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J Wrist Surg 2023; 12(02): 170-176
DOI: 10.1055/s-0042-1750874
Wrist and Carpal Anatomy Article

Midsectional Magnetic Resonance Imaging Analysis of the Sigmoid Notch of the Distal Radioulnar Joint

Flavien Mauler
1   Department of Plastic Surgery and Hand Surgery, Cantonal Hospital Aarau, Aarau, Switzerland
2   The Hand Clinic - Geneva, Geneva, Switzerland
,
Sana Boudabbous
3   Diagnostic Department, Division of Radiology, Geneva University Hospitals, Geneva, Switzerland
4   Clinical Medicine Section, Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland
,
Jean-Yves Beaulieu
5   Division of Orthopaedics and Trauma Surgery, Hand Surgery Unit, Geneva University Hospitals, Geneva, Switzerland
6   Faculty of Medicine, Anatomy Sector, University of Geneva, Geneva, Switzerland
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Abstract

Purpose This study describes the anatomy and analyzes the variations of the midsectional morphology of the sigmoid notch.

Methods The wrists of 50 patients with suspected scaphoid fracture were evaluated by magnetic resonance imaging (MRI). Sigmoid notch length, volar and dorsal rim heights, insertion length of the volar radioulnar ligament, and Tolat morphology classification were measured on T1-weighted axial plane MRI. Ulnar variance and distal radioulnar joint (DRUJ) inclination were assessed on anteroposterior radiographs.

Results The most common sigmoid notch shapes were types C (C-shaped, 60%) and B (ski-slope, 30%), followed by types D (S-shaped, 6%) and A (flat, 4%). Types A and B had a flat dorsal rim (mean 0.77 ± 1.09 mm, range 0.0–1.54 mm, and mean 0.22 ± 0.3 mm, range 0.0–0.76 mm, respectively). Types C and D had more prominent dorsal rims (means 1.47 ± 0.59 mm, range 0.66–2.57 mm, and mean 1.6 ± 0.97 mm, range 0.8–2.68 mm, respectively). The average volar lip length was 1.60 ± 1.11 mm (range, 0.0–4.10). The dorsovolar length of the radius was 18.4 ± 2.01 mm; the length of the sigmoid notch was 14.3 ± 1.73 mm. The type of sigmoid notch according to Tolat was significantly associated with volar lip length (p = 0.005). The type of sigmoid notch was not associated with ulnar variance or DRUJ inclination. The length of the sigmoid notch was significantly associated with the type of sigmoid notch (p = 0.005). The analysis demonstrated a negative association between the sigmoid notch length and the volar insertion of the radioulnar ligament (p = 0.019).

Conclusions The transversal morphology of the sigmoid notch was either flat with the least congruence (similar to type A of Tolat), with volar congruence only (similar to type B), or with volar and dorsal congruence (similar to types C and D). A shorter sigmoid notch may be compensated by a broader insertion of the volar radioulnar ligament.

Clinical Relevance The measurements and correlations demonstrated in this study can be a guide when considering reconstructive procedures or dealing with the instability of the DRUJ.

Keywords

distal radioulnar joint - morphology - sigmoid notch - variation


Publikationsverlauf

Eingereicht: 22. Januar 2022

Angenommen: 22. Mai 2022

Artikel online veröffentlicht:
25. Juni 2022

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