Use of a cast compared with a functional ankle brace after operative treatment of an ankle fracture. A prospective, randomized study

Abstract

Background: Controversy continues with regard to the optimal postoperative care after open reduction and internal fixation of an ankle fracture. The hypothesis of this study was that postoperative treatment of an ankle fracture with a brace that allows active and passive range-of-motion exercises would improve the functional recovery of patients compared with that after conventional treatment with a cast. Thus, the purpose of this prospective, randomized study was to compare the long-term subjective, objective, and functional outcome after conventional treatment with a cast and that after use of functional bracing in the first six weeks following internal fixation of an ankle fracture.

Methods: One hundred patients with an unstable and/or displaced Weber type-A or B ankle fracture were treated operatively and then were randomly allocated to two groups: immobilization in a below-the-knee cast (fifty patients) or early mobilization in a functional ankle brace (fifty patients) for the first six postoperative weeks. The follow-up examinations, which consisted of subjective and objective (clinical, radiographic, and functional) evaluations, were performed at two, six, twelve, and fifty-two weeks and at two years postoperatively.

Results: There were no perioperative complications in either study group, but eight patients who were managed with a cast and thirty-three patients who were managed with a brace had postoperative complications, which were mainly related to wound-healing. Two patients in the group treated with a cast had deep-vein thrombosis. All fractures healed well in both groups. The difference between the two groups with respect to the complication rate was significant (p = 0.0005). No significant differences between the study groups were observed in the final subjective or objective (clinical) evaluation. At the two-year follow-up examination, the average score (and standard deviation) according to the ankle-rating scale of Kaikkonen et al. was 85 +/- 9 points for the group treated with a cast and 83 +/- 10 points for the group treated with a brace, and the average ankle score according to the system of Olerud and Molander was 87 +/- 8 points and 87 +/- 9 points, respectively.

Conclusions: The long-term functional outcome after postoperative treatment of an ankle fracture with a cast and that after use of a functional brace are similar. Although early mobilization with use of a functional ankle brace may have some theoretical beneficial effects, the risk of postoperative wound complications associated with this treatment approach is considerably increased compared with that after conventional cast treatment. Thus, the postoperative protocol of treatment with a functional brace requires refinement before it can be generally advocated for use after operative treatment of an ankle fracture.