Modifications to the mechanical behavior of the wrist after fracture of the scaphoid. Modeling by finite element analysis.

Although based on their long-term clinical evolution there appeared to be no doubt that fractures of the scaphoid modify the mechanical behavior of the carpus, the mechanisms of these modifications have not yet been investigated. This study based on finite element analysis provides insight into the sequence behind the onset of arthritis of the wrist, highlighting the existence of pressure peaks at the nonunion and at the midcarpal interface (scaphoid-capitate and lunate-capitate). This evidence explains the clinical evolution of nonunions of the scaphoid. Our study indirectly demonstrates the role played by the scaphoid within the wrist as a force transmission column. The use of finite element analysis for the modeling of simple or complex osteoarticular systems may prove to be a highly useful tool for the understanding of these mechanisms.