Master of Engineering Science
Dr. James Johnson
Dr. Graham King
Carpal kinematics have been previously investigated, yet there remains no consensus regarding the relative contribution of each bone to total wrist motion. A more detailed understanding of carpal kinematics is essential in the effective diagnosis and treatment of injuries of the wrist, as many injuries manifest as an alteration in intercarpal kinematics. The scapholunate (SL) ligament is one of the most commonly injured intercarpal articulations resulting in a cascade of degenerative changes included cartilage wear and altered joint kinematics. The SL ligament is considered the primary stabilizer of the SL joint but is surrounded by a complex network of secondary ligamentous constraints, each contributing to the maintenance of normal SL kinematics. The ligamentous anatomy of the SL ligament and secondary stabilizers has been well established, although the functional and stabilizing role of each structure remains unclear. This work investigates the relative role and contribution of the scaphoid, lunate, and surrounding ligamentous restraints during planar wrist motions. An in vitro study examined the kinematics of the scaphoid, lunate, and capitate during planar motions of wrist flexion and extension. Scaphoid and lunate motion was found to correlate linearly with wrist motion throughout flexion and extension, with the scaphoid contributing at a greater degree throughout flexion-extension. Both the scaphoid and lunate were found to contribute more to wrist motion during flexion when compared to extension. A subsequent in vitro study examined the effect of the sequential sectioning of the SL ligament and two secondary stabilizers, the scaphotrapezium-trapezoid (STT) ligament and the radioscaphocapitate (RSC) ligament, on scaphoid and lunate kinematics during wrist flexion-extension and radial-ulnar deviation. The SL ligament was found to be the primary stabilizer of the SL joint, as sectioning caused the largest angular change in SL kinematics, and the STT and RSC ligaments are secondary stabilizers, as the additional sectioning induced further postural changes in SL kinematics. A more detailed understanding of role and stabilizing function of the SL ligament and secondary stabilizers may assist in the development of more effective treatment strategies following injury to the SL articulation.
Stoesser, Helen L., "A Biomechanical Investigation of Scaphoid and Lunate Kinematics During Wrist Motion" (2016). Electronic Thesis and Dissertation Repository. 4360.