1.The Impact of Systemic Metabolic Disorders on Rotator Cuff Tears and Surgical Outcomes
Sung-Jin PARK ; Jong Pil YOON ; Seok Won CHUNG
The Journal of the Korean Orthopaedic Association 2026;61(1):38-49
Rotator cuff tears are a common musculoskeletal disorder that significantly impairs shoulder function, especially in the elderly. Traditionally, mechanical wear and age-related degeneration have been considered the leading causes. Recent studies, however, emphasize that systemic metabolic disorders, such as diabetes mellitus, obesity, and dyslipidemia, play a crucial role in the development and healing of rotator cuff disease. This narrative review comprehensively examines the biological mechanisms and clinical outcomes associated with these metabolic comorbidities in rotator cuff degeneration and surgical repair failure. Based on relevant clinical and experimental studies, this study analyzed how each metabolic disease contributes to tendon injury and impaired regeneration. Diabetes mellitus induces chronic inflammation, inhibits collagen synthesis, and impairs microvascular perfusion, hindering tendon healing. Obesity increases the mechanical load on the shoulder and promotes systemic inflammation, exacerbating fatty infiltration of muscles and delaying tissue repair. Dyslipidemia accelerates tendon degeneration through the accumulation of fat, oxidative stress, and fatty infiltration of the rotator cuff muscles. These systemic factors are associated with higher re-tear rates, delayed functional recovery, and poorer surgical outcomes. As the prevalence of metabolic syndrome increases, precise assessment and perioperative management of these metabolic disorders are essential to improve patient outcomes and develop personalized treatment strategies for rotator cuff tears.
2.Current Biological Approach to Improve Rotator Cuff Muscle Quality
Sung-Jin PARK ; Jong Pil YOON ; Seok Won CHUNG
The Journal of the Korean Orthopaedic Association 2026;61(1):22-37
Rotator cuff (RC) injuries cause degenerative changes, including muscle atrophy and fatty infiltration, which remain key pathophysiological factors limiting functional recovery and increasing the risk of re-tears even after surgical repair. In particular, these changes tend to progress to fibrofatty replacement over time, highlighting the limitations of surgery-focused treatments alone. Recent research has addressed this by increasingly focusing on biological therapeutic strategies that directly target the degenerative pathology of the RC muscle. This review article examines the current trends in preclinical and clinical research on three main biological approaches: stem cell-based tissue regeneration, modulation of pathological signaling pathways, and metabolic reprogramming strategies that restore the pathological metabolic environment. Building upon these pathophysiological foundations, this review aims to develop recent biological treatment strategies and explore their potential clinical applications.
3.Data-driven life-stage classification for companion dogs and cats using age-specific diagnosis patterns in South Korea
Jin-Young PARK ; Seogjin KANG ; Yoon Jung DO ; Eun-yeong BOK ; Jong Ryul PARK ; Tae Woo KIM ; Chang-Min LEE ; Woong-Bin RO ; Jang Yeop KIM ; Dong Yun LEE ; Heyong-Seok KIM ; Kyung-Duk MIN
Journal of Veterinary Science 2026;27(1):e5-
Objective:
To classify life stages for companion dogs and cats by identifying clusters in age-specific disease proportions derived from medical records, providing a data-driven foundation for health examination programs.
Methods:
We collected 505,667 medical records from 82 veterinary facilities in South Korea between 2020 and 2023. Diagnoses were standardized using GPT-4o and S-BioBERT. Following preprocessing, data from 27 facilities yielded 222,706 canine and 39,910 feline records for the final analysis. Principal component analysis and K-means clustering (K = 4) were applied to age-specific disease proportions to identify life stages.The 10 most highest-proportion diagnoses diseases were determined for each cluster.
Results:
Canine life stages were classified as ≤ 1 year, 2–5 years, 6–10 years, and 11–15+ years.Feline life stages were 1–2 years, 3–8 years, 9–12 years, and 13–15+ years. In dogs, developmental diseases were common in the youngest age group, while chronic diseases were more prevalent in older groups. In cats, oral and urinary diseases were high-ranking, conjunctivitis was most common in the early stage, and chronic diseases increased with age.
Conclusions
and Relevance: Age-specific diagnosis patterns support four practical life stages for dogs and cats in South Korea. These boundaries can inform evidence-based preventive examination schedules, animal health policy, and pet insurance product design.
4.Transformation of Pleomorphic Xanthoastrocytoma with Germline ATM Mutation into a SMARCB1-Deficient Rhabdoid Tumor: A Case Report
Hyeonseung LEE ; Hyun Jin PARK ; Bo Kyung KIM ; Kyung Taek HONG ; Hyoung Jin KANG ; Sung-Hye PARK ; Ji Hoon PHI ; June-Young KOH ; Jung Yoon CHOI
Clinical Pediatric Hematology-Oncology 2026;33(1):34-38
Secondary rhabdoid tumors (RTs) with atypical teratoid/rhabdoid tumor-like features rarely arise from, or coexist with, pleomorphic xanthoastrocytomas (PXAs), and their clinicopathological and molecular characteristics remain poorly understood. We report a 17-year-old girl with a temporal lobe mass that, upon gross total resection, pathologically contained both RT and PXA components. Immunohistochemistry revealed loss of INI1 expression restricted to the RT component, while the PXA area retained INI1. Next-generation sequencing identified a shared BRAF::TRIM24 fusion and homozygous deletion of CDKN2A/2B in both components, indicating a shared clonal origin. Additionally, a germline ATM frameshift mutation (c.5288_5289insGA) was identified in both tumor components, making the first such report in central nervous system tumors. SMARCB1 loss was confined to the RT component, further supporting the hypotheses of clonal evolution and secondary transformation. Despite gross total resection, craniospinal irradiation, and chemotherapy, the patient developed rapid leptomeningeal dissemination and died 5 months after surgery. This case provides clinicopathological and molecular evidence for clonal evolution and secondary transformation of PXA into an RT. The presence of germline ATM mutation may have therapeutic and biological relevance. Further studies are required to clarify the pathogenesis and optimal management of these rare and aggressive tumors.
5.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.
6.Twig-Like Middle Cerebral Artery : Acquired Lesion Rather than Congenital Anomaly
Yung Ki PARK ; Byul-Hee YOON ; Eui-Hyun HWANG ; Jae Hoon KIM ; Hee In KANG ; Yu Deok WON ; Jin Whan CHEONG
Journal of Korean Neurosurgical Society 2026;69(1):51-60
Objective:
: A twig-like middle cerebral artery (T-MCA) is a rare condition characterized by steno-occlusion of the M1 segment of the middle cerebral artery (MCA) with nearby collateral arterial networks. Despite unclear pathophysiology, it is often classified as a congenital anomaly caused by failure of fusion of the plexiform MCA arterial plexus. We aimed to improve understanding of the pathophysiology of T-MCAs by analyzing incidental T-MCA findings and their natural history.
Methods:
: A retrospective chart review was performed between January 2011 and December 2023 at three medical centers treating both ischemic and hemorrhagic strokes. Patients with suspected MCA lesions were selected through radiology reports from computed tomography, magnetic resonance angiography, and digital subtraction imaging.
Results:
: We identified 51 T-MCA cases from a radiology report search spanning 13 years across three medical centers. The study included 9875 patients with ischemic stroke and 2097 with hemorrhagic stroke. Of the 51 T-MCA cases, incidental findings accounted for 25 (49.0%), ischemic stroke for 18 (35.3%), and hemorrhagic strokes accounted for eight cases (15.7%). T-MCA related ischemic and hemorrhagic strokes accounted for 0.18–0.38% of all strokes. The RNF213.R4810K mutation was identified in seven of 15 patients (46.7%) tested. We found three cases of a de-novo T-MCA that progressed from a normal MCA architecture.
Conclusion
: T-MCAs may represent an acquired secondary anomaly rather than a congenital lesion, followed by steno-occlusion of the focal MCA with new arterial network formation. Both Moyamoya angiopathy and chronic atherosclerosis likely contributed to disease progression. Formation of a microaneurysm, dilatation of the lenticulostriate artery, and hemodynamic stress can lead to stroke.
7.Prosthetic rehabilitation of traumatized maxillary anterior teeth using a digital workflow: a case report
Jong-Hyun SHIN ; Sang-Ah LEE ; Lee-Ra CHO ; Chan-Jin PARK ; Kyung-Ho KO ; Yoon-Hyuk HUH
The Journal of Korean Academy of Prosthodontics 2026;64(1):84-94
The maxillary anterior region is critical for esthetics and function, requiring precise analysis and restoration when damaged by trauma. This case report presents the restorative process using a digital workflow for a patient with anterior trauma. A 22-year-old female exhibited fractures and extrusive luxation of maxillary central incisors, diagnosed with pulp necrosis. After endodontic treatment, intraoral and facial scans were performed, and provisional and definitive restorations were digitally designed. Various shade-matching techniques were employed to achieve natural esthetics. The definitive prosthesis improved harmony between the incisal edge and lower lip, as well as tooth axis, length, and zenith position, fulfilling the patient’s esthetic demands. This case suggests that combining digital technology and gingivectomy with a minimally invasive approach enables esthetic and functional restoration of the maxillary anterior region.
8.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.
9.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.
10.Risk Factors and Clinical Characteristics of Graves’ Ophthalmopathy: a Retrospective Multicenter Study in Korea
Yoon Young CHO ; Hyunju PARK ; Jung HEO ; Jiyeon AHN ; Min Kyung LEE ; Jae Hyuk LEE ; Ju-Yuen LEE ; Yun Jin KIM ; Seo Young SOHN
International Journal of Thyroidology 2026;19(1):85-94
Background and Objectives:
Graves’ ophthalmopathy (GO) is an autoimmune inflammatory disorder that can adversely affect quality of life in patients with Graves’ disease (GD). The objective of this study was to characterize the clinical features of patients with GO and to identify risk factors associated with its development and the need for anti-inflammatory treatment.
Materials and Methods:
In this multicenter, retrospective observational study, 818 patients with GD were identified via electronic medical record review. Clinical characteristics were assessed, and logistic regression analyses were performed to identify risk factors for GO development and the need for anti-inflammatory treatment.
Results:
Among the 818 patients with GD, 135 (16.5%) developed GO, and 60 (7.3%) of these patients received anti-inflammatory treatment. GO was diagnosed at the time of GD diagnosis in 54.8% of cases, and proptosis and eyelid/orbital swelling were the common presenting features. In multivariable analysis, female sex (odds ratio [OR]: 1.75, confidence interval [CI]: 1.02-3.03), goiter (OR: 1.71, CI: 1.08-2.71), and smoking (ex-smokers: OR, 2.18; 95% CI: 1.02-4.65; current smokers: OR, 3.11; CI, 1.78-5.44) were independently associated with GO development, whereas diabetes (OR: 0.35, CI: 0.14-0.89) was inversely associated. Higher total cholesterol (OR: 1.31, CI: 1.01-1.04) and elevated thyrotropin-binding inhibitory immunoglobulin levels (OR: 1.07, CI: 1.02-1.11) were also significantly associated with the need for anti-inflammatory treatment.
Conclusion
This study delineated the clinical features of GO and identified risk factors for its development and the need for anti-inflammatory treatment in patients with GD, providing valuable information for the management of GO in Korean patients.

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