Is lateral pin fixation for displaced supracondylar fractures of the humerus better than crossed pins in children?

Abstract

Background: Closed reduction and percutaneous pin fixation is considered standard management for displaced supracondylar fractures of the humerus in children. However, controversy exists regarding whether to use an isolated lateral entry or a crossed medial and lateral pinning technique.

Questions/purposes: We performed a meta-analysis of randomized controlled trials (RCTs) to compare (1) the risk of iatrogenic ulnar nerve injury caused by pin fixation, (2) the quality of fracture reduction in terms of the radiographic outcomes, and (3) function in terms of criteria of Flynn et al. and elbow ROM, and other surgical complications caused by pin fixation.

Methods: We searched PubMed, Embase, the Cochrane Library, and other unpublished studies without language restriction. Seven RCTs involving 521 patients were included. Two authors independently assessed the methodologic quality of the included studies with use of the Detsky score. The median Detsky quality score of the included trials was 15.7 points. Dichotomous variables were presented as risk ratios (RRs) or risk difference with 95% confidence intervals (CIs) and continuous data were measured as mean differences with 95% CI. Statistical heterogeneity between studies was formally tested with standard chi-square test and I(2) statistic. For the primary objective, a funnel plot of the primary end point and Egger's test were performed to detect publication bias.

Results: The pooled RR suggested that iatrogenic ulnar nerve injury was higher with the crossed pinning technique than with the lateral entry technique (RR, 0.30; 95% CI, 0.10-0.89). No publication bias was further detected. There were no statistical differences in radiographic outcomes, function, and other surgical complications. No significant heterogeneity was found in these pooled results.

Conclusions: We conclude that the crossed pinning fixation is more at risk for iatrogenic ulnar nerve injury than the lateral pinning technique. Therefore, we recommend the lateral pinning technique for supracondylar fractures of the humerus in children.

Fig. 1

This flow chart summarizes our study selection process, the exclusion steps, and the resulting studies that were left for analysis. RCT = randomized controlled trial.

Fig. 2

Comparisons of iatrogenic ulnar nerve injury, loss of reduction, and Flynn criteria between lateral entry and crossed entry pin fixation are shown. The size of each square is proportional to the weight of the study. *Mild or major displacement (change in the Baumann angle > 6°) based on the criteria of Skaggs et al. [49]; ^†excellent grading of Flynn criteria [13]; M-H = Mantel-Haenszel; Fixed = fixed effect; Z = p value of weighted test for overall effect; df = degrees of freedom; I² = test statistic; CI = confidence interval.

Fig. 3

This is a funnel plot of iatrogenic ulnar nerve injury to assess publication bias. SE = standard error; RR = risk ratio.