We reviewed 12 children, mean 5 (1-12) years, after corrective osteotomy of the ulna, combined with open reduction of the radial head for malunited anterior Monteggia lesions (Bado type I). A simple corrective osteotomy was used in the first 6 patients (group A) and a posterior angular osteotomy was used in the second group of 6 patients (group B). All osteotomies healed uneventfully, but 3 patients had a persistent dislocation of the radial head. Children who had been treated with an angular osteotomy had the best clinical outcome).