Objective:To investigate the diagnosis and treatment of posterolateral elbow dislocation in children.Methods:A total of 19 children with posterolateral elbow dislocation were diagnosed and treated at Department of Children's Orthopedics, Sichuan Orthopedic Hospital from April 2018 to April 2021. They were 12 boys and 7 girls, aged from 7 to 14 years (average, 10.9 years). Internal epicondyle avulsion fracture of the humerus was complicated in 11 cases, external epicondyle avulsion fracture of the humerus in 5 cases, capitulum avulsion fracture of the humerus in 3 cases, and fracture of the ulna coronoid process in 4 cases. After evaluation of the elbow stability, stable elbows were treated nonsurgically while the unstable ones complicated with fracture were treated with open reduction and internal fixation. After treatment, the injured limbs were fixated with elbow flexion 90° in forearm pronation position for 4 to 6 weeks.Results:In this group, 4 children received nonsurgical treatment and 15 ones were treated surgically. Internal epicondyle fractures of the humerus were treated by open reduction and internal fixation with Kirschner wire and hollow screws, and external epicondyle avulsion fractures or capitulum avulsion fractures of the humerus by suture fixation with Kirschner wire tension band or absorbable anchors. Three coronal process fractures were treated with plate internal fixation but one coronal process fracture was not treated with internal fixation. All the children were followed up for 6 to 30 months (average, 13.3 months). The last follow-up showed that fractures got united in all children, with no ectopic ossification, fine anatomical relationship of the elbow, and no recurrence of elbow dislocation or instability. The last follow-up showed that the Mayo elbow performance scores (MEPS) ranged from 75 to 100 points, averaging 93.2 points.Conclusions:In the treatment of posterolateral elbow dislocation in children, the key point is to rebuild the stability of the elbow. Non-surgical treatment is recommended for cases of a stable elbow with posterolateral rotation and dislocation while surgical treatment for cases of an unstable elbow because surgery leads to fine functional recovery and efficacy in children.