Reliability of the Sigmoid Notch Classification of the Distal Radioulnar Joint.

Area of Science:

• Orthopedic surgery
• Radiology
• Anatomy

Background:

• The Tolat classification is frequently used for distal radioulnar joint (DRUJ) characterization.
• Its reliance on limited joint assessment may cause inaccuracies in sigmoid notch evaluation.

Purpose of the Study:

• To evaluate the reliability of the Tolat classification for sigmoid notch assessment.
• To determine if the Tolat classification accurately reflects the entire sigmoid notch anatomy.

Main Methods:

• Assessed 52 cadaveric forearm models using the Tolat classification on 3D models and slices (0mm and 4mm proximal).
• Inter- and intrarater agreement analyzed using Cohen's and Fleiss' kappa statistics.

Main Results:

• Moderate agreement was found between iterations, surgeons, and radiologists.
• Slight agreement existed between all slices; fair agreement across all raters and slices.
• 3D classifications of 'other' models were consistent, often resembling a reverse ski slope.

Conclusions:

• The Tolat classification demonstrates only fair to moderate reliability.
• Axial views of the distal radius may not accurately represent the entire sigmoid notch anatomy.
• Future classifications should aim for a comprehensive evaluation of the entire sigmoid notch.