Force transmission through the wrist joint in Kienbock's disease: A two-dimensional theoretical study

This study quantifies the changes in force and pressure distributions across the wrist joint in different stages of Kienbock's disease using a 2-dimensional computer simulation model. Twenty-four cases classified as Lichtman's stage II, IIIA, or IIIB (8 cases in each category) were analyzed using the rigid body spring model technique. A 2-dimensional model in the posteroanterior plane of the wrist was loaded through the metacarpals under a total force of 142 N. The joint forces, peak pressures, and ligament tensions calculated on the involved side were normalized against the controlateral normal side values of the same patient. The results demonstrated that significant changes of the force transmission across the wrist joint occurred only from stage IIIA to IIIB, in which scaphoid rotation was prominent. On the basis of this study, scaphoid rotation plays an important role in affecting the wrist joint contact pressure distribution. This may be responsible for the progression of Kienbock's disease. Copyright (C) 1998 by the American Society for Surgery of the Hand.