Objective To discuss the elbow skin fold extension line in Kirschner wire internal fixation of extended supracondylar humeral fractures in children. Methods The clinical data of 58 children with extended supracondylar fractures of the humerus who met the selection criteria between August 2021 and July 2024 were retrospectively analyzed. In 28 cases, needle placement of medial epicondyle of humerus was performed with the assistance of the elbow skin fold extension line (study group), and 30 cases were assisted by routine touch of the medial epicondyle of the humerus (control group). There was no significant difference in baseline data such as gender, age, side, cause of injury, Gartland type, Kirschner wire configuration, and time from injury to operation between the two groups (P>0.05). The closed reduction rate, total operation time, time of medial humeral condyle pin placement, fluoroscopy times during medial pin placement, rate of one-time determination of medial entry point, ulnar nerve injury incidence, and fracture healing time were recorded and compared between the two groups. At the same time, the closed reduction rate of patients with the time from injury to operation ≤24 hours and >24 hours was compared. The elbow function was evaluated by Mayo elbow function score. Results The closed reduction rate of the study group was significantly higher than that of the control group (P<0.05). Among all patients, the closed reduction rate of patients with the time from injury to operation ≤24 hours [73.3% (22/30)] was significantly higher than that of patients >24 hours [42.9% (12/28)] (χ2=5.545, P=0.019). The total operation time, medial needle placement time, and fluoroscopy times in the study group were significantly less than those in the control group, and the one-time determination rate of medial needle entry point in the study group was significantly higher than that in the control group (P<0.05). There were 4 cases of ulnar nerve injury in the control group, and no ulnar nerve injury in the study group, but there was no significant difference in the incidence of ulnar nerve injury between the two groups (P>0.05). All patients were followed up 6-12 months (mean, 8 months). There was no bone nonunion in both groups, and the fracture healing time of the study group was significantly shorter than that of the control group (P<0.05). Volkmann ischemic contracture, heterotopic ossification, myositis ossificans, and premature epiphyseal closure were not observed after operation. No complications such as loosening or fracture of Kirschner wire occurred. At last follow-up, the Mayo elbow joint function score was used to evaluate function, and there was no significant difference between the two groups (P>0.05). Conclusion In the treatment of extended supracondylar fractures of the humerus in children, the elbow skin fold extension line can help to quickly locate the medial epicondyle of the humerus, quickly insert Kirschner wire, and reduce the operation time and trauma.
