The role of SLIL in 3D movement of scaphoid and lunate during wrist radio-ulnar deviation

Abstract

Objective To observe the effects of transection of scapholunate interosseous ligament (SLIL)and its subregions on the 3D movement of scaphoid and lunate during wrist radio-ulnar deviation, and study the rule of SLIL subregions in 3D motion of the scaphoid and lunate. Methods Twelve fresh adult cadaver upper extremities (6 left side and 6 right side) were divided to normal control group, proximal SLIL subregion transection group, proximal and dorsal SLIL subregion transection group, proximal and palmar SLIL subregion transection group and entire SLIL transection group (6 each). 3D laser scanning and reconstruction techniques were applied to measure 3D motion of the scaphoid and lunate during wrist radio-ulnar deviation, and data were statistically analyzed, on the normal and sequential sectioning of SLIL subregions during wrist flexion-extension and wrist radlal-ulnar deviation were determined. Results In the intact wrist specimens, the scaphoid and lunate deviated radially and ulnarly during wrist radial-ulnar deviation, along with obvious flexion and extension.At the same time, there was minimal scaphoid and lunate pronation-supination. With sectioning of proximal subregions of the SLIL, no significant kinematics changes were observed in the scaphoid and lunate bones. After sectioning proximal and palmar or proximal and dorsal subregions of the SLIL, kinematics of the scaphoid and lunate were changed. Sectioning the whole SLIL caused increased volar flexion of the scaphoid and decreased volar flexion of the lunate. Conclusion 3D laser scanning and reconstruction can precisely measure 3D motion of the scaphoid and lunate. Kinematic study of SLIL subregions showed that partial or complete sectioning of SLIL led to obvious change in volar flexion of the scaphoid and lunate. However, the proximal subregion of SLIL has no prominent effect on the motion of scaphoid and lunate. Key words: Carpal joints; Scaphoid bone; Lunate bone; Ligaments,articular; 3D movement