The posterior intrafocal pin improves sagittal alignment in Gartland type III paediatric supracondylar humeral fractures

Introduction Closed reduction and percutaneous Kirschner wire fixation are widely recommended for displaced supracondylar humeral fractures. However, the optimal K-wire configuration is still controversial. The purpose of this study was to compare the results of crossed pinning with or without a posterior intrafocal pin in Gartland type III supracondylar humeral fractures. Patients and methods We retrospectively reviewed 93 children who underwent crossed pinning for Gartland type III supracondylar humeral fractures between January 2009 and December 2013. One surgeon preferentially added one posterior intrafocal pin onto the crossed pins in 35 children, and the other surgeons used standard crossed pinning technique in 58 children. Results were assessed by range of elbow motion and radiographic measures including the Baumann angle, the lateral humerocapitellar angle and the position of the anterior humeral line (AHL). Results The demographic data were comparable between the 2 groups. Children treated with the additional posterior intrafocal pin had greater range of elbow motion (138.7° vs. 133.6°, p = 0.01) and had a greater lateral humerocapitellar angle (44.9° vs. 37.8°, p = 0.01) measured 3 months postoperatively. The percentage of AHL position in the posterior third was significantly higher in children with the posterior intrafocal pin immediately after fixation (odds ratio [OR]: 6.26) and 3 months later (OR: 2.84). The percentage of AHL position in the anterior third was also significantly lower in children with the posterior intrafocal pin 3 months postoperatively (OR: 0.29). No pin site infection or nerve injury was associated with the additional posterior pin. Conclusions Adding one posterior intrafocal pin to crossed pinning can facilitate fracture reduction and enhance fixation stability. Better sagittal alignment and elbow motion support this safe and effective technique in treating type III humeral supracondylar fractures.