Intrarater and Interrater Reliability of the Soong Classification for Distal Radius Volar Locking Plate Placement

Area of Science:

• Orthopedic Surgery
• Radiographic Assessment
• Surgical Outcomes

Background:

• Distal radius fractures are common, often treated with volar locking plates.
• Accurate assessment of plate placement is crucial for optimal outcomes.
• The Soong classification provides a standardized method for evaluating this placement.

Purpose of the Study:

• To evaluate the intrarater and interrater reliability of the Soong classification.
• To determine if the classification is a dependable tool for assessing volar locking plate placement.
• To test reliability across varying physician experience levels.

Main Methods:

• Six physicians reviewed 40 radiographs of distal radius fractures with volar locking plates.
• Radiographs were assessed twice, 4 weeks apart, using the Soong classification (grades 0, 1, 2).
• Intrarater reliability was measured using weighted kappa; interrater reliability was assessed with the intraclass coefficient.

Main Results:

• Intrarater reliability (weighted kappa) ranged from 0.229 to 0.946.
• Interrater reliability (intraclass coefficient) was 0.944 for the first randomization and 0.877 for the second.
• The Soong classification showed substantial agreement among observers.

Conclusions:

• The Soong classification is a reliable tool for assessing distal radius volar locking plate placement.
• Reliability was maintained across different levels of physician training and with a random selection of radiographs.
• This classification can be confidently used in clinical practice and research.