Normal Range and Influencing Factors of Distal Radioulnar Joint Translation: A Descriptive Study.

Area of Science:

• Orthopedics
• Biomechanics
• Radiology

Background:

• Distal radioulnar joint (DRUJ) instability assessment relies on clinical tests like the ballottement test.
• The normal physiological range of DRUJ translation and influencing factors are poorly defined, limiting diagnostic precision.

Purpose of the Study:

• To quantify the normal range of DRUJ translation in healthy adults.
• To identify factors influencing DRUJ translation.

Main Methods:

• Recruited healthy adult participants.
• Recorded demographic and anthropometric data (occupation, gender, age, height, weight, handedness, wrist circumference, forearm length, grip strength).
• Measured DRUJ translations (palmar, dorsal, combined) in pronation, supination, and neutral positions using a custom device; analyzed data with univariate and multivariate methods.

Main Results:

• Mean combined DRUJ translation was 11.9±4.2 mm (pronation), 12.4±3.9 mm (supination), and 13.3±4.6 mm (neutral).
• Significant side-to-side differences were noted in pronation and neutral positions, but not supination.
• Multivariate analysis showed combined DRUJ translation in supination is influenced by grip strength, forearm length, weight, and age.

Conclusions:

• Established reference values for DRUJ translation, demonstrating influence of forearm position and patient factors.
• Recommended performing the ballottement test in forearm supination, comparing both limbs, to enhance clinical utility.
• Highlighted specific factors (grip strength, forearm length, weight, age) affecting DRUJ translation in supination.