To compare clinical and functional outcomes after operative and nonoperative treatment of undisplaced, unstable, isolated fibula fractures.

Randomized multicenter clinical trial.

Six level 1 trauma centers.

Eighty-one patients with undisplaced, unstable, isolated fibula fractures as confirmed by an external rotation stress examination demonstrating an increase in medial clear space to 5 mm or greater were followed for 12 months after treatment.

Forty-one patients were treated operatively by open reduction and internal fixation of the fibula. Forty patients underwent nonoperative treatment, which included the use of a short leg cast or brace and protected weight bearing for 6 weeks.

Functional outcomes determined using the Olerud-Molander Ankle Score and the Short Form 36. Radiographic outcomes included measurement of union and displacement at each visit.

There were no statistically significant differences in functional outcome scores or pace of recovery between the operative and nonoperative groups at any time interval (β = -0.28, 3.49; P = 0.936). Complications in the nonoperative group included 8 patients with a medial clear space ≥5 mm and 8 patients with delayed union or nonunion. In the operative group, 5 patients had a surgical site infection and 5 patients required hardware removal.

Patients managed operatively had equivalent functional outcomes compared with nonoperative treatment; however, the risk of displacement and problems with union was substantially lower in patients managed with surgery.