The effect of coordinate system selection on wrist kinematics

Area of Science:

• Biomechanics
• Orthopedics
• Kinesiology

Background:

• Three-dimensional motion analysis of the hand and wrist is crucial in biomechanical research.
• Current methods rely on post-testing analysis to create anatomical joint coordinate systems (JCS) for wrist motion data.

Purpose of the Study:

• To compare four previously described joint coordinate system (JCS) methods for wrist motion analysis.
• To evaluate the clinical relevance and accuracy of different JCS generation techniques.

Main Methods:

• Five cadaveric upper limbs were tested using a wrist motion simulator for flexion-extension and radial-ulnar deviation.
• Clinical wrist angles were measured with a goniometer.
• Wrist angles were recalculated using four distinct JCS methods for comparison.

Main Results:

• Subtle differences were observed between the four JCS methods for both flexion-extension and radial-ulnar deviation.
• Root Mean Square Error (RMSE) values were within 6.6° for flexion-extension and 7.1° for radial-ulnar deviation.
• No single JCS method demonstrated significant superiority over others.

Conclusions:

• All four analyzed JCS generation methods are comparable and suitable for wrist biomechanical research.
• The minor differences identified are unlikely to be clinically significant.
• Methods utilizing palpable surface landmarks for JCS digitization offer practical advantages.