Distal Ulnar Centering and Eccentricity (DUCE) grading: assessing the degree of instability in the distal radioulnar joint
Abstract
Distal radioulnar joint (DRUJ) instability is challenging to diagnose. The Distal Ulnar Centering and Eccentricity (DUCE) method was introduced as an anatomy-based assessment of DRUJ articulation to reduce rotation-related variability of existing metrics. This study evaluated its responsiveness to increasing instability, developing a point-based grading system. Twelve cadaveric forearms were scanned in stable condition and underwent stepwise induction of instability (TFCC lesion, Galeazzi, Essex-Lopresti). Cone-beam CT scans were obtained in pronation and supination at each stage of instability. DUCE parameters Centering (distance from ulnar head centre C to a notch-derived axis), and Eccentricity (distance from C to deepest notch point) were measured. Responsiveness of DUCE parameters to instability was analysed using a mixed-effects model and compared to radioulnar ratio. Thresholds for DUCE Grading were derived via linear regression. Diagnostic accuracy was assessed using ROC analysis, Youden’s Index, and weighted kappa. RR showed no significant change with increasing instability, whereas DUCE parameters increased progressively (P Centering = 0.005, P Eccentricity <0.001). The DUCE Grading showed good discrimination between stable and unstable joints (AUC 0.78, 95% CI 0.69 to 0.88), with 76.0% overall accuracy (95% CI 66.6 to 83.5) and moderate agreement with the true instability grade (quadratic weighted κ = 0.42). In this cadaveric proof-of-concept study, DUCE Grading provided an anatomy-referenced quantification of DRUJ instability and allowed preliminary severity stratification. As the thresholds were derived and internally validated within a single cohort, they require prospective external validation before the system can support clinical decision-making.
Related
- Temporary Proximal Radioulnar Joint Transfixation and Biceps Chemodenervation for Recurrent Anterior Radial Head Instability After Monteggia-Variant Injury: A Case Report
- Rotational behaviour and morphological associations of the CT-based distal ulnar centering and eccentricity (DUCE) method in cadaveric specimens
- Centering Veteran expertise: Advancing Peer-Led Harm Reduction in the Veterans Health Administration.
- F2D-RetinaNet: a feature-to-decision dual-path network with fractional operators for retinal disease detection and grading
- Serum Galectin-3 in Diabetic Foot Infections: A Case-Control Evaluation of Its Diagnostic and Severity-Grading Utility
BibTeX
@article{barbari2026distal,
title = {{Distal Ulnar Centering and Eccentricity (DUCE) grading: assessing the degree of instability in the distal radioulnar joint}},
author = {Jan Siad El Barbari and Florian Kordon and Holger Kunze and Jonas Armbruster and Paul Alfred Grützner and Sven Yves Vetter and Marc Schnetzke and Benedict James Swartman},
journal = {Scientific Reports},
year = {2026},
month = oct,
doi = {10.1038/s41598-026-68511-9},
url = {https://www.nature.com/articles/s41598-026-68511-9},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Distal Ulnar Centering and Eccentricity (DUCE) grading: assessing the degree of instability in the distal radioulnar joint
AU - Jan Siad El Barbari
AU - Florian Kordon
AU - Holger Kunze
AU - Jonas Armbruster
AU - Paul Alfred Grützner
AU - Sven Yves Vetter
AU - Marc Schnetzke
AU - Benedict James Swartman
PY - 2026
DA - 2026/10/21
JO - Scientific Reports
DO - 10.1038/s41598-026-68511-9
UR - https://www.nature.com/articles/s41598-026-68511-9
AB - Distal radioulnar joint (DRUJ) instability is challenging to diagnose. The Distal Ulnar Centering and Eccentricity (DUCE) method was introduced as an anatomy-based assessment of DRUJ articulation to reduce rotation-related variability of existing metrics. This study evaluated its responsiveness to increasing instability, developing a point-based grading system. Twelve cadaveric forearms were scanned in stable condition and underwent stepwise induction of instability (TFCC lesion, Galeazzi, Essex-Lopresti). Cone-beam CT scans were obtained in pronation and supination at each stage of instability. DUCE parameters Centering (distance from ulnar head centre C to a notch-derived axis), and Eccentricity (distance from C to deepest notch point) were measured. Responsiveness of DUCE parameters to instability was analysed using a mixed-effects model and compared to radioulnar ratio. Thresholds for DUCE Grading were derived via linear regression. Diagnostic accuracy was assessed using ROC analysis, Youden’s Index, and weighted kappa. RR showed no significant change with increasing instability, whereas DUCE parameters increased progressively (P Centering = 0.005, P Eccentricity <0.001). The DUCE Grading showed good discrimination between stable and unstable joints (AUC 0.78, 95% CI 0.69 to 0.88), with 76.0% overall accuracy (95% CI 66.6 to 83.5) and moderate agreement with the true instability grade (quadratic weighted κ = 0.42). In this cadaveric proof-of-concept study, DUCE Grading provided an anatomy-referenced quantification of DRUJ instability and allowed preliminary severity stratification. As the thresholds were derived and internally validated within a single cohort, they require prospective external validation before the system can support clinical decision-making.
SN - 2045-2322
ER -