Ben A Marson, Adeel Ikram, Simon Craxford, Sharon R Lewis, Kathryn R Price, Benjamin J Ollivere

Elbow supracondylar fractures are common, with treatment decisions based on fracture displacement. However, there remains controversy regarding the best treatments for this injury. To assess the effects (benefits and harms) of interventions for treating supracondylar elbow fractures in children. We searched CENTRAL, MEDLINE, and Embase in March 2021. We also searched trial registers and reference lists. We applied no language or publication restrictions. We included randomised and quasi-randomised controlled trials comparing different interventions for the treatment of supracondylar elbow fractures in children. We included studies investigating surgical interventions (different fixation techniques and different reduction techniques), surgical versus non-surgical treatment, traction types, methods of non-surgical intervention, and timing and location of treatment. We used standard methodological procedures expected by Cochrane. We collected data and conducted GRADE assessment for five critical outcomes: functional outcomes, treatment failure (requiring re-intervention), nerve injury, major complications (pin site infection in most studies), and cosmetic deformity (cubitus varus).  MAIN RESULTS: We included 52 trials with 3594 children who had supracondylar elbow fractures; most were Gartland 2 and 3 fractures. The mean ages of children ranged from 4.9 to 8.4 years and the majority of participants were boys. Most studies (33) were conducted in countries in South-East Asia. We identified 12 different comparisons of interventions: retrograde lateral wires versus retrograde crossed wires; lateral crossed (Dorgan) wires versus retrograde crossed wires; retrograde lateral wires versus lateral crossed (Dorgan) wires; retrograde crossed wires versus posterior intrafocal wires; retrograde lateral wires in a parallel versus divergent configuration; retrograde crossed wires using a mini-open technique or inserted percutaneously; buried versus non-buried wires; external versus internal fixation; open versus closed reduction; surgical fixation versus non-surgical immobilisation; skeletal versus skin traction; and collar and cuff versus backslab. We report here the findings of four comparisons that represent the most substantial body of evidence for the most clinically relevant comparisons.  All studies in these four comparisons had unclear risks of bias in at least one domain. We downgraded the certainty of all outcomes for serious risks of bias, for imprecision when evidence was derived from a small sample size or had a wide confidence interval (CI) that included the possibility of benefits or harms for both treatments, and when we detected the possibility of publication bias.  Retrograde lateral wires versus retrograde crossed wires (29 studies, 2068 children) There was low-certainty evidence of less nerve injury with retrograde lateral wires (RR 0.65, 95% CI 0.46 to 0.90; 28 studies, 1653 children). In a post hoc subgroup analysis, we noted a greater difference in the number of children with nerve injuries when lateral wires were compared to crossed wires inserted with a  percutaneous medial wire technique (RR 0.41, 95% CI 0.20 to 0.81, favours lateral wires; 10 studies, 552 children), but little difference when an open technique was used (RR 0.91, 95% CI 0.59 to 1.40, favours lateral wires; 11 studies, 656 children). Although we noted a statistically significant difference between these subgroups from the interaction test (P = 0.05), we could not rule out the possibility that other factors could account for this difference. We found little or no difference between the interventions in major complications, which were described as pin site infections in all studies (RR 1.08, 95% CI 0.65 to 1.79; 19 studies, 1126 children; low-certainty evidence). For functional status (1 study, 35 children), treatment failure requiring re-intervention (1 study, 60 children), and cosmetic deformity (2 studies, 95 children), there was very low-certainty evidence showing no evidence of a difference between interventions. Open reduction versus closed reduction (4 studies, 295 children) Type of reduction method may make little or no difference to nerve injuries (RR 0.30, 95% CI 0.09 to 1.01, favours open reduction; 3 studies, 163 children). However, there may be fewer major complications (pin site infections) when closed reduction is used (RR 4.15, 95% CI 1.07 to 16.20; 4 studies, 253 children). The certainty of the evidence for these outcomes is low. No studies reported functional outcome, treatment failure requiring re-intervention, or cosmetic deformity. The four studies in this comparison used direct visualisation during surgery. One additional study used a joystick technique for reduction, and we did not combine data from this study in analyses. Surgical fixation using wires versus non-surgical immobilisation using a cast (3 studies, 140 children) There was very low-certainty evidence showing little or no difference between interventions for treatment failure requiring re-intervention (1 study, 60 children), nerve injury (3 studies, 140 children), major complications (3 studies, 126 children), and cosmetic deformity (2 studies, 80 children). No studies reported functional outcome. Backslab versus sling (1 study, 50 children) No nerve injuries or major complications were experienced by children in either group; this evidence is of very low certainty. Functional outcome, treatment failure, and cosmetic deformity were not reported.  AUTHORS' CONCLUSIONS: We found insufficient evidence for many treatments of supracondylar fractures. Fixation of displaced supracondylar fractures with retrograde lateral wires compared with crossed wires provided the most substantial body of evidence in this review, and our findings indicate that there may be a lower risk of nerve injury with retrograde lateral wires. In future trials of treatments, we would encourage the adoption of a core outcome set, which includes patient-reported measures. Evaluation of the effectiveness of traction compared with surgical fixation would provide a valuable addition to this clinical field.