Radiographic optimization of the Eaton classification.

Area of Science:

• Orthopedics
• Radiology
• Hand Surgery

Background:

• Thumb basal arthritis diagnosis relies on the Eaton classification.
• The trapezium's shape and orientation complicate its visualization on standard X-rays.
• Improving the reliability of the Eaton classification is crucial for accurate diagnosis and treatment planning.

Purpose of the Study:

• To assess if combining multiple X-ray views enhances intra- and interobserver reliability for the Eaton classification.
• To determine the optimal radiographic views for evaluating thumb basal arthritis using the Eaton classification.

Main Methods:

• Six hand surgeons evaluated 40 sets of X-rays.
• X-rays were assessed using posterior-anterior (PA) and lateral wrist views, Bett's (Gedda's) view alone, and a combination of all three views.
• Intra- and interobserver reliability was measured using kappa statistics, with assessments repeated after at least one week.

Main Results:

• Using only PA and lateral views with the Bett's view yielded only fair agreement for Eaton classification stages.
• A trend towards increased reliability was observed when all three X-ray views were utilized.
• Intraobserver reproducibility was good, while interobserver reliability was moderate when employing the three-view approach.

Conclusions:

• Combining posterior-anterior, lateral, and Bett's views shows potential for improving the reliability of the Eaton classification for thumb basal arthritis.
• The three-view approach offers better intraobserver reproducibility compared to using fewer views.
• Further research may be warranted to optimize radiographic techniques for thumb carpometacarpal joint arthritis assessment.