214 patients with isolated ankle fractures treated with immobilization (with or without open reduction and internal fixation) were included in this randomized controlled trial to assess if the addition of a supervised exercise to advice provided improvements in activity limitation and quality of life over 6-month follow-up in comparison to advice alone. Additionally, fracture severity, age, and sex were evaluated as possible moderating factors. The results at 1, 3, and 6 months indicated similar improvement between groups in activity limitation on the Lower Extremity Functional Scale (LEFS) and quality of life on the Assessment of Quality of Life (AQoL) instrument. The treatment effects did not appear to be moderated by fracture severity, age or sex. However, clinically important differences (non-significant) were found in favor of the advice group for secondary outcomes of physical activity, and return to pain-free walking and full prefracture work. Both methods incurred similar total costs. It should be noted that enrollment was stopped prior to reaching the predetermined sample size due to exhaustion of funds.