Abstract:To compare the effects of internal fixation and non-internal fixation in the treatment of old Monteggia fractures in children after ulnar osteotomy.Methods A total of 79 children with old Monteggia fractures admitted to our hospital from June 2015 to June 2021 were selected as the research objects, and were divided into internal fixation groups according to different surgical methods (n=40, internal fixation after ulnar osteotomy) And non-internal fixation group (n=39, non-internal fixation treatment after ulnar osteotomy), record the operation time, blood loss, postoperative complication rate, Nakamura good and good rate, forearm pronation, supination, flexion and extension activity in the two groups (ROM), Mayo score, fracture healing time.Results The treatment time, blood loss and fracture healing time of the non-internal fixation group were lower than those of the internal fixation group (P<0.05),at the last follow-up, the scores of forearm pronation, supination, flexion and extension ROM and Mayo scores of the two groups were improved compared with those before operation (P<0.05), but there was no significant difference between the two groups (P>0.05); There was no significant difference in the excellent and good rate of Nakamura (P>0.05).Conclusion Ulnar osteotomy, internal fixation and non-internal fixation for the treatment of children's old Monteggia fractures, with fewer complications, can improve children's forearm ROM and elbow joint function, and the effect is significant. The treatment time of the non-internal fixation group was short, the amount of bleeding was less, and the fracture healing time was short.