A Slightly Dorsally Tilted Lunate on MRI can be Considered Normal

Area of Science:

• Radiology
• Orthopedics
• Anatomy

Background:

• Lunate bone angulation can indicate carpal pathology.
• Dorsal angulation of the lunate on MRI may be misinterpreted as abnormal in healthy wrists.
• Variations in lunate tilt across MRI slices can lead to misdiagnosis.

Purpose of the Study:

• Determine the average radiolunate angle on sagittal wrist MRI.
• Assess radiolunate angles in different parts of the lunate.
• Evaluate interobserver reliability for angle measurements.

Main Methods:

• Retrospective analysis of 140 wrist MRIs from adult patients.
• Measurement of radiolunate and capitolunate angles using tangential and axial methods.
• Independent measurements by two observers on 46 MRIs for reliability assessment.

Main Results:

• The average radiolunate angle was 8.7 degrees dorsal.
• No significant differences in radiolunate angles were found across different lunate regions.
• Excellent interobserver agreement was achieved for radiolunate and capitolunate angle measurements.

Conclusions:

• The lunate typically exhibits slight dorsal angulation on healthy wrist MRIs.
• A normal radiolunate angle range of 10-15 degrees dorsal tilt is proposed.
• Provides normative anatomical data for improved diagnosis of wrist conditions.