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Steven F. Viegas, MD, Galveston , TX
During the last two decades, we have studied the load mechanics under a variety of conditions using pressure sensitive film. A variety of normal, traumatic, and surgical treatments have been simulated and studied. Whenever a simulated pathologic or traumatic condition was tested, the areas in which a localized, concentrated increase in contact area and pressure occurred, coincided with the areas in which degenerative changes developed in the clinical situation that was being simulated. The areas in which there was a decrease or no change in contact area and pressure coincided with areas that were spared from degenerative. Study of the anatomy of the wrist has shown that there are several areas, which have a high incidence of variability in the skeletal morphology. In the CMC joint, the greatest area of variability is the fourth carpometacarpal joint. At the midcarpal joint, there is variability both at the scaphotrapeziotrapezoid joint and at the lunate. Recent study of the dorsal ligaments of the wrist has increased our awareness of their importance and function. The dorsal ligaments of the wrist have been shown to have a unique lateral "V" construct, which allows indirect dorsal radioscaphoid stability throughout wrist motion while allowing the radioscaphoid distance to vary threefold.
More recently we have used three-dimensional reconstructions of CT scans and motion analysis to study carpal kinematics. These techniques have been used to analyze the contribution of individual carpal bones, the proximal and midcarpal joints, the specific ligamentous anatomy and the effect of various types of carpal morphology on the kinematics of the wrist. As new anatomic, biomechanic and kinematic studies further our understanding of the wrist, it will also hopefully promote a better understanding of the various injuries and pathologic conditions that affect the wrist and the effectiveness of current and future treatments.
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