We randomised prospectively 60 consecutive patients who were undergoing internal fixation of similar fractures of the ankle into two groups, one of which was treated by immobilisation in a below-knee cast and the other by a functional brace with early movement. All were instructed to avoid weight-bearing on the affected side. They were seen at 6, 12, 26 and 52 weeks. The functional rating scale of Mazur et al was used to evaluate the patients at each follow-up and we recorded the time of return to work. After one year the patients completed the SF-36 questionnaire. By then 55 patients remained in the study, 28 (mean age 45.5 years) in group 1 and 27 (mean age 39.5 years) in group 2. Those in group 2 had higher functional scores at each follow-up but only at six weeks was this difference significant (p = 0.02). They also had higher mean SF-36 scores, but this difference was significant only for two of the eight aspects investigated. For patients gainfully employed, not on workers' compensation, the mean time from surgery to return to work was 53.3 days for group 2 and 106.5 days for group 1; this difference was significant (p = 0.01). No patient developed a problem with the wound or had loss of fixation. Our findings support the use of a functional brace and early movement after surgery for fractures of the ankle.