{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,20]],"date-time":"2026-03-20T01:27:58Z","timestamp":1773970078498,"version":"3.50.1"},"reference-count":18,"publisher":"Georg Thieme Verlag KG","issue":"02","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Wrist Surg"],"published-print":{"date-parts":[[2026,4]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The kinematics of the distal radioulnar joint (DRUJ) are complex and not fully understood. Much current knowledge is based on cadaveric and static imaging studies. Management of DRUJ pathology will remain a challenge until the anatomy and kinematics at the normal DRUJ are defined. The aim of this study was to report kinematic findings at the DRUJ and their relationships in normal wrists using static and dynamic computed tomography (CT).<\/jats:p>\n                  <jats:p>This was a retrospective cohort study of patients who underwent dynamic CT scanning of one or both wrists at Tauranga Hospital between March 2018 and July 2022, utilizing a previously described protocol. Sigmoid notch and ulnar head dimensions in the axial and coronal planes were measured on static imaging, with sigmoid notch morphologies described utilizing the Tolat classifications. The degree of translation of the ulnar head with the wrist in full pronation, neutral rotation, and full supination were measured relative to a perpendicular line drawn across the midpoint of the sigmoid notch. The ulnar variance and sigmoid notch gap on coronal views were measured with the wrist in radial and ulnar deviation and with a relaxed and clenched fist.<\/jats:p>\n                  <jats:p>A total of 38 wrists were studied in 24 patients, consisting of 15 females and 9 males with a mean age of 38.0 years (range 15\u201361). There was no statistically significant difference between ulnar variance or translation of the ulna relative to the midpoint of the sigmoid notch in each position when compared for morphology types in coronal or axial planes. The mean radius of curvature of the ulnar head was 8.3\u2009degrees, with the mean radius of the sigmoid notch measuring 17.1\u2009degrees (p\u2009&lt;\u20090.001), at a mean ratio of 0.51. The ulnar head was most dorsal to the midpoint of the sigmoid notch in full pronation (mean \u22122.8\u2009mm dorsal), and translated volarly as the wrist moved toward neutral (mean \u22121.1\u2009mm dorsal) and to full supination (mean \u22120.6\u2009mm dorsal) (p\u2009&lt;\u20090.001), but remained dorsal to the sigmoid notch midpoint in each position. The mean sigmoid notch gap was 1.3\u2009mm relaxed, which increased to 2.0\u2009mm in a clenched fist (p\u2009=\u20090.001). Mean ulnar variance measured \u22121.0\u2009mm relaxed, and \u22120.5\u2009mm in a clenched fist (p\u2009=\u20090.014). The mean sigmoid notch gap on radial deviation was 2.0\u2009mm, and 1.4\u2009mm on ulnar deviation (p\u2009=\u20090.012).<\/jats:p>\n                  <jats:p>The ulnar head remains dorsal relative to the midpoint of the sigmoid notch throughout the range of forearm rotation but becomes relatively more volar as the wrist rotates from full pronation to a position of full supination. The morphology of the notch was not associated with any parameter measured in our study. We have shown that ulnar variance is dynamic in response to deviation and loading. We have presented new data that loading and ulnar deviation increase the gap at the distal sigmoid notch between the radius and ulna. Our findings have implications in the surgical management of pathologies at the joint, particularly in reconstructive procedures for DRUJ instability. Further study is indicated to investigate the relationship between morphology and kinematics at the DRUJ.<\/jats:p>","DOI":"10.1055\/a-2506-6910","type":"journal-article","created":{"date-parts":[[2025,1,30]],"date-time":"2025-01-30T18:44:31Z","timestamp":1738262671000},"page":"161-167","source":"Crossref","is-referenced-by-count":0,"title":["Kinematics of the Distal Radioulnar Joint: A Dynamic CT Analysis"],"prefix":"10.1055","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-8248-7153","authenticated-orcid":false,"given":"Euphemia","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Tauranga Hospital, Tauranga South, Tauranga, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3258-996X","authenticated-orcid":false,"given":"Gregory I.","family":"Bain","sequence":"additional","affiliation":[{"name":"Upper Limb and Research, Department of Orthopaedic Surgery, Flinders University and Flinders Medical Centre, Adelaide, South Australia, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3395-1991","authenticated-orcid":false,"given":"Simon B. M.","family":"MacLean","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Tauranga Hospital, Tauranga South, Tauranga, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"194","published-online":{"date-parts":[[2025,1,30]]},"reference":[{"issue":"04","key":"ref1","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1177\/1753193417693170","article-title":"Distal radioulnar joint: functional anatomy, including pathomechanics","volume":"42","author":"J R Haugstvedt","year":"2017","journal-title":"J Hand Surg Eur Vol"},{"issue":"05","key":"ref2","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1016\/S0266-7681(96)80136-7","article-title":"A cadaveric study of the anatomy and stability of the distal radioulnar joint in the coronal and transverse planes","volume":"21","author":"A R Tolat","year":"1996","journal-title":"J Hand Surg 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MacLean","year":"2020"},{"issue":"04","key":"ref10","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1055\/s-0038-1675385","article-title":"\u201cLocked\u201d scapholunate instability diagnosed with 4D computed tomography scan","volume":"8","author":"G I Bain","year":"2019","journal-title":"J Wrist Surg"},{"issue":"06","key":"ref11","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1097\/RCT.0b013e31826dbc50","article-title":"The new 4-dimensional computed tomographic scanner allows dynamic visualization and measurement of normal acromioclavicular joint motion in an unloaded and loaded condition","volume":"36","author":"T D Alta","year":"2012","journal-title":"J Comput Assist Tomogr"},{"key":"ref12","first-page":"15","article-title":"Dynamic computed tomography of the distal radioulnar joint versus magnetic resonance imaging in detecting foveal tears of the triangular fibrocartilage complex","volume":"x","author":"Z V Braig","year":"2024","journal-title":"Hand (N 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sigmoid notch classification of the distal radioulnar joint","volume":"12","author":"H D'Sa","year":"2022","journal-title":"J Wrist Surg"},{"issue":"11","key":"ref17","doi-asserted-by":"crossref","first-page":"1083.e1","DOI":"10.1016\/j.jhsa.2020.04.021","article-title":"Three-dimensional automated assessment of the distal radioulnar joint morphology according to sigmoid notch surface orientation","volume":"45","author":"S Roner","year":"2020","journal-title":"J Hand Surg Am"},{"issue":"01","key":"ref18","doi-asserted-by":"crossref","first-page":"3159","DOI":"10.1038\/s41598-023-29726-2","article-title":"Quantification of the methodological error in kinematic evaluation of the DRUJ using dynamic CT","volume":"13","author":"J GM Oonk","year":"2023","journal-title":"Sci Rep"}],"container-title":["Journal of Wrist 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