Influence Of Ulnar Bow Sign On Surgical Treatment Of Bado Type Ⅰ Missed Monteggia Fracture In Children

Objective: The aims of this study were to explore the influence of ulnar bow on the surgical treatment of children’s Bado type I missed Monteggia fracture,and to provide objective evaluation basis of the injure.Methods: This is a retrospective review of 24 patients between November 2010 and January 2018,including 18 males and 6 females.The patients were younger than 10 years at the time of surgery,with an average age of 6.3 years and the time from injury to surgery was 2-12 months,with an average of 5.5 months.According to the position of the maximum ulnar bow(MUB),it was divided into the middle segment group(group A,14 cases,the MUB was located at the distal 40% to 60% of ulna)and the far segment group(group B,10 cases,the MUB was located at the distal 20% to 40% of ulna).Surgical procedures included open reduction and ulnar angulation osteotomy with combined anterior and posterior approach.Temporary kirschner wire fixation was implemented according to the assessment of intraoperative stability.The influence of ulnar bow on surgical treatment was discussed by comparing the maximum ulnar bow,ulnar angle,radial head stability of postosteotomy and postoperative forearm function.Results: All patients,followed up for an average of 37months(12~102 months),obtained stable reduction at the last follow-up,and the postoperative elbow flexion function was improved significantly compared with that before surgery,with statistically significant difference(P<0.05).Compared with group B,the MUB ratio measured in group A was larger than that in group B,and the dorsal angulation angle intraoperatively in group A was larger than that in group B,with statistically significant differences(P<0.05).Postoperative elbow function of group A was a little bit worse than that of group B,with no statistical significance(P > 0.05).Five cases were assessed as unstable after osteotomy and required temporary fixation with klinohumeral(4 cases in group A and 1 case in group B),with no statistical significance(P > 0.05).Conclusion: Open reduction combined with ulnar osteotomy is a reliable and effective method for the treatment of Bado type I missed monteggia fracture in children.The MUB was larger and greater posterior angle was needed after the ulna osteotomy to achieve stable reduction of the radial head in middle segment group,when compared preoperatively the cases that ulnar arch sign located in the middle segment of ulna and the cases located in the far segment of ulna.Exellent elbow function was obtained in both groups after operation and the position of ulnar arch sign had no significant effect on postoperative elbow function.