Fifteen children with chronic Monteggia lesions were treated with open reduction, annular ligament reconstruction with fascia of the forearm, and ulnar osteotomy. Mean age was 8 years 3 months (range 3-16 years). The chronicity of missed Monteggia was from 6 weeks to 2 years (mean 12 weeks). All patients were classified as Bado type I, except one with Bado type III. Mean follow-up was 4 years 3 months after surgery. There was a loss of pronation in six cases with the mean of 16 degrees. However, only four cases had rotational loss; the others had a mean rotational arch increase of 5 degrees. The flexion arches improved in all patients, with a mean of 27.7 degrees. The functional result was excellent in 11 patients, good in 3 patients, and poor in 1 patient. This one-incision approach is safe in treating chronic Monteggia lesions in children.