{ "abstract": "Background: Skeletal muscle mass and quality are critical determinants of outcomes in hip fracture patients. However, most prior studies have relied on 2D cross-sectional area measurements, which may not accurately reflect the complex 3D muscle distribution. This study aimed to quantify 3D thigh muscle volume and intramuscular adipose tissue (IMAT) in a large elderly East Asian hip fracture cohort using an AI-assisted segmentation pipeline. Methods: A total of 1,287 patients from a multi-center hip fracture cohort were included. Preoperative whole-thigh CT scans were analyzed using a validated AI-based 3D UNETR segmentation model to delineate 26 individual muscles. Height-normalized muscle volumes (cm³/m²) and IMAT percentages (%) were computed for four anatomic regions: anterior, medial, posterior, and gluteal. Results: The gluteal group exhibited the largest height-normalized muscle volume (855.64 ± 216.38 cm³/m²), followed by the anterior group (784.57 ± 243.17 cm³/m²). On an individual level, the gluteus maximus was the largest single muscle. Paradoxically, the gluteal group showed the highest IMAT percentage (1.43 ± 0.84%), higher than the anterior (0.57 ± 0.42%) and medial groups (0.71 ± 0.51%). Specifically, the highest IMAT percentages were observed in the multifidus (1.93 ± 1.31%) and tensor fasciae latae (1.92 ± 1.03%), which contrasts with the relatively preserved primary locomotive muscles such as the vastus medialis (0.38 ± 0.32%). Conclusions: Elderly hip fracture patients exhibited a dissociation between muscle quantity and quality. The relatively high fatty degeneration observed in stabilizing muscles, including the gluteal muscles and multifidus, despite their large volume, may reflect muscle composition patterns potentially related to postural function. These findings should be considered hypothesis-generating and require validation in prospective studies incorporating direct functional assessments.", "abstract_shown": true, "affiliations": [ "Department of Orthopaedic Surgery, Daejeon Eulji Medical Center, Eulji University School of Medicine, Daejeon, Republic of Korea", "Department of Orthopaedic Surgery, Ajou University School of Medicine, Ajou Medical Center, Suwon, Republic of Korea", "Department of Orthopaedic Surgery, Nowon Eulji Medical Center, Eulji University, Seoul, Republic of Korea", "Program in Biomedical Science and Engineering, Inha University, Incheon, Republic of Korea", "Department of Orthopaedic Surgery, Inha University Hospital, Inha University College of Medicine, Incheon, Republic of Korea" ], "article_type": "Research Article", "arxiv": null, "author_total": 5, "authors": [ { "affs": [ 0 ], "name": "Yong-Han Cha" }, { "affs": [ 1 ], "name": "Jung-Taek Kim" }, { "affs": [ 2 ], "name": "Jin-Woo Kim" }, { "affs": [ 3 ], "name": "Hyun-Bin Kim" }, { "affs": [ 4 ], "name": "Jun-Il Yoo" } ], "bibtex": "https://research.draconitic.com/paper/dzxkxemwa08vy.bib", "cited_by": 0, "doi": "10.1371/journal.pone.0359317", "fulltext_url": null, "id": "dzxkxemwa08vy", "issns": [ "1932-6203" ], "landing_url": "https://doi.org/10.1371/journal.pone.0359317", "language": null, "licence": "CC-BY-4.0", "licence_label": "CC BY 4.0", "licence_source": "journal", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "2746|Hip and Femur Fractures" ], [ "plos", "/Biology and life sciences/Anatomy/Biological tissue/Muscle tissue" ], [ "plos", "/Biology and life sciences/Anatomy/Musculoskeletal system/Muscles/Skeletal muscles" ], [ "plos", "/Biology and life sciences/Anatomy/Musculoskeletal system/Skeleton/Pelvis/Hip" ], [ "plos", "/Biology and life sciences/Neuroscience/Neuroimaging/Computed axial tomography" ], [ "plos", "/Biology and life sciences/Physiology/Muscle physiology/Muscle functions" ], [ "plos", "/Medicine and health sciences/Anatomy/Biological tissue/Muscle tissue" ], [ "plos", "/Medicine and health sciences/Anatomy/Musculoskeletal system/Muscles/Skeletal muscles" ], [ "plos", "/Medicine and health sciences/Anatomy/Musculoskeletal system/Skeleton/Pelvis/Hip" ], [ "plos", "/Medicine and health sciences/Diagnostic medicine/Diagnostic radiology/Tomography/Computed axial tomography" ], [ "plos", "/Medicine and health sciences/Health care/Geriatric care" ], [ "plos", "/Medicine and health sciences/Radiology and imaging/Diagnostic radiology/Tomography/Computed axial tomography" ], [ "plos", "/Medicine and health sciences/Surgical and invasive medical procedures" ], [ "plos", "/Research and analysis methods/Bioassays and physiological analysis/Muscle analysis" ], [ "plos", "/Research and analysis methods/Imaging techniques/Diagnostic radiology/Tomography/Computed axial tomography" ], [ "plos", "/Research and analysis methods/Imaging techniques/Neuroimaging/Computed axial tomography" ] ], "openalex": "W7220954841", "pdf_url": "https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0359317&type=printable", "pmcid": null, "pmid": null, "published": "2026-10-08", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/dzxkxemwa08vy.ris", "sources": [ { "first_seen": "2026-10-30T12:17:30Z", "native_id": "10.1371/journal.pone.0359317", "source": "plos", "url": "https://doi.org/10.1371/journal.pone.0359317" } ], "subjects": [ { "field": "medicine", "origin": "plos:anatomy", "subfield": "physiology" } ], "title": "Artificial intelligence-based thigh muscle volume profiling on CT in elderly East Asian patients with hip fracture", "title_text": "Artificial intelligence-based thigh muscle volume profiling on CT in elderly East Asian patients with hip fracture", "type": "peer-reviewed", "updated_at": "2026-10-30T12:17:30Z", "url": "https://research.draconitic.com/paper/dzxkxemwa08vy", "venue": "PLOS One", "versions": [] }