We retrospectively reviewed the results of operative treatment of chronic Monteggia lesions (Bado type I or the equivalent) with anterior radiocapitellar dislocation in seven patients. The mean age at the time of the reconstruction was six years and nine months (range, eleven months to twelve years), and the mean time from the injury to the operation was twelve months (range, five weeks to thirty-nine months). The mean duration of follow-up was four years and six months (range, two years to eleven years and three months). There were fourteen complications, including malunion of the ulnar shaft in one patient; residual radiocapitellar subluxation in two patients (one anterior and one posterolateral); radiocapitellar dislocation (dynamic anterior subluxation of the radial head in supination) in one patient; transient ulnar-nerve palsy in three patients (with residual weakness in two); partial laceration of the radial nerve in one patient; loss of the fixation in two patients; and non-union of the ulnar osteotomy site, compartment syndrome, conversion reaction, and possible fibrous synostosis of the forearm in one patient each.The patients lost a mean of 36 degrees of pronation and a mean of 27 degrees of supination of the forearm compared with the contralateral, uninjured extremity. Two patients demonstrated a loss of flexion of the elbow of 8 and 13 degrees and three had a loss of extension (mean, 15 degrees) compared with the contralateral side. There were three good, two fair, and two poor results.