Bone Surface Variation With vs. Without GWMD (LT)

Carpal bone instability occurs when the ligaments holding the scaphoid, lunate, and triquetrum together (the scapholunate (SL) and lunotriquetral (LT) ligaments) are torn, allowing these bones to shift out of alignment during wrist motion. Tracking each bone's cross-sectional area across the motion cycle provides a way to assess whether the imaging plane is capturing this motion, since larger fluctuations can reflect out-of-plane displacement.

This video compares the lunate and triquetrum surface area over time in the oblique axial plane aligned to the LT axis, acquired with and without the guidance wrist movement device (GWMD). Without the device, both curves show sharp, transient drops, consistent with the bone briefly moving out of the imaging plane during motion. With the device, the curves are comparatively smooth and contained. This illustrates the trend toward reduced bone-area variation with the GWMD in the axial planes, although this effect did not reach statistical significance in the LT/SL comparisons.