A Kinematic Analysis of Wrist and Carpal Function Using Four-Dimensional Computed Tomography Technology: A Dynamic Perspective

Purpose: An emerging imaging modality, four-dimensional computed tomography, can provide dynamic evaluation of carpal motion, which allows for a better understanding of how the carpals work together to achieve range of motion. The objective of this work was to examine kinematic motion of the carpus through a flexion/extension arc of motion using four-dimensional computed tomography.

Methods: A convenience sample of 20 uninjured participants underwent a four-dimensional computed tomography scanning protocol through a complete arc of flexion/extension motion. Kinematic changes in motion were quantified using helical axes motion data for each carpal. Rotation angles were compared between bones to identify differences in kinematic motion between bones.

Results: The bones within the proximal carpal row, the lunate, scaphoid, and triquetrum, rotate significantly to differing magnitudes at the ends of motion (40° of flexion and 40° of extension). The scaphoid rotates to the highest magnitude, followed by the triquetrum, and lastly, the lunate. The distal carpal row bones rotate to similar magnitudes throughout the entire range of motion.

Conclusions: This work describes the kinematics of the carpals throughout dynamic in vivo flexion and extension.

Clinical relevance: This study adds to an understanding of wrist mechanics and the possible clinical implications of pathological deviation from baseline kinematics.