620 patients with an unstable ankle fracture were randomized to treatment with either close contact casting or internal fixation. The purpose of this study was to determine if functional outcome within the first 6 months after casting was equivalent to internal fixation. Secondary clinical and functional outcomes, radiographic nonunion and malunion, and complication rate were also assessed. Results demonstrated equivalent 6-month Olerud-Molander Ankle Scores between the casting and internal fixation groups. The incidence of nonunion and malunion were significantly higher in the casting group compared to the internal fixation group.