Atlantoaxial instability in acute odontoid fractures is associated with nonunion and mortality

BACKGROUND CONTEXT: Odontoid fractures are the most common geriatric cervical spine fractures. Nonunion rates have been reported to be up to 40% and mortality up to 35%, and poor functional outcomes are common. Atlantoaxial instability (AAI) is a plausible prognostic factor, but its role has not been previously examined. PURPOSE: To determine the effect of severe AAI on the outcomes of nonunion and mortality in patients with acute odontoid …