Abstract
Background The scapholunate ligament (SLL) is the most commonly injured intercarpal ligament
of the wrist. It is the primary stabilizer of the scapholunate (SL) joint, but the
scaphotrapeziotrapezoid (STT) and radioscaphocapitate (RSC) ligaments may also contribute
to SL stability. The contributions of SL joint stabilizers have been reported previously;
however, this study aims to examine their contributions to SL stability using a different
methodology than previous studies.
Purpose The purpose of this in vitro biomechanical study was to quantify changes in SL kinematics
during wrist flexion and extension following a previously untested sequential sectioning
series of the SL ligament and secondary stabilizers.
Methods Eight cadaveric upper extremities underwent active wrist flexion and extension in
a custom motion wrist simulator. SL kinematics were captured with respect to the distal
radius. A five-stage sequential sectioning protocol was performed, with data analyzed
from 45-degree wrist flexion to 45-degree wrist extension.
Results Wrist flexion and extension caused the lunate to adopt a more extended posture following
sectioning of the SLL and secondary stabilizers compared with the intact state (p < 0.009). The isolated disruption to the dorsal portion of the SLL did not result
in significant change in lunate kinematics compared with the intact state (p > 0.05). Scaphoid kinematics were altered in wrist flexion following sequential sectioning
(p = 0.013). Additionally, disruption of the primary and secondary stabilizers caused
significant change to SL motion in both wrist flexion and wrist extension (p < 0.03).
Conclusions The SLL is the primary stabilizer of the SL articulation, with the STT and RSC ligaments
playing secondary stabilization roles.
Clinical Relevance Understanding the role primary and secondary SL joint stabilizers may assist in the
development of more effective treatment strategies and patient outcomes following
SLL injuries.
Keywords
scapholunate instability - wrist - biomechanics
