BackgroundIn general, stable type B ankle fractures are treated conservatively with cast immobilization or a walking boot during six weeks. Some disadvantages of casting are joint stiffness, muscle wasting and lack of comfort. This study was designed to evaluate whether functional treatment with a removable brace is a safe and more comfortable alternative. Material and methodsRandomized controlled trial. In the period March 2013 - May 2015, 44 patients visiting the emergency department due to a stable type B ankle fracture were included. During the first week both groups received a splint. After one week the patients were randomized: one group received a cast, the other a removable brace. For outcome Olerud & Molander Ankle Score, Visual Analogue Score for comfort and pain, American Academy of Orthopaedic Surgeons (AAOS) Foot and Ankle score questionnaire, EuroQol-5D and range of motion were used. Results44 patients participated (21 cast, 23 brace). There were no differences in baseline characteristics. After 6 weeks, VAS for comfort (cast vs brace; 5.74 vs 7.21; p = 0.02) and total range of motion (40° vs 49°; p = 0.00) showed significant differences in favour of the brace. VAS pain (3.15 vs 2.05; p = 0.16), OMA-score (51.75 vs 61.32; p = 0.22) en EuroQoL-5D (7.26 vs 6.74; p = 0.33) did not show significant differences. Week 52 showed no significant differences at OMA-score (89.29 vs 96.18; p = 0.16), EuroQoL-5D (6.00 vs 5.35; p = 0.15), VAS pain (1.07 vs 0.82; p = 0.69) and AAOS score (91.71 vs 96.06; p = 0.21). No complications occurred in both groups. ConclusionFunctional bracing showed significant differences for the VAS comfort score and range of motion at 6 weeks compared to casting. After a year no significant differences were found. Treatment with a brace is a safe and more comfortable option for stable type B ankle fractures.