After WAS, memory function and depressive-like behavior were investigated in Tg2576 mice. Tg2576 WAS mice exhibited more depressive-like behaviors than WT WAS and Tg2576 control (CON) mice. Strikingly, Tg2576 CON mice showed more depressive-like behaviors than WT mice. Moreover, corticosterone and phospho-glucocorticoid receptor (p-GR) levels were also higher in Tg2576 WAS mice in comparison to Tg2576 CON mice. Spinster homologue 2 (SPNS2) is a member of non-ATP-dependent transporter. The role of SPNS2 was widely known as a sphingosine-1-phosphate (S1P) transporter, which export intracellular S1P from cells. Using GEO database to analyze SPNS2 gene expression changes in patients with AD and depression, we show that SPNS2 gene expression correlates with AD and depression. Interestingly, Tg2576 WAS mice displayed significantly increased levels of SPNS2 w1hen compared to Tg2576 CON counterparts. SPNS2 levels were also higher in Tg2576 CON mice in comparison with WT CON mice. Remarkably, we found a decrease in S1P brain levels and an increase in S1P serum levels of Tg2576 WAS mice in comparison with Tg2576 CON mice. Accordingly, WAS induced group further decreased S1P levels in the brains. However, the level in the serum further increased in comparison with non-induced group. Therefore, these results suggest that AD and depression could be associated, and that Tg2576 transgenic mice are more susceptible to stress-induced depression through the release of S1P by SPNS2 up-regulation.
10.Tanshinone, a Natural NADPH Oxidase Inhibitor, Mitigates Testosterone-Induced Hair Loss
Yeo Kyu HUR ; Jin Yeong CHAE ; Min Hye CHOI ; Kkotnara PARK ; Da-Woon BAE ; Soo-Bong PARK ; Sun-Shin CHA ; Hye Eun LEE ; In Hye LEE ; Yun Soo BAE
Biomolecules & Therapeutics 2025;33(1):210-220
Previous studies have shown that testosterone activates the GPRC6A-Duox1 axis, resulting in the production of H 2O 2 which leads to the apoptosis of keratinocytes and ultimately hair loss. Here, we elucidated a molecular mechanism by which the non-genomic action of testosterone regulates cellular redox status in androgenetic alopecia (AGA). Building upon this molecular understanding, we conducted a high-throughput screening assay of Nox inhibitors from a natural compounds library. This screening identified diterpenoid compounds, specifically Tanshinone I, Tanshinone IIA, Tanshinone IIB, and Cryptotanshinone, derived from Salviae Miltiorrhizae Radix. The IC50 values for Nox isozymes were found to be 2.6-12.9 μM for Tanshinone I, 1.9-7.2 μM for Tanshinone IIA, 5.2-11.9 μM for Tanshinone IIB, and 2.1-7.9 μM for Cryptotanshinone. Furthermore, 3D computational docking analysis confirmed the structural basis by which Tanshinone compounds inhibit Nox activity. These compounds were observed to substitute for NADPH at the π-π bond site between NADPH and FAD, leading to the suppression of Nox activity. Notably, Tanshinone I and Tanshinone IIA effectively inhibited Nox activity heightened by testosterone, consequently reducing the production of intracellular H2O2 and preventing cell apoptosis. In an animal study involving the application of testosterone to the back skin of 8-week-old C57BL/6J mice to inhibit hair growth, subsequent treatment with Tanshinone I or Tanshinone IIA alongside testosterone resulted in a substantial increase in hair follicle length compared to testosterone treatment alone. These findings underscore the potential efficacy of Tanshinone I and Tanshinone IIA as therapeutic agents for AGA by inhibiting Nox activity.

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